Cyberpunky

I recently fitted a Tial F38 Dual port and Turbosmart e boost controller. Unkown to me Tial was fitted backwards, so car would overboost massively to 18-20lbs. I tried pulling settings down on eboost but nothing had any effect, even with every thing set to 0. I then bypassed it totally and ran waste gate in single port mode, and was still over boosting. I then realised it must be waste gate

I searched google for "944 turbo tial" and had a look at images and realised waste gate was on backwards. I then got it put on right. In mean time it had developed a problem where any boost over about 8lbs would cause to run like a pig. I can not use WOT at all.

When I stay off boost and potter around it can run fine for a while but it will sometimes randomly start to run bad, even though I am staying off any serious boost or WOT. Hard braking and turning can sometimes trigger it too(electrical ?).

When it runs bad, it will idle fine but I need to give extra revs to get moving or it will stall, and when driving the throttle will suddenly loose response and car will start to die. Then it will kick and buck and pick up. If I give it too much gas, it will back fire when it kicks.

All I can think is that the problem is the turbo has been damaged. The fact it still produces plenty of boost makes me doubt that. I have a new TPS to fit, and have a fitted a new FPR. I have also fitted new Rogue DME. It could also be Barn door sticking I guess or leads or rotor button or injector leads or a million other things lol

I don't have my ZT2 fitted yet as that I will fit it on wednesday but won't have AFR hoooked up till I can get bung welded in.

I have tried searching and can't find anything like this.
Any ideas ?

fejjj

Bruce,

I would start with new TPS.

jmj951

You're right, it could be anything - or more than one thing. You'll have to do all of the basic diagnostic tests first, and if I were you, I would start by putting as much of the original stuff back as possible before even bothering to start diagnostic tests.

The behavior of the car sounds similar to one that has a small-to-moderate leak in the intake plumbing - losing a significant amount of metered air somewhere after the AFM. Does it sound right to you that it runs okay when there is vacuum in the intake, but when it starts to build boost, it begins to have problems?

Paulyy

Un metered air sounds familiar. Take your intake off and check all the vacuum lines under it. or pressure test it before you do that.

Rule out the turbo at the moment as a stuffed turbo will wine really loud, lag heaps and or leak oil internally.

Did you swap out the DME with your a-tune?
is the cycling valve connected or disconnected?

shortyboy

please check your electronic boost controller settings. Please pay close attention to offset, peak hold and over boost settings. i had the same issues with overboosting and it was caused by incorrect boost controller settings.search the forum for EBC settings

ehall

I agree. Check the electronic boost controller first. Put a *** back in and see what happens.

Cyberpunky

Going to replace the TPS tomorrow as the idle was high after fitting rogue ecu last night. Think I can rule out eboost as this was happening with it completely bypassed and is set so boost is no more than 9.5 lbs.

Mark924S

check all of the intake piping at those pressures if you have the stock IC piping you will easily pop connectors loose and any positive pressure would show as running bad (more fuel than metered air)

Paulyy

Normal for the idle to change with a new tune.
Use this method to adjust
http://www.clarks-garage.com/shop-manual/fuel-08.htm

Cyberpunky

Well I have come down with the flu so haven't done anything I planned to do today but I am going out to set idle now(thanks Pauly I didn't even think of that). Will have a look at hoses etc as that makes sense Mark924S as it was a lot of boost.

Paulyy

If you get in boost and it's miss firing, check your FPR or vacuum to FPR. I knocked mine off while doing spark plugs and cause a huge issue. I could drive it but soon as i got a few psi it would run ****.

Cyberpunky

FPR was replaced with 3 bar unit for A tune and all vacuum lines have been replaced in last year or so but problem is not when I am boosting(can hit redline without it missing at all) but after a boost or WOT run, where it runs rough even off boost(from idle). It's like a dead spot in throttle that has to be riden out. If I give it more gas it backfires but if I ride it, it coughs and slowly picks up

I set the idle and the A tune/Rogue ECU idles a fair bit smoother than older set up but with current issues cannot tell if it has improved things in other areas

Paulyy

i know you changed the FPR befor the tune, if you changed it at the same time this started happening, it could be a rich condition. it's 7-8 psi of extra pressure in the fuel rail.

Cyberpunky

Nah the problem started well before I changed FPR and before I got WG around right way and as A tune was on it's way I figured was worth trying. Someone mentioned that a bad FPR might cause issue so I fitted new one to see if it helped. It made no difference so is just one of the possible things ticked off the list. If it had mad things worse it is a quick job to change old one back in.

Paulyy

Did it happen after you did something to the car?

How new are your:
plugs
leads
cap & rotor?