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!

 

[TurboLaserRS]

Well I don't have an ISC hooked up, so there's nothing really to adjust. I've driven it almost a year without an ISC and it never used to do this before.
No I have not done a boost leak test because I don't have a boost leak tester. Even if I had one it wouldn't do much for me because I can't blow very hard, and my puny little electric tire pump takes like 10 mins to put 5psi in a tire.

I'm going to do the hairdryer on the PTU in the morning and report back, since I'm really at a loss to what it could be. My three main guesses are PTU, CAS, or the coil itself.

 

[pauleyman]

No isc? And you didnt think this might be a problem?

 

[airmail96]

No isc? And you didnt think this might be a problem?

It can be a problem but not totally necessary.

 

[AWDPetmitsu]

How many miles are on the car? Is the CAS original?

 

[TurboLaserRS]

152,874 miles on the odometer. It appears that I have fixed the stalling issue. Today I busted out the hair dryer and heated the CAS up good and hot. Nothing, no stalling at all. So I move my big industrial HID lamp towards the drivers side firewall corner. I notice that there is no clip on the ICM plug and that the bottom is pulled away slightly. (car is running at this point). I pulled it just barely and the car started to die out. I pressed it back in firmly and now it idles! It's surging a bit but it is able to stay running now when the car is hot and even when the fans kick on.

I also cut the vac lines off of my MBC and looped them together so I'm at what would be wastegate pressure. So this leads me to believe there is something wrong with the wastegate. Thing is though, I don't really know what can be done about that? For now I can keep my foot out of it while I do some research.

I went out to the garage and played around with the WG arm. I cannot move it at all, no matter how hard I pull. I'm going to take the cotter pin out of it tomorrow and see if the flapper itself can move or not.
If it's indeed the WG actuator, can I use one of those adjustable ebay ones?

 

[WES_393]

What do you mean by looped the lines? Isn't there only two? You need a straight boost source to the actuator.

 

[TurboLaserRS]

One line goes from the nipple on the J pipe to the manual boost controller. On the bottom part of the MBC a line runs from there to the wastegate actuator. I took those two lines, and made them one. Wastegate is hooked directly to the nipple on the J pipe now.

 

[TurboLaserRS]

It appears that I have fixed the infinite boost building problem. I pulled the wastegate actuator off yesterday and it was not stuck at all. I pulled the vacuum lines off completely and inspected them. The 'nipple' on the wastegate actuator was sticking through the side of the vacuum hose. Apparently it burst in a rather violent manner.
With that fixed, at WOT my car no longer makes that horrendous screeching sound anymore. It pulls nicely (but not as hard unfortunately).

So that leaves the initial problem which is this; The car still stalls and I don't know why. At first I was sure that it was the ICM, or the ICM plug rather, but every time the car is stalling I jiggle the plug and it seems to run okay again for awhile.
Here's the catch though, I have to pop the hood to do so,. I think that this lets SOMETHING cool off. I have noticed if my car starts to get choppy at idle and I turn the fans on, it will idle forever no matter what. Now this is a band-aid, but I want to find the real fix for it. With the hood down and fans off, once it reaches the very middle of the temperature gauge the car starts to stutter and stall when off throttle. I got the ICM boiling lava hot with my hairdryer as well as my cam position sensor (CAS) and the car never hiccuped while the rest of the components were still cold.

I also wanted to pose another question that maybe a wiseman can answer. Why is it that my car never hit fuel cut? I hit 20PSI by accident when I first realized that the wastegate may be having issues. I have the blue injectors which I believe to be stock, and no tuning software/solution at all. I have no idea how long I may have been hitting boost way beyond what my fuel system is supposed to handle, but it never seemed to miss a beat. I hope and pray my engine isn't damaged from this.

 

[VisegripMech]

"If you've added any mods to your car that increase airflow through the engine (especially IC pipes or a frontmount IC), you may have a problem with the car stalling, or the idle oscillating up and down when coming to a stop. One of the most common causes is the BISS screw being out of adjustment. "

??

 

[TurboLaserRS]

The BISS doesn't have any effect on me. I don't use the idle control motor as it's fried, and fried the drivers in the previous ECU. I just leave it unhooked and never had a problem up until now.

 

[pauleyman]

Up until now.....the weather has likely changed and your car has no way to compensate without an isc. Youve disabled the very thing that controls the "problem" you're having. Fuel cut is not a function of boost. Its a function of mass flow rate. This is why cars may cut in winter but not in summer.

 

[VisegripMech]

Wow I'd give that screw a turn or two just to see what happens. I'm assuming that you have the FIav blocked as well? Even with out an ISC doesn't the biss affect idle?

 

[TurboLaserRS]

Up until now.....the weather has likely changed and your car has no way to compensate without an isc. Youve disabled the very thing that controls the "problem" you're having. Fuel cut is not a function of boost. Its a function of mass flow rate. This is why cars may cut in winter but not in summer.

I have been driving it for a year now. It has seen cold, and snow, and rain, and over 105F before. It's not due to the weather or anything. If I turn on the fans when the car approaches the middle of the temp gauge, it no longer dies. I am rolling with this until I get some more cash up and then I'm going to try replacing the coolant temp sensor and see if it may be malfunctioning and causing the car to start dying @ full operating temperature.

I've honestly entered the "I hate the previous FING owners" phase. I was driving to a interview and suddenly it lost gears 2, 4, and reverse
The shift cable bracket that secures it to the transmission just *decided* it didnt feel like being part of the car anymore. There were no bolts to be found that would hold it in and I know that I never loosened them for any reason ever. Pretty scary because I pulled out in front of a truck and wound out first and go to shift into second, let the clutch out and it just revs. Try to slam it back into 2nd... nothing just rev rev. I managed to make it home using gears 1 3 and 5 luckily, but it just makes me suspect that all kinds of non obvious little crap could be lurking just around the corner. I guess that's what you get when you buy a 23 year old sports car for $500.

 

[TurboLaserRS]

Well the stalling issue appears to be taken care of. I replaced the coolant temp sensor and the fans kick on a bit earlier on the gauge than before and everybody seems happy!

I keep exploding vacuum lines running to my wastegate and it's really starting to piss me off. The way my injen intake pipe is situated causes the coupler to really jam into the nipple on the wastegate actuator. That puts a pinch in the line and it blows the damn side out of the line in 1 or 2 pulls. WTF This wasn't happening before so I don't know wtf to do. It seems like such an easy issue to fix but it keeps happening and I really am considering just drilling a big hole in my exhaust mani and going ebay external gate.