Off Idle Problems
- Thread starter johnmbod
- Start date
-
- Tags
- backfire power loss tuning
- Joined
- May 28, 2001
Rpm actual vs programmed is too far off the target.
Does the backfire come thru the intake, or exh?
The log will help.
Fuel psi is?
Does the backfire come thru the intake, or exh?
The log will help.
Fuel psi is?
Backfire is through the intake. Fuel pressure is 40 with the line attached, 45 removed. I drove it around, if I am ginger with the throttle I can get it to accelerate, but I cant get to boost. Here are the log files. LogFile is recorded while driving around, LogFile after drive is parked in garage. IAC numbers are off. LogFile after drive IAC adjust, is after I readjusted IAC and TPS.
- Joined
- Feb 18, 2006
Pull the valve covers and check rocker travel. I would do the driver side first and look at number three exhaust. What you describe sounds like a worn cam lobe
I put the TR6 in mode 3 to check cam sensor alignment. The sensor was 25deg retarded. Manual recommends 5 deg advance. I set the sensor correctly, and took it for a drive. I gingerly accelerated and got it up to ~7lbs of boost. I came back and checked plugs, #6 looked lie the pic. It looks like it melted. I replaced all of the plugs, still doing the same thing, it is still backfiring the same as before. I also added a ground to the TR6. Here is the log from the drive. I checked the rockers, no bad lobes.
Last edited:
- Joined
- May 28, 2001
At some point in it's life, that was an extended tip plug. Detonation has not only "eaten" the electrode off, there's a considerable amt of porcelain gone.I'd suggest taking a "look" w/ a scope.
.Is this the only plug that has parts "missing in action"?
What do the rest of them look like?
Did you put the same # back in?
.Is this the only plug that has parts "missing in action"?
What do the rest of them look like?
Did you put the same # back in?
No disintegrations
Well-Known Member
- Joined
- Dec 27, 2015
The thing to take away from this is data loggers and scanners are good, but checking the plugs should be step one or near the top of the list. Also pull boost and timing and add octane or you'll run over the crank as Chuck likes to say. 
Last edited:
- Joined
- Feb 18, 2006
Sounds like injectors need to be checked. Chuck can do it.
- Joined
- May 28, 2001
Suggest you get the right plugs, and quit screwing around w/ a time bomb....
Are those Champion plugs? If so there's a little thing you need to to to make them work.
First remove all six and hold them in your dominate hand. Then walk out onto the back porch and throw them as far as you can. Next, walk out there pick them up and throw them again.
Back when i was a cervix manager I used to make a fortune ''fixing'' machines by putting NGK's in place of Champions.
You backfiring descriptions sounds exactly like an issue I had a few yeas ago with crudded up injectors. No matter what I did or how I laid into it, at 5PSI it would fall on it's face and backfire. It felt and acted soooo much like electrical.
After a week or troubleshooting and swapping I sent the injectors to Chuck. Turns out my fuel filter came apart and dumped a bunch of fine rust into my injector baskets at once.
First remove all six and hold them in your dominate hand. Then walk out onto the back porch and throw them as far as you can. Next, walk out there pick them up and throw them again.
Back when i was a cervix manager I used to make a fortune ''fixing'' machines by putting NGK's in place of Champions.
You backfiring descriptions sounds exactly like an issue I had a few yeas ago with crudded up injectors. No matter what I did or how I laid into it, at 5PSI it would fall on it's face and backfire. It felt and acted soooo much like electrical.
After a week or troubleshooting and swapping I sent the injectors to Chuck. Turns out my fuel filter came apart and dumped a bunch of fine rust into my injector baskets at once.
We fixed it. The TR6 was malfunctioning, and arcing to ground. Put in some AC delco plugs, and put the stock ignition back in. The reason it was breaking up in the first place that started all of this looks like the cam sensor alignment. The good news is that I didn't hurt the motor. Thank you all for the help, couldn't have done it without you. Track time tomorrow!
