'12 120R....D&D 2to1
A buddy bought a used unit. I helped him out with the map install. It has a bad stumble in the 2200-2500 RPM range. He says it's fine above there.
*O2 sensors test okay. (according to their test)
*No intake leak detected.
*Fuel pressure checks out okay.
*Rear cylinder will not level out, running rich. Below called for AFR (13 <> IIRC)
*Doesn't show errors detected.
*New plugs
He reinstalled the SE box and it doesn't stumble but he would like the Autotune unit. He does have 02 sensors for the SE unit still installed as there are 18mm bungs also.
I'm pretty well stumped on where to go from here. I thought I would post here before trying to talk to Zippers. I wanted to run a recording to send them but he (Frenchman :emoGroan: ) was too impatient. I have updated the adjusted fueling a few times to see if it will clear up to no avail.
Anyone?
Have you performed a leak down and compression test yet? How were the plugs and is there any oil in the intake or exhaust runner. Oil will tend to produce a black puff on hard throttle and run rich like a diesel with the added oil mix,.
Which map is installed?
kd - He did a comp test and IIRC it was a bit low but even. I will dig out my leakdown kit a check it out and tell him
to take a look for the oil. He said the plugs are good. You will understand when I say "Frenchman" eh?
rigidthumper - TBW #430
FWIW, I suspect something mechanical. That POS just won't stay together. He runs good fast but doesn't beat it. OCD for maintenance. Doesn't stay together for more than a year or two.
BTW, it has S&S Super Stock heads. Stock ones didn't last long.
More info.... 58mm throttle body, Woods 408-6 cams, no info on the injector size. Compression 195/185.
Quote from: fbn ent on June 21, 2022, 09:32:00 AMkd - He did a comp test and IIRC it was a bit low but even. I will dig out my leakdown kit a check it out and tell him
to take a look for the oil. He said the plugs are good. You will understand when I say "Frenchman" eh?
rigidthumper - TBW #430
FWIW, I suspect something mechanical. That POS just won't stay together. He runs good fast but doesn't beat it. OCD for maintenance. Doesn't stay together for more than a year or two.
BTW, it has S&S Super Stock heads. Stock ones didn't last long.
Randy, I only suggested the tests and checking the ports for oil contamination because I had the same issue with a 120. It seemed to be rich and even belched black smoke on a heavy hit (contrary to what I expected for oil burning). It showed as wet in the intake runner by holding the throttle blade open with a screwdriver and using a light and would make you tear up like it was rich. Finding that is followed by no good news. My test was 205+ in both cylinders and even. That Wood cam has a bit of overlap and will carry oil back into the intake at the rpm you are experiencing the symptoms if it is in the cylinder. Take a peak.
Try Changing the Speed sensor and Crank Position sensors ...Ive seen either one cause things like this and not throw any codes
Quote from: HV on June 23, 2022, 02:38:32 AMTry Changing the Speed sensor and Crank Position sensors ...Ive seen either one cause things like this and not throw any codes
Yeah, I know the crank sensor is always a possible issue, I have a couple spare he can try. Didn't think the speed sensor could do it. I'll try some more when he decides to try the TMAX again.
I had one with a speed sensor out of rage reading low MPH all the time... it caused issues with performance at high speed ( on a stock ECM )
Quote from: HV on June 25, 2022, 08:57:40 AMI had one with a speed sensor out of rage reading low MPH all the time... it caused issues with performance at high speed ( on a stock ECM )
The issue isn't present now that he put the SE box back in BUT it doesn't run as well as the TMax when it is out of the problematic RPM range.
When you say SE box- is this a factory ECM with a SE 120R tune in it?
Also the stock ECM is a speed Density program... T Max is Alpha N it is not as dependent on a speed