Timing vs. Idle vs. Throttle Spacer WTH?

[pmndlt]

Hey all I’m absolutely lost. Had this truck for a couple months and have no clue how to get running right. 1988 C3500 5.7TBI. Bringing it home it died at every stop the SES light came on. Code 22.

Changed out the TPS, but realized as I removed it PO had installed wrong (tab was on wrong side of arm) reinstalled original TPS - code disappeared. Since then done: cap, rotor, plugs, wires, CTS, cleaned IAC and still runs like crap. Dies at every light.

Today I checked timing (properly with EST removed) and it was 8+ advanced. I set it 0 and now I can barely get it into gear before it dies.

Any suggestions? I don’t want to run advanced, hoping to be a daily driver and carry my TC for summer but so far can’t even get out of garage.

ALSO PO out a Throttle body spacer on it (no chip). Could this be the issue? Know nothing about them, can I simply remove without modification?

Thanks so much.

 

[PlayingWithTBI]

Changed out the TPS, but realized as I removed it PO had installed wrong (tab was on wrong side of arm) reinstalled original TPS - code disappeared. Since then done: cap, rotor, plugs, wires, CTS, cleaned IAC and still runs like crap. Dies at every light.

Today I checked timing (properly with EST removed) and it was 8+ advanced. I set it 0 and now I can barely get it into gear before it dies.

Any suggestions? I don’t want to run advanced, hoping to be a daily driver and carry my TC for summer but so far can’t even get out of garage.

How about trying a couple tests without spending too much money?

1) Shine a flashlight behind the injectors and see if they're spraying a nice even cone with no drips.

2) Borrow a fuel pressure gauge and see what it is, s/b 11 - 13 PSI. GM says 9 - 13 but, when you get 10 or less, it's marginal. After these 2, it's probably spark related.

3) Take a water bottle and spray the coil, not the wires and see if it stumbles. If so, you have a bad coil which, in turn can take out your ICM.

4) Take a look at this, HTH!

https://easyautodiagnostics.com/gm/4.3L-5.0L-5.7L/distributor-mounted-icm-tests-1

 

[pmndlt]

Thanks @PlayingWithTBI really appreciate the quick response and suggestions I will try these out tomorrow. Have a good night.

 

[df2x4]

My red '97 did a similar thing to me once. It wanted to die idling at every stop light. In my case the cause ended up being a large crack in one of the vacuum lines. Replaced it and all was well. Might be worth checking for vacuum leaks if you haven't already.

 

[pmndlt]

Good suggestion @df2x4 I never paid attention to the hoses... Thanks!

 

[1989GMCSIERRA]

Hey all I’m absolutely lost. Had this truck for a couple months and have no clue how to get running right. 1988 C3500 5.7TBI. Bringing it home it died at every stop the SES light came on. Code 22.

Changed out the TPS, but realized as I removed it PO had installed wrong (tab was on wrong side of arm) reinstalled original TPS - code disappeared. Since then done: cap, rotor, plugs, wires, CTS, cleaned IAC and still runs like crap. Dies at every light.

Today I checked timing (properly with EST removed) and it was 8+ advanced. I set it 0 and now I can barely get it into gear before it dies.

Any suggestions? I don’t want to run advanced, hoping to be a daily driver and carry my TC for summer but so far can’t even get out of garage.

ALSO PO out a Throttle body spacer on it (no chip). Could this be the issue? Know nothing about them, can I simply remove without modification?

Thanks so much.

first thing I would do is make sure the distributor is stabbed in right. Pull the distributor cap. Ground the coil.
Crank bump the engine till the #1 is at TDC. the distributor should be pointing to the #1 cylinder. Yi7 could be off by one tooth and your timing will not be correct from your setting to what it actually is.

if the distributor is right put it all back together.

do this at night in a dark garage. Pop the hood and open it. Start the truck keep all the lights off. If you have any electrical or plug wires that are arcing to ground you’ll see the blue arc light.

you may have a vaccum leak. I used brake cleaner or carb cleaner. Spray lightly around hoses the manifold, the TBI base and if you have a vacuum leak you’ll see the truck stumble.

 

[Schurkey]

could be off by one tooth and your timing will not be correct from your setting to what it actually is.

Nope. Assuming the damper hasn't turned on the hub, the timing as shown by a timing light is correct even if the distributor is a tooth--or five--off of where it "should" be.

do this at night in a dark garage. Pop the hood and open it. Start the truck keep all the lights off. If you have any electrical or plug wires that are arcing to ground you’ll see the blue arc light.

Partially-failed plug wire insulation can create a faint "glow" even if it's not "arcing" to ground. This is called "Corona Effect".

Yes, it means you need new plug wires.

you may have a vaccum leak. I used brake cleaner or carb cleaner. Spray lightly around hoses the manifold, the TBI base and if you have a vacuum leak you’ll see the truck stumble.

DON'T use "brake cleaner".
1. Some "brake cleaners" aren't flammable; so they don't burn and won't change the idle speed

2. When some "brake cleaners" burn, they create phosgene gas, which can genuinely **** YOU UP. Maybe even kill you. If you don't die, recovery can take months. Phosgene is nothing to screw with. DO NOT TRY TO BURN BRAKE CLEANER, and don't use it to de-grease metal you're going to weld on.

Aerosol carb spray doesn't seem to have that Phosgene problem.

 

[kenh]

Phosgene gas is produced from burning a chlorofluorocarbon (refrigerant) Very few if any aerosols use any type of refrigerant as a propellant any more. Look at the can to see the ingredients. I know Oreillys and walmart branded brake cleaners use primarily methanol. Propane is a popular propellant these days.

FWIW... Back in the day a common leak test for refrigerant involved a propane torch with a long hose. You passes the hose near a suspected leak and watched for the flame to change color! All the while knowing what you were about to produce!

Ken

 

[1989GMCSIERRA]

Nope. Assuming the damper hasn't turned on the hub, the timing as shown by a timing light is correct even if the distributor is a tooth--or five--off of where it "should" be.


Partially-failed plug wire insulation can create a faint "glow" even if it's not "arcing" to ground. This is called "Corona Effect".

Yes, it means you need new plug wires.


DON'T use "brake cleaner".
1. Some "brake cleaners" aren't flammable; so they don't burn and won't change the idle speed

2. When some "brake cleaners" burn, they create phosgene gas, which can genuinely **** YOU UP. Maybe even kill you. If you don't die, recovery can take months. Phosgene is nothing to screw with. DO NOT TRY TO BURN BRAKE CLEANER, and don't use it to de-grease metal you're going to weld on.

Aerosol carb spray doesn't seem to have that Phosgene problem.

Brake cleaner shouldn’t be used for welding as welding heat is high enough to do as you stated. I’ve used carb cleaner before to find leaks. I also made a smoke machine for vaccum lines

as far as the timing I’ve always installed a distributor with the rotor pointing at #1 and piston at TDC. THENi adjusted timing *.

and yea I know about the Corona effect. That’s why I was telling him to do that. If he has a wire that’s just a bit cracked he will see it better than in daylight.

 

[LC2NLS6]

Also when checking fuel pressure, at idle it might be ok psi and keep up, but give it throttle to make sure pressure doesn't die off.