I bought AutoEnginuity PC Scan Tool to run more tests. Running Cylinder Contribution test showed no problems, but was unable to run this test while the problem was actually occurring (the test would not run until oil temp was above a certain level, and I could not get the problem to recur at that time).
Running Injector Buzz Test: Inconsistent results. Once it passed okay, other times it showed some or all of the following faults:
P0261 Cyl #1 Injection Circuit Low
P0262 Cyl #1 Injection Circuit High
P1271 Cyl #1 High to Low Side Open
P1273 Cyl #3 High to Low Side Open
P1293 Injector High Side Open Bank #1
I have not yet changed the UVC harnesses on bank #1 (passenger's side). I did notice that there was a lot of oil in the outside connector for cylinders #1 & #3 (the whole cavity was filled with oil). I cleaned it out, along with the terminals, and applied dielectric grease. I had noticed that the whole bank's injector circuits would show ~4k ohms continuity to ground when the front connector was in place, and zero continuity to ground when that connector was removed (which suggests some leakage on the #1-#3 UVC harness). I measured the resistance across the injectors themselves, from the IDM connection, and found around 3.0 ohms for the driver's side (which has new UVC harnesses), and around 4.0 ohms for the passenger's side.
Other pertinent items I have noticed:
1) I have now run the engine with the problem occurring for up to 10 minutes, with no fault codes being set. I suspect my previous fault codes were unrelated to this problem or a secondary issue (possibly caused by the rough running?)
2) When the problem occurs, the CEL turns on a just BEFORE the engine starts running rough, which makes me think it is in some sort of limp home mode.
3) When the problem occurs, the left bank shows a increase in EGT just to idle (up around 350°F for idling compared to 220-250 normally). The post-turbo pyro shows a normal temperature.
4) I can completely duplicate the way the engine runs during the problem (except for the CEL turning on) by disconnecting BOTH injector harnesses on the passenger's side valve cover (causing it to run on 4 cylinders). This leads me to believe that the IDM is turning the right bank completely off when the problem happens.
5) Not sure if it is relevant or just a coincidence, but I have never had the problem occur when the engine was up to normal operating temperature. It always occurs within the first few minutes of startup.
Is it possible that the slight discontinuity in the UVC harnesses is causing the IDM to turn off that bank, without setting a code? Or is my IDM just going nuts? A friend is shipping his extra IDM to me to test, but it may not arrive by the weekend.
I am trying desperately to get this thing running in time for the NHRDA race this Saturday (I am sitting in 4th place in points). I also need it for testing our new gauge line (although I am getting plenty of gauge testing while troubleshooting this stupid problem!).
A local wrecking yard has a '99 IDM for $275. Is this a good price?
1995 F350 PSD Crew Cab Dually, 271k miles
10 ISSPRO Prototype Performax™ gauges in Pillar & Overhead pods & sitting on dash, Tymar Intake, Gutted EBPV, Tymar 3x4" downpipe, Tymar 5" exhaust, Cat's hiding in the shed, Baby Swamps, Swamps tunes, Tricumulator springs and Accumulator Valve, Tru-Cool 4590 Trans Cooler, Lock-Right Locker
1998 S&S 9.5' slide-in camper
32' enclosed tag trailer with 2 drag cars (73 Vega Super-Gas & 74 Vega ET Super-Pro)
1992 GMC Typhoon, 1973 Chevy Blazer with Pontiac 400, 1973 Trans-Am 455
2000 VW Jetta TDI - Kerma tune, Der Chimera Stage II Clutch
NRA member and certified firearms instructor, GOA Life member, IDPA member