Car lags/shuts off during acceleration, BOV doesnt work.

[acroatt]

I bought a 1995 Talon TSi 3 days ago and something funny happened on the drive home.. I test drove the car about 2 weeks ago and everything was fine. When I bought it, it drove fine for about 30 minutes and then when I was trying to accelerate in 5th gear, the car would not accelerate. It then slowed down to about 20 mph (was going maybe 75).

We pulled over and look under the hood and nothing was smoking but the car temp was nearly 3/4 the way up. It started fine but idles a low with almost like a mild thudding. When I tried to pull back onto the road it lagged with acceleration and would cut down and slow down after reaching 3000 rpms. When I applied maybe 1/6 throttle or less it accelerates a little but when it reaches near 3000 rpm it stops accelerating and slows down to 1000 rpms or even shuts off. I can maybe can reach 60 mph if accelerate slowly. The BOV now does not work ever since this started.

I have had a few friends who own DSMs check out the intercooler hosing to make sure there isn’t a crack or leak. They said it looked fine..

Basically, the car lags or cuts out with acceleration and the BOV does not work. HELP ME IM NEW TO DSMs!

 

[Dsmj89]

First off get your bov replaced with either a 1g bov or any other reputable aftermarket bov and make sure you recirculate it.
After you get this done, do a boost leak test.
Last but not least, change your spark plugs and spark plug wires, they might be out of shape and thus causing your car to have poor accelerating performance, happened to me once.
Report back when you get these done.

 

[chico904]

Could be a couple of things. Do a boost leak test, check your wastegate flapper arm, check maintenance things like plugs/wires, filter, check timing.

 

[acroatt]

Any ideas on why the BOV doesnt work anymore all of the sudden?

 

[Dsmj89]

Have you checked if the adjustment screw on your bov is too loose ? Therefore not closing complete and leaking boost.

 

[acroatt]

No, I didn't even realize there was a screw on the BOV. Sorry, Im new to all this. Please hang in there with me. Thanks for the help, it means a lot man.

 

[Dsmj89]

No problem. I believe the screw on top is an allen screw, play with it until you get the right setting.

 

[acroatt]

just checked the spark plugs, they look new but the ends are really black. underneath the cover over the where the plugs are on the head there is oil and i dont know what its from? the idle is not good, it keeps dropping from the normal idle at about 1200 RPM down to 200 RPM almost cutting out it will just die sometimes, also there is black stuff coming out of the exhaust possibly carbon?

 

[GoldenEagle]

check the idle adjustment screw on the throtle body, make sure its there. if u pushed it hard it might have popped off. It happened to me before, i had some of those symptoms plus a loud swooshing leak offcourse..

 

[acroatt]

The idle screw is in there but what should I set it to?


***** Also, when driving in any gear, it wont go past 2500 RPMs even with throttle all the way down. Anyone know whats wrong??

 

[JEFFREYCASTGSX]

The bov doesnt work because you might have blown a coupling and there is no air to set off the bov, and you might have a BIG boost leak..... just a theory.

 

[tkelly27]

You can't see a boost leak. You need to pressurize the system from the turbo inlet and check for air leaks. Black plugs say boost leak to me. Either that or your fuel pressure regulator took a dump, but it's most important that you check for leaks before you do anything else or ask any other questions. You're running around in circles otherwise.

The BOV won't work if you don't make any boost. If it's running real bad its probably not making any boost, even with the tiny T25.

 

[DSM4me44]

Top three things that come to mind

1. Spark plug or wire issue

2. Boost leak or bov issue. This can cause black smoke.

3. FPR problem or vacuum line came off from it. This can cause A LOT of black smoke.

 

[acroatt]

What would cause the problem of not being able to go past 2500 RPMs?

 

[tkelly27]

A boost leak can do that. Do a boost leak test and then report back to us.

 

[acroatt]

Alright, how do I do that? Sorry, might be a stupid question

 

[chico904]

IC Pipe Tester

 

[JMiller]

Might be a little repetitive but do a boost leak test, Its sounds like when you went to accelerate in 5th you blew a coupler in some sort of way (could have slid off some or could have cut in it).

 

[acroatt]

Alright, I will try to get one of these gadgets made sometime soon. Check back for updates, thanks in advance.

 

[acroatt]

Just ran a boost leak test and there was no hissing noise that I could hear anywhere.. I had a friend check all around and nothing was leaking to our knowledge.

BUT, the boost gauge DID NOT move at all.. it stayed below zero and did not jump or move in the slightest bit.

Think it could be the MAS? Ideas? ANYONE?!?!

Thanks very much in advance!!

 

[stefanOst]

Was that the gauge on the dashboard, or an aftermarket one such as by autometer? The stock one won't really tell you anything, and I don't think it even reads anything if the engine isn't on. Get a mechanical boost gauge, they are pretty cheap from autometer, then you can tell how much pressure you are building up. I suppose if there is a big enough leak, like a major major one, you won't be able to build any pressure at all, and won't hear anything

 

[acroatt]

It was an after market gauge. Did not move AT ALL..

 

[acroatt]

bump

 

[DSM_ThuNDeR]

all your timing marks were set to TDC before the boost leak test?

 

[acroatt]

Problem solved. Thanks for all the help guys. I will be sure to stick around and stay active.