Idle + Boost problem (already searched)
05-31-04, 11:40 PM
#1
Idle + Boost problem (already searched)
It's times like these when I understand why people say to do one mod at a time, so you can diagnose what you've done wrong lol...but oh well.
Here's what was done, in hopes it helps
- Installed Efini Y-Pipe + crossover pipe
- Changed airbox (M2 + hardpipes), which included disconnecting and reconnecting the BOV
- Switched out a polished TB for my existing TB
- Switched out AST for polished AST
- Installed HKS Twin Power
For the most part, everything went smoothly. The FIC on the TB had a crack in it, and was leaking coolant, so I figured now was as good a time as any to get rid of it lol. I basically took the hose that goes into the upper portion of the TB facing the firewall, and instead of connecting it there, I connected it to where the other hose at the underside of the TB feeds back into the coolant pipe. Figured that was the simplest and quickest way to bypass it. I also took off the FIC, and wired the flap thingy open on the TB (not sure what it's called).
After everything was done, I noticed the idle was too high (at 2000rpm). So we adjusted the TPS, and via the PFC, the voltage was correct. We backed out the throttle stop screw all the way, completely closed the TB air bypass screw, and made sure the ISC solenoid was connected.
We checked, double checked, and triple checked everything. It all looks good, nothing loose, nothing disconnected (from the stuff we touched). I don't think it's an intake leak in the LIM, since a) I have a 94 (i understand it's a prob in 93s due to the paper-like gasket), and b) we didn't touch the UIM or LIM.
The car ran SOLID after all the installs though...no probs at all. Didn't sputter, didn't stall. Everything was A-okay minus a high idle. Or so I thought.
On my way back home, I noticed it was making boost sluggishly (didn't notice earlier since the ground was wet, so I was takin it easy). Then later on into the drive, as I got into an area where it hadn't rained, I noticed a very noticeable hiss, very much like what you hear when the turbo on a big 18 wheeler is spooling up hehe. I'm serious. The hiss would be heard anytime I got to -5psi (vaccum), and got louder as I went into positive boost. I got on the throttle, and at WOT, I could only generate 6 psi once, and another time I tried it I managed to get about 8 psi. It just stayed there at 8 psi at WOT, for over 5 seconds, w/ a loud hiss the whole time. Once I back off, the BOV goes off, so it sounds like the BOV is working just fine.
I think that's about it...I think it's obviously a boost leak (not quite sure how that would make my idle high though). I'm hoping the symptoms plus how loud the leak sounds can tip someone off as to where it might be coming from...cuz otherwise I wouldn't know where to begin looking.
Thanks
EDIT: I also read on the forum that a good way to test for a boost leak is to spray some WD-40 or starter fluid around manifold and intake & boost plumbing, etc. Is this correct/would it help in my case? (And do I need to worry about something catchin fire? lol)
Here's what was done, in hopes it helps
- Installed Efini Y-Pipe + crossover pipe
- Changed airbox (M2 + hardpipes), which included disconnecting and reconnecting the BOV
- Switched out a polished TB for my existing TB
- Switched out AST for polished AST
- Installed HKS Twin Power
For the most part, everything went smoothly. The FIC on the TB had a crack in it, and was leaking coolant, so I figured now was as good a time as any to get rid of it lol. I basically took the hose that goes into the upper portion of the TB facing the firewall, and instead of connecting it there, I connected it to where the other hose at the underside of the TB feeds back into the coolant pipe. Figured that was the simplest and quickest way to bypass it. I also took off the FIC, and wired the flap thingy open on the TB (not sure what it's called).
After everything was done, I noticed the idle was too high (at 2000rpm). So we adjusted the TPS, and via the PFC, the voltage was correct. We backed out the throttle stop screw all the way, completely closed the TB air bypass screw, and made sure the ISC solenoid was connected.
We checked, double checked, and triple checked everything. It all looks good, nothing loose, nothing disconnected (from the stuff we touched). I don't think it's an intake leak in the LIM, since a) I have a 94 (i understand it's a prob in 93s due to the paper-like gasket), and b) we didn't touch the UIM or LIM.
The car ran SOLID after all the installs though...no probs at all. Didn't sputter, didn't stall. Everything was A-okay minus a high idle. Or so I thought.
On my way back home, I noticed it was making boost sluggishly (didn't notice earlier since the ground was wet, so I was takin it easy). Then later on into the drive, as I got into an area where it hadn't rained, I noticed a very noticeable hiss, very much like what you hear when the turbo on a big 18 wheeler is spooling up hehe. I'm serious. The hiss would be heard anytime I got to -5psi (vaccum), and got louder as I went into positive boost. I got on the throttle, and at WOT, I could only generate 6 psi once, and another time I tried it I managed to get about 8 psi. It just stayed there at 8 psi at WOT, for over 5 seconds, w/ a loud hiss the whole time. Once I back off, the BOV goes off, so it sounds like the BOV is working just fine.
I think that's about it...I think it's obviously a boost leak (not quite sure how that would make my idle high though). I'm hoping the symptoms plus how loud the leak sounds can tip someone off as to where it might be coming from...cuz otherwise I wouldn't know where to begin looking.
Thanks
EDIT: I also read on the forum that a good way to test for a boost leak is to spray some WD-40 or starter fluid around manifold and intake & boost plumbing, etc. Is this correct/would it help in my case? (And do I need to worry about something catchin fire? lol)
Last edited by FDNewbie; 05-31-04 at 11:58 PM.
06-01-04, 01:39 PM
#4
Originally posted by Scrub
I'm suprised no one else has said anything.
I'm suprised no one else has said anything.
It's weird cuz it seems like initially it was minor, but then it became a considerable and very loud leak...
I remember you told me your 94 had a paper gasket too...so I guess you never know. Is there any way to find out if it's the LIM gasket, short of removing the LIM, like using WD-40 or starter fluid or something?? (and if so, how?)
Last edited by FDNewbie; 06-01-04 at 01:42 PM.
06-01-04, 03:07 PM
#5
Track junkie
Check the two bolts on the Y-pipe to the crossover pipe. They probably have come loose due to the heat. Mine did the same thing. As for the idle I have had a similar problem for quite a while.
06-01-04, 03:30 PM
#7
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this sucks,
i'm pretty much having the same problem.....except my car is all stock, and its a 94 too, someone said they upgraded the gasket in 94? but i guess not? but people are telling me its probably my LIM gasket too. I get the worst boost, in certain gears i can get up to about .8 bar......but after the switchover i get nothing really, and i have an idle at about 1500 which just started a little while ago.
i'm pretty much having the same problem.....except my car is all stock, and its a 94 too, someone said they upgraded the gasket in 94? but i guess not? but people are telling me its probably my LIM gasket too. I get the worst boost, in certain gears i can get up to about .8 bar......but after the switchover i get nothing really, and i have an idle at about 1500 which just started a little while ago.
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06-01-04, 03:50 PM
#8
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the wd40 trick is good for a manifold (vacuum) leak. to test if it's a boost leak, hook you guage to the y-pipe and get a reading and then hook it to the uim and get a reading. with a stock ic, you should see about a 2-3 psi drop. if it's more than that, you have a leak between the turbos and the manifold. as for where to look, the first place to check is then couplers that hold the ic piping together. you should take them off and examine them by bending them since they can have a crack that is not visible when not under pressure. by bending the couplers any cracks will show up.
06-01-04, 11:27 PM
#9
Patfat, I'm going to check the two bolts tomarrow morning. When you say I'd hear the gasket leak...umm what am I listening for? Because like I said, anytime I hit -5psi (still in vaccuum!) or more, I can hear a large hiss...it's very VERY audible.
legal-z, I have a PFS SMIC. I suppose I can try taking off the couplers for the IC, elbow, and hard intake pipes...but that's gonna be a PITA.
Could I get these symptoms from a crack in a coupler to a hard intake pipe?? Cuz I remember I had trouble w/ one of them rubbing against the screw in a t-clamp and it might have compromised the coupler...
Looks like I got some work ahead of me tomarrow
legal-z, I have a PFS SMIC. I suppose I can try taking off the couplers for the IC, elbow, and hard intake pipes...but that's gonna be a PITA.
Could I get these symptoms from a crack in a coupler to a hard intake pipe?? Cuz I remember I had trouble w/ one of them rubbing against the screw in a t-clamp and it might have compromised the coupler...
Looks like I got some work ahead of me tomarrow
06-03-04, 08:29 PM
#10
K...lets see
The Good:
- took off the TB, plugged that coolant pipe that we had left (just in case)
- found out the boost leak was from a bad coupler going from the IC to the crossover pipe. fixed it, she's now running 13psi again, *strong*
The Bad:
-you know how the TB has screws coming out of it so the elbow can be fastened on to it? Well I was tightening a nut on one of those screws, when the screw snapped, so it's flush with the surface of the TB. I'd imagine that screw is welded to the TB, so you can't replace it, can you? This stupid TB (wasn't my original) has been giving me issues ever since I put it on... parts weren't working (TPS), other parts were cracked (FIC), etc...
The other option I thought about is since I'm always gonna have the elbow sitting on top of the TB, I can just find any screw, don't have to weld it in, and just run it through and secure it w/ a nut + open washer. Any thoughts?
- There's also a coolant leak. I can't tell exactly where it's coming from. There's coolant on that frame plate that the PFS SMIC bracket sits on (the underside of the IC), so the leak is from somewhere right around there. It's not the AST, I checked it. Don't see any coolant around the filler neck. All the other hoses look fine. I guess I have to take off the IC to check the lines running underneath it??
- Aaaand...I STILL idle at 2K rpm lol...I'm simply out of answers, my back hurts too damn much from bending over the car, and I'm pretty frustrated. Seems like I got a classic FD haha
The Good:
- took off the TB, plugged that coolant pipe that we had left (just in case)
- found out the boost leak was from a bad coupler going from the IC to the crossover pipe. fixed it, she's now running 13psi again, *strong*
The Bad:
-you know how the TB has screws coming out of it so the elbow can be fastened on to it? Well I was tightening a nut on one of those screws, when the screw snapped, so it's flush with the surface of the TB. I'd imagine that screw is welded to the TB, so you can't replace it, can you? This stupid TB (wasn't my original) has been giving me issues ever since I put it on... parts weren't working (TPS), other parts were cracked (FIC), etc...
The other option I thought about is since I'm always gonna have the elbow sitting on top of the TB, I can just find any screw, don't have to weld it in, and just run it through and secure it w/ a nut + open washer. Any thoughts?
- There's also a coolant leak. I can't tell exactly where it's coming from. There's coolant on that frame plate that the PFS SMIC bracket sits on (the underside of the IC), so the leak is from somewhere right around there. It's not the AST, I checked it. Don't see any coolant around the filler neck. All the other hoses look fine. I guess I have to take off the IC to check the lines running underneath it??
- Aaaand...I STILL idle at 2K rpm lol...I'm simply out of answers, my back hurts too damn much from bending over the car, and I'm pretty frustrated. Seems like I got a classic FD haha
Last edited by FDNewbie; 06-03-04 at 08:37 PM.
06-03-04, 09:11 PM
#11
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1. you're welcome (just kidding)
2. you can drill and tap out that screw in your t.b. let me know if you need more specific instructions on how to do that.
3. there are coolant hoses in the area you describe. before taking the ic off, take the undertray off and jack up the car. SECURE it with jackstands and start it. get under there and look. you will have a much better view of what's going on than you will from the top.
andy
2. you can drill and tap out that screw in your t.b. let me know if you need more specific instructions on how to do that.
3. there are coolant hoses in the area you describe. before taking the ic off, take the undertray off and jack up the car. SECURE it with jackstands and start it. get under there and look. you will have a much better view of what's going on than you will from the top.
andy
06-03-04, 10:53 PM
#13
Andy, thanks lol.
If I drill and tap out the screw in the TB, how do I replace it? Do I have to get one welded in like the one I'm trying to remove, or can I just run one through the hole and not worry about it?
I looked underneath the car w/o lifting it (from the side), and the coolant was dripping down the middle of the radiator I believe...to the right of the coolant drain plug in the radiator (when you're looking through the front airdam). Then I looked around the IC, and I saw some coolant dripping off the left front edge of the IC (again, when you're standing in front of the car), so I knew it had to be higher than the radiator. I just couldn't see any coolant (or coolant lines for that matter) above that point, so I concluded it's prob a leak from one of the lines right under the IC, and it's spraying a little onto the edge of the IC, hence the dripping off it's edge.
As for the idle adjustment screw, this was one of the first things I did... (see below)
~Ramy
PS...oh yea, Andy, you also forgot one more step after jack up the car, start it, and get underneath: get burned by hot coolant lol
If I drill and tap out the screw in the TB, how do I replace it? Do I have to get one welded in like the one I'm trying to remove, or can I just run one through the hole and not worry about it?
I looked underneath the car w/o lifting it (from the side), and the coolant was dripping down the middle of the radiator I believe...to the right of the coolant drain plug in the radiator (when you're looking through the front airdam). Then I looked around the IC, and I saw some coolant dripping off the left front edge of the IC (again, when you're standing in front of the car), so I knew it had to be higher than the radiator. I just couldn't see any coolant (or coolant lines for that matter) above that point, so I concluded it's prob a leak from one of the lines right under the IC, and it's spraying a little onto the edge of the IC, hence the dripping off it's edge.
As for the idle adjustment screw, this was one of the first things I did... (see below)
Originally posted by FDNewbie
After everything was done, I noticed the idle was too high (at 2000rpm). So we adjusted the TPS, and via the PFC, the voltage was correct. We backed out the throttle stop screw all the way, completely closed the TB air bypass screw, and made sure the ISC solenoid was connected.
After everything was done, I noticed the idle was too high (at 2000rpm). So we adjusted the TPS, and via the PFC, the voltage was correct. We backed out the throttle stop screw all the way, completely closed the TB air bypass screw, and made sure the ISC solenoid was connected.
PS...oh yea, Andy, you also forgot one more step after jack up the car, start it, and get underneath: get burned by hot coolant lol
Last edited by FDNewbie; 06-03-04 at 10:57 PM.
06-10-04, 02:44 PM
#14
OK...good news is I believe the coolant leak is taken care of. Now the stupid idle...
Am I correct in saying that my idle prob could simply be from a popped off vaccum hose? Cuz if so, I'm gonna try that brake cleaner spray stuff...see if I can find a vaccum hose leak...
I just don't understand how a vaccum leak would raise your idle...
Am I correct in saying that my idle prob could simply be from a popped off vaccum hose? Cuz if so, I'm gonna try that brake cleaner spray stuff...see if I can find a vaccum hose leak...
I just don't understand how a vaccum leak would raise your idle...
07-10-04, 12:14 PM
#15
I just did the pulley install, hose job, new plugs, new FPD, and balanced the injectors. I have the same idle problem. I wonder if it is related to the pulleys? It runs at about 1500 rpms and I have tried the idle screw adjustments with no luck. I am interested if anyone else has a solution for this problem?
07-10-04, 12:21 PM
#16
Well my idle problem turned out to be 2-fold....
1) a VERY finicky TPS...
2) the new TB I had installed...apparently when it was polished, it was taken apart and reassembled in a way that the blades weren't closing all the way...so it kept the idle high no matter what...
Also, I found a vaccuum leak by spraying brake cleaner right on the TB and elbow junction...bad gasket!
1) a VERY finicky TPS...
2) the new TB I had installed...apparently when it was polished, it was taken apart and reassembled in a way that the blades weren't closing all the way...so it kept the idle high no matter what...
Also, I found a vaccuum leak by spraying brake cleaner right on the TB and elbow junction...bad gasket!
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