Silentkillzr Posted May 9, 2012 Report Share Posted May 9, 2012 Im making a new thread for this. My grand prix has been having surge issues as i was talking about in this thread. Anyway here is todays current update of what my car seems to be doing. First of all to give you a low down, i got the car and it had a high idle issue, rev'd up to 2500 on start and slowly went down to 1500, A tb gasket and tb cleaning fixed that issue, idle is dead on pretty good now warm and cold, motor revs up fine without load (not driving) cold or hot. My temp gauge seems to not work properly i suspect that is because from looking under the hood it appears the PO wired the gauge into the temp sensor on the tstat housing. So the tstat housing temp sender feeds both pcm and gauge, which isn't right there's supposed to be one on back of head IIRC. The problem with it now is after its been driving for about 2-5 minutes it start surging on light throttle. It sucks off the line so i have to get into the throttle to get it to go. But today i noticed something, once the car got pretty warm (i think, not sure if gauge is accurate) the problem seemed to be gone, not sure if it was a fluke or something but yeah. When you turn the key to on without starting the temp gauge should read accurately correct? If it helps my drivers side fan is on when i start the car and i think all the time its on.. Anyway thanks for reading guys your a great help! Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 9, 2012 Report Share Posted May 9, 2012 ..... if the guage is wired into a 2 wire temp sensor, that is a significant problem. it NEEDS to be connected to it's 1 wire sender. if it's connected to a 3 wire temp sensor, assuming all 3 wires are matched correctly, that's not a problem. Quote Link to comment Share on other sites More sharing options...
Silentkillzr Posted May 9, 2012 Author Report Share Posted May 9, 2012 Heres a picture of the temp sender on the tstat, wiring is ridiculous. Never seen anyone write on the intake when the gaskets were done, thats a new one for me lol: Overall motor picture: Quote Link to comment Share on other sites More sharing options...
skitchin Posted May 9, 2012 Report Share Posted May 9, 2012 That temp sender looks a bit nuts - the electrical tape makes me think there's almost no way you're not going to have a problem. Also, not important but you could probably tuck your wires a bit better. Don't have a full engine bay shot, but here's a partial Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 9, 2012 Report Share Posted May 9, 2012 yeah, pull all the tape off, see what exactly they did, because that looks screwed. much better to have the ECM at least know the actual coolant temp and have a non functional gauge than to have both be wrong. Quote Link to comment Share on other sites More sharing options...
revnrob Posted May 9, 2012 Report Share Posted May 9, 2012 My 95 GP only has 2 wires, Yellow and Black from that sensor Quote Link to comment Share on other sites More sharing options...
Silentkillzr Posted May 9, 2012 Author Report Share Posted May 9, 2012 Yeah... I am going to tuck everything nicer next time i work on it. Clearly the PO did not know the right way around a GM. lol... I am pretty sure the temp gauge only reads accurate when the car is off but key in on position. Where is the temp sensor for the gauge again and what color wires run to that? Quote Link to comment Share on other sites More sharing options...
revnrob Posted May 9, 2012 Report Share Posted May 9, 2012 Try in the C100 connector, Position G2, I think it's a dark green Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 10, 2012 Report Share Posted May 10, 2012 it does eventaully hit the C100 connector, but starts off from a little "stud" on the backside of the head. if it's not present, then it sounds like the heads at least were swapped from a 96-up engine, since 96 did away with the dual sensors and used a single 3 wire or 2 wire sensor, depending on the application. Quote Link to comment Share on other sites More sharing options...
Silentkillzr Posted May 11, 2012 Author Report Share Posted May 11, 2012 (edited) I am checking this out today, ill get back to you guys with results and pics thanks fellas UPDATE: The sensor turned out to be a 3 prong temp sender, dont worry about two yellow wires, the one is spliced into the green on the harness to the temp gauge. Apparently they wanted to use yellow instead of any other color... regardless i cleaned up the connections and the temp gauge seems to work better, car runs better now, no hesitation really. Now the car still surges, im going to flush the trans and do the fuel filter and see what happens. Am i correct that there is no MAF on my car/motor? Also i did not see a sensor on the back of the heads. Edited May 12, 2012 by Silentkillzr Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted May 12, 2012 Report Share Posted May 12, 2012 If your "surge" is actually the transmission hunting for the right gear, you likely have a bad throttle position sensor....you mentioned a 2500 RPM idle before, then it seemed OK, if you have access to a scantool, I'd bet you're going to find a bad spot in the TPS, which confuses the ECM about throttle position, which causes it to do weird things to the transmission, because it's not sure what driver demand is, due to bad information. It might not be your problem, but a strong possibility. Quote Link to comment Share on other sites More sharing options...
Silentkillzr Posted May 12, 2012 Author Report Share Posted May 12, 2012 If your "surge" is actually the transmission hunting for the right gear, you likely have a bad throttle position sensor....you mentioned a 2500 RPM idle before, then it seemed OK, if you have access to a scantool, I'd bet you're going to find a bad spot in the TPS, which confuses the ECM about throttle position, which causes it to do weird things to the transmission, because it's not sure what driver demand is, due to bad information. It might not be your problem, but a strong possibility. Yes but it has a new TPS sensor, just put on less than a week ago. Quote Link to comment Share on other sites More sharing options...
skitchin Posted May 12, 2012 Report Share Posted May 12, 2012 I've heard a bad brake switch can also cause it to do this - in my car it was like overdrive would engage and then disengage rapidly. Various things were replaced on my car but I think it wound up being a bad ignition coil that caused it. Quote Link to comment Share on other sites More sharing options...
Silentkillzr Posted May 12, 2012 Author Report Share Posted May 12, 2012 I've heard a bad brake switch can also cause it to do this - in my car it was like overdrive would engage and then disengage rapidly. Various things were replaced on my car but I think it wound up being a bad ignition coil that caused it. ill check that out thanks man. Can someone take a pic of their 95 gp engine bay with a 3.1... I'm pretty sure im supposed to have a MAF but there is not one existent on my setup.. Haynes manual shows a maf but there isn't one on mine, Shows it before the airbox. Dont see any wires just chilling so im lost. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 12, 2012 Report Share Posted May 12, 2012 93-95 3100 W-bodies do NOT use a MAF. Quote Link to comment Share on other sites More sharing options...
Silentkillzr Posted May 13, 2012 Author Report Share Posted May 13, 2012 93-95 3100 W-bodies do NOT use a MAF. Alright i figured as much. Still trying to nail this issue down. Plugs/Wires changed last fall, idk about coil packs. Quote Link to comment Share on other sites More sharing options...
skitchin Posted May 13, 2012 Report Share Posted May 13, 2012 I'd check for any obvious signs like cracks. Not really sure if any misfires register in the computer with this issue - though if it does you could probably figure out which coil based on what cylinder was misfiring. Beyond that I think the only for sure way might be to test with a new/known good module one by one. Quote Link to comment Share on other sites More sharing options...
Silentkillzr Posted May 13, 2012 Author Report Share Posted May 13, 2012 Alright thanks for the advise. I found my original window sticker in the car today though! lol Quote Link to comment Share on other sites More sharing options...
Silentkillzr Posted May 16, 2012 Author Report Share Posted May 16, 2012 (edited) Update: i had the car on a snapon scanner today, It displayed just about every code i think it could. I tried clearing with absolutely no luck. I saw fuel stuff, o2, temp sensor, MAP sensor, all voltage stuff, and most important that caught my eye was "Internal ECM Failure" So i am gathering my ECM is fried causing all these codes to show up and make it run like crap? Edited May 16, 2012 by Silentkillzr Quote Link to comment Share on other sites More sharing options...
AL Posted May 16, 2012 Report Share Posted May 16, 2012 I would agree with that... Good thing a PCM is a dime a dozen at the JY Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted May 16, 2012 Report Share Posted May 16, 2012 ..... you shouldn't have that many codes getting triggered. remove the battery fuse for the ECM for a few minutes, replace it, then scan without starting the engine. you shouldn't have many, if any, codes set. Quote Link to comment Share on other sites More sharing options...
Silentkillzr Posted May 16, 2012 Author Report Share Posted May 16, 2012 Codes are still there, no change. Quote Link to comment Share on other sites More sharing options...
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