Hesitates under load mid rpm.

[g4ebguy90]

HI, I just got a 91 turbo talon. Of course it has problems.
Guy says he changed the alternator and it just started doing this in the morning when he drove it.

You give it gas, you hear the turbo spool feel a little boost, and then it just vrooommmm pa pa pa vroommmmm pa pa vroom pa until you let off again.

It's not back firing, its more like just hits a wall or something. I have no idea what DSM's do when they have fuel cut or etc. My old Turbo cars used to overboost and either BEEP and the engine would die for 3 secs, or they would stumble a bit.

Umm, specs from what I was told is. The car was a GS converted to GST.
272 cams, rebuilt. I just got it so im sure I will find more out soon enough.

Thanks for any help or ideas.

Traded a 01 cougar I bought for $800 for it, and $150 cash

 

[beendenied]

O, I thought for a second it was a real turbo talon, well, originally turboed, anyway have you checked that your wastegate has a vacuum line hooked up a pressure source or boost controller? or is the turbo just spooling until it runs out of fuel, which would cut and sputter

 

[g4ebguy90]

I believe it has GST engine. But its just installed into a GS. The harness looks clean no cuts or splices that I saw. I will check that, but I mean the turbo Doesn't spool that much like *loud* but then again it dont have a chance to. O hope its not just running out of fuel, that would be not good. Ill keep updating.

What is stock boost for the wastegate, if I just went from the compressor to the wastegate? the turbo is probaly the larger manual stock one.

built 91 gst 4g63 Forgive the engine specs... He didn't build it, original owner did.

 

[Junkyardspecial]

Sounds like you got an okay deal, turn boost down with an MBC til it stops. Sounds just like basic fuel cut.

 

[TSIMonsteR]

at what rpm do you hit the "brick wall"?

 

[Alex7747]

check for boost leaks. spark plug gaps, wires.. thats where your problems gonna be..

 

[g4ebguy90]

OK, I will check what you guys mentioned tomorrow.

As for as RPM's. Its around 3-3.5k at medium throttle to full. Low RPM's and throttle seem to be the only way for the car not to do this at those rpms. Highway driving it runs fine.
Idles rough around 1-1.5k. But i figured it was cause of the cams.
Not really a brick wall just a short bog followed by another and it goes on till you lift off.
Best explanation is, as soon as it starts pulling good it just loses power bogs, then gets power instantley back and bogs and loses power again. happens very fast and rough.

 

[eligst21]

Or like someone mentioned, sounds like fuel cut. But be sure to check the plugs and wires and everything. And turn the boost down, until you know what fuel pump it has and injectors. Or you get a wideband to help monitor your afrs. A lot has to go in before one can just hope in a car and turn up the boost.

 

[g4ebguy90]

I know the injectors had blue wrapped around them. Are those 450's??????
Previous owner did say something about bad plugs or cam sensor.
The car has no working boost gauge and I don't believe it has a aft. mkt. Boost controller but i got to look. Im going out right now to look if its not to dark.
As for the pump,

Like i said fellas, the guy said it ran fine until he replaced the alternator last night, then this morning it started doing this.
He wasn't very mechanically inclined, he called the cam sensor the TPS.

( Well I just went out in the dark and I found a Couple issues.

The vacuum line going from the charge pipe to the turbo was taped up. The Battery had tape over the terminals, and there were some random wires hanging from the alternator. But they appeared to be going to something. The intake pipe from the MAF to turbo looked pretty old and the rubber didn't look in good condition either.

 

[eligst21]

The blue tops are the stock 450s. And if its the plugs, its cheap just to buy a new set for insurance anyways. Get some ngk bpr63s and gap them to .028 and try that. They're cheap from extremepsi.com. Also, you shouldnt be running a boost controller if the boost gauge doesnt work. How will you know what boost youre running? Also, are there any cel on? Or anything? We'd have to have some pics, because i really dont understand what you mean about the hoses or vacuum lines.

 

[g4ebguy90]

OK GUYS, IT WAS THE SPARK PLUGS .

They were gapped below .015, and one was gapped so bad it was like .004 almost grounding itself out.

I hooked up a boost gauge, and boost was a good 8 psi, maybe 9 psi at MOST.

IM happy. Thanks for the help and ideas. I gapped the plugs to .032 and used copper NGK's.

But for another thread, there is a groove on the timing belt, and when I unhook the idle control motor, idle doesn't change at all.