Evo5 starts, then dies after a few seconds... log inside

[crcain]

Friend of a friend brought an Evo5 over to look at with an odd issue I've not seen before. Every now and again, it will get into this mode where it will start, then suddenly die for some unknown reason. When it does die, it dies abrubtly, without any kind of rpm waver or bog, and even if you are giving it some throttle.

Here is a log of it happening:



What I find strange is that it appears from the log above, that the ECU is cutting fuel to cause the stall based on injector time.

Also, the check engine light seems to come on intermittently when this issue comes up and I've read the code and it says Vehicle Speed Sensor, but I think this is strange as vehicle speed during logs where the car is driving fine shows no issue with the sensor. I'm wonder if EvoScan is not translating the code properly? But it doesn't give a code, just a description.

Any suggestions are very much welcome!

[lan_evo_mr9]

Most likely a crank sensor taking a dump, or that fault maybe a result of the car dying. I would lean towards the sensor though

[Ceddy]

Also check the MAF plug and wires. EcuLoad will give better info then LoadCalc, if EcuLoad is 0 or locked at one value, most likely MAF.


Timing looks weird, it should bounce around 0-15* to maintain idle speed. Maybe ignition switch is stuck in start position. Or not sure if Evo5s have the Ground for Base Timing Terminal, but it could be grounded.

[crcain]

Originally Posted by Ceddy

Also check the MAF plug and wires. EcuLoad will give better info then LoadCalc, if EcuLoad is 0 or locked at one value, most likely MAF.


Timing looks weird, it should bounce around 0-15* to maintain idle speed. Maybe ignition switch is stuck in start position. Or not sure if Evo5s have the Ground for Base Timing Terminal, but it could be grounded.

Timing is probably flat 5 in this log because right after startup, on this log, the driver was pumping the throttle to see if keeping the revs up would avoid the stall issue, which it didn't.

What I'm wondering, is if you look at how the injector pulse width just stops, what could cause that? It looks to me like the ECU intentionally is stopping the motor.

[crcain]

Originally Posted by lan_evo_mr9

Most likely a crank sensor taking a dump, or that fault maybe a result of the car dying. I would lean towards the sensor though

Yes maybe but why would it start perfect everytime, then lose sync at exactly 3-5 seconds after startup and just die all of the sudden. I'm not ruling out crank or cam sensors but I'd suspect they'd exhibit themselves in a hard start or something.

[crcain]

I also realize I didn't include all the log until RPM falls to zero... but basically, from the moment you see injector pulse width go zero in the screenshot I posted, the rpm's fall like this:

3937.5
4531.25
4187.5
3875
3593.75
3312.5
2968.75
2687.5
2437.5
2218.75
2062.5
1875
1718.75
1531.25
1343.75
1187.5
937.5
750
531.25
468.75
343.75
281.25
281.25
281.25
125
125
125
125
125
0
0

[lan_evo_mr9]

Are the injectors scaled correctly and latencies adjusted?

[crcain]

Originally Posted by lan_evo_mr9

Are the injectors scaled correctly and latencies adjusted?

It's a stock car, but yes I did check the trims and they were fine. The car runs great, and then every now and again, this issue comes up.

By the way, when I run a DTC MUTII check in EvoScan, and EvoScan says there is a Vehicle Speed Sensor code, is EvoScan translating the code the ECU spit out to "Vehicle Speed Sensor"?

[_Speedy_]

are you running tephra mods? this happened to me when I accidentally put the vehicle into Valet mode. (hold foot on accelerator after turning car on, wait for flashing CEL light, then start the car in un-valet mode)

[crcain]

Originally Posted by _Speedy_

are you running tephra mods? this happened to me when I accidentally put the vehicle into Valet mode. (hold foot on accelerator after turning car on, wait for flashing CEL light, then start the car in un-valet mode)

Nope, no Tephra but thanks very much for suggestion!