Chevrolet: 1988 Caprice - Stall, chevy caprice, quadra jet

Question
Keith,

I plugged the vacuum hose to the EGR valve and although it ran roughly as expected when it was at idle, the stall still happened in approximately the same manner.  Any other ideas?

Rob    
-------------------------
Followup To
Question -
-------------------------
Followup To
Question -
Keith,

We have a 1988 Chevy Caprice with the 305 V8 engine with the distinguishing VIN letter “H”.  It has a Quadra jet carb, AC and all of the options.  The plugs, wires, rotor, and cap were replaced in the last couple of years.  Its fuel pump is mechanical (original) and the car has 130,000 miles.  It stalls intermittently after it is warmed up.  It runs smoothly with plenty of power otherwise.  It is far less likely to stall when it is not moving so it is challenging to test.   I tried a new coil and ignition module in the distributor cap (I used plenty of dialectic grease); no change was detectable.  I have changed the fuel filter three times and although it helps, I suspect it is related to the natural cooling or something similar.

It feels like it takes a gulp of contaminated fuel when the problem begins and it typically stalls.  Trying to restart immediately sometimes works but it is a challenge.  When it has set for a few minutes, it is much easier to start.  The stalling is more frequent and I can get it to occur within 4 miles of the initial start.  The last time I got it to stall at home, I did not try to restart it for 15 minutes in an attempt to see if the fuel bowl had bad fuel; instead, it fired up instantly.  

I used a tester to verify spark, and it was strong.  Fortunately, I got it to stall when parked and was observing the tester which showed spark through the last engine revolution.  There is a clicking sound from the carb; specifically, it comes from what I think is the solenoid on the top side with the two wire all-weather connector lead.  I can hear it with the ignition on and the engine is not running.  The clicking stops after several seconds.  When I unplug the wires it stops clicking.  Unplugging the wires while the engine is running seems to have no effect; the engine ran normally.  Any suggestions are most welcome.

Thanks,
Rob      

Answer -
Hi Rob, Your problem may be in the lockup torque. I have seen this problem numerous times, Especially on older vechiles. And the torque only becomes active with a warm engine.The problem is that the switch becomes sticky and the torque stays engauged thus stalling out the engine. Try unplugging it to determine if this is the problem or not.There is a square plug on the transmission, under the car, unplug that and this will disable the switch. test drive the car to see if it is the problem. Let me know how it goes, Or if you need more help let me know. Thanks Keith

Keith,

That was an excellent idea and I tried it;  however, the same problem remains.  Do you have any other ideas?

Rob
Answer -
Hi Rob, Have you checked the EGR. system? Check to see if it is sticking or activating at the wrong time. I hope this helps, let me know how it goes. thanks, Keith.

Answer
Hi Rob, Your problem is hard to find, Especially when I cant see the car. Its been a long time since i worked on a carb engine. But i think you should have the carb checked to rule that out. Some of them v8,s have a computer that contolled the distrubtor find out if it has one and have it checked. let me know how it goes. Regards, Keith: