Timing Issue

KIER24601

KIER24601

Darrick
My 92 Typhoon has been down for repairs for the last couple of weeks and I'm running out of ideas. It started when I was just about the get on the freeway. The light turned green and as I tried to accelerate it felt like I was getting held back(kinda like I pulling a big trailer). It took awhile but it got up to highway speeds and was fine but felt like it was taking a lot more power to hold at cruising speed then normal. When I got it home I checked for vacuum leaks there was non. I had an new EGR valve that I bought but never replace so I switched that out, didn’t fix it. I then bought 2 new PCV valves and spark plugs. I checked the compression in all cylinders 145psi all the way around and put the new plugs in, also replaced PCV valves. Still didn’t fix it. I through a timing light on it. Timing was off and the distributed was a little loose so I disconnected the bypass wire set the timing back to zero and reconnected the wire. It started right up and idled fine but when I took it out on a test drive I gave it boost and everything seemed to work. Then down the street it cleared up I boosted again and the RPM's stopped at 3k and it started doing the same thing again and when I came to a stop it die. Took a while but finally got it home fooling with the distributor. I check the pickup coil it checked out ok and the book says you need a special tool to check the module in the distributor and as that’s the only other electrical peace I replace that but didn’t fix the problem. Now the crazy thing is when I disconnect the wire(under the dash) to bypass the computer to set base timing back to zero it idles fine and the timing mark stays at zero doesn’t float around at all. Then when I hook the wire back up it wont even idle. If I leave the wire disconnected and try driving it, it will only get up to 10 mph. I’m not sure if I should just buy a whole new distributor or if it maybe is the ECM, or worse yet the timing chain is stretched. Just wondering is anyone had the same problem or have any ideas.

92 Typhoon 125,000 miles


Parts Replaced
MSD coil (replaced about 2 years ago)
Balancer (6 months ago)
Rebuilt Tranny(2 years ago)
Cap, rotor, wires (6 months)
plugs (new)
PVC and EGR (new)
PTE 51 turbo w/exhaust (6 months)


sure there is more but cant remember

Thanks for the help

Darrick
 
jwaller

jwaller

Evil Genius/SyTy Guru
Re: Timing Issue

if you have some type of scanner you can see what the ecm is commanding and use an adjustable timing light to verify that on the balancer. that way you can check to see if they match up, if they dont you most likly have a dist prob but it could be a timing chain.
 
KIER24601

KIER24601

Darrick
Re: Timing Issue

I do have the equipment to do that, the only issue I think I'm going to have is after I plug the bypass wire back in and start it, it doesnt want to idle at all, so im not sure how much the desired timing advance in the computer is going to be jumping around. Do you think if the timing chain is stretched that it would affect the car that much to where is wont even idle? I dont get any movement on the timing mark when i set base timing, you would think it would jump around a little if the timing chain was loose.

Thanks for the help I'll try test it out this weekend

Darrick
 
Don W.

Don W.

Stab it and steer it
Re: Timing Issue

If you didn't pull both ECM (one may do it but I've always been told both) fuses after resetting the timing with the wire disconnected, do that. (Resets the ECM and clears codes) Before you do that though have you checked that timing mark is, in fact, at TDC? The dampener is known to slip. If timing has indeed slipped then I'd suspect the dist first. Make sure you cannot move the dist after tightening the hold down. I found mine loose with the bolt tight 'cuz the fork thingy was off the dist. Still loosing timing? Pull the dist and check the gear.
 
KIER24601

KIER24601

Darrick
Re: Timing Issue

I diconnected the battery to reset the computer. Yeah I noticed when I had the distributor out that the fork moves in and out so I was careful when putting it back together. I haven't had a change to check TDC against the balancer, but I'll be sure to check that as well.

Thanks for the advise

Darrick
 
KIER24601

KIER24601

Darrick
Re: Timing Issue

I took a look at the turbo and it spins free as a bird. I also had no problem creating boost when I was on my way home when it started messing up.
 
berzerker

berzerker

wookie
Re: Timing Issue

truck still have the catylitic convertor ?? if so could be plugged . leaking boost pressure from a small hole in intake piping / hoses . or your knock sensor is whacked and the ecm is pulling a bunch of timing . my .02$
 
KIER24601

KIER24601

Darrick
Re: Timing Issue

I do still have a cat but I also have a electric cutout which I tryed but didnt solve the problem. I checked for intake leaks but didnt find any and i also had the laptop hooked up and no knock. My truck caught itself a good cold
 
KIER24601

KIER24601

Darrick
Re: Timing Issue

I just checked TDC today it is set right at 0 on the dampener. When I was at the junk yard the other day I found an ECM that works in SYTY and tryed that too but thats not the problem either. So Im down the the distributor and a worn out timing chain, unless someone has any other ideas
 
Don W.

Don W.

Stab it and steer it
Re: Timing Issue

Lets see if I understand.

Very low on power and boost. Correct?
Timing is at -0- with wire disconnected. Reconnect wire and reset ECM. Correct?
It's not the cat because of the cutout.
Is the intake and air-filter clear?
Usually if timing has gone late because of a bad chain or whatever the motor will overheat. Notice that at all?
If timing is really going south you'd see it with a light. (It would change each time you checked.)
Also if timing is way late the engine will have trouble even revving in neutral, How does it rev in neutral?
Is there a point where it seems to go bad? Part throttle, just off idle, boost coming on...

Based on the posts I've seen here some sort of scan tool is next.
 
KIER24601

KIER24601

Darrick
Re: Timing Issue

Don

Yes very low on power but boost seems to be where it should be, well when I was able to drive it(if you could call it driving), its gotten worse and wont even idle anymore. I have the timing set at zero and reset the computer, but it wont idle when bypass wire is connected. When I disconnect wire and check timing its still at zero. When i have the bypass wire disconnected the wide band shows me running at 14.7:1 so i would assume my intake is clear because i am getting the right amount of air to fuel, but when i reconnect wire i cant check the air/fuel because the RPM is all over the place and it wont stay running. As far as overheating it doesnt appear to be running hot, like i said before i cant keep it running with the wire is connected but with its unconnected it seems to run at 175deg. No i cant rev it in neutral it does the same thing in every gear. My brother brought home the scan tool they use at the auto repair shop he works at and it doesnt show any codes and it didnt look like anything was unusual but im not sure if there is anything i should be paying attention to. I hope i answered all your questions

darrick
 
Don W.

Don W.

Stab it and steer it
Re: Timing Issue

Do you have an adjustable timing light? With that you can see what the timing is doing with the tan wire connected. Also I'm curious, you said you found an ECM at the junk yard. I was under the impression that our ECM's were specific to our trucks. What did you pull it from? You say you can't rev in neutral. What happens? Does it just quit? Run rough? An engine that going late in timing will sound like it's under load when revving in neutral, does it sound that way?

I'm no expert on ECM's, far from it, just doesn't make any sense to me that it won't run with the tan wire connected.
 
midnightbluS10

midnightbluS10

Banned
Re: Timing Issue

Don W. said:
I was under the impression that our ECM's were specific to our trucks. What did you pull it from?
Click to expand...

No, they're not. If so, there'd be no syty's left with ecm's considering how many people are running the 7749.
 
KIER24601

KIER24601

Darrick
Re: Timing Issue

I got this from www.SYTYauthority.com

"GM put the Sy/Ty ECM [GM #1227749] in only a few vehicles. This is the list of vehicles that contain the '7749 ECM.

'87-'90 2.0 liter Turbo cars [VIN engine code "M"]: Sunbird, Skyhawk, Calais, Grand Am, Skylark
'88 2.3 liter Quad 4 cars [VIN engine code "D"]: Grand Am, Calais, Skylark
'91-'93 4.3 liter Turbo trucks [VIN engine code "Z"]: Syclone, Typhoon

Don't confuse the ECM with the MEMCAL that is plugged into the ECM. Any of the above ECMs will work in a Sy/Ty, but only a Sy/Ty MEMCAL will work properly in a Sy/Ty."

I got mine out of the 88 Quad 4, only ecm in the whole junk yard. Update on my truck ITS FIXED!! I replaced the distributor and now it runs like a champ. I dont know what was exactly wrong with it as i replaced the module and supposedly the pick-up coil was good from the test it told me to do in the repair manual. Thanks for everyone's help

Darrick
 
Don W.

Don W.

Stab it and steer it
Re: Timing Issue

Well that explains that. :rotf: Live and learn. That still don't explain why it won't run with tan wire connected. Have you tried an adjustable timing light?
 
gjp

gjp

another post whore
Re: Timing Issue

could it be the computer was trying to advance and the dist. would not let it.??
 
Don W.

Don W.

Stab it and steer it
Re: Timing Issue

I just posted to another thread by 92typhoon1679 with similar issues. It just occurred to me that, at least on my truck, there are 2 timing marks. Make sure you're using the correct one. Can my truck be the only one with two marks. Never heard anyone mention this before.
 
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