Nobody

Mods: Comptech SC, stock pulley, T1R exhaust, test pipe, Fujitsubo headers, EMS.

Sequence of events:
Tues: Install headers and put silencer in to ensure I'm not running too lean for a drive down to LA. Keep the car under 6K the whole way there.

Wed: Conservatively drive to LA, no issues.

Thurs: Take car to Sean Church for EMS install and tuning. Found out he doesn't do installations, just tuning. Anyway...they disconnected the Blue and Green wires to the Comptech ESM and leave unplugged. EMS 1052 unit gets plugged into ECU's place, they tune the car for ~1.5 hrs. Car sounds great and runs with safe A/F ratios. Car dynos a little weak apparently at 311.7hp. Leave the parking lot, but the EMS is just dangling from the three harness plugs. I stop, put foam on the back of the EMS and duct tape it to the footwell so the harnesses aren't under tension. Everything runs ok, but I'm shifting conservatively and don't rev much past 6500 RPM on the way to the track.

Fri: Buttonwillow. Experienced three issues related to power loss:

1) Full throttle at high RPMs (7-9K) my car would cut out for a moment at the same time a "BUUH" burbled out the exhaust. Car would then continue revving to redline.

2) Under high G-loads I was getting fuel cut out completely--like I was hitting the rev limiter even if I was at 6 or 7000 rpm. After maybe a half a second, power would be restored and on my way I'd go.

3) Heat soak. More than normal--way more.

When I left the track and got on I-5 for the drive home my V1 didn't have power--and because my Comptech AC pump runs off the same power as the V1, I realized why the heat soak issues were so bad (and hoped that was causing no. 1 and 2 above).

Then today--on the street I was getting a fuel cut-out as described in #1 above. I turned around to come back home, punched it onto the freeway, hit ~7K rpm in second and the car died completely. Car would turn over, but wouldn't start. After stopping I turned the ignition off and back on I wouldn't hear the fuel pump. Figured fuel pump was dead. Called tow truck.

Get home. Disconnected EMS, plugged in stock ECU and the fuel pump came on. Car started after 5 or 6 seconds gassing it in conjunction with start button. Seems ok.

While disconnecting the stock ECU, I noticed the Brown wire with green stripe (?) has been cut and a male/female connector that had been spliced in (assume that Comptech did this)....but they were disconnected. Replugged them back together. Thought that this may be responsible for the fuel pump cut-off, but when I disconnected them the fuel pump still came on. Not sure what this wire is/does...?

Re-plug EMS in and viola--car started, idled a little rough, but seemed fine.

So though all is well (I think), I'm fearful that the same thing will happen again, leaving me stranded with an $80 tow again. Do fuel pumps normally go out like this? Is this a fuel pump issue or is it probably electrical? Have the fuel-cut outs been making me run dangerously lean? Or maybe are these issues being caused by the Comptech ESM (which is still plugged into Red and Black). What to do?


Thanks in advance.

xviper

Your questions may be better served in the F.I. forum. Moving.

ultimate lurker

I would definitely go back and recheck all wiring. The two wires that were left connected were the power and ground for the ESM. I don't know where they were tapped into, perhaps from the fuel pump lead (I hope not!).

Running hot with the intercooler pump off could create an issue, but your knock sensor was active, so it would be pulling out timing and dumping extra fuel to protect you in that case.

I haven't seen any pump failures on Comptech cars, but I've seen three Vortech cars with failed, or failing, pumps. If they use the same pumps, its something to think about.

Keep me posted!

UL

Nobody

Thanks for the feedback, UL.

Everything SEEMS fine now...although I do get a momentary "Boof" when at or near full throttle at various RPMS. Not sure if this could be the fuel cutting out or if it's extra unburnt fuel getting into the exhaust....

The ESM is connected with 'vampire' clips with a female clip. I can just remove the male lead/ground wires plugged in without affecting the lead that they're plugged into, right?

ultimate lurker

You can unplug the leads without issue. The miss at full throttle bothers me though. Keep an eye on it.

UL

evf2000

I had around the same problem about two weeks ago..turns out the car was running too rich as the EMS was dumping too much fuel in the car as the O2 sensor was going bad.. I had the same power loss and the car did eventually die. Once it was towed and checked the Ems was reset and plugs+O2 were replaced..car runs fine now.