91LuminaEuro Posted February 20, 2010 Report Share Posted February 20, 2010 (edited) Ok, so here is my problem, the car idles like crap probably 60% of the time... At time the idle jumps rapidly, from say 400rpm-1000rpm (and it stalled today when it did that) Usually the jumping happens after it has just been started... I've checked for vacuum leaks, the injectors are all good, PCV is good, throttle body, i've changed everything (other than plugs & wires) and nothing seems to help.. The idle seems better when the heat/AC is on.. I have no idea what the hell this could be...im thinking is it possible the fuel pump is intermittent/weak? I just need some advice, my dad and i are at a loss for ideas.... Edited April 3, 2010 by 91LuminaEuro Need help ASAP, plans have changed i cant get rid of the car.. Quote Link to comment Share on other sites More sharing options...
WhatTheFehl Posted February 20, 2010 Report Share Posted February 20, 2010 I know this is a stupid question but you didn't post this specifically so I gotta ask... Did you check the TPS? Quote Link to comment Share on other sites More sharing options...
91LuminaEuro Posted February 20, 2010 Author Report Share Posted February 20, 2010 Yes sir, i kid you not we tested, and or replaced EVERYTHING we could think of. The only other options are the Fuel Pump or the computer....that i can think may cause this. Which is why i asked for help, hopefully some one can give some insight on what may cause this... they always say when you work on something for so long to step away and have some one else look at it, because after so long you overlook stuff... Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted February 20, 2010 Report Share Posted February 20, 2010 So, it idles like crap and doesn't throw a code? Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 20, 2010 Report Share Posted February 20, 2010 when's the last time an idle learn was done? Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted February 20, 2010 Report Share Posted February 20, 2010 I'm actually having a similar issue as of late, only my car will bounce between 500 and 800 rpm nonstop while in idle. Its very repetitive, precise, and predictable. How does one do an idle relearn? Quote Link to comment Share on other sites More sharing options...
91LuminaEuro Posted February 20, 2010 Author Report Share Posted February 20, 2010 Correct, it idles like this and throws no codes. The idle bouncing was kind of a guestimate, i know that my idle i believe on avg sits at around 500rpm, and i know it goes over 1000 when it bounces, and at least 400. And mine is never predictable, it may be fine for a week or more and then one day its horrible. As far as an idle learn, im not sure, im with xtreme, what does that entail? It may have been done and i just dont know because my dad says "do this" or we do something and i never actually know what it is. The car also gets horribly wretched MPG when it acts like this. Quote Link to comment Share on other sites More sharing options...
rockfangd Posted February 20, 2010 Report Share Posted February 20, 2010 Did you change the o2 sensor? o2 sensor can cause these problems, especially fuel economy drop. Your fuel pump pressure should be around 50 with key on engine off and 37-43 psi with engine on Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted February 20, 2010 Report Share Posted February 20, 2010 if you don't have access to a Tech 1 or better, then this is the manual way of doing it. Quote Link to comment Share on other sites More sharing options...
91LuminaEuro Posted February 20, 2010 Author Report Share Posted February 20, 2010 Sweet! I'm headed to my dad's shop today, maybe we'll give that a shot! Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted February 21, 2010 Report Share Posted February 21, 2010 Well I fixed my problem. Replaced the IAC and did an idle relearn. The moment I started the car and put it in drive after disconnecting the battery, the car threw an SES code 341 for an intermittent camshaft sensor. I cleaned the MAF sensor, tried it again, and now the idle only fluctuates 50-80 rpm. Quote Link to comment Share on other sites More sharing options...
91LuminaEuro Posted April 3, 2010 Author Report Share Posted April 3, 2010 Ok, so this problem hasn't gone away, and i really need some help guys. My original plans were to get rid of the car this summer and get something newer, well long story short, i've got two handicap parents, my dad is going to need a hip replacement this summer, and my mom..who knows but im gonna have to help my dad at his shop as much as possible and money is going to be even more tight that i have ever expected, so i need to get this thing running perfect so i can stop worrying about it. Here are some details: 1991 Lumina Euro 2 Door. 3.1l Jasper Engine installed in 2005 -New Injectors, New Throttlebody -New Plugs & Wires -Prom & Computer replaced Everythign electrical has been changed & replaced, basically everythign except the entire engine has been looked at or replaced. Here is the problem, -Sometimes when you start it, it will start, and then just die instantly, and you can do this several times before it will spit and sputter and then catch its breath and run, but runs really badly. If you give it some gas and bring the RPMS up it will somewhat even out, but even then it doesn't run great. -With the A/C off, it idles a little low and kind of rough, if you turn the A/C on it will even out and run a little better. -And every now and then if it starts the first time, the idle will jump irradically all over the place, until you bring the RPMs up and it will again kind of even out -Most of the time the idle is somewhat rough, not really bad but not what it should be.. I really need some help getting this thing to run right, my dad and I are at a loss and i just need the car runnign good, once its running good im gonna psned $30 on spray paint and masking tape and spray bomb her black and have a decent car for a while.. So please...help... Any/All suggestions are helpful, just dont tell me to replace the car...i have one possible option with replacing it but id rather get it running right.... Quote Link to comment Share on other sites More sharing options...
jeremy Posted April 3, 2010 Report Share Posted April 3, 2010 were you ever able to replace the IAC and do the idle relearn??? Quote Link to comment Share on other sites More sharing options...
91LuminaEuro Posted April 3, 2010 Author Report Share Posted April 3, 2010 IAC had been previously replaced and didn't fix the issue. We also did an idle re-learn months ago with no change... And i spoke with my dad, and the Idle Re-learn didn't seem neccisary (again) because the problem is not constant, its intermittent...so if it were in need of an idle re-learn it would act strange like this all the time.. Quote Link to comment Share on other sites More sharing options...
Jonpro03 Posted April 3, 2010 Report Share Posted April 3, 2010 My tgp idles very roughly as well. I've replaced icm, coils, plugs, wires, iac, o2, injectors, topend gaskets, and I checked for fuel in the fpr vacuum line. Oddly enough on my car when I do an idle relearn, it will idle perfectly during the relearn. Then when I start driving the car the idle will go bad again. It would run high when moving and then when I'd come to a stop, the idle would drop suddenly and the idle was very rough, to the point it sounded like a cammed chevy big block. It turns out that IAC valve is doing its job, the ecm is telling it to open when moving and slam shut when i come to a stop. To fix my idle, I did another relearn. When it would even out and sound normal, I get under the hood and unplug the IAC valve. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 3, 2010 Report Share Posted April 3, 2010 When it would even out and sound normal, I get under the hood and unplug the IAC valve. while that could work decently, you would probably need to give it throttle while starting in colder than normal conditions... and it may idle too high in hotter than normal conditions.... but the ECM will retard/advance spark to attempt to meet the desired idle speed if the IAC alone can't do it... Quote Link to comment Share on other sites More sharing options...
91LuminaEuro Posted April 3, 2010 Author Report Share Posted April 3, 2010 Where should I look for causes, im seriously at my witt's end...i've tried EVERYTHING i can think of..... Quote Link to comment Share on other sites More sharing options...
Jonpro03 Posted April 3, 2010 Report Share Posted April 3, 2010 You should get an idea of what you're fuel pressure is. Is the fuel pump original? Also, a bad fuel injector will cause all sorts of hell. I had a bad one in my tgp when I got it that was just barely spitting any fuel out. One cylinder was running lean, so the ecm would add fuel. So I would have 5 cylinders running rich and 1 cylinder running lean. Quote Link to comment Share on other sites More sharing options...
91LuminaEuro Posted April 3, 2010 Author Report Share Posted April 3, 2010 Fuel pressure is fine, all the injectors are new, and we've done bleed down tests on all of them. So if there was a fuel pressure problem it would have shown itself there. The fuel pump, im un-sure if it is orignal or not...its probably been replaced at some point....i guess there is a possibility that it could have intermittent issues? Quote Link to comment Share on other sites More sharing options...
Jonpro03 Posted April 3, 2010 Report Share Posted April 3, 2010 When my fuel pump went on my 96gp, the car would either start and run, or not start at all. Eitherway, the next time it starts to act up... hook up a fuel pressure gauge and see what you've got Quote Link to comment Share on other sites More sharing options...
White93z34 Posted April 3, 2010 Report Share Posted April 3, 2010 Have you replaced the ICM/coils at this point? Quote Link to comment Share on other sites More sharing options...
91LuminaEuro Posted April 3, 2010 Author Report Share Posted April 3, 2010 Yes and yes Quote Link to comment Share on other sites More sharing options...
91LuminaEuro Posted April 4, 2010 Author Report Share Posted April 4, 2010 Ugh, so talking with my dad today i think we're gonna trying cleaning the IAC and seeing what that does...i know we just did stuff with it when we did the UIM but it seems like the most logistical thing to do... Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted April 4, 2010 Report Share Posted April 4, 2010 Ugh, so talking with my dad today i think we're gonna trying cleaning the IAC and seeing what that does...i know we just did stuff with it when we did the UIM but it seems like the most logistical thing to do... want to record the Torx size necessary to pull it off? i'm planning on doing it to the GP myself and i have no idea what size it is... Quote Link to comment Share on other sites More sharing options...
Crazy K Posted April 5, 2010 Report Share Posted April 5, 2010 injectors done? check please do a fuel pressure test. my 93 vert had hard start issues when warm... while I never did get an actual fuel pressure test, I did replace the pump which seems to have alleviated the issues that car had(although the car has not been driven since). TIP: Next time the car won;t start, open the hood and remove the shrader cap from teh fuel rail. wrap the area with a rag and press the valve. How much and how high did it shoot? if you have what I think you do you are going to get vapor, or just a dribble out. yes... I am suggesting vapor lock. also, have you done a compression check? Quote Link to comment Share on other sites More sharing options...
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