[quote=“Rob in VA” post=58788]Are there any plans of doing the tech checks again?
Looks like a good group of drivers. I’m not sure about that Cameron dude though. :silly:
hahah I’m going to remember that!
Mid Ohio - Aug 2011
SpeedSmith
#22
Man down…
My season may have taken an ugly turn for the not-so-good. In troubleshooting the issues from this past event I found some melted wiring. Unfortunately, this wiring leads from the main relay (little guy next to the fuel pump relay), through the the main harness (under the intake), across the firewall, and to the kill switch (which was properly wired). From there it hits the ECU and on to the fuel pump.
This troubleshooting began when I went to back the car out of the trailer. I turned the key, got a healthy starter, got healthy spark, but no fuel (I believe the pump should cycle at key turn for a few seconds to prime the line). So I pushed the car into the garage, swapped the kill switch (the old one had three out of four very loose pin terminals, but no scoring, plus wiring looked good). Next I swapped the fuel pump relay and later the fuel pump (per the Bentley). Nadda…the fuel pump never turns on. So that got me tracing wires under the car, as well as looking at the main relay and harness to the ECU. That’s when I found the melted wire. What’s odd is that the melt looks to be very old - there’s no melted-wire-smell. Weirder is that the car ran at Mid-Ohio, I drove it into the trailer under it’s own power (no electrical fire smoke or smell). So far I’ve traced melted wiring from the main relay, up to the engine block. I’ll trace it further tomorrow.
So…does anyone have a wiring diagram for the engine harness (with Main relay)? My Bentley is lacking this valuable info. The car is post 88, so Metronic 1.x with the single (in-tank)fuel pump. The melted wire is red and yellow (comes of the center pin of the main relay and has a jumper to the fuel pump relay which is not melted). I’ll get some pics once the camera has charged. I need to know what this red and yellow wire is supposed to do. From there I’ll carefully open up the rest of the loom to assess the damage. If it’s bad, I’ll likely need to consider an engine harness which has other ramifications.
Anyway, this has turned into a house of cards. If I can’t make this weekend, I don’t qualify for Nationals, and that bumps the suck factor up to 11. Wish me luck!
SpeedSmith
#24
Thanks! For some reason, the only reference to the Main Relay is a picture of it. 
I’ll keep digging.
Z3SpdDmn
#25
I fried my harness in April and had another swapped in. That resulted in a host of other problems, but the fuel pump is now hard wired to a dash switch. I would suggest doing this regardless.
FishMan
#26
Kyle, swapping the engine harness isn’t difficult and can be acomplished in two hours or so. I swapped mine on Saturday because the car wouldn’t run after the coil shorted on the manifold. If you don’t like the idea of a fuel pump switch, swapping to a different harness is likely less time consuming than chasing down electrical gremlins.
SpeedSmith
#27
Thanks guys! It looks like this is not limited to the engine harness. I’ve traced the carnage back to the fuse panel. The red/yellow wire splits off towards the fuse panel, entering at the diagnostic port near the firewall (to the left of the fuse panel when viewed from the front of the car). This wire turns to a solid light brown wire (or maybe light brow and white). Its hard to tell as it’s very melted. It doesn’t appear to terminate at the fuse panel. Instead, it follows the main bundle through the firewall under the dash. A quick under dash inspection hasn’t yielded any melted wires. But it’s late and I’ve got to be in the office early tomorrow.
More to come tomorrow night.
Z3SpdDmn
#28
See if it goes to your ignition. That’s what happened to mine. But there was something in the chassis harness that was still bad.
Rich, you got lucky that you only harmed your engine side harness…
Z3SpdDmn
#29
Does anyone have a fuel level sending unit for an early ('87) car? I can’t figure out if it’s bad or not through testing, although it seems to be bad… I supply power and ground and don’t get a reading out of the middle pin.
SpeedSmith
#31
Guy’s I’m out for the weekend. I still have a fair amount work trying to figure out what’s what. Near as I can tell the old fuel pump took a dump. In the process it cooked a lot of wiring. I did find that someone had swapped the 7.5 Amp fuse in position 10 with a 30 amp fuse. That didn’t help the situation any. I still feel like this is fixable, but not for this event.
Have a safe and fun weekend!!!
Elephant4
#34
[quote=“Z3SpdDmn” post=59164]Who has video from Sunday?!
I don’t :([/quote]
I don’t either, in my rush to switch to drys I had forgot to start the camera. I had some great footage of Anthony (almost went off, nice save) & Rob. Plus the start where I got gobbled up from all sides and then was just a pinball in the middle. And then there was the GTS3 car that was parked in the middle of the track over madness, I went to go around the front of his car (I had a car to my outside) and he started moving as I was trying to drive by, I had to drive off into the grass to avoid clobbering him. Definitely an eventful race with the changing conditions, I was definitely on the right tire though. Great weekend all around, I’m ready for Nationals.
barkerdm
#35
I’ll have my video from Sunday up soon. Yeah, it doesn’t show the exciting battle up front, but Sean and I had a pretty good finish.
StageOne
#39
Saturday: http://vimeo.com/27817959
Sunday: http://vimeo.com/27820237
Had a good race with Denny on Sun, the last few laps were fun.
Sean