Hey all,

My 3.1 is having issues with getting timing set at the moment. Quick backstory on this: two Fridays ago, my cat delete pipe finally rusted off of the factory Y-Pipe on the way home from work (been running it as a daily without a cat for about 5 years now), so she was essentially running open headers. This was very unfortunate, as I had to drive 3 hours south for my buddy's wedding that day. Made it there and back with no issues (aside from hearing loss), and then it sat for a couple days because I was working from home. Finally had to go back into the office last Wednesday, and the car suddenly developed a pretty bad misfire while on the way (15 minute drive each way). I was able to limp her home after work, and was working from home the next two days. Finally had a chance to take a look at things last Friday, she was running rough; backfiring through the intake at idle and all. Started pulling it apart and noticed that the cyl 2 spark plug was incredibly black (the others were fine). At this point, I had already made the mistake of trying to fix the timing; new spark plugs did nothing, so I took the backfiring as a sign of wrong timing (which seemed odd to me, not sure how it'd lose timing suddenly like that).

Long story slightly less long, turned out that the the cyl 2 exhaust rocker stud was sheared clean off. I replaced both of the cyl 2 studs and readjusted the valves (the usual method of tighten until the pushrods can't move up and down, then give it an extra half turn). This is about where I am now; the car is running fine, but I can't seem to get it back into time. I've spent pretty much all of my free time after work trying to get it back into time the last couple days, to no avail. This isn't the first time I've done timing on the 3.1, had to when I replaced the distributor about 4 years ago.

When the engine is cold, it idles just fine; once it warms up, it seems a little unhappy no matter where I set the timing. I made sure that my timing mark was still aligned with TDC on cyl 1, and it is; also verified that the rotor is pointed at the cyl 1 post on the cap, and that all wires are where they should be. I pulled my brand new spark plugs yesterday, and they are all already fouled; I cleaned em up best I could, will probably need to replace them again though (or throw the old ones back in, they look better at this point). Anywho, when I do the whole song and dance with the EST wire and all, and try to get it to 10 BTDC while the motor is warm, it starts stumbling and quits. It doesn't seem to want to stay running while warm anywhere near 10 BTDC; I can get it to idle semi decently with the timing mark around 12 o'clock on the balancer (So maybe 30 BTDC initial or something ridiculous), but the car doesn't like to start that advanced.

I'm going to go through and pull the cap completely off to check the contacts, and pull the IAC to see if it needs cleaning (certainly might with how it was running before the rocker stud was replaced). I'm not super hopeful that this will fix the issue though, so I'm posting this a little early to see if anyone has any suggestions for other parts to troubleshoot. I mentioned all the problems in the last couple weeks in case something further could have been caused by either running open headers for a couple days, or driving the 15 or so miles on the broken rocker stud (miraculously, the rocker and broken stud were both still sitting on top of the valve spring, but not touching the pushrod; the valvetrain is completely unharmed. Ensured the pushrod was still straight as well). I'm getting sick of having to borrow my mom's SUV to get into work, and I really miss driving the Firebird, so I'm hoping that this isn't going to be another big job. The timing chain seems to be alright, but I cannot confirm this 100%; after reading through other threads from folks with 3.1 timing issues, I'm reckoning I should watch the rotor while I spin it over so I can check the slop. Didn't feel like it had a whole lot when I was spinning it over by hand, but this motor does have a fair bit of miles on it. I already regret loosening the distributor to try to fix that misfire, so I'd like to avoid trying to fix something else that doesn't need fixing

Apologies for the long post, just throwing in as much detail as I can about the current situation.

TL;DR: Car doesn't want to start or idle at 10 BTDC like it should

Thanks!
-Matt P

 

Now it might just be coincidence that the #2 rocker stud broke, but that information, not being able to time the car, along with high milage, would make me wonder if something didn't happen to the timing chain and/or timing chain gear(s).

 

Thanks for the reply! Timing chain is what I've been fearing after pouring over so many other threads here... wouldn't put it past my car to have two unrelated issues pop up out of nowhere at the same time Really kicking myself for moving the distributor in the first place, but "broken rocker stud" was definitely not what I was expecting at the time. I'm still stuck at work for the next 3 hours, but I'm going to check the slop between the crank and rotor when I get home.

I'm not 100% sure how many miles the motor has on it either, but I know it's at least around 135k; Car itself has approx. 235k on the clock, but the motor was replaced back in 2005 or so when the previous owner still owned it; body had 100k on it at the time. He's pretty sure it was a used motor that went in (he had a shop do it), but had no clue about mileage. Probably wouldn't be a bad idea to replace the timing chain soon regardless, but here's hoping it's just something small like a bad rotor (it did look a bit chewed up at the end) so I can get her back on the road quick and mom can have her SUV back

 

Alright, here's the update:

Replaced the cap and rotor; rotor was chewed up, cap had some nicks in the inner contacts. Replaced the spark plugs with some cheapie Accels for testing (not gonna foul another set of nice plugs lol). Pulled the IAC and cleaned it out with carb cleaner, it was pretty grimy.

Checked the slop on the timing chain: I'm seein about 4 deg before it grabs and starts turning the distributor rotor..... I've seen a few other threads mention that 4deg is acceptable for timing chains, but 5+ is a good sign that it needs replacing. I'd like to hear y'alls thoughts on this, especially after this:

So, I got her running well by ear. Still not perfect, but it was good enough to drive around the block without backfiring or dying at stops. Idles at around 1k. Stumbles, but catches when going into gear and idles around 550. However, it is noticeably down on power from where it usually is. When I give it gas, it doesn't stumble, but it sure takes its sweet time building revs. No weird noises, but the exhaust sounds a little "flat" to me, if that makes sense; not the same as it usually is. Could also be because I had to replace that rusted pipe I mentioned in the OP.

NOW, the interesting part of all that: it isn't anywhere near 10 BTDC when I check with the timing light.... closer to 30 or 35; about 12 o'clock on the damper. Still having that issue where it won't run right when you try to bring it near 10... I'm wondering if it's possible that it jumped a timing gear or somethin? I've timed the car successfully in the past, and it seemed happiest around 18 BTDC (which is where she sat for about 4 years, until recently). And again, I did confirm that the timing mark lines up at 0deg on the tab when cyl 1 is at TDC, so my mark isn't off. This doesn't seem like a good sign for the health of my timing chain, but I also don't have any experience with diagnosing bad timing chains or anything of the sort, so I may be talkin nonsense. Hope today's results help get to the bottom of this weirdness, can't wait to have her running right again! Glad she ran well enough to putt around the neighborhood today at least, think I may actually be able to sleep tonight

Edit: I am ordering a timing chain preemptively, they're cheap enough on RockAuto. Figured I might as well order one now and be ready for the inevitable, but still holding onto hope that I can put that job off for a bit

 

Maybe I missed it but while timing is est disconnected ?
say you said song and dance, not sure what you mean. But est plugged back in you can see around 20.

 

Thanks for the reply! When I say that, I mean I followed the guide from the factory service manual; let it get to temp, unplug the EST, set the timing, tighten the distributor, check the timing again to make sure it's right, turn the motor off, plug the EST back in, disconnect the battery and leave it for at least 30 sec, reconnect the battery. This is how I did it when I replaced the distributor 4 or 5 years ago as well, and as I mentioned, I think even back then I had to have it set close to 20deg BTDC initial (with EST unplugged) for it to run happy. Factory spec is 10 BTDC.

I'm just still not fully convinced that it's the timing chain, considering the timing mark still lines up at 0deg when cyl 1 is at TDC... but again, not really an expert, could be a red herring. I'm starting to wonder if somehow, I just clocked the distributor wrong when I installed it initially? Didn't have much experience with motor work back when I installed the thing, but also not sure how possible it is to install a dizzy wrong. At this point, I'm thinking I might as well check. As annoying as it is to deal with that clamp, it'd be easier than pulling the timing cover. I'll do some more reading on that while I'm still stuck here in the office (Fridays are slow ) and maybe give it a shot once I'm home.

 

Gotcha, sounds like the timing is being set in the right sequence. On sbc I’ve checked timing chain play with pulling the plugs and the cap and slightly rotate the crank counter clockwise. You can observe the crank movement then the rotor will move. A few degrees seems okay but I’m sure 4 or more the chain is really stretched.

 

Yep, that's how I checked the play yesterday. Spun the motor clockwise with the plugs out to get the timing mark to 0, then slowly turned it counter-clockwise while watching the rotor. I could feel a noticeable gap when turning it counter-clockwise, which is where I got the 4deg reading from. Almost felt like it contacted nothing... maybe it really is the timing chain then I looked into the possibility of the distributor being clocked wrong as well, looks like that'd only really be an issue if I couldn't rotate it far enough to get it to 10 BTDC, which is not my issue. I suppose I better order myself a pulley puller and mentally prepare to tear apart the front of the motor. Thanks again for the replies, hopefully the new chain does the trick!

 

A chain will help, I don’t know how much. The last sbc I had was around 6. It seemed to run a lot smoother at idle once I replaced the chain.

 

Fair enough, I am still thinking that there's some kinda other issue, but a chain would probably be a good start considering the unknown miles on the motor. I believe it is also still using the factory ignition coil (still riveted in), but the spark seemed just fine yesterday. When I had the timing mark up to 12 o'clock and putted around my neighborhood, I didn't hear any misfires or backfires, just slow to rev. It does also still have the factory Multec injectors, which I'd like to replace soon, but I don't reckon that it's a fuel issue either. I'd like to take a break from tearing into the motor for today since it's been eating up my free time all week, but may pull one of the new plugs to see if it's still running super rich. Now that I mention injectors actually, I do notice that sometimes I hear a sort of bubbling sound when the pump is done priming... I had the top end of the motor apart when I fixed the rocker stud, and couldn't see any fuel leaks (also put new o-rings on the lines a couple months ago), but maybe an injector or 2 are getting hung open? Not sure. Don't reckon it'd be the TPS or IAC either, engine hasn't thrown any codes recently. TPS was replaced about 6 years ago, O2 sensor was replaced about 3 years ago, IAC is still factory but is clean... might be worth pulling the intake air temp sensor out and cleaning it up, probably got grimy from the backfires I was getting with that exhaust valve down. I did try unplugging it while the car was idling yesterday, didn't seem to change much (did throw a code until I plugged it back in though).

Probably a stupid question, but should there be a noticeable change in the idle when the EST wire gets disconnected? Only difference I really see is that my tach starts reading 0. I think there's a section in the factory service manual about troubleshooting problems with the EST wire, I'll check that out after work today.... Sorry about being so rambly, the ADHD has my mind wandering all over the place

 

The 90-92 have issues with the tach filter, you could do a fuel pump prime and watch fuel pressure. I can’t remember how hard the test port is to get to on the 3.1. Tach shouldn’t drop when est is disconnected it’s still getting a rpm signal from the coil. When est is plugged back in idle might increase and engine will smooth out.

 

Right on, thanks for the info! The pressure test valve is at the back of the fuel rail, I reckon I can get to it without taking the upper intake off. I might have a pressure gauge laying around somewhere, but it might be for compression testing... I'll poke around a bit more on Saturday, might have to borrow a gauge from the local shop if the one I have doesn't have the right fittings.

 

I just remembered the rail isn’t to easy to get to unlike tpi test port. Worth checking out. Not a fan of the older multec grey body injectors. But @southbay08 has you covered with a reasonably priced replacement if needed.

 

The fuel pressure test port is located just behind the intake manifold and can be accessed without removing anything from the engine.
It has a valve cap on the Schreuder valve to keep the dirt out.

Remove the dust cap from the Schreuder valve and attach the fuel pressure gage. Key on and engine not running, my 2.8L MPI fuel pressure is a little over 40 psi. and when the engine is running it is around 35 psi.
Gage attached.

 

Good deal! I've had the top end apart quite a few times at this point (from changing valve covers a couple times/ adding my new rocker arms and all), but couldn't remember for sure if the schrader valve actually poked out the back of the plenum. Looks like there's plenty of room, I'll have to pick up a gauge just so I can knock that off the list.

I've read a lot of good things about SouthBay as well, definitely interested in picking up a set of Bosch injectors from em. My Multecs seem to still work just fine, but I'd like to daily this car for as long as I possibly can, so I don't feel too bad about swapping them out before they fail.

Thanks again to both of you, hopefully I'll have good news to report on Saturday!

 

if you have the old multe s and are planning to keep the car for a while we have the Bosch replacements. If you decide to get a set we have 10% off with free shipping until the end of the month

 

Oh right on, I reckon I'll order a set soon! Was thinking about it anyways after reading so much about the old Multecs... I see that y'all have 15lb and 17lb injectors available, and that the 17s are compatible with the factory tune... would there be any benefit for me to go with the 17s over the 15s? My motor is pretty stock, just have a CAI and 1.6 rockers for now

 

Ecms flow rate is set to 16.7 on the 3.1L f body.

 

Ah, good deal; didn't even think to check the numbers in TunerPro, good to know! I suppose 15s are for 2.8s. Thank you!

 

Probably i haven’t looked at a 302 in quite awhile

 

You have now described two classic symptoms of a failed fuel pressure regulator......

 

Ah, no kidding that wouldn't surprise me. Just ordered one of those as well, might as well since I got new injectors on the way too. Haven't had a chance to test the fuel pressure at the rail yet, overslept today (didn't get much sleep this last week because I've been so worried about the car....) Even if fuel isn't my issue with the timing woes, it'll be nice to know that the fuel system is all up to snuff as well thankfully my pump still sounds strong (knock on wood), not looking forward to having to replace that eventually though... but hey, that's a problem for future me Thanks for the insight!

 

Your welcome, and here's how ya check it;

At the back of the throttle body, where the throttle body joins the upper intake plenum, there is a black plastic (rubber perhaps?) block with two (stupidly fragile ) plastic hoses going into it, one larger & one smaller. The one smaller is the one that goes to the top of the fuel pressure regulator to supply it with the vacuum it uses to control the diaphragm (and thus regulate the rail pressure). When the regulator diaphragm fails, it allows raw fuel to be pushed through that small plastic tube which literally drowns the engine with fuel (and fouls the plugs in a blink of an eye). So you CAREFULLY remove that block with it's two plastic tubing pieces still attached (just carefully wiggle it a little bit as you pull it back out) and then turn the key to make the pump do it's 2 second prime. If fuel shoots outta the little tube, yeah, your regulator diaphragm is shot (cracked/ripped/whatever) and is why your plugs turned black so quickly.

No real pitfalls to replace, beyond of course that they couldn't have used good ol "Torx" heads on the 6 bolts holding it to the fuel rail, , , 'course not, they just HAD to go and use "security" Torx, the ones with the little pin in the middle of the bolt head, cause almost nobody has the tool for that kickin round in the ol toolbox

 

If it’s bad enough, you can pull off the intake bellows and hold open the throttle blade and see fuel.

 

10-4; I'm relatively familiar with the upper/ mid intake area, I've had it apart quite a few times for changing valve covers/ gaskets/ the rockers and all... only work I ever really did to the rail was replacing the o-rings on the lines. I'll have to pull that block off tomorrow and see what's what, couldn't today because I ended up goin fishin with my dad. I actually can't remember what that 2nd vac line on the block goes to (the hard plastic one), I plugged it like 6 years ago must have been something emissions related, I suppose. Didn't think about it until you mentioned it, but it makes total sense that it'd make those bubbling noises with fuel coming out into the vac line All the parts I ordered won't be here until Wed/ Thurs next week unfortunately, but I might go ahead and start tearing the motor down again to get ready. Thankfully, I DO happen to have those tricky security torx bits on hand! I do a lot of computer work, so I have one of those lil kits with obscure bits and sockets

Any tips for removing the crank bolt/ pulley/ damper? I've changed out the water pump before, but never touched the crank pulley... I know I'll need to get myself a puller, but I've been trying to work out the best way to loosen that crank bolt without just spinning the motor over. Also, I've seen conflicting reports on this: should I plan on needing to pull the oil pan when I pull the timing cover? Seems like there's an overlap between the pan and cover, but half of the posts I've read say the pan can stay on, and the other half say you'll need to pull it as well. Probably should have asked earlier, but better to order a new pan gasket now than find out I need one on Wednesday. Doubt any local shops would have a 3.1 pan gasket on hand. Thanks again, y'all!

 

Also: thanks again for the heads up on the FPR; finally had a second to go outside and check it. Lo and behold, little bit of fuel trickled outta the vac port when I pulled it. Not a ton, but enough to make the regulator housing slightly wet.

 

Hi LLCooLM495,

I really think you oughta replace the FPR first, replace the plugs, and then set the timing to where the engine runs it's best & test drive it before you dive in to the timing chain.

Why do I say this? Because an engine running pig rich will exhibit the worst running deficiencies at idle, as well as lacking power when stepping on the go pedal, which is where you mentioned in your above posts as having the most difficulty. Now I'm not saying your chain ain't worn a bit, it very well could be, but the smart troubleshooting technique is to repair the known & proven malfunctions first, and see if that rectifies the poor performance issues. You now know your FPR is faulty, because the normal amount of fuel you shoulda seen in that test is zero, not even the hint of a whiff much less a drop of it, and replacing that, setting the timing, and of course replacing the fouled plugs, very well could restore acceptable operation.

PS, I know the plugs are pretty close to new, but once fouled to the degree of being dripping wet black, I'd personally be replacing them along with the FPR

 

Yep, my thoughts exactly! The chain and FPR are supposed to both get here on the same day, it'll be quick and easy enough to do the FPR first and see where that gets me. Hope I don't tear the new upper intake gaskets, just put those on last week... it'd sure be easier than tearing into the timing cover here's hoping that the engine is just unhappy because of all the extra fuel, but I do have some doubts since it was running well enough for years with a (presumably) bad FPR... that bubbling noise isn't exactly new, I just never thought much of it. Here's a couple pics I took of the plugs last Monday:


Brand plug after running for about 20 min

New plug on left after being cleaned up; 2-ish year old plug on right

The plugs that were in there for the last couple years didn't look too terrible, but the new ones certainly weren't too happy. Granted, the 20 minutes or so they were running, I was trying to set timing, so that may have played a big part in it. Could also be somethin to do with the new plugs being iridium, but I've run iridium plugs in the past without issue. I got a cheap set of copper plugs in there for now, not sure how they look. I'll go ahead and pull one when I do the FPR, I'd imagine they're lookin similar to the iridium plugs here though. All of em were gapped to .045 per factory spec btw (old ones were closer to .05, but that'd just be from wear. I know I gapped em to spec before they went in)

 

Hey y'all, finally got an update. Timing chain finally came in on Friday, finished replacing it over the weekend. I had my suspicions that the chain wasn't the issue, and this confirmed it; my heart definitely sank when I saw that the timing marks on the gears were still lined up, but I'm over it. Old chain appeared to still be the original, teeth were pretty marked up, but overall in good shape. Anyways, I got the new chain installed and got everything back together, absolutely 0 change in how she's running on the bright side, she's got a new chain now, and I managed to fix a timing cover leak while I was in there, so that's alright by me.

Also pulled the cyl 1/ 2 spark plugs while I was dinking around the engine. 1 was looking pretty much brand new still, so it seems like the new FPR and/or injectors are helping with that (installed those on Wednesday). I forgot I had done the old "penny mod" to my FPR back in highschool, found a nickel in there probably part of why she was running rich... the cyl 2 plug had a little bit of oil on the electrode, but otherwise looked about the same as cyl 1. Kinda odd that cyl 2 would be the one that had oil on it, I replaced the valve stem seals on that one a few months back (when I originally damaged that rocker stud that I had to replace). Also, with the new FPR, I am still getting that bubbling sound after the pump primes, so I'm honestly not sure where it's coming from.

Still not throwing any codes, not sure what else it could be. I'm going to do a compression test on cyl 2 when I get home from work today just so I can rule out any kind of valve damage it might have had when that rocker stud went, but I reckon that it'll be fine since the engine runs well enough when the timing is way advanced. There is something I have noticed though: it seems like the engine is sucking in way more air at idle than it used to (prior to the rocker stud incident). I've had a cone filter on it for the last 6 or 7 years, so I can hear the induction noise pretty well, and I know what it oughta sound like. Right now, it's louder at idle than usual. Part of me is thinking that it could be the IAC, but again, not sure why it wouldn't be throwing codes. Might try running through the process of resetting/ relearning the IAC after work as well, but part of me thinks that this is another red herring; I read in another thread that if your idle drops when the engine warms up, the IAC is likely functioning properly, and mine does indeed drop the idle at operating temp.

SO: It wasn't the chain, isn't the fuel, isn't the spark (I've checked that the plug wires are hooked up right countless times already; figured this wasn't the issue anyways since this issue was present even before I replaced plug wires)... starting to run out of ideas. I'm hoping that it isn't some kind of weird electrical issue, but I'm gonna double check the ground strap on the back of the pass side head when I get home. I suppose it is possible that it got damaged when I was trying to get a socket on the distributor bolt, so I'll cross that off the list. I have also noticed that if I move the distributor far enough in one direction with the car off/ keys out, the fuel pump relay goes off and the pump primes. I do find that quite odd, might look into that a bit more as well. Also going to check and make sure the ICM wires all look good, possible that something got damaged there when I was trying to get at the distributor bolt as well (had to put an extension between the two plugs to get at that bolt). I'll test/ check all of the things I talked about in this post after work, and keep studying up in my factory service manual in the meantime (brought it with me today).

Apologies for yet another lengthy post, but hopefully I haven't left anything out. If anyone has any suggestions on other possible causes I could check out, I would very much appreciate it!

 

Got another update.... still at work, but might have hit paydirt while staring at the wiring charts in the factory service manual (6E3-C4-4 in the '92 manual). I think I mentioned it in one of my earlier posts, but I was finding it odd that I was losing tach signal when disconnecting (what I thought was) the EST wire. After looking at this page, I think I might have just been disconnecting the tach this whole time I guess you aren't supposed to lose the tachometer when you disconnect the EST wire, but the wire I was unhooking was the only one I saw poking out of a harness.... I read that the EST wire may be tucked up under the drip tray, so I'm gonna see if that's where it's hiding as soon as I'm home from work. I hadn't touched the dizzy in about 4 years, so I very well may have tucked the EST wire back up there. The connectors also look different, from what I can tell. The wire I've been unplugging is tan, but with a grey connector. Also needed to use a screwdriver to press down on it and disconnect it. From what I can see, the EST wire should be a black connector with a little clip you can take off by hand... which does sound vaguely familiar. I'll post another update with my findings later on, here's hoping that I've just been an idiot this whole time if that's all the issue is, least I got to fix up my fuel system and those front cover leaks!

EDIT: Also looks like Tuned Performance mentioned that I shouldn't be losing tach signal when disconnecting the EST wire.... not sure how I overlooked that, brain must have been moving too quick for it's own good that day. ADHD can be kinda funny sometimes...

 

Good and bad news. Good news, I found the EST wire.... it was the other tan wire that was sticking out of the harness, about 6 inches to the left of the tach wire. I think the tach wire might have been white at some point, but they're both tan now... go figure.

Bad news, seems like that wasn't the only issue. Sent a video to one of my friends because occasionally, I was hearing what sounded like rockers hitting the valve cover. Don't think that's what it was now after investigating, but still odd... sounds like occasional tapping towards cyl 2. Only at low revs, and seemingly only when the motor is hot. NOW, I wasn't able to find my compression tester today, but I did let the car run for a bit just now and used a laser thermometer to check the temp of each runner on the manifold... wouldn't you know it, seems like cyl 2 isn't firing. It was sitting at around 170F when the other 5 had already reached 250... so something is still up with cylinder 2 (for those keeping track, this is the same cyl that snapped a rocker stud earlier this month). I'm gonna test spark tomorrow, but I can't think of any reason as to why it wouldnt be getting spark. MAYBE the damn thing just needs another new set of plugs?? I remember when I replaced my dizzy the first time, I thought my plugs were still good (looked fine, had the right gap and all). Car wouldn't run right, new plugs fixed it. I have a few different sets of plugs on hand that I can test with in the event that it is a spark issue, but we'll see. Never had the motor give me this much trouble before, can't help but feel it's my fault somehow... damn rocker stud.

 

Got more updates.... the issue is getting weirder. So, I had to go and rent another comp tester from AZ because I couldn't find mine. Ran comp tests on Cyl 2, 4, 6. Respective results were 150psi, 140psi, 145psi on a cold motor, and they all held the pressure solid. She has plenty of compression... used an inline spark tester, she's getting strong spark. Cyl 2 plug was wet again, smelled like gas; also stuck a boroscope into cyl 2, top of the piston was decently wet (cylinder looked good as well, can still see crosshatching. Piston was a little carboned up, but not bad). Assumedly, she has fuel. I have base timing set to 24deg, because that's where she's wanting to idle now (still high, but more reasonable now that I realize which wire is actually the EST... still feel stupid about that).
She has compression, spark, air, fuel... there's no reason she shouldn't be running on all 6. I ran the motor with the cyl 2 plug wire off as well, just to make sure I wasn't misidentifying the problem; car ran exactly the same. Tried a couple different plugs in cyl 2, tried gapping the plug slightly tighter (from the 0.045 factory spec to 0.040), no change. I'm running out of options here, this is a real humdinger. After work today, I'm gonna try a couple more tests: it was suggested that, despite the inline spark tester showing spark, and despite trying several plugs (known good plugs from other cylinders, even), I should try grounding the plug to the block to see the spark for myself. It'll be easy enough to do so, and it'll rule spark out entirely. The only other thing anyone can think of is fuel; I DID just put new injectors and a regulator in, but I'm going to swap the injectors on cyl 2 and 4 to see if it makes any difference. After that, only other suggestion I've had is to run a leak-down test to completely eliminate bad valves. I'll be pulling the valve cover when I go to swap injectors around so I can get a better eye on things, but I watched the rockers with a boroscope yesterday while it ran and they looked to be opening/ closing both valves perfectly fine. A fuel issue seems like the most likely cause at this point, but that still seems very odd to me, considering the new injectors and all. I hadn't pinned down the missing cylinder while I still had the old ones in, but it ran about the same. Oh, tested both injector circuits for shorts too (probed each side of the fuse holder with the 2nd wire on ground, no resistance), and it checked out fine. I'll double check the cylinder head grounds, but don't reckon that it's the issue since cyl 4 and 6 are both firing. Cyl 1, 3, 5 are all firing as well. We'll see what the results of the testing are today, but I've got no clue why she isn't running on all 6 for now.

 

I think doing a leak down is a good next step

 

It seems odd that the timing is out as far as it is. I believe these engines use the reluctor rotor and stator to determine engine position.
Is it possible that the reluctor rotor or reluctor stator is loose on the rotor shaft or distributor base and one of them is moving, causing your issue?


The only other reason that I can come up with for the timing to be out that far, is that you haven't got the EST disconnected when you are checking the base timing.
This is what it looks like on my 1986 2.8L.

 

It’s not odd to see timing around 20 if the est is plugged in

 

Agreed mine is actually closer to 30 degrees BTDC with the EST plugged in and running well.

Maybe I misread the earlier post, but I thought the OP was indicating that he is getting 32 degrees BTDC with the EST unplugged.
If I'm mistaken then by all means please disregard my last two posts.

 

The "timing" issues I was having when I started this thread actually turned out to be a miss on the #2 cyl... also didn't help that I was unplugging the tach wire the whole time instead of the EST they're both tan on my car, that was on me. Now that I have the timing set properly, it's idling well enough for me to have realized I have a consistent miss on the #2 cylinder. Before I started fussing with the distributor and caused myself all that headache, I believe the base timing was set around 17-20 BTDC when I replaced the distributor several years ago.

I'll have to rent a leak down kit to do the testing for the valves, but that will probably have to wait until tomorrow; my dad is going to be using his air compressor today, and we only have the one. I'm planning to watch the spark plug outside of the block to make sure it's firing properly, and then I'll probably try swapping injectors around to see if the one on #2 is having an issue (unlikely, since the Multecs were having the same issue, but I'd like to rule it out anyways). Also going to pull the valve cover off and redo the rocker adjustment on the #2 cyl/ double check that the pushrods are still straight. The valves looked like they were opening and closing properly when I was watching them with the boroscope (from the top) yesterday, but if I'm pulling the upper intake off, might as well spend another 10 minutes to get a better look at the valvetrain again.

Thanks once again for the replies, and apologies for my confusion with those two wires

 

Y'all may wanna sit down for this one.... I fixed it. After tearing apart the engine again, readjusting the valves, checking the pushrods, swapping fuel injectors, testing all the wiring..... I had the spark plug wires for cylinders 2 and 6 mixed up I had the old plugs numbered when I was doing my initial testing, back before I found the broken rocker stud, and evidently I didn't manage to get the new ones on properly. I must have checked those wires dozens of times in the last two weeks, but I guess I never noticed since I had the wires zip tied up and out of the way already. Ended up pulling on the distributor end of the cyl 2 wire, and wouldn't you know it, the plug on 6 moved. I got em swapped back around, and she fired right up.

So, apologies for wasting everyone's time with this, but hopefully others can learn from my mistake I was overlooking the most simple explanation for the issue, and it sure bit me... but at least I got a new timing chain and a leak-free front timing cover out of it the new injectors/ fuel regulator are working great too, no more popping on deceleration... getting the nickel outta the regulator probably helped as well. I'll be embarrassed for now, but this has been a great learning experience, and I appreciate all the help y'all offered along the way.

 

Well it could of been worse and been a predestination issue with engine damage.

 

Yep, for sure! Very glad it was something that simple, I was about ready to pull the head off