Possible Solution for the 89 Z24 random stall
MechEng1
11-28-2007, 07:40 PM
Instead of asking a question, I am offering a solution to some of the 89 Z24 2.8 Cav owners. My issues were stalling, stuttering, choking and the humpty jumpy thing while under normal driving. Here is what I did and it resolved 99% of the issues. Please read all the way to the bottom because you will never believe the last solution.
1. A REAL tune up, plugs, wires, modules, vac lines, fuel rail rebuild w/injector orings, intake clean, new fuel pressure reg, all visible sensors topside, fuel filter and idle adjust (torx and must bust cap to get to it).
Result: Slightly better, then worse than before.
2. Check all connections and ECM codes.
Result: Nada
3. New exhaust, complete with O2 sensor.
Result: Sounds good but no improvement for running.
New Problem: Will not start, dumps antifreeze and dies. Towed home and cranks but will not fire.
Solution: New oil pressure sensor, radiator, hoses and hotwire fuel pump to a switch. They are linked.
Next New Problem: Back to the herky jerky stuff, horribly fast idle and stalling randomly. Sometimes when taking off from stop sign or light and others while tooling along at 30 to 50 like it is choking.
Solution: Disconnect the TCC (blue connector going to trans).
Same Problem: Herky jerky stuff stops but stalls and chokes randomly like a "flat spot" in the accelerator.
Solution: Adjust idle valve Result: Still hesitates, stalls and chokes random.
The Fix: Believe this or not but from experience with Chevys since I was a teenager I know they are rather cold blooded. I lubed the EGR, adjusted the idle, got high grade gas with injector cleaner and tried something so very simple. Instead of letting it run for a minute or two I let it run until I had three bars on the temp gauge. The oil pressure leveled out at around half of the gauge without erratic movement and the drive was smooth with no stall or hesitation. There is something within the combination of the sensors and the ECM that it has to reach a certain temp before it will level out the system. Good luck guys! and gals :)!
1. A REAL tune up, plugs, wires, modules, vac lines, fuel rail rebuild w/injector orings, intake clean, new fuel pressure reg, all visible sensors topside, fuel filter and idle adjust (torx and must bust cap to get to it).
Result: Slightly better, then worse than before.
2. Check all connections and ECM codes.
Result: Nada
3. New exhaust, complete with O2 sensor.
Result: Sounds good but no improvement for running.
New Problem: Will not start, dumps antifreeze and dies. Towed home and cranks but will not fire.
Solution: New oil pressure sensor, radiator, hoses and hotwire fuel pump to a switch. They are linked.
Next New Problem: Back to the herky jerky stuff, horribly fast idle and stalling randomly. Sometimes when taking off from stop sign or light and others while tooling along at 30 to 50 like it is choking.
Solution: Disconnect the TCC (blue connector going to trans).
Same Problem: Herky jerky stuff stops but stalls and chokes randomly like a "flat spot" in the accelerator.
Solution: Adjust idle valve Result: Still hesitates, stalls and chokes random.
The Fix: Believe this or not but from experience with Chevys since I was a teenager I know they are rather cold blooded. I lubed the EGR, adjusted the idle, got high grade gas with injector cleaner and tried something so very simple. Instead of letting it run for a minute or two I let it run until I had three bars on the temp gauge. The oil pressure leveled out at around half of the gauge without erratic movement and the drive was smooth with no stall or hesitation. There is something within the combination of the sensors and the ECM that it has to reach a certain temp before it will level out the system. Good luck guys! and gals :)!
elca69
11-29-2007, 10:02 AM
Thanks....having the same symptoms in a 90, 3.1 Z-24 !!
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