Cuts off at times

[SpecM]

My m20 has a strange driveability issue

Randomly, it will stumble and choke. The CEL will come on (but no codes stored when I try to access them), and it usually only lasts 2-5 seconds. It only does it at idle, or when I press in the clutch. It does it inconsistanly, only 1-2 times a day, and 1 out of 5 times it will cut off and need restarting.

I had a simular issue before, but it was corrected with a new main relay. This issue is different, with the main relay the engine would "cut off" for a second and the tach would die. Now, the engine just stumbles, the engine speed drops but the tach continues to read (just reads low, duh). Therefore I doubt an issue with the main relay, CPS or DME.

The car runs GREAT at all other times. I have swapped AFMs, did not fix issue. I would suspect issues with the ICV, TPS or ignition system but would like some feedback on the issue too.

Paging: Jim Levie (but before you ask, I alread did a smoke test!)

[jlevie]

Does the stomp test return a 1444?

A problem with DME power/ground, CPS, or the DME itself could do this and not result in a stored code.

[SpecM]

Does the stomp test return a 1444?

A problem with DME power/ground, CPS, or the DME itself could do this and not result in a stored code.

Yes, a 1444 "no codes"

but wouldn't a fault in the DME or CPS result in a "0" tach reading? Thats how it happened when the main relay was faulty. The tach now drops with engine speed.

[jlevie]

If the DME completely looses the CPS signal, the tach will drop towards zero. Likewise if the DME looses power. But I have seen CPS drops that cut spark and injection but don't zero out the tach. I've also seen that happen with a DME power or ground issue.

A clue here is that the DME is not storing a fault code. But there may be another clue. Do you see the econometer drive towards zero in an event? That could indicate a problem with the fuel system.

[SpecM]

Do you see the econometer drive towards zero in an event? That could indicate a problem with the fuel system.

I wasn't paying 100% attention to that, but my memory is telling that it was actually increasing (in the same way that is moves when you rev an m20 from idle)

[SpecM]

Since the CEL comes on when this happens, I'm leaning away from the DME or it's power/ground. Is this faulty reasoning?

I'm trying a CPS tomorrow

Sent from my Vortex using Tapatalk

[paperplane94]

I would still keep the ecu and its grounds in question because how can the CEL come on and then come up with no codes stored. It is my understanding that if it comes on there will be codes unless they were reset by the driver or something else that cuts power to the ecu.

[Mr.SWISS]

Eta was doing this. Hesitating like out of gas no power and a simple restart and it went away for a bit. Unplugged TPs and it stopped but idles high. IMO I need a TPS and u do to.