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-   -   High AFRs and dodgy running. Misfire or other? (https://www.miataturbo.net/megasquirt-18/high-afrs-dodgy-running-misfire-other-94790/)

ManicGTI 10-05-2017 04:45 AM

High AFRs and dodgy running. Misfire or other?
 
3 Attachment(s)
I'm having an intermittent running issue and can't work out what the hell the problem is, any suggestions? It feels like a misfire (lumpy running, but doesn't stall) and AFRs read super high on the WB02. I've logged it but can't see anything specifically out of place aside from high Timing Error (Running MS2, DIYPNP).

Tune, Log (see at about 100, 140 and 180 secs), and Snapshot of log attached for info.

Attachment 229709

Things I have done so far:
- New (aftermarket) Coilpack, Leads and Plugs
- Checked Compression (just because I could)
- New OEM Fuel Filter
- Replaced CAS with used one, no difference.

- Finally, I replaced all of above with Toyota COPS (wasted spark config)...The problem still occurs.

Is the Timing error increase a clue? Am I looking in the wrong place, ie could it something like a knackered Cambelt tensioner, or something in the fuel system? Or my second CAS could be dodgy?

Any suggestions help would be really appreciated, sorry I've repeated this Q a few times, I'm at a bit of a loss!

Dave

ManicGTI 10-16-2017 04:04 AM

Any thoughts guys? I've reached the limit of my knowledge and i'm struggling on this tbh!

:)

Barton 10-16-2017 05:59 AM

Have you tried adding fuel to those areas of the VE table??

ManicGTI 10-16-2017 06:24 PM


Originally Posted by Barton (Post 1445887)
Have you tried adding fuel to those areas of the VE table??


Sorry I'm not sure I understand how adjusting the VE map would help. The problem is intermittent (occurs every few journeys), it's not constant or dependent on load / throttle.

Efini~FC3S 10-16-2017 07:46 PM

Bad gas? Water in the fuel?

WigglingWaffles 10-16-2017 10:31 PM

Perhaps the fuel pump?
Double check your base timing as well, couldn't hurt.

gooflophaze 10-16-2017 11:33 PM

You've got a lean cell (42) @ 33/800. At 92-101s, 141-142, , 181-184s are all hitting it pretty hard.

gooflophaze 10-16-2017 11:43 PM

Also at 71s.. basically, every time you loiter around the cell you go lean.

https://cimg4.ibsrv.net/gimg/www.mia...afa6777ac2.png

Braineack 10-17-2017 10:02 AM

look how your idle speed drops, then the AFRs lean out.

check to see if your TB is still tight.


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