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Username Post: 89 Cavalier V6, seeking advice        (Topic#354228)
Chew N Tobacca 
Poster
Posts: 17

Age: 36
Loc: Idaho
Reg: 05-14-14
12-05-18 05:21 PM - Post#2753528    

Hi all,

Searching for suggestions on my Cavalier. It's an 89 Z24 with the 2.8 V6 and 3-speed automatic (THM125C). Picked it up last year and have been fixing it up; somebody hack-and-slashed a bunch of stuff on it, and went through almost the entire engine. Finally got it running, now trying to figure out where I'm having stalling problems. Took it out for a decently long drive over the weekend, hoping it would smooth out after being driven a while. Plenty of low-speed accelerating and decelerating, as well as a bit of highway speeds. Didn't seem to change anything. To put it out there up front, I do use v6z24.com as a main source of information (though there's not much activity there any more). Thought I'd check with some of the experts here before I take the next step...

Here's the symptoms I'm experiencing. 1.) Starts right up without trouble, idles fine, but seems like it has an occasional miss until it starts to warm up. 2.) Will sit at idle as long as I let it. Once it warms up, idles nice but dies when you put it in gear, unless you give it two right feet to help the throttle. Such is the case in any forward gear or reverse. 3.) Seems like it takes exceptionally long to get to operating temp and the cooling fan to cycle on. My 96 Suburban with the Vortec 350 warms up considerably faster, which doesn't seem right. 4.) It does hesitate slightly when you mash on the throttle, but picks right up. 5.) Not throwing any codes to the ECM.

And the huge list of things I've done to it. I'll list mechanical parts as well as electrical. I have replaced: Timing chain and sprockets; oil pump with drive shaft and pickup screen; tranny fluid and filter; water pump and pulley; thermostat; nearly all the hoses and belt; thoroughly cleaned the entire intake including upper and lower manifolds and throttle body (which I took apart and cleaned and replaced the gaskets and o-rings); PCV valve; entire new air intake from the filter box to the throttle body. All the corresponding gaskets have also been changed.

There's probably more, but I'll start on the electrical side. Of the components I've replaced: MAP sensor; idle air control motor; temp sensor; oil pressure sender; the one fuel injector that didn't meet specs; TCC (lockup) solenoid; alternator and battery (checked all my cables, connections, and grounds); and of course, plugs and wires. All three coils and the ignition module were replaced shortly before I got it, as was the crank position sensor. I've also attempted the idle relearn as suggested by v6z24.com, but is difficult since it won't idle in gear.

I'm still struggling to figure out what's up. If any of you guys or gals have any ideas, any at all, I'm open for suggestions. Thanks for reading my long post, and thanks in advance for any feedback.

-Chew



 




Shepherd 
Frequent Contributor
Posts: 1555

Loc: Lake George, NY
Reg: 11-11-15
12-07-18 05:22 AM - Post#2753713    
    In response to Chew N Tobacca

Pretty tough to give any meaningful advice here, but, if stable idle is your base problem, check your tps setting at idle, should be about .5v also check the base idle set screw adjustment, both of these can skew idle stability. The ecu's back then were very unreliable, try tapping the ecu with a screwdriver handle when warmed up, see if the engine stumbles. I assume you have a 195t stat? Have you looked at whether the engine is going into closed loop?



 
Chew N Tobacca 
Poster
Posts: 17

Age: 36
Loc: Idaho
Reg: 05-14-14
12-07-18 05:25 PM - Post#2753790    
    In response to Shepherd

Thanks for your reply. I have not checked the TPS voltage, will do that. I have jiggled and wiggled the ECM (not banged on per say), with no change in anything. Yes, the thermostat is a 195. As far as checking for open/closed loop, how do I know for sure without a scantool or diagnostic equipment? I would imagine I would be triggering a code to the ECM if it were not?

Thanks again,
-Chew



 
Shepherd 
Frequent Contributor
Posts: 1555

Loc: Lake George, NY
Reg: 11-11-15
12-08-18 04:20 AM - Post#2753827    
    In response to Chew N Tobacca

Diagnostics back then were not very good. You need a basic obd1 scanner to look at this, should be plenty around, as most of these cars are gone.



 




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