Stalling / misfire after UICP

[TurboLaserRS]

I installed a uicp that I bought off a guy here on tooners. I switched to the 2g throttlebody elbow at the same time. For some reason now when I come to stop lights the car starts to stutter. The rpm will swing up and then just die. Sometimes if I push in the clutch rolling to a stop it just dies then too. But sometimes I come to a stop and it idles fine?? I'm really confused. I've gone back and tried to find anything unhooked and I don't see anything.. could the two vacuum lines that go on the top of the throttlebody accidently getting switched do this? I just don't understand what changed. If you give it throttle and keep it running it runs great, hits boost awesome..and spool up is super loud now.
And sorry for any confusion. This new tapatalk is terrible!

 

[kayosfrawg]

Have you gone through to make sure there are no leaks at the TB elbow and new UICP? My gut says a part is moving and so its leaky part of the time and not others. I'd also verify you got all the vacuum lines in the right places, anything you touched go over it again. I might even pull everything back out and then redo the install taking my time and being really cautious.

 

[GPTourer]

I like how you dis the site, while on the site...

Anyway, yeah it is acting like it has a major boost leak or BOV is VTA. Just have to go back over everything and make sure its tight.

 

[11Banger]

Like everyone else said you probably have a massive boost leak going on.

 

[TurboLaserRS]

The only thing I can think of is that the recirc line is at too radical of an angle? I'm running a 2g injen intake stuffed in with the uicp, and the recirc hose is at a pretty nasty angle.

Also, who dissed the site? I love this site. I just wish the new tap a talk update for my anchient phone wasn't so glitchy.

 

[TurboLaserRS]

Okay so, besides a pinhole leak, my setup is pretty solid. I unhooked my recirc hose, and plugged the intake. I started the car and it was running horrendously, I ran to the front of the car quickly and put my hand over the 1g BOV, and the car returned to a normal idle. I pulled my palm off the valve and the car kicked sputtered and died.
I'm thinking this has something to do with the way the recirc is routed. I will attach pic in a second.

 

[kayosfrawg]

Sounds like it might be a leaky BOV, and as long at it recircs to somewhere behind the MAF you should be okay.

 

[GPTourer]

Also, who dissed the site?

I installed a uicp that I bought off a guy here on tooners.

I never thought of "tooners" as a term of endearment.

Looks like it would have to be something to do with the BOV. The problems you have are exactly what my car does whenever I fool around with the intake or UICP and I leave something loose or undone.

 

[TurboLaserRS]

I've taken everything apart literally 5 times now. I had a jenk a$$ coupler. I got a new coupler in there, everything is tight now but it's still doing it!! I'm getting really pissed at the car.

Today when trying to drive I noticed if you decel with the clutch in sometimes the car just poops out. But if you decelerate with the clutch engaged and it's doing this, the car bucks wildly.
Also sometimes when I'm driving I do hear a very high pitched whistle sound, but it's not under boost or decel. It's when I'm just maintaining a speed at maybe 10% throttle. So that points to the blowoff valve I think.
Oh and now it's throwing an intermittent check engine light, usually when it's idling around 500rpm before it dies. I checked the local auto parts places and they said they can't read the code because OBD1 doesn't store codes, which I'm pretty sure is a load of bull.

The only other thing I can say is that it does not do this cold. When you start it up, it idles fine, comes to stops fine, etc. But at some point in driving when the car is warmed up it just craps out at damn near every light.

 

[kchaazz]

What blow off valve is installed at the moment? If its the stock bov, it is normal for the car to run like poop when the bov isnt recirced because the 1G bov actually hangs open under vaccum. Take the blow off valve off of the upper pipe and verify that the gasket is good AND that the flange on the pipe does NOT have two extra bolt holes in it. If the flange on the pipe has two extra bolt holes in it, it is what is known as "dual" flanged, meaning that you can bolt on either a Greddy bov, or the factory 1G bov. The problem is that if you do not plug the two holes intended for mounting a Greddy bov when using a 1g bov, you will leak like hell out of the other holes and your car will run just the way you are describing. The easiest fix is the either get a Greddy blow off valve, or fill the holes with JB weld so that youre not leaking like hell with the 1G valve on there.

 

[Bobster66]

I checked the local auto parts places and they said they can't read the code because OBD1 doesn't store codes, which I'm pretty sure is a load of bull.

Of course your ecu will store CEL codes, but there was no industry standard for OBD1 which is why you can't just buy a scanner in a parts store. As a DSM'er you need to learn to pull codes yourself.

 

[TurboLaserRS]

Pipe is flanged for 1G bov. I took the stock gasket and put just a hair of RTV on the mating surfaces.
So I tried to diagnose the check engine light but I can't. I cannot keep the car running and probe the two pins in the port with my multimeter, so I don't really know what I'm supposed to do.

Well I'm ripping everything out here momentarily and starting completely over. I'm going to take the BOV off, and check the surfaces of that, and maybe omit the stock gasket and just use rtv alone this time.

The only question I guess I really feel I should ask is this; If the car is idling and dying like I have described in past posts and I pull the plug on the maf and the car stops dying, would that indicate the MAF is to blame?

~~~~~~~~~~
6:06 PM.
Well here we are again. I took everything out, took the BOV off. The flange was in fact dual flanged as somebody mentioned. I filled both holes with RTV and smoothed them over. I also put screws in backwards into them. I get everything back together, even used a t bolt clamp for the tb connection point. Idled really solid and great, ran fine. Everything seems ok. Car creeps up to operating temperature. A sputter here and there which has been normal in the past. I let it sit idling for about 10 mins, suddenly it just dies.
At this point I'm beginning to think ignition. Could the ignition resistor / transistor unit be going bad and only crapping out when it's good and hot? I mean it is in all probability 23 years old..
I really don't know what else to check. I put a different set of wires on it and it didn't do anything, and the plugs look fine and only have 11k miles on them. Gaps are ok .028.

 

[TurboLaserRS]

Put another set of wires on it today. It didn't make any difference. Pulled MAF plug and car idle surged horrendously but didn't die. Plugged it back in and unplugged coolant temp sensor. Car idled seemingly fine. But I didn't test that theory very long so it's still a theory.

A local guy told me he thinks it could be the o2 sensor. Would I be able to verify if it was the o2 by unplugging it or not?
I feel like this has something to do with ignition.. butt I might pull the ecu out even though it had new capacitors just to see if its ok.
I gotta get this figured out, my other car has some kind of power draw and won't hold a charge so unfortunately I need the dsm to work!


Well my tachometer when funky on me today, so I am now thinking that the ECU may be suspect. Will check and update tomorrow.

 

[TurboLaserRS]

Pulled out ECU. Two capacitors look fine, one however....doesn't.
Could the capacitor leaking, even though it hasn't corroded anything yet, cause my issues?
I tried to drive the car today and at WOT it started breaking up, which it's NEVER done prior.

 

[pauleyman]

Why didnt you pull the codes. Car doesnt have to run. Just turn the key to on.

 

[TurboLaserRS]

It didn't work. I couldn't hold the leads onto the pins to get any kind of readout from the ECU. But I think what's in my pic there might be whats wrong. Either that or the cam position sensor (or CAS, even though 1g's don't have a cam angle sensor)

 

[kchaazz]

That capacitor looks to have been replaced before. Can you take a pic of the entire board, as close as you can?

 

[TurboLaserRS]

4th time trying to upload pictures. Says

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Sadly, I'm no stranger to ECU's. If this one is bad, it would be my third ECU.
So there are no funny smells coming from the board, nothing looks terribly corroded. But as I mentioned previously, the car started breaking up under boost yesterday. Another weird thing is that the tachometer went strange on me, it made very 'floaty' movements even though I was holding a steady RPM. Coming to a stop the car died over and over again. It starts right back up and makes weird misfiring pops through the exhaust but if you give it gas and take off part throttle it seems fine!
As I said before though, I was unable to make anything happen with the check engine light.

 

[kchaazz]

That board looks very good, and the caps have been replaced, though they should have soldered them closer to the board, that ECU looks fine and I do not see any signs of corrosion. If youve got a check engine light on, you need to just get a logger and see what the codes are. I do see that the clamps on the coupler at your throttle body definitely are not sufficient to hold boost on that pipe, you need t- bolt clamps on both ends of that pipe for sure and need to do a boost leak test after installing the proper clamps to ensure youve got no leaks. If youve got a bad enough vacuum leak after the maf, you will get a check engine light that goes away when you rev the motor. This is because the air at idle will literally bypass the maf to enter through the leak. When you installed the 2G elbow, did you replace the gasket there? When you removed the 1G elbow, did the throttle body come away from the intake manifold at all?

 

[TurboLaserRS]

That board looks very good, and the caps have been replaced, though they should have soldered them closer to the board, that ECU looks fine and I do not see any signs of corrosion. If youve got a check engine light on, you need to just get a logger and see what the codes are. I do see that the clamps on the coupler at your throttle body definitely are not sufficient to hold boost on that pipe, you need t- bolt clamps on both ends of that pipe for sure and need to do a boost leak test after installing the proper clamps to ensure youve got no leaks. If youve got a bad enough vacuum leak after the maf, you will get a check engine light that goes away when you rev the motor. This is because the air at idle will literally bypass the maf to enter through the leak. When you installed the 2G elbow, did you replace the gasket there? When you removed the 1G elbow, did the throttle body come away from the intake manifold at all?

I didn't see your post as a reply to mine for almost a week. Sheesh. I'll do my best to answer your questions.
I now have a monumental amount of both t bolt clamps and regular compressor clamps holding this thing together. The thing is that I am still experiencing a boost leak that I can HEAR at full boost. Also at light driving I can hear a whistle sound when I'm at a certain point in part throttle. At this point there is two possibilities and I think that it is as you have mentioned, something to do with the throttlebody. The other but less likely option (I'm guessing based on process of elimination) is the actual BOV fitting itself. I don't mean the surfaces of the BOV and flange meet, but rather the welding holding the flange to the pipe.
Thus this leads me to believe you are right in your assertion of something to do with the throttlebody. The TB did NOT pull forward from the intake manifold that I am aware of at the time. I did not use a new gasket for the TB elbow, I pushed the gasket I had against the TB, and put a thin coat of RTV on the gasket surface of the elbow and then installed it and smushed it together. That has served me fine in the past, but I think I may take it apart since you have mentioned it.

~*EDIT*~ I also feel it's very worthy of mentioning that my cars boost can no longer be adjusted. I don't know what the hell the problem is, but I hit 18psi at WOT no matter where my MBC is. So I think my wastegate is sticking shut or my actuator is pooping out on me. I won't be giving it throttle until I figure it out since I'm assuming this car still has the stock fuel pump, and I have nothing to tune with!!

 

[kchaazz]

Hmm. Well, Id definitely do a boost leak test as soon as possible to find and fix the intake tract leaks. Im not entirely sure as to why your boost is jacked to 18psi and non adjustable, but try removing the boost controller from the mix and then just attach the line from the nipple on the j- pipe directly to the wastegate actuator and see what happens. If you replace the throttle body gaskets, youve got to make sure youve got the correct gasket for the TB/intake manifold side cause they are quite a bit differrent between 90 and 91- 94 models, and if you put the later model gasket on your 90 throttlebody between TB and intake manifold, you will have a huge vacuum leak and the car will barely run.

 

[TurboLaserRS]

Well I couldn't get the vacuum lines off of the boost controller so I took it apart and took the springs and bbs out. Should be the same as what you were suggesting now. I took the throttlebody off and the PAPER gasket there was just ate up. I scraped it off with a razor blade and hit the surface with denatured alcohol. I laid on a THIN layer of rtv and put it back together. Did the same thing with the front where the elbow and tb meet. I got a tighter t bolt clamp on my uicp where it was leaking before. I've got so many clamps on this thing it would make you guys barf.

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I'm going to go start it in a bit. Wish me luck guys, I am so friggin sick of this stalling crap.

 

[DSM_love_GST]

Good luck bud. Waiting to see what this monster is

 

[TurboLaserRS]

Well here are my findings. It drives much smoother, not as jerky on decel. It *feels* much better! No more audible boost leak or smelling raw fuel. Idled rock steady at stop lights.
BUT, it still stalls.
So at this point now I very much believe that the ICM/PTU is getting hot and failing. If you keep the car moving and air going over everything it isn't stalling for brief stops. But you let it sit and idle for a few minutes, and the idle becomes very erratic, and then it stalls-right as the temp gauge hits the middle is when it starts to do this.
With no MBC, im still hitting 18+ PSI of boost, and the wastegate arm is a b!tch to move by hand, so I'm thinking the actuator has failed.

I also had a very big scare, afraid that my car had skipped time even though I did everything right. I had moved my MBC and forgot to remount it where I had it secured before, and it fell INTO the cooling fans while they were ON!! I about shat my pants when I heard the wretched grinding sound. I thought for sure my valves were gone.

 

[WES_393]

Have you ran an actual boost leak test? You can't just listen or guess when it comes to boost leaks. Pressurize the intake to 5-10psi above what you plan to run, spray soapy water over everything, and watch for bubbles. Once all the leaks are sealed up, try adjusting the idle according to VFAQ.

For the PTU/ICM , remove the connector and make sure it's clean and dry. If you think heat is causing issues then you could try aiming a heat gun or hair dryer at the PTU itself while the car idles. Be careful not to start melting things, but get it up to normal operating temperature or a little higher.

If the MBC or actuator is in question, run a line straight to the wastegate actuator. If the lines won't come off then cut them off and get new hose.

At this point your just shotgun troubleshooting. Don't just assume things are good or bad, start with the simple things and be absolutely positive they're good or bad before moving on.