87 tbi stalls at lights and shifting in gears. Unless timing disconected.

[spooky]

hey yall, i have an 87 silverado with 305 tbi 90k miles all stock except recently added msd 6a and open air filter. Rebuilt maddog stage 2 700r4 w/ shift kit 3k miles old. Since i bought it it will stall when running temp when stoping and when shifting into gear.. gotta gas it a lil to keep it running. Unpluged timing advance wire and it runs amazing. Just surges a lil at idle. Thats how im driving it now. But its killin me cause i know it aint right. Took to my local mech and he went over and over for a week. Replaced intake mani gasket various sensors. Timing and lots more. was an 1100dollar bill he ate cause he just couldnt figure it. Please help. Anyone had or fixed this? Thanks.

 

[Jims86]

hey yall, i have an 87 silverado with 305 tbi 90k miles all stock except recently added msd 6a and open air filter. Rebuilt maddog stage 2 700r4 w/ shift kit 3k miles old. Since i bought it it will stall when running temp when stoping and when shifting into gear.. gotta gas it a lil to keep it running. Unpluged timing advance wire and it runs amazing. Just surges a lil at idle. Thats how im driving it now. But its killin me cause i know it aint right. Took to my local mech and he went over and over for a week. Replaced intake mani gasket various sensors. Timing and lots more. was an 1100dollar bill he ate cause he just couldnt figure it. Please help. Anyone had or fixed this? Thanks.

Do you get a check engine light when the advance connector was hooked up?

 

[Swims350]

egr can cause this from what I read online, but many others as well, like IAC, or maybe even TPS. Maybe weak components in the dist. such as pickup coil, and ICM or ignition control module.

so basically you have tons of things to check or need checked.

 

[Stroked]

egr can cause this from what I read online, but many others as well, like IAC, or maybe even TPS. Maybe weak components in the dist. such as pickup coil, and ICM or ignition control module.

so basically you have tons of things to check or need checked.

^What he said.

My '90 K1500 would do that when I first got it. I had to replace the IAC and the EGR valve to cure it.

 

[spooky]

ok thanks,I took it to a reputable mechanic and he said he put on a new egr,hopefully the corect one. and all sensors. And swaped his dizzy in and still did the same. Even tried his throttle body. Were stumped.

 

[austinado16]

Try to prove what it's losing.

Sometimes if you can't find the cause of something like this, or the failed part, you have to come from the opposite mindset....sort of diagnosing backward.

So to start off, is it losing fuel or spark?

If it fires right back up, you know it's not spark (at least it's a real good indication that it's not spark).

If it only does the problem once it's warmed up, you know it's not spark (again....or at least it's a good indication that it's not spark related).

When you write in for help, take extra time to be very clear about the description. Use words and phrases/sentences that convey exactly what's going on. It helps others help you faster, and more accurately.

For example, here's what would be better....

It runs fine when cold, but once up to operating temurature, it'll die unless I give it gas when stopped for a traffic light or stop sign. It accelerates fine, and is fine and normal running down the road.

Anyway, back to your issue.

Let's say that it's a fueling issue. That can mean 2 things a) it's not getting enough fuel b) it's getting too much air

So if we're pursuing this line of thinking, what controls the amount of fuel that the engine gets at idle? More importanly, what controls the amount of fuel that the engine gets once it's warmed up? Engine coolant temp sensor that feeds the computer, the wiring from that sensor to the computer, the Oxygen Sensor, it's wiring, the TPS and its wiring, the fuel pump, the fuel filter.......etc.

Same thinking process for what controls the amount of air getting into the engine, and in this case, you also think about what's attached to the intake manifold that can leak air into the engine. EGR valve, IAC, Brake Vacuum Booster, Dash vent controls, transmission controls, PCV valve, etc.

My suggestion would be to set the ignition timing to factory spec, hook up the timing wire, and then pursue the issue. You may have a failed computer, and that's why, when the timing wire is hooked up, the engine runs so bad. I'd certainly get on ebay and buy a computer for it and use it to test and rule out, or cure the problem. Same with the oxygen sensor if it's not been replaced, or the new one is some cheap China junk

 

[Jims86]

I have to ask, did your mechanic check the computer for trouble codes? this should always be the first step.
You can also use the diagnostic tool to watch what is going on while someone drives the vehicle.
If you can, I would suggest removing the MSD ignition system, until this problem is figured out.

 

[spooky]

ok thanks all i will replace the computer and o2 sensor next. Doesnt look changed to me. And run all the sensors back to comp checking for shorts. Cause iv had a couple shorts. So it could be wiring. Duh didnt think of that. Thanks

 

[spooky]

also when timing wire is conected. no check engine light. And i get code 12 doesnt that mean comp is working properly?

 

[89Suburban]

also when timing wire is conected. no check engine light. And i get code 12 doesnt that mean comp is working properly?

Are you running the diagnostic process? If so, if it flashes a constant 12 code then there are no other codes stored. Each code will flash 3 times.

If it flashes a code 12 WHILE THE ENGINE IS RUNNING/DIAGNOSTIC TERMINAL NOT GROUNDED/TIMING WIRE CONNECTED, then there are no distributor reference pulses going to the ECM.

As far as checking that actual health of the ECM itself, I have no idea how that is done, but would like to know myself.

 

[spooky]

oh ok. I get the code 12 when key on motor off. With a paper clip. I had a vss code after installing new trans. But the speedo is a lil fast so i thought it was the speedo gear change. But it went away somehow. Trans was shot so i thought it was a lock up issue. But now im clueless. But gonna chang the o2 and see. hate those things!!! Oh and thanks again.

 

[Jims86]

oh ok. I get the code 12 when key on motor off. With a paper clip. I had a vss code after installing new trans. But the speedo is a lil fast so i thought it was the speedo gear change. But it went away somehow. Trans was shot so i thought it was a lock up issue. But now im clueless. But gonna chang the o2 and see. hate those things!!! Oh and thanks again.

computer is fine.
Maybe clean the Idle Air passage if its a stalling issue.
Do the cheap stuff first. I would get rid of the MSD crap first, and run stock until you figure out whats up.
Maybe get a throttle body rebuild kit with new injector filters.

 

[spooky]

I swaped the tb with a friends good running tb and it still does it.. And gets better mileage wt the msd. 19ish. cant understand that good of mileage wit the timing wire unpluged.

 

[Jims86]

I swaped the tb with a friends good running tb and it still does it.. And gets better mileage wt the msd. 19ish. cant understand that good of mileage wit the timing wire unpluged.

What is your timing set at with the wire unplugged?

 

[spooky]

retimed to factory. 0