1993 'Burb Stalling Problem

Fryall4 · #1 05-30-2007, 05:41 PM

Hello I have a 93 Chevy Suburban, 4X4, AT, A/C, All Power. The problem has been going on for months now and over the past month, getting worse. The truck will stall out when stopped at a light in gear. It starts right back up every time. I have been dropping it into N lately but it has even started to die sometimes when I do this. I have 220K miles on the truck, 22K on the new motor, 19K on the new transmission (4L60E) and 1100 miles on the new rear end. No codes come up when the truck stalls and dies. I have changed the;
Fuel Filter
IAC (Idle Air Control) Valve
Cap, rotor, plugs
TCC (torque convertor clutch lock up) Solenoid

Checked for vaccum leaks
pulled the throttle body and cleaned it up (no bad carbon)

The truck runs great other then the stalling problem. The problem has been becoming worse as time goes on, and it seems like it is searching at idle for the proper rpm level. I guess I have to try the EGR valve and then the crank position sensor, maybe even the ignition control, but any advice or suggestions would be greatly appreciated. After the $1400 rear end and the tcc solenoid, money is quickly becoming an issue. Fry-

Fryall4 · #2 05-31-2007, 09:34 AM

I am going after the EGR valve today, does anyone have any other ideas of what I should try first?

Fry-

2000CAYukon · #3 05-31-2007, 10:24 AM

You don't have a crank position sensor.

Stalling on a TBI engine can sometimes be a weak pickup coil in the dist. You should also check for a worn dist shaft bushing (with the cap removed, can you move the shaft side to side).

On my 90 GMC truck, I found 2 vacuum leaks that helped the idle quality. In my case, it never stalled but the idle hunted up and down.

1st leak was the vacuum hose to the MAP sensor. 2nd leak was at the PCV gromet in the valve cover. The gromet had become hard and was not sealing well.

//2000CAYukon

Fryall4 · #4 05-31-2007, 12:27 PM

Ahh thanks 2KYukon, I would have sounded quite the fool asking for a CP sensor at the parts store. I will look into the pcv grommet...actually come to think of it, when I cleaned out the throttle body the other day I saw the tube going to the valve cover (driver-side) was broken and someone had put a small sleeve of rubber hose over it to connect the pieces. I figured it was good and didn't detect a leak there. Hmm

Fryall4 · #5 05-31-2007, 01:38 PM

Alright, just ordered an EGR valve and gasket, PCV valve and grommet. I will be installing them shortly with testing in between to see what the problem was if it gets cleared up. Cheers-

Fryall4 · #6 05-31-2007, 06:38 PM

Ok, it is a no-go with the EGR and the PCV valve. My truck did not have a PCV valve, it does now but did not help a thing. I replaced all the plug wires today with no help. Cleaned the connections on the battery, the ground near the battery and the ground on the intake manifold = Nothing. Checked the play in the distributor and I could not move it side to side. The only time I got it to run half way descent was when I unplugged the throttle position sensor. The rpm's were not right and the check engine light was on but at least it did not die in gear. Unplugging the MAP sensor did nothing to help.

What do you all think would be the next logical thing to check? Ignition Control? Computer? Thanks a lot, Fry-

Fryall4 · #7 06-01-2007, 12:25 PM

I am going after the Ignition Control Module today. I have been doing a lot of reading and some fingers point at this part as a possible culprit. After that I think I will go with the Coolant Temp Sensor, and then the coil. I figure new parts won't hurt. Fry-

2000CAYukon · #8 06-01-2007, 12:47 PM

Quote:

Originally Posted by Fryall4

I am going after the Ignition Control Module today. I have been doing a lot of reading and some fingers point at this part as a possible culprit. After that I think I will go with the Coolant Temp Sensor, and then the coil. I figure new parts won't hurt. Fry-

The pickup coil inside the dist can also go bad and cause a stalling problem. Something to think about when you go after the ignition module.

The ignition module converts the signal from the pickup coil from AC to DC. If the pickup coil is not giving the ignition module a good signal, the ignition module is not going to give a good signal to the ECM.

//2000CAYukon

Fryall4 · #9 06-01-2007, 04:00 PM

Thanks 2k, I'll pick up both parts today, give them a try and post back. Fry-

2000CAYukon · #10 06-01-2007, 05:00 PM

Quote:

Originally Posted by Fryall4

Thanks 2k, I'll pick up both parts today, give them a try and post back. Fry-

Just to let you know, you need to pull the dist and remove the shaft to replace the pickup coil.

//2000CAYukon

Fryall4 · #11 06-01-2007, 07:00 PM

2K It is really nice of you to help me with this, and yes, that was going to be my next question. I replaced the module, didn't help, and then was looking around trying to figure out how the heck to get the magnet and pickup off the shaft. Anyway, I am sure the neighbors appreciate me quitting for the day (my rear end was hanging out the hood, LOL). I will pull the distributor tomorrow and replace the coil pickup.
I read some stuff earlier today about a tan wire a guy disconnected (he has a similar problem) and it got his truck to run a bit better. While hanging out in my engine bay today, I saw a single tan wire with a connector near the fuses and relays (pass. side firewall). I disconnected the wire, and while the check engine light comes on and the idle is even lower then it was before it stays running and doesn't stall. Does anyone have an idea of what this wire is and what affect it is having on the runability of the motor? Fry-

2000CAYukon · #12 06-01-2007, 07:25 PM

Quote:

Originally Posted by Fryall4

2K It is really nice of you to help me with this, and yes, that was going to be my next question. I replaced the module, didn't help, and then was looking around trying to figure out how the heck to get the magnet and pickup off the shaft. Anyway, I am sure the neighbors appreciate me quitting for the day (my rear end was hanging out the hood, LOL). I will pull the distributor tomorrow and replace the coil pickup.
I read some stuff earlier today about a tan wire a guy disconnected (he has a similar problem) and it got his truck to run a bit better. While hanging out in my engine bay today, I saw a single tan wire with a connector near the fuses and relays (pass. side firewall). I disconnected the wire, and while the check engine light comes on and the idle is even lower then it was before it stays running and doesn't stall. Does anyone have an idea of what this wire is and what affect it is having on the runability of the motor? Fry-

The Tan wire is for setting the timing. Disconnect the wire, set the timing to zero and reconnect the wire.

When you disconnect the wire, all timing advance is stopped so it will not run as well.

I have an extra dist with a new pickup coil and module but you would have to drive to San Jose to get it.

Good Luck.

//2000CAYukon

Fryall4 · #13 06-01-2007, 11:20 PM

Ahh, I see. The truck did run pretty cruddy, but hey, no stalling. Is replacing the pickup a fairly straight forward job? I am pretty sure I can figure it out unless there is some wizzard of Oz, tap your heels type of stuff going on. Lol, I may take you up on that distributor if things go badly tomorrow, hopefully not, but I appreciate it.
By the truck not stalling with the wire disconnected, does that tell me anything? Is the ring covering the pickup coil supposed to spring forward and back because when I was in there I could physically move it but there was no spring action to speak of, maybe broken spring(s)? If it is indeed part of the advance I would have to think it was fine, wire plugged in the truck stalls but runs great off idle. The wire disconnected no stalling but runs mediocre off idle. Just swinging at the fences here. Thanks again, Fry-

2000CAYukon · #14 06-02-2007, 11:01 AM

I missed the fact that it does not stall with the EST Bypass disconnected. If the pickup coil was bad, it would probably stall even with the wire disconnected.

What is timing set at? This sounds more like a vacuum leak to me. The EGR solenoid and MAP sensor should hold a vacuum and the hoses should be inspected.

I found the MAP vacuum hose was not holding a vacuum and was part of my idle issues on my 90 K1500.

//2000CAYukon

Fryall4 · #15 06-02-2007, 02:20 PM

Hey 2K, well, as suspected I changed the pickup coil, the one installed was hammered, Ill try and post a picture. I reset timing (0 degrees with tan wire disconnected) and still have the same thing. I have the battery cable pulled right now waiting on the computer to reset, hoping this will help but will not hold my breath. Ill check and make sure 0 deg. is what it is supposed to be, Ill post again with my findings. Fry-

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