Still Cutting Out At High RPMs. What To Try Next?

K

klmnla

Watson LA
Joined
Feb 22, 2008
I have read dozens of posts on this and tried to find the most logical solution, but nothing is working. It just keeps cutting out at high RPM, as in between shifts. Once it shifts, I can roll into the throttle and it pulls fairly well. My scanmaster readings look good, and the FP is set at 42 with line off. IAC at idle is 23 and TPS is at .42 and 4.4. Airflow is at about 240 at WOT. I can tap the MAF while the car is running and it does not flinch. The coil packed ohmed out good, about 12k across the 3 banks. Boost is low at about 12 for now. I have tried adding and reducing fuel and timing through the translator, but makes no difference. Below is what I have done in the last few months:
New Walbro fuel pump and sender unit from Racetronix
new intake hoses and clamps
rebuilt turbo
replaced all gaskets including head gaskets
new radiator
10.4mm Taylor plug wires
R43TS plugs gapped at .32
New RJC manual boost controller
new caspers cam sensor cap
new turbotweak 5.7 chip
 
If it cuts out during a shift,the first thing I suspect is the cam sensor.
 
First, check to see if you have a spark plug with a cracked insulator. #6 is tough to get in, and you may have cracked one. Ask me how I know!:D If that doesn't help, go get a set of CR 43 TS plugs, and gap them at .025. I really prefer the CR plugs. The electrode is at least twice as big as the regular R plugs. I know .025 is tight but my car was blowing the fire out at.035. It just wont idle quite as smooth. But when you stand on it, the damn thing wont be cutting out either.
 
Im willing to try anything at this point. I will look into valve springs next. The new wires ohm out good, about 1/10th the resistance of the MSDs I took off. I hope its not the cam sensor, but I did get a new cap and timed it properly. The fuel pressure is great with the new pump and does rise in sync with the boost. I installed a hood mounted fuel pressure gauge.
 
It does cut out between shifts, or when the RPMs climb during a down shift. The trans holds the gear a long time before shifting, so it does cut out between shifts. It cuts out, and even sounded like a backfire once or twice. I certainly dont want to blow another head gasket. If I replace the coil pack, would I need to replace the ignition module also?
 
If it's holding the gear too long, you might be hitting the fuel cut, which is at 6000rpm in your chip. See if you can monitor what rpm its shifting at.
 
klmnla said:
It does cut out between shifts, or when the RPMs climb during a down shift. The trans holds the gear a long time before shifting, so it does cut out between shifts. It cuts out, and even sounded like a backfire once or twice. I certainly dont want to blow another head gasket. If I replace the coil pack, would I need to replace the ignition module also?
Click to expand...
It's not going to be two things and I doubt that it is the coil or module. Do you have a data logger?
 
I do not have a data logger, only a scanmaster. I will look at the RPMs on the scanmaster when it changes gears and see if Im hitting 6000RPMs.
 
Reset the tv cable. That should eliminate the variable of it taching 6000 rpms. I'm telling you dude, the issues you are having with it popping or backfiring are exactly what my car was doing.
 
Thanks. I will adjust the TV cable and possibly change the plugs again. Ill start with the basic stuff first as always.
 
Okay, I adjusted the TV cable and now it shifts closer to 2800 RPM, which is good for now. It did fine for about 5 minutes, and then started cutting out and sputtering again at wot. It never reached more than 3200 RPM. It seemed to get worse at it got hotter. Maybe I will try a set of CR43TS plugs before I move on to valve springs.
 
klmnla said:
Okay, I adjusted the TV cable and now it shifts closer to 2800 RPM, which is good for now. It did fine for about 5 minutes, and then started cutting out and sputtering again at wot. It never reached more than 3200 RPM. It seemed to get worse at it got hotter. Maybe I will try a set of CR43TS plugs before I move on to valve springs.
Click to expand...
There's only one adjustment for the TV cable. It must pull to its maximum travel at WOT. If you can grab the cable and pull it farther,when the throttle is wide open,you're not there yet.
 
klmnla said:
Okay, I adjusted the TV cable and now it shifts closer to 2800 RPM, which is good for now. It did fine for about 5 minutes, and then started cutting out and sputtering again at wot. It never reached more than 3200 RPM. It seemed to get worse at it got hotter. Maybe I will try a set of CR43TS plugs before I move on to valve springs.
Click to expand...
Did it act up during a shift?
 
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