Yeah my data logs have always been spotless on the ignition/rpm signal. Once in a great while I'll get a dropout in the ignition when driving around.

Wires are all MSD 8mm (yes I finally did the driver side too!) with about 1100 miles on them now. Just had all of them off two weeks ago and nothing burned/split etc. Breakup only occurs in boost (over 12ish). Anything under that and you can turn the rpm as high as the tpi will let you with no breaking up. Kinda eliminates the module and ecm. Then again who knows. I was very particular with powering the MSD with its own big wire and protected the ground pad during painting. That said, it is grounded to the body and not directly to the engine. Engine is very well grounded to the body though and it will be yet another waste of time to run a wire.

Springs are beehive Comp Cams 26918-16 with the following specs:

OD: Top 1.075" Bottom 1.310"
ID: Top .650" Bottom .885"
Seat Pressure: 125 lbs @ 1.800''
Open Pressure: 367 lbs @ 1.150''
Coil Bind: 1.100"
Spring Rate: 372 lbs/in

It really does have a valve float sort of feel too.. but at almost $200 these springs had better not be the problem!

 

Just watched my video from this morning... dash tach started jumping around during breakup. This hasn't ever shown up in the MS datalogs. Perhaps the MS is getting a clean signal but the MSD doesn't like, or correctly get, what the MS is sending. I think it might be worth the effort to replace the ignition module again.

Distributor cap and rotor were new with the engine swap. I even complained to my wife because she spent the extra money on Accel vs oem stuff when she went to the store to get it for me. Distributor is the small cap HEI.

 

maybe the msd is picking up noise?

 

That's what I'm wondering. I'm going to eliminate the entire distributor part of the equation. Just bought a reman dist with new ignition module and pickup coil included. This is the only part of the original Iroc left inside the engine.

Film at 11!

 

the tach jumping around erratically is usually either an arching plug wire and or a missfire, both of these will make the tach jump around. i chased the same problem on my v6 turbo car for 2 months, the wires wouldnt arc under light load but under heavy load they were arcing everywere.replaced the wires with new taylor wires and the problem completly disapeared.
plug gap should be .022-.025 to start , u may have to tighten it up even a lil more then that even with the msd ignition

 

Steve, I shot you a PM w/link as I asked some of the guys over on Turbo Buick to look into it as well. gnxtc2 and TexasT are pointing to a weak igniton system, either spark scattering in the cap, or too weak of spark to jump the gap. Bison agrees with Precision, and suggested closing the gap down to .010-.015 to see if that helps to alleviate the breakup...

http://www.turbobuick.com/forums/tur...ml#post2946398

 

Well... hmm

I replace the distributor and it seems to pull very smooth up top but it still feels slow at the same time. It is more eager to spin the wheels now.. 30-40 in 2nd will spin but nowhere in 3rd and thats at 19 psi. So obviously power is still down. I'm beginning to see higher pressure in the downpipe - hard to tell from this pos interlaced camera I was filming with but I think I saw it exceed 12 psi. So perhaps the dist fixed the misfire, but now it has even more exhaust volume and even more backpressure than before. Only one way to tell.. dropping the exhaust once more and running DP only.

Also had a starting problem yesterday and this morning. Found the battery lead loose at the starter. Fixed the starting issue but no change to the other issues. So in the end, I see once again what seems to be 'some improvement' but no smoking gun.

Street Lethal, got your link.. I'll be over to visit that thread!

 

DP dropped.. car doing exactly what it was doing a week ago. Not seeing the tach problems now so I think that jumping I saw yesterday was from the loose battery lead that I fixed this morning. Still sounds like it's breaking up/running rough at 16+ psi. I could regap the plugs, but it doesn't make sense to me that the car isn't flying at lower boost. This thing should be stupid at 13 psi.

Anyone looking for a turbo iroc project?

 

Try what Precision and Bison recommended, and gap them to .010-.015 just to see if that helps any. If it doesn't, well at least that will be eliminated from the equation...

 

Definitely do that whenever you get the chance, as these guys are the top Buick Grand National guys on the planet, and they're asking to see the condition of your ignition now in that thread. Post up over there whenever you get the chance, k Steve...

- Rob

 

It has been determined that the exhaust valve has the correct lift and the correct closing point. I am unable to verify the intake side due to the limited flexibility of my new 'custom dial indicator mounting system'.

Anyway considering it was right on the money with the closing @ .050" and the correct lift, I feel pretty safe in thinking that the rest of the cam specs are right. Once I get a working magnetic base I will check the intake side as well but I know it will be right. Everything so far has been right and functioning properly. It's just the system as a whole sucks.

 

Ok now I'm a bit baffled. Decided that I needed some fun tonight and threw the exhaust back on the car at 10pm.. and the rocker arm that I had off to check the cam lift and timing. For my fun, I decided I would 'assume' that the timing in the MS was higher than what was actually happening at the distributor.

My butt dyno says the car would need about 12 degrees of additional timing to make the power it should be (this assuming that everything else about the engine was right but the timing was wrong). In the interest of preserving the engine I cut that in half and added 5-6 degrees of timing above 180 KPA between 3700 and 5400 rpm. Drove the car around, no detonation at all. Felt slightly better but I've been fooled before. Next I pulled over and added another 2 degrees of timing. This time I smoothed in the additional timing below 3700 and also between 100 and 180 KPA as well. The car seems to be coming alive now. It's not amazing yet but I actually felt a little impressed at the performance. This was with about 14.5 psi on the gate.

This puts me at "28.2 degrees" of timing at 4600 rpm and 15 psi. To me this seems excessive on 93 octane and 8.6:1 compression. Now the more interesting part... I looked at my data log expecting to see it a bit lean because of the additional timing. Instead I now show rich, very rich in fact. As rich as 10.2 and averaging about 10.6 in during boost. It seems some strange things are at work here.

Possibly it's been misfiring/not burning all of the fuel due to extremely retarded timing, which manifests itself as a lean condition and was addressed by adding more fuel... and now the correct amount of timing is burning all of the fuel, but the excess fuel is now creating a rich condition. With an AFR of 10.2-10.6, this could also be padding the timing a bit and preventing detonation. I'll have to be careful as I lean the tune.

The next thing is... if the above is the case, how could it be that 23-25 degrees is no where near enough timing at 15 psi? I mean to the extent that it would generate a misfire or unburnt fuel situation.

The only clue I have is in the setup of my megasquirt. Instructions for connecting it to HEI state to set the ignition trigger to 'rising edge'. My car will not run correctly at that setting, so it is at falling edge. In theory, this should be ok as long as your idle timing table matches a timing light, but perhaps triggering off the falling edge exponentially generates a late timing error as RPM increases? Not really sure how to verify my high rpm timing other then standing over it on the dyno! Not really what I like the thought of doing.

So the bottom line is it is responding 'ok' to additional timing. Once I get the fuel back to 10.9, it should make some more power. Will it be enough is the question.

 

Very interesting. If you were dumping a ton of extra fuel into the exhaust and burning it that "might" explain the excess back pressure as well theoretically. Why the engine would all of a sudden want more timing is odd as well.

If you're at 8.6:1 with aluminum heads they say you lose basically a full point of compression due to heat dissapation. That would put you a lot lower than you think you are, and make 15 PSI not really "all that much" boost.

 

as u increase the timming ur afrs will change. 10.9 is way to rich and will kill power.

put it this way my v6 car was running at 10.2-1 afr when i first took it to the track witht he new motor and ran a 14.0 knocked the afrs back to 11.0-1 and ran a 13.4 with no other changes., last run of the night ileaned it out more to 11.5-1 for the most part and ran a 13.001

i picked up a full second and over 8mph just by leaning out the afr

u should be trying for an afr range of 11.5-1 to 12.2-1 afr under boost anything below 11.5 is just reducing power

bring the timing back to 22-24* under boost and take some fuel out of that thing

if ur not that comfortable with that afr and timming number knock the timming back to 18-20* and then start to lean the motor a bit

also wether or not u use rising edge or falling edge on the trigger depends on the ign input setup on the board.

 

113 castings, same as zz4 heads, typically run much more timing than other aftermarket heads with better designed chambers. Give the motor what it wants. Timing does seem very excessive for 15psi but if the motor its ok with it, then thats what it is.

I'd also try leaning it out and maybe pull some timing at first to slowly move the air fuel ratio. This is where you NEED a dyno or track to see what the power actually does.

Check timing at high rpms while free reving and see if it matches. Get someone to hold the pedal for you, or even better, hold the timing light and check for you

 

I said a few posts back that I think it is your ECM and I still think it is. I am happy that you are starting to explore this. Have you verified the latency table for the ignition module is correct? Have you verified the trigger edge? Have you verified the timing vs rpm with a timing light up to 3K rpm in park?

It is normal that your AFR changes vs timing. Normal tuning is changing timing a little, tune AFR, then timing, then AFR, etc.

 

Remember, timing changes air fuel ratio seen in the exhaust by the o2 sensor.... the actual air fuel in the chamber/cylinder is set by air flow in past the valve and fuel injected by the injector as commanded by ECM. None of that changes with timing changes. You can still be rich when o2 is showing what most would think is "lean" as its just a number. This is where you need to give motor what it wants.

Timing just changes when it is burned and that has direct effect on power made, but what you see by the o2 sensor doesnt really mean as much. This is where spark plug readings come in handy and so do EGT measurements. Thats why we tune for max power and not tune for a desired air fuel ratio, because not all combos will make best power at a said air fuel ratio

 

Huh?
Timing sets how efficient the fuel & air is consumed. Plain and simple. What is the point of using a WBO2 if this is true? "You can still be rich when o2 is showing what most would think is "lean" as its just a number"

 

Yes, how efficient the air/fuel is consumed will change power output and all, but doesnt change air fuel ratio of the chamber. It just changes what comes out of the chamber. The o2 sensor is reading what ever is left over. You can have too rich mixtures in the chamber that cause misfires that will show up on the wideband as too lean, so you will think lets add more fuel. This would be incorrect.

You can have instances where the fuel is burning in the exhaust, thus consuming o2 that was left over. The o2 sensor will read less o2 and the air fuel would be more rich, but the motor wont be making max power there. If you changed the timing, and consume the air and fuel in the chamber so it does not burn in the exhaust path, then o2 may read same and car will be making more power. Same air fuel ratio, two different burn characteristics, two different power outputs.

So just be careful when tuning to a "air fuel ratio". Thats all I'm saying. Its better to watch EGT's and power output as well as to monitor plugs while making changes to fuel and spark. Wideband is a great tool but it can be fooled by certain conditions.

 

yup. i would take it to the track and tune between passes. watch the mph each pass. if it goes up each time you add fuel, keep adding fuel until it slows down or doesnt improve. once you have that figured out, add timing each pass until it slows down or doesnt improve. i somewhat gave up trying to tune with a wideband.

 

He needs to lean it not richen it I. Garennttee that thing picks up once he leans it out. Afr.s in the 10,s and low 11,s kill power

 

I would agree with that. I picked up a ton of power goin from 10's to 1 to low 11's to 1. Assuming the mixture is indeed too rich in the chamber at present time and the wideband is getting a good reading. Go slow with it however.

 

my comment wasnt saying to richen or lean it out, i was just saying that is how you tune a car at the track. how are we sure the wideband is even working correctly? it could be lean or rich for all we know....

 

I wouldn't lean out the mixture just yet Steve. Your coil and ignition module are more than likely suspect at that boost pressure level, and perhaps you are getting a false rich reading because the ignition is unable to burn the fuel. Your old ebay turbo doesn't flow nearly as much air as the Precision turbo. I would consider better spark plug wires and a better ignition module (and coil if you didn't upgrade yet) first before leaning the mixture out...

 

That is backwards. If the coil/ign was weak it would misfire and show lean on the WBO2. The WBO2 measures using oxygen levels. If it is showing rich then with no lean spikes then it is firing fine.

 

How is that backwards junk? He is misfiring though, isn't he? He is breaking up at 15+ boost pressure, and has already indicated a backfire in the exhaust during one of his video's. His air fuel ratio is fine before 15 pounds of boost...

 

Missfire fllodss the ex with raw fuel displacing oxegenanda causes a false lean reading. Its even covered in the ms tunning manual and in most other manuals

 

It could be burning off in the exhaust tho, using up oxygen making rich condition show up too. You'd beable to tell just by egt's I would think and looking at the glowing red manifold.

 

Misfire situation is unknown at this moment, except that it seems to be running a little better up top.. and the O2 reading going rich as heck after advancing the timing quite substatially. I don't know if its misfiring because the exhaust is back on the car to drive across time to the dyno.. which I called and cancelled for tonight because of heavy rain. Also the Buick guys are suggesting that I check the position of the distributor rotor relative to the lug for the spark plugs at a given advance. They think the spark could be jumping to the second nearest lug, causing a misfire condition. They, too, suggested leaning it into the 11's.

I haven't had my hands on an adjustable timing light to verify timing at higher RPM. Need to get one of those for myself. That's next on my list I guess.

 

I won't argue with Dusty, he is a Turbo Buick guru. But I personally wouldn't lean out anything, especially when we assume that the 02 is in fact working properly, until the obvious has been exhausted. Which ignition module and coil are you running, anyway? Misfires happen during partial ignition, and although you may only need 15K for the spark to jump the gap at wide open throttle from the coil, as RPM increases, the coil may have difficulty recharging between firings, add to that more air and fuel to burn at higher RPM's. Did you at least test the coil yet...?

 

That wouldn't matter though, because if his air fuel ratio is good at 14-psi with no misfire, then his fueling really can't be that much off a little higher than that when he is in fact misfiring. If he pulls fuel, then later finds out that it was a weak spark up top, fixes the ignition issue, then forgets to add that fuel back in, he might detonate during his wide open throttle pull. Why take chances...

 

Don, another Turbo Buick guru, brought up something interesting as well...

Here his fueling is tuned beforehand, but because of a weak spark due to insufficient dielectric grease, the engine will misfire on him and suddenly give a false reading. Does he pull fuel? No. He adds more dielectric grease and he is back to normal. This is what I mean by exhausting/eliminating the obvious first, as your ignition doesn't seem up to par to begin with. By the way here is Donnie in action, eight second turbo buick with 1.83" intake valves (running methanol)...

 

Don's solution is great, but he's also running 30 psi from what I can gather. My problems seem to start low, as the car isn't really making the kind of power it should be even at 12-14 psi. So it is something I will do after I rule out some other things such as whether or not the timing from the megasquirt is the same as the distributor is actually creating.

My ignition setup is currently an MSD 6AL wired direct to battery, Blaster 3 coil, MSD 8mm wires, plugs gapped to .025" and a stock small cap HEI distributor with an Accel cap and rotor. I just put the Blaster 3 on to replace the external HEI style MSD. No difference noticed.

 

Did you try bringing the spark plug gap down to .018" yet...?

 

someone is selling stuff on ebay using pics of your car.
http://www.ebay.com/itm/UNIVERSAL-RA...ht_6970wt_1163

 

LOL.. nice.. And mine is a PTP blanket, not their cheapo junk. Thanks for the info, I'll be following up shortly.

Haven't gapped the plugs yet nope.. lots of work to get to the ones under the turbo.. and I don't think it's the fix because there is no way a .025" gap is affecting the power at 13 psi with my current ignition system. I want to rule out other possibilities before I take on the terrible task of getting to plugs # 2, 4 and 6!

 

DMCA take down notice?

 

Crazy things over here. The total boost has dropped. What used to be 17-19 psi is now 14-15.. yet the car is faster at 12 psi than it was at 15 before. I've got the wastegate cranked almost all the way in now and it makes about 15.5. It feels very strong now yet the mixture is still slightly rich (it gets into the 10.8 range). I have not yet verified the timing actually occurring vs the megasquirt tables. Also I have not had a chance to test pre-turbo exhaust pressure since these changes. Anyway tonight I took a friend for a ride who had never been in it before. The car just came alive and impressed both of us. It feels stupid in third gear. Not so much in first and second because it would only spin every time I'd get in it. It will be interesting to see if this timing increase and subsequent fuel reduction has any effect on the backpressure issue. Right now I'm just shocked that the core issue seems to have been my reluctance to go this high on timing. Just never thought I'd see numbers like 28.2 degrees at 205 KPA together.

Shall keep you posted. Thanks for all the input everyone has been giving.

 

I am not surprised with those timing numbers, the compression, the IC, and the MS ECM. Have you verified the latency table yet? Or if there is even one in the MS-II? That right there can show you being off up to 3*. So your 28 could really be 25* and you don't know it. The module timing changes vs RPM.

Start adding up a few degrees here and there for errors and before you know it you might really be at a lot less timing than you think. I never felt it was your plug gap and still feel the same way. I think you should be able to run bigger gaps than you have now, but the effort doesn't sound like it is worth it.

 

Junkcltr, I agree that the timing is likely not as high as the tables say. The answer is to use a timing gun and verify with a locked timing figure. There is a latency setting and I have mine at the recommended setting for HEI. Thanks for the tip though, now I know where I can adjust things if the timing turns out to be lower than I thought.

A short video from this morning... http://www.youtube.com/watch?v=3WttsW0JhlI with 3 people in car.

 

A very well spent $100.. a digital timing light confirms what Junkcltr said. My timing is WAY WAY off, exponentially incorrect as rpm increases.

850 RPM - dead on the table

3000 RPM - 5 degrees behind table

5000 RPM - 9 degrees behind table

This means my previous 23 degrees at full boost in the 4500-5400 range was actually only 14 to 15 degrees. My current "28" degrees is only 19. It makes me feel good to know it's running as strong as it is with only 19 degrees.

Now I'm trying to figure out where a latency setting is for my ignition type in the MS. I'm sure this has to do with the rising edge/falling edge setting, but tonight I gave it a good shot to make rising edge work and it will not. The spark timing is all over the place and it runs like crap at idle. I must make it work with falling edge.

This is the only thing I can find regarding spark latency in the docs, and it doesn't look helpful:

Spark control method: How the code technically controls the spark output. The bit-bang spark outputs on MS2/Extra have been coded to have around 10us latency. So while this seems "worse" than MS2 on the face of it, the calculations that lead up to the commanded advance time may well have more error than the pure hardware accuracy, so the latency is not likely to be an issue. Also, while the code works to a 0.1deg resolution the resulting accuracy will depend on the wheel mode used, weight of flywheel, accuracy of engine acceleration and many other factors. There is also the ability of the tuner and tuning methods

 

Congrats Steve, I'm glad she is finally coming along. Gotta ask yourself though, wonder just how much you left on the table with the old ebay turbo with the timing all skewed up...

 

get me a picture of both the top of ur ms circut board and the bottom so i can see al the jumper wires.

there is a hardware latency setting in tuner studio that u can adjust

also if the trigger offset is not set big enough it will cause the timming advance while at high rpms not to be correct also same if it is to small

what is ur actual trigger offset ??

 

I just shut down the laptop and came in to see you ask that! I'll have to answer that one tomorrow cause I'm not waiting 15 mins for it to boot back up. All I know is I had to adjust the trigger offset until the timing table number matches the timing light. Can't remember what the number was even though I was just looking at it. Will get it for you tomorrow. Jumpers are set as per the MK-HEI kit from DIY:

http://www.diyautotune.com/catalog/p...kit-p-325.html

Per that page, I see now that they specify the trigger setting DOES have to be changed to falling edge with that kit... so that explains the variation from the manual and sorta removes that as the source of the issue.

It is installed as per this video:

http://www.diyautotune.com/videos/pr...hei/mk-hei.htm

 

Well I haven't gotten the offset number for you yet Project89, but I do have a bunch of other things to tell...

Dynoed the car this weekend and have figured out several things. The first thing was my friend who owns the dyno said I've got blue smoke coming out while backing up the dyno ramp. We pulled the PCV and what do you know, I've got blowby now. I just recently checked for this because an engine he built a while back did the same thing... and mine was 100% perfect. Recently being within the past 200 miles of driving. So now I've got (@*$@&@$ blowby, so the engine will come out to see what's going wrong.

Meanwhile it dynoed at 406 rwhp and only 405 rwtq. I realized between the dyno graph and the data log that my stall is flashing too high. It's a 2800 but it flashes into the 3800 range and puts the engine will above its peak torque range. I'm sending the converter back to Precision Industries to get restalled and checked out. It's always made a weird tapping sound anyway.

So the rwhp is about what I expected. On the high side I predicted 415. Now on the other hand, a modded Z06 put down around 385/370 and got the notion that he was so close to my numbers that we'd be a good race. Leaving the shop we put it down on a 20 mph roll. My car fishtailed through the gears and still walked right away from him. His car only spun for a few feet. So even though the numbers are never great, the car isn't a slug at this point. I think the converter is just too loose and is killing the torque output.

As for the blow-by and smoke... no idea. I haven't been excessively rich and I haven't had any detonation (that I can hear and this car is super QUIET). Possibly a cracked head or leaking head gasket perhaps?

Also I'm going to be moving to a FAST or Big Stuff this spring. So my plan is to pull the whole drivetrain and go through everything, build a new harness and replace the MS3. While i'm in the engine I'm going to look at my options for a better oil pickup system. And my turbo manifold continues to leak so I think I'll finally build a new header that will accomodate a 72 or 76mm turbo. I just made a deal with someone who wants a pair of 6766's so I can make a sideways trade + the difference.

So now I just have to decide how long I want to risk damaging the block before I take if off the road. Just bought a boat so that's got my attention right now (and extra funds) but hopefully I'll have some cash flow for the Iroc by April or May.

 

do u have acess to a leak down tester ?

u have an ms3? or ms2 in the car ?

 

would be interesting to see what the manifold pressures look like once you get the timing up where it should be.... could that have been the problem all along? lighting off some of the fuel in the manifold?

 

It's a MS 2 3.0 board. Yep I'm gonna leakdown test it soon.

It looks like my downpipe pressure is gone since changing the timing. I'm going to move the gauge back to the pre-turbo fitting soon.

 

u said theres only what 200 mile son the motor ? i wouldnt worry about it to much just yet the rings may not be fully seated just yet .

what kind of rings did u put in the motor

also it could be that ur pcv valve is not shutting under boost and ur just blowing boost into the crankcase as well

but a leakdown test will show u if thats the issue or not

 

This especially with the tune being off. I'd run it a bit and see if she settles down as long as it's quiet.