Ok, here is the story...

Sunday night, I was coming back from the fair. I went to hit the gas a little and the car backfired and wanted to die. Couldnt give it any power. Basically, coasted it to my house.

At home, I tried to restart it. It cranked forever, and then started real slowly. I got a timing light on it, and my timing was perfect at 0* TDC with the ESC disconnected. Fuel spray was good from both the TBI injectors. I shut it off, and it wouldnt start again for that day.

Monday, my dad suggested I turn the distributor. I cranked the car over while he turned it. We finally got the car to start. I had to turn the distributor as far to the left (counterclockwise) as possible without taking the wires off the cap. It runs OK enough to move the car, but real rough.

Yesterday, on someones suggestion, I pulled the distributor to check the "shear-pin" in the bottom. The whole thing looks brand new, it was replaced last winter by me. The rotor could not move independantly from the gear.

So my natural assumption is that somehow my timing chain slipped a tooth!! But everyone says this is nearly impossible. The factory motor has 65k miles, and it didnt make any noises.

Also, right as it sits, with the distributor to the left to keep it running, if I shoot the timing it shows like 2" advance off of the timing indicator. When it was at 0*, it wont even start. Both these are with the ESC wire unplugged.

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So before I go order a cheap timing set and all the supplies, is there anything else I can check?? What do you guys think, is it possible to jump a tooth at 65k on a factory chain?

 

I just finished dealing with a wierd timing thing too. While it was dying the last time you drove it, was it idling fine, but dying when you put your foot in it, like the timing wasn't advancing?? I would check the electronic ignition module (little box in the distributor) and see if its any good, or switch it out with one you know is good. Usually, when they are dying, they work when cold, but crap out when they get warmer. Mine started acting up by not putting timing in when I stomped on the pedal...the car would cough and nearly die. After a few of those, then it started to die altogether after 5 mins of running or so. Then it wouldn't start at all. Fortunately, by that time, I figured out what the problem was. I doubt the timing jumped...that would be very surprising. Good luck.

 

The ign module was brand new with the distributor last year. I saved the old one, however it was not known good. It had problems with heat / moisture.

I dont think that it would do this though so soon again?

 

Sounds like something came loose in the distributor. The pick up coil comes to mind. May have slipped.By the way good looking car

 

Ok, well I think I might bring my IGN module back to autozone and get it tested. Dont I need to buy something special to stick it back onto the distributor base, or would like antisieze work?

Also, how do I tell if the p/u coil is loose? I have never even taken it out, so I dont know what to even look for...

Thanks for the input guys - I really hope it doesent work out to be the timing chain. Has anyone even heard of the chain slipping before on a SBC motor? I know that hondas and stuff always hop a tooth on their belt sometimes, but I didnt expect a chain to do that...

 

Your right a timming chain usaly jumps time when you cut the engine off. It will not start back up. The pick up you have is held on by a clip that may have popped off.

 

Well, I just got back from Autozone. I got the IGN module tested, and it passed with flying colors. He ran the test at least 10 times, but it worked great!

I checked the p/u coil, I tried moving it by the plug that goes to the module. Now, the way it sits in there, I can rotate the coil by moving the plug, however the metal walls keep me from turning it much at all...

So now I can almost be sure it is a timing chain, right? I guess I will have to settle down and start trying to get it fixed...

 

Timing chain?
You say the base ignition timing is at zero mark on the balancer?
So that would mean the dissy is aligned correctly, right?
So what spins the dissy? The cam right? What spins the cam? The timming chain right? And the crank spins that ?
So if the dissy is the last thing to get spun and its still aligned with the crank , then that means every thing in between must still be aligned right? Meaning your chain didnt jump and you cam is still in the right spot.

 

Let's stay on the easy stuff first. Did you look at the rotor cap to be sure the "finger" did not break loose? Also look very closely inside the dist cap. A hairline crack or carbon tracking will allow voltage to jump around. Did the car back fire any? It is very unusal for a chain to "jump" a tooth unless the cam gear/crank gear is almost totally worn down. Even a chain with excess stretch will usually only show signs of timing float. Can you try a different dist, beg or borrow one possibly? Good luck

Joel

 

The cap and rotor look good, that was the first thing I checked! Those were replaced last winter anyhow.

When I was at autozone, I asked about trading that distributor for another reman one. I happened to throw away the reciept about 3 weeks ago, but they said that they could probably find my name in the computer. However, I had no evidence that there was anything wrong with mine!
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About the timing light... if the chain had slipped, that would cause the reading on the timing light to be off?? Because when I got home, I checked the base timing before I even touched anything.

I dont know anybody that has a distributor like mine. I really wish i did. But I cant justify spending another $100 on the same thing I bought last year...

 

I would see if autozone will swap the dist. out for you. Try that first.

 

Questions:
Fuel Spray: I know you checked when you checked your timing with the car running, but did you check when it was not able to start. Aka have someone else crank as you watch?

Did you check for any damaged spark plug wires?
Have you pulled a plug to check it out, might give you some more signs, such as running too rich.
I worked on a car once with a TBI that had a leaky injector and it just dripped for a bit after shutoff.
Basically it flooded the engine and the car would not start after it ran for a bit and was turned off.

As you mentioned you tested the timing, and that was good, so I would not worry about the chain.
But just for the record, timing chains on third gens can and do jump teeth once in a while, I owned two separate ones that did this. One was an 86 the other an 87. Both used that dang plastic coated timing chain, and after years of use the plastic started to break off. When pieces broke off, the chain jumped a tooth.
But like I said, since you timing is correct I would not worry about it.

I am leaning to something throwing your timing way off once the problem starts.
I know the TPIs have a wire you can disconnect so that you can set base timing.
Does that TBIs have this as well?
If so, I would try to disconnect that wire to see if the car will start.

If you have a bad sensor feeding the computer the wrong data, or the computer is going bad, you might have the same symptoms you are experiencing.
I had a car do this to be as well and after killing myself trying to track down the issue, I eventually changed the computer and everything was good again.

Let us know what you find.

 

Every time I check the timing, I unplug that ESC wire. Actually, it has been un-plugged since the minute I got home when the car fisrt acted up.

I figure, the car used to be able to run and drive fine with the ESC wire unplugged. It would just be slower, at base timing. But I want to be able to get it running good on base timing, before I try and let the computer start playing with it at all!

I just uploaded a video for you to see, the car is cold and the wire unplugged.

http://www.youtube.com/watch?v=I3BqXL2KJ4M

might be a little bit before its available.

 

The car is not going to run right with the ESC unplugged (except for setting the timing).

 

I know it doesent run right, but it shouldnt stall and backfire either

 

All you should expect out of it with the ESC wire disconnected is for it to idle.

 

Well, the first time I ever set the timing (like a year ago) I took it for a spin with the ESC wire unplugged, and it drove around OK. Not great, but OK.

And it wont even idle with the esc unplugged and timing at 0. With the ESC plugged in, it runs even worse! I tried it tonight.

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Also, I just got finished putting in a new distributor from autozone. It did not help the problem at all!!

What else is there that could have slipped inside the motor, that wouldnt affect the timing on the balancer??

Also, what is it that makes the motor start right up and run with crazy advance, but when i retard the timing back to 0* it just shuts off??

 

Check for timming chain slack. Pull the cap.use a wrench and turn the engine untill the rotor moves. Then turn the engine the other way and check how far you have to turn the engine before the rotor moves. The rotor should move with the crank. If you turn the engine alot before the rotor moves. the chain has slack and may have jumped.

 

Well, I am probably gonna start tearing into it tomorrow. I just need to get the tools together to do the job. I would rather at least know that the timing chain is new, and then reset the motor to TDC. If I still have the problem then, I will need to start looking for a motor.

Here is the main issue that confuses me. Like you guys said, even if the chain slipped, or even if the distributor slipped a tooth on the cam gear, that would theoretically move where the timing mark on the balancer shows up under the light. But when I first checked it when it started backfiring and stalling, the mark was at 0* TDC, exactly where I had put it at 3 months ago.

If you watch the video, you can see that the motor runs like crap with the timing at 0* and actually stalled when I feathered the throttle. What you cant see is that it was pouring grey fuel smoke too. With the timing advanced really far, it smoothes out and runs clean, and I can rev it fine.

I was trying to figure out though, how does the computer control the timing? Is there something in the distributor that moves? Also, is there any control from the computer at all with the ESC wire unplugged? I am trying to rule out a bad ECM...

Finally, is it possible for the cam gear to slip on the distributor gear? If that happened, the rotor would be pointing at the wrong cyl even on the new distributor, because I have just been puting it in the same way it came out. However, like I said that would have thrown off the timing mark, unless the harmonic balancer slipped the same exact amount as whatever else did. That would be like a 0% chance though...

 

Really, check your fuel pressure before you tear into that motor.
Your timing can't slip and read dead on with a timing light. I believe you have lost significant fuel pressure and are running lean. A lean mixture will cause backfires more than over advanced timing. A lean mixture burns very slowly but by over advancing the crap out of your timing you may be able to get it to half assed run.

 

Well, my dad is dead set that my timing chain slipped. He talked to a mechanic and he said the only 2 things that it could be were that shear pin in the dizzy, or the chain.
My dad said he either wanted me to start tearing into it, or get it out of his garage. So, i had to do something to keep him happy.
$200 later in parts, I decided to start working. I told one person I had got parts for the car, and 10min later half the red-necks in manchester are at my house helping.
We got it this far in less than 1 hour!




I dont think the chain slipped. Its not that loose. But now that I got it this far, I might as well put the new one in. And my water pump was gonna go soon too anyhow.
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There is one thing that confuese me - on the new "cloyes" OEM timing set I got, only one sproket has a Dot in it. I thought they were both supposed to have a dot??
I just gotta get the plugs out to turn the motor easier, and then will be able to make more progress...

 

That's too bad, the mechanics were not relayed the whole story or are idiots.
You verified your timing was correct when you checked it with a timing light.
That timing chain appears to be in good shape, with steel gears it is just short if impossible to jump time. Now you will have to deal with the pain of putting that timing cover back without oil leaks, reassemble, and find the original problem.

 

Good job man looks good. The chain looks good to me. You changed the dist. with another, that rules out the pin on the shaft. Have you checked the codes? I wonder if the knock sensor is bad. I know the coolant temp. sensor will make a TBI engine run like you discribe.I would put it back together and have scanner put on the car. Good luck.

 

I changed the CTS last winter before I ended up replacing the distributor. Not sure it needed one, but it is less than a year old now.

The only code I got was the one when I disconnected the ESC wire. Before that, the SES light never even came on!! How can the computer be so stupid to not even realize the motor is barely running??

Right now I am kinda stuck. I need to find a safe and easy way to rotate the crank. I cant find anywhere that sells the crank turning socket that shifty capone had.

Once I can get the crank rotated, I will see if it lines up dot-to-dot. Either way I am gonna put the new chain in. But I still wanna know.

Also, when I get the engine TDC on #1, I am gonna pull the cap and make sure the rotor is pointing at #1. If not, ima pull the dizzy and drop it back in the right way.

Once all that is done, I will at least know that the mechaincal timing is 100% good and tight.

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Also, it wasnt a total waste of time. Like I said, I did find that my water pump will need to be replaced soon anyway. It had play in the shaft, and was starting to weep once in a blue moon.

 

The computer is not for diagnostics. It can tell you if things it monitors are out of range and it can't tell you anything about systems it does not monitor. It does a limited number of self checks but they rely on the motor running. Stupid is right, it has a zero IQ and can only do exactly what it was programmed for.

If you have an adjustable wrench, adjust it down tight against the crankshaft and rotate against the crankshaft key. Make sure the wrench is adjusted tight and allow compression to bleed off as you rotate to limit the pressure on the key.

Good plan.

At least you have that, eh?

 

Ok, bad discovery. I was just looking at something.

It appears that this morning, when I was trying to rotate the crank by using the crank bolt and a block of wood with a hole in it, I somehow messed up the threads.

Right now, I cant get the bolt threaded into the crank snout. The threads on the bolt are visibly bad. I tried to look into the crank, but those threads look not as bad (hopefully)

So what I need to know is, what is the exact thread size of that bolt?? I am gonna try and buy a new one, but I might have to get a thread-chaser to re-thread the crank snout too!

 

Well, i was able to get the bolt at autozone. They dont carry them by make and model, but they had one that works on any SBC in the chrome/performance aisle.
The bolt threads in nice for like 4 or 5 turns, then starts to hang up. Now, I think I can get by because if I use the ratchet, I can get it to keep going in. I think the bolt is "fixing" the threads in the crank as I put it in father.
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Right now I am stuck on how to get the crank sproket off... the crank sproket puller I bought at autozone is made to pull a sproket with threaded holes in it.
The crank sprokets I have (old and new) dont have any threaded holes in them! So how do you install and remove them?

 

you should be able to gently pry it off the crank by prying evenly on both sides. A small amount of heat my help but be careful not to ignite any fuel that has accumulated in the crankcase from all the cranking attempts. Gas vapors in the crankcase can/will explode.

If all fails, a jaw style puller will take it off but the sprocket should not be fit that tightly.

Be careful using a bolt to clean threads, you can actually make them worse.

 

I could get ahold of a jaw style puller, but How would the new one go on??

Would it hurt to leave the old crank sproket on? It doesent appear very "worn". There are contact marks, but no metal is missing...

The new set I got is a Cloyes, and the sprokets and chain look totally different. However, I was able to get the chain to fit with the new cam sproket and the old crank sproket. It was somewhat tighter than the old one, but not alot.

 

You can reuse the old crank spocket if it matches the new chain. It is not recomend. You can drive the new crank gear on with a large scocket or piece of pvc pipe.

 

Well, if I cant get ahold of a puller tomorrow, I will probably end up re-using the old sproket.

I understand that its not recommended, because its not good to put a new chain on a worn sproket. But my car is still pretty low milage for its age, its only got 65k on it. I bet that sproket has years left in it!

But like I said, if I can I will put the new one on. Why not use it if I paid for it?

 

Well, I finally got the crank sproket off! After trying the puller that Napa rented me (too big) and autozone's was too small, I got some rinky-dink puller at taylor rental... it cost me $10 for the day, but its was worth it. Considering I needed to use the impact on the puller to get the sproket off, because the 1/2" ratchet was turning the crank... the impact kinda messed up the puller - good thing it's not mine lol.

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After "pressing" on the new sproket (used my roofing hammer) I put the chain on dot-to-dot



Then, I rotated the motor once over (balancer and pryber) untill its now at 12 & 12.



I pulled the wires and cap to take a look at the rotor's position:



So... I wasnt sure if that is where cyl#1 is considered to be. I pulled the dizzy and dropped it back in one tooth off and this is what I got:



So which position do you guys think is most pointing to the #1 cylinder if the cap was on?? Remember, the first one should be the factory setting. I have changed the dizzy before, but I always put it back in with the rotor pointing the exact same direction.

Finally, I have been playing with the timing cover. I still cant figure out how to get it back on. If I could get the pan to budge and drop like 1/2" I would be all set, but it wont move even prying on it.

 

"So which position do you guys think is most pointing to the #1 cylinder if the cap was on??" Doesn't matter. Just hook the number one wire to the post that the rotor's pointing at. You could spin it 180 degrees and be fine as long as you shift the wires with it.

"If I could get the pan to budge and drop like 1/2" I would be all set, but it wont move even prying on it." Remove all but the rear bolts and loosen them. You'll have to drop the starter to get to some. Hope it leaked a little before this so you're not too disappointed.

Please do a little troubleshooting before throwing any more parts at it. Fuel pressure, idle control motor, egr, plugs/wires. Never assume a part is good simply because it was recently installed.

 

Nah, the motor never leaked a drop before. Even after I switched to M1 oil it never leaked a drop. But the pan gasket appears to be in really good condition...

I didnt think you had to take all the bolts out to drop the pan... I was told that the first 6 would be sufficient. I did loosen them all though, except the rear 2 big ones...

So your saying that it doesent really matter which way I drop the distributor in, as long as the timing light shows up at 0* when it's runing??

 

Exactly (although you do want to orient it approximately where it was before so that the connectors hook up in the rear-they may not reach all the way around to the front). It doesn't care which post number one is on as long as it fires it at the proper time.

Take the pan bolts out. You want to DROP the pan down, not BEND it down. Loosen the rear bolts so it doesn't bend there either.

 

How the distributor drops in does not change how the engine runs as long as they are firing at the correct time, so yes; as long as the timing is correct (as you verified it to be before you dismantled the front).

The correct (factory) setting is where #1 and #8 are perpendicular to the valve covers.

Align the teeth on the pickup coil with the teeth on the reluctor, this is roughly where "0" would be. The plug wire tower the rotor is pointing to is the cylinder that would be firing.


The potential for leaks and difficulty in installing the timing cover were the basis for my initial pleads for you to not tear into the timing chain. You will have to break the bond between the pan and the block to get the pan to drop. Once you do there is no guarantee it will reseal when you bolt it back up. It is difficult to keep oil from contaminating the sealing surfaces; if it does there will be seepage. If the oil pan leaks, your only resort at that point will be to replace the pan gasket which is another whole project in it’s self.

 

Ok, well thanks for all the guidance people. I finally got the motor all back together... and it runs. However, I still have the same problem I was having before!!

I have been playing with it some more, and it keeps confusing me. Just to get the motor to start at all (ESC wire unplugged) I need to have the timing at about 12-14* advance. However, once it warms up if I try to drive it (ESC still unplugged) it gets crazy spark knock. If I retard the timing, it wont start again.

Also, there doesent seem to be a one happy spot where it will both start and drive. However, with the ESC wire connected, it is worse because then it wont start at all and shoots blue flame out the TBI when climbing hills.

Also, even with the wire disconnected, it does get some spark advance with revving the RPM. I was wondering, does the computer still control the spark advance even with the wire unplugged??

What about that thing called the ESC module?? I have replaced the ign module twice now, both without needing too. However, I have no idea what that ESC module does??

Also, just for reference, the motor will not start, idle, rev, or run at all with the base timing at 0* like its suposed to be..

 

First: I trust you verified your balancer mark is correctly at zero with number 1 at TDC while you had it open?

The ignition module will still provide some spark advance with the ESC wire disconnected. If you set it at 12-14 this advance is probably enough to cause the pinging-that's normal.

The ESC module is connected to the knock sensor and sends a signal to the ECM when it detects knock-that's all. It changes the KS signal into a voltage signal the ECM can 'read'.

When you changed the ICM you didn't, by chance, reverse the two wire lead from the pickup coil that connects to it inside the dist? This will cause timing advance issues but don't think it's an issue for you unless your problems started immediately after a module change.

Have you left the ESC connected and tried to start it while slowly turning the dist?

Have you verified the EGR valve is not failing? When it's idling does manually operating the valve cause it to stumble?

Vacuum leaks?

I suspect your problem lies elsewhere and advancing your timing is just masking some of the symptoms.

 

Quote:

Originally Posted by naf

First: I trust you verified your balancer mark is correctly at zero with number 1 at TDC while you had it open?

Yes, when I was pressing the balancer on, the sprocket dots were still at 12 and 12. The timing mark notch on the balancer lined up with 0* on the timing tab...



But thats the minimum amount of advance I could get it to start and run at! And i was driving with the ESC disconnected to try and keep advance out of the question



Alright so that couldnt be an issue then...



I never changed just the ICM. I have gotten new ones aready installed on both new distributors though.



Yes, but what should I look for? It runs more tempramental with the wire connected.



The EGR valve was replaced recently this spring. It is a brand new Delphi one identical to OEM. I stuck my finger under there, and the diaphragm is closed at idle.

Quote:

Vacuum leaks?

Found one and plugged it, but it didnt affect anything accept the heater blower controls.



I think that it is something to do with the whole electronic spark system on this car. You could be right though.
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What I weas trying to accomplish yesterday, was to find a spot where if something moved, it would be identical to what 0* was before.

Before the problem, if I disconnected the ESC wire, I could still start and dive the car fine. It would idle a little erratic, and didnt make much power. But it still drove smoothely.

Since I remember what that sounded / felt like. I have been trying to find somewhere I can leave the distributor that will simulate that.

The main issue is, that it requires such different advance just to start the motor! Its like there is not one spot that will start the motor, idle, and drive.

 

I hope you figure it out. We are having the same problem with an L98. It was running great, rolled into the throttle to pass a car, it backfired and started running real rough. Little to no power. It sounds like it has a severe miss.

 

From what you've said, there is nothing wrong with the timing. Something else is off and that's why it won't run like it did before when the timing was at zero.

Time to start diagnosing and stop replacing parts.

 

Well, what can I do to "diagnose"?? I never liked throwing parts at a car, the only reason I did the timing chain was because my dad was dead set that was the culprit, and made me repace it or he was gonna send it to uncle freddy at the junkyard.

I went to the parts stores today to try and find a way to check the fuel pressure. I found both a "spectre" and a "mr gasket" mini guage with 1/4npt threads, they read from 0-15psi. They both said not for use with fuel injection. Also, I would need to find somewhere that had fittings to convert the inlet at the TBI and the outlet of the fuel line from threads to barbed ends, and use rubber hose to rig it together.

Also, is there any chance its the ECM itself? I havent thrown any codes unless I unplug something like the ESC wire or MAP sensor, then I get a code for that. I also tired disconnecting the battery for 1 hour, to re-set the ecm. That didnt change a thing.

I had it idling today, and I tested the EGR valve by pushing the diaphragm. The idle bogged and stumbled.

I tested the TPS by flicking the little lever, and the injectors shot a little pump shot of fuel into the motor resulting in a cloud of fuel smoke out the pipe.

I tested the MAP sensor by disconnecting the vacuum line, and once it was getting aptmospheric pressure the injectors poured fuel in for about 5-10 seconds, and then it smoothed out and threw a SES light.

The CTS next to the water neck has been replaced last fall. My uncle suggested the O2 sensor, but that wouldnt affect the car until closed loop, right?

I borrowed the spark tester from a kid at work, and connected it from the coil to the cap. It showed a bright orange light.

So what tests do you recommend I do to diagnose?

BTW I really appreciate the help!

 

Somebody else I know came over tonight to look at it, he is a technician at the lynch toyota, and he has a 2nd gen 301 pontiac with a 400 on the stand, a IROC, and a few old chevy trucks.

He is stumped too as to what the problem is. He got the car to run with the base timing at 0*, but it needed the ESC reconnected to stay running and you cant rev it at all or it backfires and stalles.

He also used my paperclip to pull the codes, and the only code was a MAP sensor (I had unplugged it yesterday when I was playing around) so I reconnected the MAP sensor, undid the battery, reconnected the battery, and then pulled the codes again. All we got was a code 12 which is normal.

When he had the key-on and the codes were flashing (jumped A-B terminals ALDL) I noticed a electrical buzzing on, off type noise from the throttle body area. Kinda threw me off, unsure if that is normal.

With key-on, the SES light stays lit. Once you start the motor, the SES light goes out and doesent stay on.

Another thing we noticed was that on the passenger side injector, shooting the timing light at the fuel spray, it would intermittenly go from a nice steady spray to hosing the fuel in like a garden hose. Then it would miracously go back to normal. The driver side injector stayed perfect the whole time, but either way it never ran better with or without the nice fuel pattern.

Also, the whole time the motor is running it always is literally pouring out a steady cloud of visable rich exhaust smoke. It fills the whole garage with fuel "fog" that stings your eyes. Mike said if I am running the car more than a few minutes I better keep an eye on the cat because its gonna get cherry hot.

 

You need to start a new thread in the TBI section on that problem. Sorry I can't offer any advice on a TBI system. But this could be the problem with the engine. Good luck.

Joel

 

Just curious, did you get your timing problem solved?

Joel

 

Also, make sure the balancer didn't slip. Put the balancer lined up with 0 and remove the #1 spark plug. Move the crank both ways to find TDC. If the piston is at it's highest point and the mark is still at 0, you are good. If not, the balancer slipped. Also, base timing should be at 6^ BTDC.