Stalling TBI when braking & warmed up

[Woody Burban]

The trucks runs great till driven a few miles, already replaced: Coil, Distributor, Cap, Wires, Plugs (where pretty blacked up) then replaced EGR selenoid (was bad) MAP Sensor, Idle Air Control Valve, PCV, Coolant Temp Sensor and all vacuum lines with Rubber and zip ties.

EGR Valve and Throttle Position Sensor coming this week. May order Crank Shaft Position sensor and O2 sensor.

Cleaned TBI up and one injector drips with cone spray. Looks like plenty of fuel (not fuel pump). May order new injector bodies.

Any others ideas, I started out just trying to adjust the 700R4 TV cable to get it to shift lower, RPM was to screening before shifting into 2nd.

Any help would be great!
Woody

 

[WP29P4A]

There is a ground for the sensors or TBI electronics near the thermostat housing that is important. I cleaned and tightened it on my son's truck and we had fewer problems after. Might be worth checking.

 

[Woody Burban]

Thanks, I’ll clean up that one and the block ground strap another buddy said to check.

 

[Itali83]

Does it stall immediately when stepping on the brakes or like you forget to step on the clutch if it was a manual when almost coming to a stop? I’m wondering if your brake switch for the torque converter isn’t working and the converter isn’t unlocking and the engine stalls before the trans downshifts to first ( converter can’t hydraulically be locked in first even if a sensor or switch or solenoid is malfunctioning). The ecm also won’t allow converter lockup until coolant temp is above 140 so that could also be why it only stalls when warm. Just something to check and think about.

Ben

 

[gmbellew]

I was thinking torque converter as a potential culprit also.

 

[Woody Burban]

I’ll check out the brake switch, it started when I began playing with the 700r4 TV cable, it was shifting 1st to 2nd around 30 mph way to high in RPM. Reseting TV cable again to original position, so it could be the Torque Converter, it has a 3800 Stall torque converter in it.
Thanks
Woody

 

[Woody Burban]

I’ll replace the vacuum line to the brake switch too.

 

[Woody Burban]

Replaced the TV cable it was shot, replaced all emission controls, test drive in the morning!

 

[Woody Burban]

Still stalls out once it’s warmed up. I’ll check out the brake switch today. Definitely above 140 when the issue starts, rough idle and then stalls after braking. Torque converter makes sense. Will start right back up in P or N. Could TV cable adjustment cause this too? I’m trying to adjust outward and get the truck to shift 1st to 2nd below 25mph

 

[gmbellew]

the torque convertor should also unlock when you let off the gas or hit the gas. there is a range of TPS where it locks and everything outside that range should unlock.

but if it isn't the Torque Converter....

could be the wrong EGR. I had a replacement part that was listed for my 1990 V1500 tbi, but it operated differently. mostly that caused an off idle stumble.

I've had a lazy IAC before, but that has kept me idling high after running down the road.

it could be the dripping/leaky injector that is flooding it upon idle down? that is extra fuel the computer isn't accounting for

if it is only doing it warmed up, it is something computer controlled.

you may try and wiggle the harness around after it is warmed up and see if the idle changes. I did have an issue with weird currents causing idle issues when I had the TPS harness too close to the CTS and EGR solenoid harness. when I moved the harness, the issue went away.

I am not a 700r4 expert, but the 1-2 shift is almost always under 25mph. I think there is only 1 way to adjust the TV cable and I would review the GM manuals in the reference library to make sure it is right. I have heard a misadjusted TV will burn a tranny in a hurry.

and anybody with TBI would be well served with ALDLDroid and a Bluetooth tooth scanner for the OBD1 port to trouble shoot engine issues, especially closed loop engine issues

 

[Woody Burban]

Replaced the Ignition Control Module, was all rusted up. Fired right up, idling OK gonna try taking her for a ride tomorrow.