ENGINE FULL OF GAS!!

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PostPosted: Tue May 08, 2018 9:28 am
Pay attention to this:

There is a problem with a FEW of the ECU's that short the fuel relay that make the pump run and not shut off. It effect the number 4 injector.

At Daytona this weekend my car would not turn over. It did a weak plug fire when I turned on the ignition switch (!) but the starter would not turn the engine over. It was strange to get a plug to fire by just turning on the ignition switch and not pushing the starter button. I knew something electrical was going on.

So, I charged the battery for 30 min and it still would not turn the engine over. Hummm, now I put in a new starter, battery and master switch. Still, the engine would not turn over. However the ground cable for the battery got really hot and started smoking.

We pushed the car outside and tried to push start it but the rear wheels would not turn when the clutch was released. We did this twice and realized there was something else wrong. The engine was seized!

I notice as we pushed the car back into the garage that there was a fuel leak. Great, another problem...

All the fuel fittings were tight but there was fuel leaking down the back side of the engine. I traced it to the throttle body. Then I noticed another puddle and it was from the breather bottle.

I emptied the breather bottle and it was mostly fuel and some oil. How did fuel get into the bottle....

I removed the spark plugs and looked inside of the cylinders and they were full of fuel. I left the master switch on but the IGNITION SWITCH OFF and turned the engine over with a towel over the cylinder head and tons of fuel came out of the cylinders.

I put the plugs back in a turned on the master switch again and carefully held my finger over the opening of the breather hose into the breather bottle and a stream of fuel was running into the bottle.

Soooooo, with the breather hose high up on the block, I was thinking there is a lot of gas IN the engine. I was correct. When I drained the oil pan, I got over 2 gallons of oil/gas!!!

I changed the relay for the fuel pump but that did not help. Luckily I had a second car there that I was going to do the test day with so I took the ECU from it but that did not cure the problem. I left the spare ECU in the car and got another relay.

That fixed the problem. A new ECU and a new relay.

The original ECU has a couple of shorted wires inside that make the number 4 injector open and the fuel pump run. This was the second event on the car.

After draining the engine, hoses, oil cooler and changed the oil and filter I started the car and it ran fine. I changed the oil and filter again and ran the car in the next test session where it ran fine. I qualified 4th so the car was running OK.

So here is my message, if the car will not turn over and you have a good battery, pull the plugs and look inside of the cylinders and see if there is a puddle of fuel on the pistons. If so, try another ECU and fuel pump relay. And change your oil, clean out the oil cooler and lines and a new oil filter. Probably do the fuel filter also.

The next day, Mike Davies and Kevin from Comprent said it is a problem with a few of the ECU's. It's a problem that we need to know about.

I had help on this issue from Duane Neyer and his crew guy Chris and Mark Eaton. We got it figured out and the car ran great in the races the next day.
Mick Robinson

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PostPosted: Tue May 08, 2018 11:08 am
You are very very lucky it didn't actually try to turn over.

I put a hole in an LS6 that had fuel lock in a cylinder due to an ECU issue. Engine tried to start, fuel didn't compress in cylinder, and hole appeared in block.....

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PostPosted: Tue May 08, 2018 3:30 pm
I was more amazed that when the ignition switch was turned on, a plug fired!!! Not sure what would have happened if some of the fuel ignited that was in the throttle body and the intake manifold. BOOM!
Mick Robinson
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PostPosted: Wed May 09, 2018 3:09 pm
Thanks for the warning Mick! I'm headed out for my maiden voyage this weekend. I hope I don't have one of those ECUs.
Kurt Breitinger
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PostPosted: Mon May 14, 2018 9:30 am
Andrew W had this happen this past weekend at VIR, thankfully we were aware of the problem and John Hagerman was there with a spare ECU to save the weekend.

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PostPosted: Mon May 14, 2018 12:02 pm
Mick, first of all thanks for posting this problem. Had you not done so, we would not have been aware of this situation and that is not good.

So if I understand the situation correctly, the ECU malfunctions, causing the fuel pump to run continuously rather than the 5 seconds or so it normally runs. This leads to a defective relay which needs to be replaced along with the ECU not to mention all the work and expense purging the system.

The key is to identify this as soon as possible, so that you can avoid purging the oil system and perhaps a very big boom and a $5,800 bill for a new engine. It would seem to me that there might be several other owners out there, like us, that had no clue about this issue.

Perhaps our situation is unusual, as we are not regularily at the track and when we do there are times, at regional races, where there is no CSR present. Basically what that means is our weekends would be over, even if we found the problem prior to any damage unless we have a spare ECU. So my first reaction was the need to have a spare ECU at races where there are no CSR's or for other races, the CSR's have several on hand to loan.

So when checking the cost of a spare ECU it looks like they go for about $1,200, not crums, even to some politicians. Won't mention any states.

So as I see this, the vendor of our ECU's should have a vested interest in avoiding, as Mick would say a big boom! For those of us who do regional races, where there are no CSR's present, it would seem making a spare available at a decent price would be in order. Thoughts?

Pat

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PostPosted: Mon May 14, 2018 12:13 pm
kurtbob wrote:Thanks for the warning Mick! I'm headed out for my maiden voyage this weekend. I hope I don't have one of those ECUs.


A working theory that I heard at VIR is that it is an ECU board failure (age/vibration, etc) that causes the continuous grounding of the #4 injector, which means it is always "on" and injecting. It could be a random thing that might affect anyone.
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PostPosted: Mon May 14, 2018 12:45 pm
Something similar happened to me last summer after a big heat spell in Northern California. Car was idling rough while in the driveway with fuel pouring out the exhaust pipe. Took the plugs out and several of the cylinders were full of fuel, number 4 injector was wide open. Several others cars were affected similarly, one engine had even hydo-locked with too much fuel. Calls were made to Enterprises, the prevailing theory was that the circuit boards in the ECU were de-laminating due to time and the high heat and causing shorting. Never heard the final diagnosis though. We all did get replacement ECUs from Enterprises/PE? and all was good again. Just my 2 cents.
Jerry Aplass SRF #204
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PostPosted: Mon May 14, 2018 2:07 pm
I am reading all that this thread has been and offered and not a word from Enterprises! No official bulletin nor anything else. Communication..........
In industry, we had machines that had built into them, provisions that stopped conditions such as this. If something "ran away", software and hardware built in sensed it before a human could and shut down the culprit. Sounds like this needs to be looked at in a very serious and expedited manner by Enterprises and the ECU gurus. And those of you who have been affected are lucky that there has not been a serious fire/explosion.
In the 60's, Apollo rockets sensed this kind of issue and it was analog! Shut down an offending engine before catastrophic failure. Certainly in this day and age, this serious issue can be rectified.
Mark Fick

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PostPosted: Mon May 14, 2018 3:04 pm
Excellent points Mark!

Seems to me a bulletin would be in order, considering the situation. We aren't talking about just replacing a fuse. It seems to be more of just a coincidence, that at this point another failure recently occurred. I can see that race cars are subject to more stress than street cars. However, you would think that this would be engineered in by the ECU source as they are selling them for that purpose.

We all accept the risk of racing, knowing that things do fail with use and that is what maintenance is all about and our responsibility to maintain. What bothers me is when it is out of our control.

For example, if there is any way we can reduce the chances of this happening, please tell us how to do it. If vibration might the culprit, and I say might be the culprit, lets error on the conservative part and suggest what we can do to lesson the chances of a failure.

It's hard for me to think that heat might be the culprit considering the location, but I would most certainly be open to suggestions. As far as the delamination of a circuit board, my guess is they would know this after checking a failed unit. Has this been done?

These conversions have been out for a few years now. Is there a relationship between use and failure? Are we looking into it? If we know this is not the case, then it would point to either a MFG problem or vibration installation problem.

In the mean time, it's difficult for me to pony up $1,200 for a spare, based on what little is known and this time.

Pat
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