Can't figure out whats wrong

[LuminaMan93]

Ok so here's the deal. I have a 93 Lumina with the 3.1 and 4t60e. I have been having a lot of problems with it lately. The car idles really rough. When I come to a stop sign, it idles high then low to the point it stalls out. When I am driving, it is sluggish. Sometimes it wont start, just a click. I took it to my mechanic and he said it was the valve body in the transmission. That only fixed the starting problem. It starts fine now, but idles like crap. He put in a new IAC, but it still idles rough. I don't know if he did the idle relearn or not. I'm going to try it after work today. He said he didn't know what else to try.

 

I just recently replaced the,starter,altenator, and the battery.

 

I was thinking maybe it could be the crank sensor, ICM, or coils. I am going to replace them as soon as i get the time. Any ideas?

[Robby1870]

anything spark related is a good place to start.

[1990lumina]

I try the idle relearn just because it is a free fix, if indeed it works. However I'm gonna say it probab;y won't help.

 

Are you getting any SES lights/codes??

[LuminaMan93]

Nope, the SES light is not coming on, and the low volt light does not come on either.

I parked the car in front of a fence and watched the headlights dim and get brighter as the engine idled low then high.

[1990lumina]

Check the volts being put out by the alternator using a voltimeter or multimeter. A low voltage condition can cause wierd things to happen, both for electrical, and things mechanically that are operated by the ECM.

 

You should have a constant 14.4volts or at least 14 volts at idle. Put all the accessoryies on, the voltage should drop, then kick back up right away. If it doesn't this indicates something is wrong with the alternator, even if you just replaced it a coulpe months ago it could be the alternator.

 

Or maybe it is simple as a bad ground somewhere..

[LuminaMan93]

I'll check the volts when I get done work tonight, and i'll check to make sure that all the grounds and connections are good.

 

Also, the power steering leaking, it sprayed on the underside of the hood and on the coolant overflow resivour, most of that side of the engine bay. Do you think that it could cause the serp belt to slip and damage the new altenator, causing the problem. I'm going to fix the leak this weekend.

[GP1138]

I'll check the volts when I get done work tonight, and i'll check to make sure that all the grounds and connections are good.

 

Also, the power steering leaking, it sprayed on the underside of the hood and on the coolant overflow resivour, most of that side of the engine bay. Do you think that it could cause the serp belt to slip and damage the new altenator, causing the problem. I'm going to fix the leak this weekend.

 

Yes, the P/S fluid could definitely cause the belt to slip. I've heard of that happening numerous times before.

[1990lumina]

And if it is slipping that could reduce volt and amp output...plus if it got inside the alternator as well that could have messed something up

[LuminaMan93]

Thanks for your input guys. I'm gonna fix the power steering leak and probably get a new altenator and go from there. Hopefully that will fix the problem.

[bartonmd]

At the point of STARTING To troubleshoot, which is REALLY where you are, the thing to do it troubleshoot, NOT throw parts at it YET...

 

I've had cars run like you're talking about when 2 things were bad

1. O2 sensor

2. Mas Airflow sensor (Not sure if that car has a MAFS though, don't remember if it's speed/density or MAF)

 

FWIW, Sounds like your mechanic was just throwing parts at it too if the first thing he did was replace the IAC without checking/cleaning it first...

 

Mike

[Crimson Fury Z]

if its spraying from the top, check the hex nut that connects the rail hose to the top of the pump. mine was loose, but loose enough to have a good flowing leak.

[Hairdo12]

check the o-ring on the iac

[DaveFromColorado]

it honestly sounds like the intake manifold gasket -

 

most engines when ideling too low will not be able to charge the battery properly and or run the accessories ... what I don't understand is how can changing the valve body in the transmission do ANYTHING for the issue of a hard start.

 

Also, the battery + secondary terminal may be comming loose - perhaps when he changed the valve body, he ended up tightening this item up, and without realizing it, fixed that one issue.

 

I'm gonna say Intake Manifold Gasket on this one because it's got the classic symptoms - hard start - rough idle - unable to hold a steady idle - lack of power

 

I'd get the lower intake manifold gasket replaced - but I'd also find a new mechanic because the valve body in the trans should have NOTHING to do with the rough idle - he may have thought your converter was staying in "lockup" when you were stopping, but again that doesn't need a full new valve body, just a new TCC solenoid..

 

--Dave.

[LuminaMan93]

if its spraying from the top, check the hex nut that connects the rail hose to the top of the pump. mine was loose, but loose enough to have a good flowing leak.

I already tried that and it still leaks. So it 's leaking from somewhere else.

but I'd also find a new mechanic because the valve body in the trans should have NOTHING to do with the rough idle

I am never going back to him again. He has been good in the past, but this time he charged me $550 for nothing . The car still doesn't start sometimes and it is just like before I took it to him.

[Jcrow]

Check your grounds, The ECM is known to go bad. It could be a vacuum leak too

[GnatGoSplat]

I would pull the plugs making sure to make note which cylinder they came out of, and look for dark oily ones.

 

1 plug dark and oily = bad injector.

2 plugs dark and oily on the same coil = bad coil.

 

If all plugs look the same, I would check fuel pressure.

If that's okay, I would swap in a spare ECM (you can pick one up for $20 or less on Ebay).

[LuminaMan93]

Ok, so on Wed night after work I drove the car around the block. It stalled out at the bottom of my street, then it wouldn't restart. So I waited a couple minutes and it started up and I drove it back to the house. So I disconnect the battery and start taking the serpentine belt off cause I was going to take the altenator off and work on the power steering. My friend called me and told me he had a volt meter for the altenator, so I put the belt back on tighten everything back up, and reconnect the battery. The altenator was putting out 14.4 volts, so thats not the problem.

 

While I was doing that my dad called the mechanic back and he told us to drive it back and take him for a ride in it. So I reconnect the battery and take it over, it runs fine, doesn't stall and no rough idle. So I continue to dirve it for an hour, stopping at stops signs for awhile listening to the idle, shut it off and start it up several time and had no problems at all, so I'm like WTF? So for the last 2 days it has run perfect, except for the power steering. I don't know what happened, but I'm glad its fixed, for now:D