'93 Integ racer - Stalling at WOT, 4th/5th Gear

Hey all,

I'm new here at the board, but not to Integras. We've been racing our '93 in 24-Hrs LeMons and Chumpcar events since 2009. I did a search and read through the FAQ, but didn't find any threads exactly covering our issue, which is stalling at WOT, sometimes in 4th but mostly in 5th gear at pretty good speed.

This thread is similar, but we've had our injectors cleaned and flow checked:

http://www.clubintegra.com/board/showthread.php?t=81309

Engine was recently rebuilt, car runs strong other than having this issue. Below is a video clip of our testing at VIR last week. Problem begins about 3 mins in, 5 times during a 10 min stint. We tried swapping the distributor, swapped ECU, battery, and tried plugging a vac line near the fuel rail. The solution after the stall is to turn ignition OFF/ON for a bump-start, which was not acceptable for racing, so we opted not to start. Huge bummer, but hoping to set this out before next race.

FYI, we had a similar issue a couple years ago coming out of hard right hand turns. It seemed to go away after we swapped ECU and some wiring. Now it seems to happen in right handers, but sometimes happens in the straights, so it's more random. We are at a loss to what's going on. Any help or insight is greatly appreciated!

Thanks in advance,
Aaron

Video Link: http://youtu.be/KmTatBT6H6w

[YOUTUBE="http://youtu.be/KmTatBT6H6w"][/YOUTUBE]

Im leaning towards a power failure caused by the ignition switch. (or main relay possibly)

Thanks! We haven't yet replaced the lock cylinder, but it is next on our list.

Yea it seems something may be getting too hot as well and causing a short or failure. Possibly around the distributor, igniter maybe, or more likely a relay. You definitely seem to loose spark, not fuel or it wouldn't cut off so quickly.

If he could replicate this in a controlled environment, maybe drive it around the parking lot until it happens, then do some diag with your multimeter. I think he'll find that nothing has power (ecu, fuel pump, ignition etc). Or if an individual component doesn't have power then you can easily troubleshoot it.

Thanks for the replies. Muckman: we cannot replicate the problem except under the loads and conditions you see in the video. It will never stall under any driving on public roads. In fact, prior to our race at VIR, we tested the car at Gingerman raceway and had zero problems.

This issue has only occurred in 4th and 5th gears at ~95 mph and over.

Then perhaps Aussie is correct about a short. Is it possible to do a test lap to recreate the condition and then tow it back to the pits for diag?

Unfortunately, we don't have a track at our disposal. We attempted to isolate the cause for 6 hours on test day (see video link). We ran out of parts to change. Since we have no way to diagnose, and track time is limited, we want to make some educated guesses at what the problem might be, replace suspect parts, then go test again. So far, some good ideas!

Diagnosis can be difficult, as the problem is fixed by resetting - switching key OFF to ON to restart. One driver said he let the car slow down and was able to bump start without turning the ignition off. I need to confirm this with the video.

Are those solid motor mounts? Excessive vibrations could be intermittently killing your electronics causing you to stall when there's the most GeForce present, but this is just a guess.

That's a good point. There are a lot of vibration in the car, but partly it's the lack of sound-deadening insulation. I'll take a look at the mounts - I think they're OEM...

I'm just theory crafting here, but if you were to bypass the main relay and setup an independent wiring/toggle just for the fuel pump and re create the same scenario. If it won't solve the problem you can atleast cut the fuel system out of the list and go straight to ignition.

It's gotta be ignition, in fact I'd say it's not the main relay because that will cut fuel as well won't it? There was no stutter when it died, it acted exactly like a rev control that uses ignition cut. This would be so much easier with some data-logging, but I understand this is lemons as that's probably not in the budget

Thanks for the ideas. We agree it seems more like ignition than fuel. I was at first thinking fuel because of the tendency to occur in high-G right turns, but these forces could also have an effect on wiring or the ignition cyl. And it did occur a couple times in the straights...

My data logging equipment is OBD II, so this car is a few years early for that. I'm not sure what we would need to log a scan on this car.

What are your under hood temps?

This could be intertwined with the engine fail safe to kill the engine after it gets too hot.

Extreme temp spikes maybe? It would be worth looking into.

Could remedy the problem with coolant addictives, lower temp thermostat etc.

Oil coolers.

There's no temperature fail-safe on these. The only thing that would restrict the motor is the knock-sensor if it has it but it's definitely not that.