Occasionally jumping rich while cruising

[J&H Ryan]

Hi,

Setup is a TIII with a 255 Walbro, stock fuel pressure regulator, +40s, also have methanol injection.

Problem is that occasionally and randomly the car will go from happy ~14.7 cruising and jump to ~10.5, stumble for a fraction of a second, then ok for 30 seconds, then does it again. Has no pattern that I've been able to determine, i.e. after acceleration, cold, warm, etc.

Now I was thinking that maybe it was the pump w/o an adjustable regulator, but don't want to just throw parts at it since its so random. I would think if there were too high a pressure, it would always be rich. Full boost is at a happy 10.5-11 tops. I also though maybe it was one of the methanol injectors leaking, but it seems to do it with the system off too.

Any thoughts or ideas?

[cordes]

Will it do it only at cruise? I've had a faulty ign. switch cause a condition like this before which was a nightmare to track down. I've also had a faulty alt. do this for some time before it died. Once the new one was installed, the car never did it again.

[fixit]

coil plugs wires?

[wheming]

Had something fairly similar happen on my 8v and eventually got worse to much worse. Found out is was a bad ignition coil.
I know the TIII is a bit different, but might be a flaking coil pack?

[GLHNSLHT2]

TPS. car thinks it's going to WOT and floods the motor. Had it happen on my 8v. Can't remember if I could see it on the scanner or not.

[wheming]

TPS. car thinks it's going to WOT and floods the motor. Had it happen on my 8v. Can't remember if I could see it on the scanner or not.

O.P. can you log using MPScan or some other way?
Or monitor with a scan tool?
I think you should see something.

[J&H Ryan]

Will it do it only at cruise? I've had a faulty ign. switch cause a condition like this before which was a nightmare to track down. I've also had a faulty alt. do this for some time before it died. Once the new one was installed, the car never did it again.

That sounds like fun. How did you check the switch, just swapped it?

O.P. can you log using MPScan or some other way?
Or monitor with a scan tool?
I think you should see something.

So I haven't been active with my TM in a decade and had no idea what you were talking about. I found the software https://sites.google.com/site/mpsuite/mpscan but not a real good guide to use it. The links I did find at TD.com were all dead, including those posted by Rob Lloyd himself. On here there is a thread: http://www.turbo-mopar.com/forums/showthread.php?47905-MPScan/page2

Seems I need https://www.amazon.com/JBtek-WINDOWS...4356108&sr=8-8 ? Install, plug it into my car and run? Any good tutorial(s) out there (i haven't found any or the videos someone mentioned)?

[cordes]

It took about 6mo. to track down the switch. It finally died with enough regularity that I was able to see that an entire bus of the fuse block would be off when the car would not start. I traced it back to one pin on the ign switch. I had a short in my blower motor which was causing it to pull enough amps to run some serious current through that switch and kill it. That happened a couple of times before I figured out the problem. A relay at the blower motor solved the issue for good.

[wheming]

So I haven't been active with my TM in a decade and had no idea what you were talking about. I found the software https://sites.google.com/site/mpsuite/mpscan but not a real good guide to use it. The links I did find at TD.com were all dead, including those posted by Rob Lloyd himself. On here there is a thread: http://www.turbo-mopar.com/forums/showthread.php?47905-MPScan/page2

Seems I need https://www.amazon.com/JBtek-WINDOWS...4356108&sr=8-8 ? Install, plug it into my car and run? Any good tutorial(s) out there (i haven't found any or the videos someone mentioned)?

Ok, I had been away for a while too at one point. When i got back, this was a new development. It is pretty cool what we have now, thanks to several smart folks that have made all sorts of developments.
Now, i will say the learning curve can be a bit involved, depending on your computer knowledge / competence.

If you've got the software from the MPScan thread, that's good.
Go here for the FTDI cable setup:
http://www.turbo-mopar.com/forums/sh...d.php?p=593977
If you need a cable, that could be the hard part. I don't know if anyone is making the cable available "turn-key", but the end user can make their own. I think the info is in the same thread. (That is for the MPTune software, but they use the same cable to communicate to the diagnostic port on your engine harness. )

Once you have those pieces setup, we can help with the next phase, setting up a gauge layout so you can log. Morris (wowzer on here) has some youtube videos that are very helpful to get a basic setup working.

The logging software is also available in android version, but you need an android operating system device (phone or tablet ) and you still need the FTDI cable, and a usb OTG (usb on-the-go) connector to plug the cable to the phone/tablet. You will of course need the android version software, MPScanDroid2. Setup as far as gauge layout stuff is similar, so it is not wasted effort learning either or both.
(Its nice having a couple options if you have PC problems you can still log with your phone...)

MPTune is the tuning software for use with chip burning or flashable engine controllers.

The cable you referenced will need to be verified by one of the more knowledgeable guys. I know the BoostButton flash cable i bought had a small board built into the end, it was more than just making up the spade terminals. There might be more discussion in those threads, but i know looking through all of those posts is a challenge.

The next big evolution is very close, and the flash cable will not be necessary, but it is still a little bit before a finished product will be available. So, while you might eventually be out the cost of the cable, i wouldn't wait for what ability you gain now to be able to log and aid in diagnostics.

I think i have some videos on youtube of logging or troubleshooting, and of the new device MPSciLink.

Testing MPSCANDROID: https://youtu.be/sphOZ_Ft0MQ

MPSCILINK testing: https://youtu.be/DgbLcneqRMk