Question : Z34 Keeps dying

[LifefulDeath]

First off, I'm new... Hi.

Any way. I have a 92 Lumina Z34 that keeps dying. Thought it was the IAC. Replaced it and it still ran the same but it didn't die on me for about 2 weeks. Stuck mostly to the highway... Till today.

Once the engine is warm the voltage goes up and down. At night when I step on the breaks, the headlights will dim or even flash. Sitting in park and rolling up the window, the engine will slow or chug.

Battery is good. Guy who tested the alternator said it was working but might not be putting out enough.

Any input would be helpful.

Thanx

[GTP091]

First off, I'm new... Hi.

Any way. I have a 92 Lumina Z34 that keeps dying. Thought it was the IAC. Replaced it and it still ran the same but it didn't die on me for about 2 weeks. Stuck mostly to the highway... Till today.

Once the engine is warm the voltage goes up and down. At night when I step on the breaks, the headlights will dim or even flash. Sitting in park and rolling up the window, the engine will slow or chug.

Battery is good. Guy who tested the alternator said it was working but might not be putting out enough.

Any input would be helpful.

Thanx

I've had lots of vehicles throughout the years and my GTP did some strange things when the alternator went out that other vehicles did not. The Ignition Control Module is very dependant on having enough voltage to power the coils. I would say you are in need of an alternator. Test the voltage when you are operating your accessories with the engine running. The alternator should be able to keep the system between 14.4 and 12.5 volts. Any less and I'd think it's surely on the way out. Of course you want to check the main engine grounds but that's a given. Shops can't really test the amp output of an alternator accurately just the voltage which doesn't help much. Whatever you do don't pay a shop to change it they always list around 6-8 hours and say they need to do more work than is necessary. Get the part and we can give you the easy way. check this out>>

http://www.alternatorparts.com/cs130_&_cs130d_alt.htm

I have the 170 amp alternator....

[LifefulDeath]

Well, yeah. Guess that does make sense. I tested it with the engine running and turned on and off different things. Then turned everything on and pumped the brakes and the voltage would drop but without doing it while driving, it wont die. I don't remember the voltage drops but they'd go pretty low.

The grounds are good. They guy that had it before me must of had a good sound system in it. The battery has a second ground cable. Wouldn't think that would mess with anything now...

I do have a Kenwood CD deck with ipod usb. I've noticed without the ipod hooked up, it runs a little better.

So assuming it is the alternator. I should get either the CS-130 140 or 170 amp. Should I get the Internal standard or self exciting? Never replaced one with anything but stock...

Thanx again for your input!

[55trucker]

Sounds as tho your alternator has *pooped* a diode in the rectifier pack. This will see a significant drop in the output at engine idle because the alternator is spinning slowly but when you get the engine RPM up the alternators remaining good diodes can pass enough current (DC) to keep things running reasonably well. I agree with GTP's link....get the 140 amp (at least) the self exciting is really not needed because the alt. is wired for the field circuit thru the ignition. If you've never changed the alt. on a 3.4 DOHC it can be intimidating, but take your time and if your '92 has the remote blower motor for the alt. there is a coolant (air) hose that fastens to the back of the alternator to blow cool air on the rectifier pack to keep it from overheating given the alternators location.

[GTP091]

Well, yeah. Guess that does make sense. I tested it with the engine running and turned on and off different things. Then turned everything on and pumped the brakes and the voltage would drop but without doing it while driving, it wont die. I don't remember the voltage drops but they'd go pretty low.

The grounds are good. They guy that had it before me must of had a good sound system in it. The battery has a second ground cable. Wouldn't think that would mess with anything now...

I do have a Kenwood CD deck with ipod usb. I've noticed without the ipod hooked up, it runs a little better.

So assuming it is the alternator. I should get either the CS-130 140 or 170 amp. Should I get the Internal standard or self exciting? Never replaced one with anything but stock...

Thanx again for your input!

I recommended this alternator as it's only a little more expensive than buying a remanufactured alternator at a parts store. I liked the fact that they have better heat dissipation than standard which will make them last longer. I bought the 170 amp because I have two large amplifiers and wanted the extra output. A regular old 105 amp will still do the trick, but won't last as long. When you go to change it out don't drop the sub frame our lift the engine like GM says that's a load of crap, and why shops want 800 to change it out . A ratcheting wrench (12MM?) and pulling the axle is all you need to do.

[LifefulDeath]

Ok, so now the idle is floating...

At low speeds. Hitting the gas and letting off quickly, the idle will drop to about 500-600rpm. If it's been doing this for long enough it will die.

When warmed up and stopped in gear, the idle will sit around 600rpm. I thought it'd be around 1000rpm?

Now, the best ideas I've heard are the alternator, a stuck torque converter, or simply that the computer is shot.

Messed up thing is that I also have a 01 Grand Prix GT that I've been working on. I went out and started it up and warmed it up. Reving it up every now and then. Once it was warm I noticed that if I reved up above 3000rpm and let off quickly the idle would fall under the 1000 mark and the lights in and out would dim.

Feels like and alternator disease running through my garage!

[55trucker]

Just a question........do you have any codes set in the ECM?.(I'm referring to the '92 Z)..Not all codes will cause the SES to stay on permanently..if you don't have a scanner there is a way to *read* the codes via the SES light in the instrument panel. Remove the plastic cover from the ALDL connector under the drivers side dash panel....the 2 connectors to the far right on the upper row of pins are the diagnostic test pin and the ground. Using a paper clip you can send the ECM into test mode by closing this circuit. Turn the ignition to *run* do not start the engine) then you read the codes by watching the SES light flash. For example..a code 55 (ECM error) will flash...5 times then a short break..then 5 times again...Code 51 is MEM CAL error. Code 35 is Idle speed Control. Code 44 & 45 are O2 sensor (weak & and rich respectively) Code 13 is O2 sensor open circuit. The engine warm idle is in the range of between 700 - 850 (my engine idles at 725), 500 is a bit low, at that rpm the alt is not really turning fast enough to keep the field circuit closed to keep charging.

[LifefulDeath]

It's not throwing any codes... I think the alternator maybe be on it's way out but I'm not going to worry about that until it does. I'm pretty sure it's the torque converter sticking. The transmission fluid smells burnt and it wants to push forward when I hit the brakes.

I don't know if it's part of the problem but do these engines have really bad torque steer?

Also I've noticed that ever since I had my mufflers and part of the pipe replace, there's smoke coming out after I shut the car off. I wiped the inside of the tips and it was black and smelled sweet. Not like antifreeze though. Maybe I'm just paranoid and it's just road gunk and steam from melting ice...

[LifefulDeath]

It's the torque converter... Today on the way to work, I got off the highway and slowed down and just coasted. Then it tried to take off on me. Felt like I just slightly pressed the gas, but my foot was on the brake.

[55trucker]

The *stator* in your Torque Converter may have failed or the Lock-up may also be in question.... TORQUE CONVERTER DIAGNOSIS

The torque converter is the fluid coupling between the engine and transmission. If the transmission is making noise in gear, but the noise goes away when it is shifted into neutral, the problem may be worn needle bearings in the torque converter. Needle bearings are used inside the torque converter to separate the stator from the impeller, the stator from the turbine, and the turbine from the converter housing.</P>

Torque converters contain a one-way clutch. If the clutch jams and locks the stator (which normally keeps the stator tuning only one way), the converter cannot circulate the fluid properly between the impeller and turbine. The resulting turbulence inside the unit can cause a lack of power at highway speeds and may cause the engine to overheat during cruise conditions. A locked one-way clutch will also cause the fluid to run dangerously hot, which can damage the transmission and lead to transmission failure. ****If the one-way clutch fails to hold its position and freewheels in both directions, the torque converter cannot multiply torque normally and the vehicle will accelerate slowly (like starting out in 2nd gear)****. The only cure for either condition is to replace the torque converter. Most late-model automatics have some type of lockup torque converter to improve fuel economy. If the lockup fails to engage, there will be some slippage and fuel economy will drop. Causes here include a bad lockup solenoid, incorrect sensor input information to the transmission controller or PCM (typically a speed sensor) and hydraulic control problems. ******If the lockup fails to release, the engine may shudder and die when coming to a stop. Causes here include a faulty lockup solenoid, a sticking lockup valve, grounded lockup solenoid wiring or a missing lockup solenoid spacer plate screen.*****

[LifefulDeath]

Okay, I'm taking the car in on Monday. Most places I called wanted $650 to just replace the TCC and let me go. Guy I'm going to will inspect the outside of the tranny and wiring for free and quoted $545 for the TCC. He thinks it's more likely to be the solenoid.

I'm not sure if it's getting worse but the other day, going down the highway, the engine just bogged way down then revved back up, then down and then leveled out and the SES light came on. Hasn't done it since...

I do know the MPG suck! If I try to hold my speed (gas pedal has to be in just the right spot) the engine rocks. Like gentally pumping the gas. Back and forth. Stop and go traffic makes it stall. Engine has never gone over 180 since I've had it. It does accelerate like... poo.

I've been told to "Just unplug it". Guessing they ment the sensor but when the heck is it? Or would this help me at all?

[GMfan1111]

the computer could be shot but just to be safe I'd do a transmission flush and fluid change since you did mention that the fluid did smell like it was burnt alot of folks don't do that until it's too late and that can cause problems when it comes to shifting

[55trucker]

Well, be patient, go see this trans mechanic?, let him do the wiring diagnosis (he should be able to test the TCC remotely and also let you know what the recent SES code that was set is), ask him to inspect the fluid, ask him his opinion as to whether the fluid being in a burnt state (whether or not it is due to a failed stator or burnt trans clutches) is enough concern for further internal problems and can be rectified by just replacing the fluid along with a solenoid change.

[LifefulDeath]

Okay, I just got back from the trans guy and there is nothing wrong with my transmission and it's not the alternator either... The code it threw was an EGR code. I am at a complete lose now. Does anybody know the common issues that it could be?

Car's going in on Wednesday. Kinda want to know what I'm walking into.

[55trucker]

When the trans mechanic had his scanner on the car did he clear any(or all) of the previous codes that were set?....once a code is set, it won't necessarily re-repeat (flash the SES) itself it the code is already in the ECM. The ECM needs to be cleared of all codes so that if there IS a fault it will be reset. If the trans is clear and the problem is engine related only now you need to diagnose where the damned annoyance is....hope these charts may help you