unclehotte Posted July 19, 2008 Report Share Posted July 19, 2008 Hello. I have two similar problems with two different cars. The first one: Cutlass Supreme 1992 3.4 I fixed fuel pressure regulator and IAC. Car still likes to idle up to 2000 rpm when cold. And when I say cold....its over 90 degrees outside. I just checked MPGs end get 14 mpgs, just city driving. I assume (or hope) that I still have a bad temp sensor causing the bad mpgs. I was told it was under the Throttle body. I couldn't find it. Can somebody tell me more exact??? The second car: Buick regal. 1993 2.8 SAME PROBLEM. Where is the temp sensor on this engine? My books dont help me. Here I also replaced the FPR, not the IAC yet. Do you all agree the sensors might be my problem???? Thanks for your help. Quote Link to comment Share on other sites More sharing options...
birdman Posted July 19, 2008 Report Share Posted July 19, 2008 well on the 3.4, if i remember correctly its at the bottom of the thermostat housing (follow the radiator hose on the right side of the motor) and its kinda at a 45 degree angle pointing downwards. really easy to replace i did mine a few years back. Quote Link to comment Share on other sites More sharing options...
ns87 Posted July 19, 2008 Report Share Posted July 19, 2008 Let me know if that helps at all. I have the 2000 RPM warm up idle all the time too. Once I drive about 2 minutes it goes away Quote Link to comment Share on other sites More sharing options...
w-bodys_are_the_best Posted July 19, 2008 Report Share Posted July 19, 2008 pics: 3.4, this is all on the driver's side under the TB, pics are of my motor that's already out of the car: Here's some shots of my 90 3.1 in my Cavalier Z24, but all 3.1's and 2.8's should be the same or pretty close. You have a 2.8 in a 93 Regal? Was the 3.1 replaced? Anyways it should be the same. The first one is the ECM temp sensor, the one you want to replace. I replaced both because my Haynes manual told me the ECM was the back one, but the back on is for the guage. I am including it though because I thought I read that some 2.8's had them back there, it will give you the 2 places to look anyway. This one is under the TB, and threads into the thermostat housing, you're going to need an 18 MM and ALOT of patience. You can see it alot better once the rubber tube is off. Here is the back one, it threads into the rear head, and is down by the exhaust manifold. You will see a green wire coming from it. hope this helps, let me know if replacing the sensors helps. My Z24 fan quit working, so I replace both sensors, fan relay and fan motor, and it still didn't work, so I ended up wiring it to a relay and switch. Make sure you use thread tape on the threads that red stuff that usually is on the threads of the new sensors is anti-galling compund NOT thread sealer. Quote Link to comment Share on other sites More sharing options...
unclehotte Posted July 19, 2008 Author Report Share Posted July 19, 2008 oh man....I am stupid. The Buick HAS a 3.1 engine. I dont know why I wrote 2.8. Both have the original engine and the Buick just rolled over 100.000. Thanks for all the replies. Those pics will help me for sure. Lets see if I can get rid of those last problems now. Quote Link to comment Share on other sites More sharing options...
Andrew Posted July 19, 2008 Report Share Posted July 19, 2008 high idles until warm are usually vacuum related. on the 3.4, its commonly the lower intake gaskets, but could be a plethora of other things too. Quote Link to comment Share on other sites More sharing options...
unclehotte Posted July 19, 2008 Author Report Share Posted July 19, 2008 Since I had a shop replace the fuel pressure regulator on the cutlass........wouldnt they have replaced the lower intake gasket,too??? Or is this not related? Quote Link to comment Share on other sites More sharing options...
ManicMechanic Posted July 19, 2008 Report Share Posted July 19, 2008 high idles until warm are usually vacuum related. on the 3.4, its commonly the lower intake gaskets, but could be a plethora of other things too. X2...That fixed my 3.4. FPR has nothing to do with intake gaskets. Quote Link to comment Share on other sites More sharing options...
jake63 Posted July 22, 2008 Report Share Posted July 22, 2008 high idles until warm are usually vacuum related. on the 3.4, its commonly the lower intake gaskets, but could be a plethora of other things too. X2...That fixed my 3.4. FPR has nothing to do with intake gaskets. Right, the fuel rail is on top of the lower intake, so they would not have removed it. I agree if the problem goes away when warm that it's gasket related because gaps get closed when metal expands. My 3.4 will stay at high idle indefinitely if I don't restart it several times until idle is normal. Then, after a while, the idle will fluctuate and stall. Not trying to hijack, just putting this out there in case you're having the same issue. Quote Link to comment Share on other sites More sharing options...
Drummer Posted July 22, 2008 Report Share Posted July 22, 2008 my 3.4 also had a high idle around 2000 rpms for a while before the intake gasket failed and antifreeze started pouring out over a hot engine. Scared the crap outa me thats for sure. Quote Link to comment Share on other sites More sharing options...
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