1G idle revs up and down park and neutral need help

[91gsdohc]

i have a 1991 gs 2.0l dohc and when im at idle in park or neutral my rpms rev up and down when i bought the car the guy said he replaced the fuel pressure reg but instaled the turbo one and said that was the problem but while he was saying that he pointed to the camshaft angle sensor (i dout that has anything to do wit the idle but wanted to put that in there just incase) do you guys thing those things could be the problem or do you think i should just replace the IAC

 

[2gGSXEclipse]

i have a 1991 gs 2.0l dohc and when im at idle in park or neutral my rpms rev up and down when i bought the car the guy said he replaced the fuel pressure reg but instaled the turbo one and said that was the problem but while he was saying that he pointed to the camshaft angle sensor (i dout that has anything to do wit the idle but wanted to put that in there just incase) do you guys thing those things could be the problem or do you think i should just replace the IAC

Can you give us more information? Whats the low idle and whats the high idle. When does it do this. How often does it cycle from low to high.

 

[91gsdohc]

does this all the time when cold its around 2000 to 2500 and warmd up around 1000to1500 and im not sure what you mean by cycle but it revs constently its never in one place at one time

 

[wowzers]

I got the same issue... I was told its the EGR so I replaced that then It didnt fix it so someone told me to replace the IAC sensor

 

[ilco187]

sounds like you need to do a fiav adjustment - http://www.dsmtuners.com/forums/articles-intake-exhaust/320951-fiav-adjustment-disable.html

 

[9!'clipseDOHC]

I have the same car, a 1991 Eclipse GS 2.0 DOHC, except mine is a manual. It used to do the same thing that you are describing except only when it was cold. When it was cold at idle it would rev up and down, very annoying. I blocked off the FIAV and the rev went away but I still wasn't happy with the idle so I ended up blocking off the whole lower portion of the throttle body, FIAV/ISC, and now I am happy.

However, if yours continues to rev even after it warms up then it is most likely something else. I can see a turbo fuel pressure regulator causing a problem like this. The turbo version came with larger injectors and therefore most likely a different pressure regulator. This would cause your car to run very rich. If your computer is reading too much fuel it will cut it causing your idle to drop, then it would build back up until it again hit cut causing a revving effect.

As far as your camshaft position sensor, that adjusts your timing and will effect idle as well as drivability. It would be a good idea to make sure that your timing is set to the factory specs.

I would replace your fuel pressure regular first. You can get a new factory OEM fuel pressure regulator for $84 from JNZ tuning, or hit up a local junkyard and see what you can find. Then I would get the timing checked or check it yourself if you have access to a timing light and a paper clip.

I hope you find this helpful!

 

[91gsdohc]

so just a quick question that i didnt get an answer on even if the guy replaced the fuel perssure reg and put the turbo one on instead of the non turbo has nothing to do wit that problem?

 

[9!'clipseDOHC]

See my above post, yes that is most likely your problem. There are different fuel pressure regulators or the the 1.8, the 2.0, the turbo a/t, and the turbo m/t. You need the correct fpr for your car.

 

[91gsdohc]

thanks but how much would it cost to see if the timming is correct?

i posted that b4 i saw ## post

and thanks that does sound helpfull exp. sine u had the same car and same problem kind of but ill try that and then see whats good

 

[9!'clipseDOHC]

If you have a paper clip and can borrow a timing light you can do it yourself for free. It is very easy and you can find detailed instructions by searching on here or by flipping through your haynes/chilton repair manual (if you don't have one... get one. Best $15-20 you can spend on your DSM.)

As far as taking it to a shop... i don't know. Never taken it to a shop for that but it can't be too much. It is a very easy job.

 

[91gsdohc]

how easy would replacing the FPR be and could you tell me the location and thanks much respect

 

[9!'clipseDOHC]

It is bolted onto the driver's side of your fuel rail. There are two bolts holding it on. Very easy to replace.

You must be logged in to view this image or video.

Found this picture in the galleries, that is your fpr. Photo belongs to B0oSteD95gsx.

 

[91gsdohc]

thought so just wanted to make sure thanks good looking out on evry thing ill post something up when im done

 

[91gsdohc]

i wanna add some thing so i was driving home to day the engines cold im in drive and i i had my foot on the brake a lil not all the way down but then my rmps startd surging took it off it stoped then put my foot back on the brake the way i had it and it did it again and then again stoped after i took it off.... alll this was happing as i was moving

 

[firefighter]

Before you begin check for vacum leaks. sometimes this causes idle surge problems.Most of the time the problem lies within the throttle body.Start by removing the throttle body. Get some throttle body cleaner and clean the inside of the throttle body.Check the gaskets. For about ten bucks I would replace the gaskets to the intake side of the manifold also I wouldreplace the BISS O ring.You can get that from the dealer. If you don't have the rubber cap to cover the BISS screw I would get one. Check the gasket on on the FIAV.Take the TPS off and check that as well.If you haven't,get a copy of the haynes manual this tells you how to check the TPS and the ICS. Remove the ICS motor and clean inside the throttle body housing more than likley there will be a lot of buildup.The only other gaskets that could use replacing could be the O rings on the throttle body shaft.All the information that you need to rebuild the throttle body is conttained on this site.For the gaskets and cleaner you can do this job for about thirty five bucks. Good luck to you hope this helps..

 

[turbotalon31]

i would point to a bad iac motor unplug it and see if it stops .

 

[casperfast]

had the EXACT same prob on my buddies car..... TPS throttle position sensor was bad, put on and adjusted new one.... ALL GOOD

 

[91gsdohc]

had the EXACT same prob on my buddies car..... TPS throttle position sensor was bad, put on and adjusted new one.... ALL GOOD

how easy of a job would this be to do myself?

 

[BIRDCLAWTSi]

unplug the idle air control valve and see if it stops lopeing. it it does, that is the problem. try to un-plug it when it is at a low point and see if it will stay low. if it does wait till it is warmed up to operating temprature and use the biss to set the idle where it needs to be. i did the same thing on my n/t and it runs fine like that. when it is cold you may have to give it a little gas till it warms up but it will not throw a check engine light. i took mine off on my TSi and blocked it with a plate... the right way to do it? maybe not to some, but i think it is fine. i dont know how far from danbury ct. you are but if you are ever in the area let me know and i will fix it for you. good luck.

 

[91gsdohc]

unplug the idle air control valve and see if it stops lopeing. it it does, that is the problem. try to un-plug it when it is at a low point and see if it will stay low. if it does wait till it is warmed up to operating temprature and use the biss to set the idle where it needs to be. i did the same thing on my n/t and it runs fine like that. when it is cold you may have to give it a little gas till it warms up but it will not throw a check engine light. i took mine off on my TSi and blocked it with a plate... the right way to do it? maybe not to some, but i think it is fine. i dont know how far from danbury ct. you are but if you are ever in the area let me know and i will fix it for you. good luck.

im over in westchester ny not that far