[Crumpler]

Hey guys.
I’m sitting in the pit.
Car gave out.

Drove to event.
First session I got several flickers on the central warning light. No specific lamps on cluster activated. Light went off but I went back to the pit.

All fluid levels good.
Trashed it around the pit, no warning lights. Oil pressure stayed fine. Vouching for coolant and oil, decided to try it again think it was some non-essential leftover connection like seat belt or brake pad sensor.

Went back out, couple good laps. Oil pressure stayed high on right and left sweepers.
Set up to pass a car saw a flicker, made a turn and noticed no steering. Looked down and car was off.

Restarted without issue, drove into pit. No central warning light or lamp.

This car is aftermarket ECU.
Odds of VEMS glitch killing car after central warning light flashed I assume unlikely.
What the hell would you look at first?
What capacity does car have to kill motor if not connected to ecu?
Alarm connection?

This is one of my lows in 928 ownership.

[maddog2020]

it depends on how the aftermarket ecu was wired. aftermarket ecu's are usually much more sensitive to low voltage scenarios. I'd check the alternator belt and voltage on the battery 1st. check grounds as well.

[worf]

check grounds as well.

—- ^ THIS x 928

And, ignition switch maybe?

What is condition of front main harness (starter->alt->jump post)? That harness pretty-much powers everything…

[lupo.sk]

The SAME thing happened to a friend of mine who tracked an RX-7. Took him 3 months to figure out.. It was the alternator belt.

I was the translator for him as his English was really bad, he was running a Haltech ECU.

[Crumpler]

Read Sterling’s post and logged drive home. Thanks guys.
Warning light came on several times. On the log, I can see a blip in battery voltage that correlates with the light, coming off rpm drops. Baseline is about 13.88v. If the dip goes down past 12.4v the light activates.
Some drop is normal correct? as rpm drops off with throttle release. The ICV is catching rpms, for this car, around 550-600 rpm.
I did have a grounding suspicion about six months ago, because of a shut off on the highway no less.
At that point I went through each ground, and moved all the aftermarket gauges to different ground locations.
But, if there was any weak connections I would buy into it. This track is in East Saint Louis Illinois, and the roads to get there will knock the fillings out if your teeth. Meaning no revenue for any road maintenance.
Help me with grounding capacity.
Ecu is grounded through stock harness grounds, this was the famous “plug and play” conversion. CE panel has stock grounding.
Thoughts after seeing this data?

[Crumpler]

Sorry, Dave the FOE harness was replaced about two years ago.
Ignition switch replaced maybe four years ago.

[maddog2020]

deoxit on the grounds. Also make sure the any relay sockets are cleaned up and getting good connections. Start at the positive terminal of the battery, and clean every connection to the ecu connector. Might need to set idle higher & have the ISV kick in at higher rpm. I could idle as low as 450 but you need to keep the voltage up, and account for decel and off idle behavior so I have it set for 800. Also look at ramping up the ignition advance @ idle below 1K.

[Crumpler]

deoxit on the grounds. Also make sure the any relay sockets are cleaned up and getting good connections. Start at the positive terminal of the battery, and clean every connection to the ecu connector. Might need to set idle higher & have the ISV kick in at higher rpm. I could idle as low as 450 but you need to keep the voltage up, and account for decel and off idle behavior so I have it set for 800. Also look at ramping up the ignition advance @ idle below 1K.

I’m going to all of that!
The pro tuner monkied my idle settings, and tightened my throttle bypass screw (S3 thing).

Now, another curve ball Sterling.
What if I told you I went out to test alternator tonight.
The car will not start. No lamp tests, no starter no fuel pump. dead key.
12.6 volts battery and 12.6 volts hot post.
No voltage top of CE panel in any key position.

Ignition switch after all?
What else? Bad relay wouldn’t cut power to CE right?

[maddog2020]

no relays to the top of the CE. check and clean the outboard connections on the positive terminal of the battery

[Crumpler]

Do you guys think everyone else makes mistakes like this or am I really just an idiot?

I ran an ancillary line from the positive battery terminal last week for a 12v outlet for a camera. SCCA wants them in each car during events.

The positive clamp was still finger loose, meaning I forgot to tighten it down in some type of undiagnosed ADD moment.

The real problem was I didn’t check it at the track before I drove home with my tail between my legs.

[lupo.sk]

Do you guys think everyone else makes mistakes like this or am I really just an idiot?

I ran an ancillary line from the positive battery terminal last week for a 12v outlet for a camera. SCCA wants them in each car during events.

The positive clamp was still finger loose, meaning I forgot to tighten it down in some type of undiagnosed ADD moment.

The real problem was I didn’t check it at the track before I drove home with my tail between my legs.

Happens to the best of us… I went offroading with my anti-theft nut still attached to the wheel. Found out back home after a long day in the mud, several water crossings and a wash.

[worf]

The positive clamp was still finger loose, meaning I forgot to tighten it down in some type of undiagnosed ADD moment.

That’ll do it.

The good news is that it’s an easy fix and you’ll never do it again.

[maddog2020]

and the fix was free.

[Crumpler]

and the fix was free.

Yes but I started where you told me to start looking, so thanks again.

[Crumpler]

You know I had another shut off this weekend at the track. It was after a high rev strait and braking/down shift.
I just restarted it on the fly and finished the session.
My thoughts were that the ICV was not catching rpm drop.
I had my lap top there so I threw some poop on the wall: revised idle reference curve for more open at higher temps, added some fuel and timing in those cells, opened throttle bypass screw at little.

One of those probably worked, no further issues.

As an aside, the boost on this car was a game changer. It’s just relentless now on on curves.