My embarrassing trip to Lime Rock - Elec issue


#1

Very excited for my first trip to Lime Rock Park. Thought I had the car sorted and ready to go, but I was sadly mistaken. Brand new RRs installed for the weekend’s 3 sprint races and an Enduro I was going to run with my father. Half way through the Test & Tune day, I noticed an occasional miss above 3,000 rpm. Ask around the paddock for recommendations, all of which included spare parts swapping with stuff that I had not brought. I fiddled with a few wires to make sure they weren’t just loose and pulled the O2 sensor connection. No changes. As the day next day arrived, I was getting more and more concerned as the car wouldn’t make any power above 3,000 and rpm would build so slowly I couldn’t manage more than 90 mph on the front straight (down 20 mph from the previous day). The rain didn’t help me in the enduro, neither did brand new RRs, and the miss made me a problem for the rest of the field. I packed it in and left a day early because I was afraid to show my face after that performance. Now I’d like to figure out what the problem is with the car, but I’m terrible with electrical troubleshooting. Here is a list of what I’ve noticed thus far…

  • If I don’t throw the kill switch and let the car sit for more than a day, I have to jump it to get it started
  • Several fuses were blown at the track including the 30A for the computer and 1 fuse for the “ignition electronics” and the power windows. Replacing them didn’t help.
  • Full or part throttle, it doesn’t matter the car will still miss
  • My main relay is zip-tied down
  • All my gauges seem to work fine
  • With the miss, I believe it smells quite rich, so it’s an ignition problem and not fuel

I have not begun swapping parts out yet, but I would love anybody to point me in a direction to start with first. The spark plug wires are a bit on the old side, the coil has about 8 track days on it, the plugs are 3 track days old.


#2

Did you ever find a fix?

I dont know you, but you probably shouldn’t have run off, It has been my experience that anyone else with an e30 would have been glad to lend you some spares to TEST if that would fix the issue.

Could be a few things. Try swapping out the Mass air flow meter box with a known good one
I know it smells rich but when was the Fuel pump/pumps filter replaced?
Swap out the ECU
Look for a vacuum leak(not sure if this would lead to your symptoms)


#3

I spoke with 2 other SpecE30 guys who made a few suggestions, but unfortunately did not have spare parts to loan out to help troubleshoot. Nor would I ask in the event I broke something and left someone short the spare parts they appropriately planned and brought. I need to start bringing more spares to the track with me, lesson learned.

I looked around a few other forums and found vacuum leaks as a possible source as well. I noticed a leak at the oil cap, which had been a source for vacuum leaks in the past. I will order another one with the other parts I plan to swap out. The fuel pumps/filter were replaced a couple seasons ago when I installed a brand new tank. They don’t have many miles on them, but they are a few seasons old. I hadn’t planned on a new ECU or air flow meter, but I’ll see if I can borrow a known good unit in addition to the other parts.

I haven’t touched the car yet, but I will soon as I hope to be at Watkins Glen at the end of September.


#4

Finally got around to replacing parts to fix this issue.

Started with things I could reach from the top. New coil, new plug wires, new plugs (which were horribly coated with crust, no gap at all on 2), new coolant temp sensor, new CPS, new fuses (because, why not…).

Next, I put the car up on the lift to check the ground strap and other wires. This is when I gently pushed on the alternator and rocked it about 1/4". The bottom bolt was loose by about 3 turns. I tightened that up and checked the ground strap at the oil pan, which looked pretty good actually.

I haven’t had a chance to take it out just yet and see what it does under load now, but I’m hoping to make WGI at the end of September.


#5

Car pulls just fine up to 6,000 rpm and will hold it for a while in any gear. Checked the car over after and noticed a ton of oil in the air box and some serious wetness around the oil cap (brand new before the test drive). Might have a crankcase pressure issue…