five-o

I posted a thread about the car bogging down under full throttle. Here's an update and any advice is appreciated.

Adjusted the TPS (although I have not disconnected it yet) and it still bogs down at about 2600 rpm. This time instead of letting off the throttle to accelerate I kept my foot to the floor. In 3rd gear, As the car was stumbling, boost was close to 1 bar on the factory guage, rpm about 2600, and then a loud bang. It backfired so loud it scared the crap out of me. Is this a fuel/air problem? I talked with 9fitty1 from here who was the owner before M@rk951 and he said to scrap the GURU chip, and that he installed a new TPS on there. Thanks

Mike

Tom M'Guinn

Does it only happen when you floor it? Can you accelerate to redline at part throttle without problems? If so, it's your ignition most likely -- bad wires in particular.

five-o

Yes only at full throttle. If I let off a little it accelerates fine all the way to redline, but pressed to the floor it stumbles at 2600. It has all new ignition wires on it, and runs fine otherwise. Thanks.

Tom M'Guinn

Does it stumble from 2600 to redline -- or stumble only at 2600 and then get better till redline?

five-o

No at WOT it doesn't want to accelerate past 2600, like it hits a wall, unless I ease up on the pedal then off she goes. When I held it at 2600 is when i head the loud pop.

Eyal 951

did it sound like a loud pop in the intake? thats lean. try changing the chips.

five-o

I guess it could have been in the intake. Not sure but it was loud as hell-like a firecracker. I'm just puzzled why it only has this problem at that RPM with the throttle in that particular position. I think I'll just break down and get a chip from Vitesse. Then I will know that's not the issue or part of it.

Tom M'Guinn

Is your motor stock or modified? Did this just start happening out of the blue or did you mod/repair something when this started?

Have you tested your Air Flow Meter signal?

five-o

It's modified from a PO-9fitty1 and M@rk951. They said 3.0 bar FPR, Accuboost controller, Tial 38mm WG, GURU Chip, new TPS, Linsay exhaust. It did it from day one when I bought it.

reno808

It could be the ignition coil. May be thats why they sold it!!

Tom M'Guinn

I see. I suppose it could be ill-tuned -- do you have a 2.5 fpr or factory chips to try? What injectors and AFM/MAF does it have?

If factory AFM, have you tested it with a multimeter as per clarks-garage?

five-o

Factory injectors and AFM. No factory chip or FPR to try. Would you suggest trying a good chip like Vitesse and telling him my set-up, or how else would I get it back in tune? Sorry but this all new to me and I appreciate the help. I am in Niles, Michigan if any of you are nearby and know anyone close that can look at it if we can't figure it out.

Tom M'Guinn

I am a big fan of Vitesse chips, but you'd hate to spend a bunch of money on chips only to learn somthing basic isn't working. Did you replace the plug wires (cap, rotor and plugs) yourself? Seems like 9 times out of 10, it turns out to be the wires when a turbo car runs fine at all times other than WOT. I'd think it's also worthwhile to test the AFM and all the I/C couplers.

DDP

Not exactly. I haven't been in contact with this car for quite some time. Hope you solve the problem.

five-o

I guess it's going to be a process of elimination. I was hoping someone else may have had this problem in the past. Well, if I ever figure this out I'll let you guys know. Thanks for the input.