[RESOLVED] Sputtering dependent on throttle %?

[fastfive0]

OK here is my current dilema. I can go 20% throttle and drive all day fine. Any boost level. As soon as i go past about 20% throttle the car starts sputtering and studdering almost like its hitting fuel cut or like a studderbox. At first I thought it was boost dependent but it seems to be more throttle dependent. I can build as much boost as I want as long as i dont go over 20% throttle. I checked and regapped all the plugs, did a boost leak and fixed a couple leaks but the problem still persists. Could this be a bad TPS? Bad Ignition coil? See profile for mods everything on the engine is only a month or so old. I also raised the fuel psi a couple psi and then dropped it a couple psi to see if the fuel had anything to do with it but it had no effect.

 

[jpbrazill]

We might need a little more information.

Did this problem just occur? Has this happened before?

What are you tuning with?

 

[fastfive0]

Problem started after i made a couple runs at the track. I had a coupler come off between my GM maf and upper intercooler pipe. So when i got it all back together it wasnt too noticeable but it got worse till now. I have a logger and wideband. Not showing really any knock or pulled timing when this happens.

 

[housegsx]

One of your plug boots is arcing. Or maybe the transistor pack is bad. That's what I'd check first since the plugs look ok.

 

[fastfive0]

Ok are the 1g and 2g transistor packs the same? Because I currently run my 2g. But I have a spare 1g. Also does it need to be grounded? When I did the 6 bolt swap I just zip tied it to something and didn't bolt it down. I don't think it's a bad plug wire as they are 1 month old taylors.

 

[blackjdm90]

Ok are the 1g and 2g transistor packs the same? Because I currently run my 2g. But I have a spare 1g. Also does it need to be grounded? When I did the 6 bolt swap I just zip tied it to something and didn't bolt it down. I don't think it's a bad plug wire as they are 1 month old taylors.

It depends on the year of the 1G. My 90 has a completely different transistor unit and coil pack as the 91-94 had. Not too sure on the 2g being the same here though. It is a possibilty take both of them out and look at them. The 90 for instance has a square block type plug in but the 91-94 has more of an oval shape to them.

Also check all of your wires connecting to the bottom of you coil pack. Pop off the little black covers on the bottoms over the wires and see if any of them are loose. This happended to me and it caused a lot of headaches ,even after I put a new transistor unit in, till I pulled out my coil pack and noticed that cyliders 2 and 3 had loose nuts holding the wires.

 

[housegsx]

I don't think it's a bad plug wire as they are 1 month old taylors.

Still a good idea to give them a quick look. My MSD wires only lasted about a month.

 

[fastfive0]

Thanks for the ideas guys I will check them all out keep em coming! I only have 5 weeks left to have this car running top notch!

 

[fastfive0]

One other thing I forgot to mention I do have a small boost leak from the tb shaft but I didn't think it's bad enough to cause the problem. Or could it?

 

[bling5tatus]

If it's really small it shouldn't cause you a MAJOR issue like you described.

I also had an issue that is like yours, but I dunno what caused it. I too had my transistor unit zip tied to something (my ps line I think) and only after doing some more reading here did I find out that the metal plate it mounts on has to be grounded too... I THINK... not sure... I hope this is the case because I can't have my car bucking and acting stupid like it was. It seemed very random too which pissed me off... there was no one thing I could do to recreate it.

 

[Bender]

It was my understanding that it needed to be grounded. I just put it on one of my intake manifold bolts when I installed my SMIM.

 

[fastfive0]

ok i checked the plug wires tonight and they looked fine, it was dark out so i sprayed them down with some water and also a little bit on the coils and didnt see any arcing. I payed more attention to my wideband when this was happening and it seemed to jump from the mid 10's to high 12's so I bumped up the fuel psi and it brought them back into the low 11's but still no help. I didnt swap the transistor pack yet. One other thing i noticed my palm logger crapped out on me at the track the same night.....so i reset it and reloaded palmnstein on it tonight....connected it to the obd2 port and tryed to pull codes and its just said "no rev" and i would try to reconnect and it wouldnt. Do I have a computer issue?

 

[Bender]

I know the 92 Talon I have did something similar when the ecu was bad. Crack it open and look for leakage/ a fishy smell. Also, check to make sure ## getting a signale on the rpm wire. I can give u a port number on it, but im in a rush. Check ceddy's website. Ceddy's Lair

 

[Bender]

ok. I got some time now. My eggs were burning. . Here is the pin out. http://ceddy.us/pic/2GECUPinout.pdf

If you get a tach signal going in, then I would say the ecu is bad. I believe you can access it easier from ## crank angle sensor, but I don't know what color wire it is.

If you don't get a signal, then you crank angle sensor might be bad.

 

[fastfive0]

ok so if i get a signal the ecu is bad but if i dont get a signal the CAS is bad?? Then how do i know if they are both good?? I'm going to swap a new power transistor in tonight and switch out my maf with another gm 3". Then if that doesnt work i will swap coils tomorrow morning and try that.

 

[fastfive0]

switched out Gm maf with another and swapped in a new transistor no help at all. checked every wire i could see and didnt find any damage. I really cant figure out why my logger will not work anymore. It's as if there is no power or something to my OBD2 port. I would think if i can figure out whats not working on the OBD2 port that is probably what is related to my issue. Bender I didnt check the wires that you suggested for signal because i need more info....do i check them while the car is running or off or key on?

 

[Bender]

Check the rpm wire while the car is running. I would leave it plugged into the ecu, and use a multi-test meter lead to stick it in the plug where the wire comes out on the CAS plug. I oftenly use a paperclip to stick in there (make sure its not coated, and it connects to the pin in the plug good, and set the multi-test meter to 12v dc, then touch one lead to the paperclip, and one lead to the ground. If you want to do it in the car, use a razor to carefully strip some insulation off the wire, and connect the lead of the mutli-test meter there. Be careful not to cut the copper in the wire, and be sure to tape it back up when you're done.

 

[Bender]

Also, from reading other posts on a similar problem, did you check your spark plug gap?

 

[fastfive0]

Stupid coil. Replaced it and the car runs strong.