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View Full Version : Help with my 3.1L Lumina


Lando Griffin
05-25-2004, 08:49 PM
About 3 weeks ago, it started skipping out once the engine got hot (driving 85mph for 45 minutes.) Then once I slowed down it died sometimes, in a seemingly random way.

Driving home from work the other day my car just died while driving normally, for fear of making the problem worse. I couldn't get it started again, so I had it towed to my storage unit, where all my tools are. Thinking it was a coil pack, I hooked a spark plug up to an old wire I had laying around (since the wires in my car are such a bitch) and tested both points on each coil pack. Getting good spark from all of them. Next, I pulled a spark plug and it was black as hell, so I went down to Oreilly and bought 6 new plugs and wires. It still idled rough, so we checked fuel pressure, which showed as a constant 38psi.

On the way from there to 280Z28's house, which is down the road, my car was jerking really bad under any sort of load (i.e. acceleration), and having a tough time idling too. Sam went and bought some fuel injector cleaner, and we dumped that in at his house (thinking the injectors were sticking, thereby killing the engine and blackening the plugs). I started it up and let her idle outside his house while we ate dinner. It idled for a good 30 minutes straight, so I thought the problem was fixed.

Then, on the drive home, it would get REALLY rough under any load (acceleration from a light, out of a turn, etc.)

I don't even know what to try. Something tells me it's a sensor somewhere mis-reading something, thereby causing the engine to miscalculate the mixture. It idles fine now, but won't drive.

Advice? :help:

DrEvyl
05-25-2004, 08:59 PM
I would look at stuff like the mass airflow sensor and IAT sensor first. Those would affect how the computer calculates the mixture. In fact the MAF would probably be a likely culprit.

Dunno anything about Luminas, though.

kanwisch
05-25-2004, 09:18 PM
Have you tried the w-body forums (http://www.w-body.com) already? Start with the Search, and then post up if you don't see anything. Good crew of people.

Will I get in trouble for directives to other forums on here? j/c.

Whitey
05-25-2004, 09:34 PM
Originally posted by kanwisch

Will I get in trouble for directives to other forums on here? j/c.

if it is to help the user you should be ok...

Fallacy
05-25-2004, 09:38 PM
I would think Emission stuff at first but let me tell u a little story about my truck. Same problem, heated up would stall on me and stuff, and finally just ran super rough and nothing I did could get it to start. Replaced egr, plugs, wires, coil, rotor and cap nothing...


Pulled the valve cover off and looked down and saw my timing chain guard broke off and put some massive slack in the timing chain. just giving u an idea.

DrEvyl
05-25-2004, 11:57 PM
Originally posted by kanwisch
Will I get in trouble for directives to other forums on here? j/c.

The rules say..

Mentioning another site for reference or as an information source is acceptable but direct solicitation aimed at our Members to bolster some other site's Membership is inappropriate and subject to Moderator disciplinary action.

Merovingian
05-26-2004, 06:15 AM
www.60degreev6.com If the people on that site can't help figure it out, the idiots at the W-Body forums won't have a clue! LOL :D

Merovingian
05-26-2004, 06:16 AM
Originally posted by DrEvyl
I would look at stuff like the mass airflow sensor and IAT sensor first. Those would affect how the computer calculates the mixture. In fact the MAF would probably be a likely culprit.

Dunno anything about Luminas, though.
91 Lumina = MAP. :)

BP
06-15-2004, 06:07 AM
I'd pull the vacuum line off of the fuel pressure regulator to make sure it's not leaking fuel.

However in my opinion the most likely cause of this problem is an internally shorted coolant temperature sensor, easily tested with an ohm meter. If so the pcm thinks it's -34 degrees outside, causing the engine to run super freakin rich.