At the track, car is giving problems

#1

The german is stubborn today. My first session out for the test day and the car completely died coming out of 11. It kind of wanted to start but wouldn’t.

I let it sit for a minute and started checking stuff out. I couldn’t find anything obvious. I did not bring my fuel pressure gauge kit with me so I can’t check that but fuel is flowing from the test port decently. Not sure how much it is supposed to spray. It wasn’t a spray though.

I started it back up and it ran just fine for some reason. I drove around the paddock and revd the crap out of it. I’ve got spark. Not sure how good of a spark…

Get back out on track for the next session and first hard corner it starts cutting out bad again. It somewhat came back on the straight making me think it was a fuel problem. Then I noticed the check engine light flickering, which it has never done before. At this point the car was bucking under any throttle application but will stay running.

I would think if it was a fuel pump or something related that it just wouldn’t run.

Ideas?

#2

Are all your relays zip-tied in tight?
Coil wire issues?

#3

it sounds electrical. Um perhaps your car is intermittently losing electrical power. Check the main connector underneath the steering column about knee level.

#4

Well, I took the pump covers off and when I was “jiggling” the connector for the pump it stopped working. Fiddling around with the connector had it going again, but it looks like I need a new connector. I took the connector apart and it literally disintegrated in my hand with light pressure.

I need to find someone with a solder gun for a temporary fix, and I don’t even know if this is the real problem.

#5

Intermittent problems can be a bastard. When I was fighting engine management issues all thru 2009 I ended up putting a fuel pressure gauge on my dash. It was very helpful to be able to rule out fuel pressure as a possible cause when chasing engine hiccups.

I’ve never heard of the CEL flickering like that. Odd.

I agree that it sounds electrical. Cleaning the pins of the master relay, fuel pump relay, and the connector to the injectors is all a good idea. Scratch up the copper surfaces a little bit and then put on some conductive grease. Put a hole in the bottom of the boot a of the injector harness connector so water can drain out isn’t a bad idea.

One of the things I did during the year of engine management problems was hardwire the injector harness with individual connectors, and disassemble, clean and put conductive grease on every significant electrical connection in the car, with special care at the grounds. None of that did any good because my problem turned out to be my AFM, but I did see a small increase in voltage pretty much everywhere in the car and the DME is quite sensitive to voltage drops. My intent here is to give you ideas for ensuring a solid electrical system, not so much suggest that my 2009 problems were related to your current ones.

Later edit. The loose FP wire fits the symptoms (obviously), except for the flickering CEL. May be more than one problem.

#6

1444 code so nothing was wrong? The car was bucking and backfiring pretty hard when it was flickering. Any throttle would cause the problem.

Took the fuel pump out and checked all the connections (first time doing this). Everything looked ok, and the screen didn’t have a ton of debris. Even the rubber lines looked decent. It looks like the sender is original, and the pump has been replaced (and with a nice bosch one!).

We shall see if this works. I do not have a ton of confidence in my soldering on that round plug, but we shall see. The whole connector just fell apart in my hand and while the engine was running, rotating the connector would have the pump cut out.

I also found that interestingly, when I wired my fan into the A/C switch, if I press that switch to turn on the fan, it appears that also stops the pump from working. Note to self. Maybe it is working, but you definitely cannot hear the faint whine. Maybe that’s because the fan is loud. Not sure.

#7

Master kill switch can do that.

#8

Did not work. Car seemed to be less touchy on right hand turns, but the slightest left hand turn has it basically shutting down.

If I let it sit and coast for a second then pop the clutch and downshift, it comes back to life, but not every time.

So strange and I don’t have many tools here.

I took the C191 connector and looked at it. I can’t tell if it has corrosion or grease in it.

I’m basically stumped now. It runs fine in the pit and just driving around. Hard cornering has it being very upset.

#9

I fixed it. Hate to admit what the problem was, but…

I went up on the curbing and jolted the car pretty good. Apparently that was enough to bump the fuel pump relay out of its holding clips. It was just sitting in there and making contact when it damn well felt it wanted to. Hard cornering would pop it just out of place and I would lose pressure.

I had left my pressure tester at home, so I went to Auto Zone and picked up a rental. Read 10psi or 0. Idle is at 38, and remove the regulator it goes to 43-44psi.

I hope that is the correct pressure, but I did go back out and it ran just fine.

#10

I’ve had exactly the same problem with exactly those symptoms. In my case it was a bad contact in the relay socket. Some contact cleaner and multiple relay insertions made it through the weekend. But the real fault was high resistance in a wires termination. For that and other similar reasons the car now has a brand new harness.

#11

I second that. I had similar symptoms when my master kill switch was slowly failing. Couldn’t figure it out until the switch finally died completely.