ECM reset

[Razor]

What can cuase the ecm to reset under high rpms and high load conditions.

I'm helping a friend chase down a problem and the car at 105mph shuts down and back up again.Using a direct scan it records the run then bam...everything goes to zero then comes back on again.

Replace the ground strap at the back of the engine,plugs,wires,ecm,chip,confirmed power at the ign and battery termials at the ecm while condition was occurring..

Help..

 

[TurboDave]

Well, first and foremost, make sure the connection point on the ECM for DS is perfectly clean. Then make sure the DS connector doesn't go on TOO far. I solved this problem with a small 1/8" wire tie (cut just long enough) to fit down into the DS connector, this keeps it from going on to the ECM's edge connector too far. Some folks use a tooth pick stuck down in the connector.

 

[BM Computer Src]

Turbodave, Razor was borrowing my DS to try and figure out the problem, so it's not the DS. Razor, Double check the wiring down by the starter, you may have to remove the downpipe, but there is some wiring that carries voltage to the ECM there, that can get knicked and short. This suggestion came from one of my favorite vendors who said they had seen it many times.

Good luck,
Bob

 

[TurboBob]

Does the problem go away when DS is disconnected from the ECM.......?

TB

 

[Razor]

Wow...that would coincide with the car getting its starter replaced and all this crap starting.Wonder what wires could be running by the starter that would be ecm related?


TurboBob, it does it without direct scan.

 

[BM Computer Src]

The ECM power wiring is in that area, I believe it is 5V power to the ECM.

Just to clarify for everyone, we are using Directscan to figure out the problem of the car cutting out.

I think you should go ahead and check over that wiring, could be your culprit.

Bob

 

[TurboDave]

Certainly sounds like an intermittent short in a power source. Generally there are two places this can occur.

1. the main power cable running down from the battery to the starter. It sometimes gets moved or shifts positions and is allowed to get too close to the passenger side header where it crosses under it. When the engine torques over under heavy load it can touch the cable, momenarilly shorting the electrical system to ground.

2. One of the fusable links (the other wires attached to the starter) could be pinched and/or frayed near the starter's heat shield, suffering intermittent shorts. One of them supplies power to the ECM.

 

[DMan]

I had this issue. Ended up being a very long ribbon cable on the ds picking up noise. Even without the ds turned on, if the cable was there, it would cause the problem.

Shortened the ribbon cable, problem solved!!! That was a three year old gremlin for me...

 

[DMan]

Do I win the award for longest time delay since a reply?

 

[TurboBob]

I think you hold the record......

Bob

 

[bmackinnon]

Hilarious.... I was just going to post a WOW!!! Where has BMComputerSvc (maker of DirectScan) been all these years... funny....

I believe you are close to the record... and TurboDave/Bob... your ages are showing!!!! :biggrin:

 

[TurboBob]

Actually, Direct Scan was developed by Kent Chu, and was sold by the Conleys.

Bob

 

[bmackinnon]

Actually, Direct Scan was developed by Kent Chu, and was sold by the Conleys.

Bob

Yea.... my bad... correct... but bmcomputersvc was a major distributer also if i'm not mistaken??.... I'm old too.... obviously... :tongue:

 

[garyk1970]

1)battery cables routed near downpipe....as already posted
2)check the alternator for ac output (regulator/diodes going out)..

hth

 

[TurboBob]

(this thread is almost 9 years old......)

although I wonder what the problem turned out to be. If Razor even remembers that far back....

Bob

 

[Just a Six??]

I had the exact same issue as the thread starter years ago. Logging a run & Bam dead spot & then back on again. I had a trunk mount battery, changed everything 10 times including pulling the engine a few times (unrelated) & after 2 summers just sold the thing for a PL upgrade. I had the shielded cable from Conley's etc & never did find it???
I have added so many extra grounds I will Never have a ground issue IF thats what it was?
Funny how this brought back many memories & I bet I have old threads about it on the other board.
Now, my EGT thermocouple I got from FT does the same thing added to PL.
I just keep the guage hooked up & set to Higest Temp so when it cuts out I still have a good idea what the EGT's are. That has happened since day one & now I hear they dont even sell the little Green transformer/converter anymore at FT. At least it works 90% of the time. The others times it just pegs high or low & dont ask if it has a good connection as I have messed with it for 2 summers! I just live with it & watch the wideband on PL.

 

[Shane]

Hilarious.... I was just going to post a WOW!!! Where has BMComputerSvc (maker of DirectScan) been all these years... funny....:

I bought his car, then I think he stopped hanging around here so much.

The car was later totalled.

 

[garyk1970]

(this thread is almost 9 years old......)

although I wonder what the problem turned out to be. If Razor even remembers that far back....

Bob

oooppppppssss