I just finished putting in my downpipe, intercooler, and new computer. I also recently did a vacuum hose job and also capped the aws hose that was connected to the intercooler elbow.

I started my car and its idling around 3k, and if i blip the gas it goes higher...like 3.5k, and it sticks there, it won't go down. What is the problem? do I need to adjust the idle screw because i added an intercooler, dp and capped the aws? Why would this cause the idle to be sooo much higher?

-mike

also, the computer is a pettit ecu

 

Check your throttle cable and make sure it's not kinked.

 

just checked the cable, doesn't appear to be kinked, a tiny bit curved near the **** thing, but nothing big

 

how was the idle after the hose job? OR did you do everything at once...idle really has nothing to do with the IC or DP. Nothing that would cause this problem.

 

Brake booster?

 

what kind of new computer did you install? did you set it up yourself or have someone else tune it?

 

i couldn't tell how the idle was after the hose job because I didn't hook up the map sensor right so it was a terrible idle...I decided to install the intercooler after I figured that out, so i don't know how it was right after the hose job...could it be a kinked hose?

its a pettit unlimited ecu, so i don't think that is the problem.

as for the brake booster, i checked it and its working correctly...blocking air in one direction, BUT, my brake is very hard to press

 

bump

 

Carb cleaner - standard vaccuum line tracing.

Don't smoke any cigarettes.

 

If your brakes are hard to press....then your not getting any vacuum assist for the brakes.

 

I'm not so much worried about the brakes...heres whats goin on so far

I just took out the manifold and put it back in, no hoses were kinked or blown off. So i started it again

At first it shot up to 2500rpm, then it would slowly rise, almost to 3500rpm (keep in mind i capped the AWS hose so it shouldn't be that high)

I decided to let it run for a few minutes to let it warm up to regular temps... After about 30 sec. The rpm's were rising slowly from 2700 to about 3500rpm. The engine didn't sound too bad, but it was almost searching for a normal rpm to settle at, and kept rising. So I shut it off and didn't let it warm all the way up. I'm going to do a compression test tomorrow just for kicks and see what it's like.

PLEASE HELP ME, i'm thinking right now either apex seal or a major intake leak, but i would think i would hear the leak...maybe adjust the idle screws??


Oh ya and vaccum was at a solid 15 at first, then by the last time i turned it on the vac was at 18...before i did all my upgrades i was getting a solid 20, but i figure that if i get up to operating temps that I would probably be around 20 again

 

It's not an engine internals issue. Definitely a vacuum line missing after the throttle body. FWIW, when I forgot to tighten down my vacuum source to my brake booster, my idle would sit right around 3000 rpms and the brakes became very hard to depress. Soon as I screwed it down properly...no more leak and 700~rpms idle

 

I would suggest that you follow jspecracer7 and clayne's suggestions.

Also, check your gaskets. I've seen a missing manifold gasket cause similar problems.

 

What do you mean by screwing down the brake booster? I've just checked the line with the check valve in it and made sure the other lines had the stock clamps on them, or are you just saying you put worm clamps on them and screwed the lines down?

Also, I started the car, it was reving at 2800, then it slowly climbed to 3300, at that point I sprayed Carb Cleaner around the UIM gasket and the car reved up fast to 3650rpms....would this tell me anything, its a brand new gasket in between the LIM and the UIM...I mean i did take the UIM out and put it back in with the same gasket yesterday, but i was having the problem before as well.

anyway, would my idle really just keep rising if its a gasket leak? **I haven't kept the car on long enough to determine if it will rise up to 4000rpm, but it seems like it would if i left it on for longer than a minute

 

Just a sanity check question, but you got both ends of this, right?

You have a vaccum leak somewhere. It might be obvious, it might not be. Check all of the obvious ones and then take off the UIM again if you have to. The hard brake pedal is probably a result of lack of stable vaccum actually - and may be unrelated to the brake booster line (which is probably fine).

 

maybe its your new computer
like the power fc will do.

 

I have that same problem after my vac hose job too.
Check this little green sensor thingy.

My vac was kinked and wasn't very noticiable. You will have to look at it from a angle to really see that it is kinked

or maybe when you install the new computer a wire must of have been cut? Loose ground causing a fried fuse.?
Cooked the idle controll valve?
Check these and see if theres something wrong with it.

 

check the tension on the throttle body cable, sometimes you can tighten it by accdient

 

I won't be posting again for a few weeks because i don't have time to work on the car until then, BUT
just have one question

i'm going to take off the manifold first and check the routes of every vacuum hose and make sure they are all correct. Then, if this does not work i'll start spraying gaskets with carb cleaner....question is

How high should I let this thing idle before I have my friend shut it down while I'm spraying? I mean it will go up to 2800rpms or so right off the bat and will rise to at least 3400 in under a minute, after that I'm not really sure what it will do because i haven't let it run long enough because i've been afraid of engine damage.
Is it fine to just let it keep running and get up to operating temperatures, or should I just spray fast and monitor the idle, then shut it off?

sorry for the questions, just don't want unneeded damage

Just thought of one more thing, How bad would it be to put in the stock fuel computer and test to see what happens, just incase something is messed up with the pettit? I mean, if i assume the idle will rise right up to 3500ish in a minute, will the stock computer cause damage? Just a thought

 

^sorry for the bump, its the last one, just want the questions just above this answered

Thanks!

 

make sure you check the cruise throttle cable at the cruise control box. The cable sheathing kind of comes out and just stuck out, like on a bicycle's brakes. Because mine did the same thing, right at 3500 rpm

M-P

 

Unless you are getting the carb cleaner in through the intake filter, the rise in the RPMs when spraying around the LIM/UIM is DEFINATELY telling you that you have an vacuum leak. Try putting a straw on the nozzle of the carb cleaner (like the little red one on a WD40 can) and spray VERY SHORT BURSTS around the outside on the UIM/LIM gasket. If the RPMs rise , you have located the point of leak. If none are found, spray a short burst around any exposed vacuum hose/nipple joints. Then spray under the UIM. Note any surges in the RPMs. If under the UIM, it'll have to come off again.


M-P has a good point too. I used the cruise bracket as a right hand rest when I did my fuel set-up. That cable will push down and stick so that when started your throttle is pulled. Make sure it is seated correctly.

 

when i'm sprayin though, how long should i let it idle, i mean its idling extremely high, should I just leave it on until i'm done spraying and have located what i think is wrong?...sorry i'm just alittle nervous leaving the car idling so high for more than a minute

 

Just pull the UIM off and re-check everything first.

 

another thing people do sometimes when replacing the UIM they screw the earth wire between the upper and lower manifolds where the gasket is, causing air to suck in and therefore raising the RPM