Misfire help

I don't remember if the engine will spin over without the ECU in place, but if it will you can always do a compression check while waiting for the ECU.

01yellercobra said:

I don't remember if the engine will spin over without the ECU in place, but if it will you can always do a compression check while waiting for the ECU.

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I haven’t sent the ECU off yet. Noid test kit will be here today. I actually ended up sending the fuel injectors off to get cleaned to ensure they are 100%. I should get the fuel injectors back by the end of the week. Waiting to hear back if they found anything.

I inadvertently drove with the misfire once or twice before I found out about the issue and it didn’t feel super low on power and there’s no CEL.

I’m hoping it’s the fuel injectors or ECU but once I get the fuel injectors back I will have it narrowed down. If the fuel injectors come back good and the Noid test shows good communication to the ECU I will do a compression test.

If compression is good I have a mechanic friend who can most likely look at the camshaft and see if it’s the timing. Trying to be optimistic

Going to attempt a compression test which i realize i have should have done this from the beginning before wasting time/money but you live and you learn lol.

Noid test was good. The light was VERY dim. Im wondering if this is due to the impedance of the aftermarket injectors (Ford Performance 60lb injectors).

Fuel injectors are good (not clogged or anything, all reading 13 ohms and getting 12volts).

I did notice the spark plugs were already a bit dirty, and smelled a little like fuel on the side thats misfiring. My mechanic apparently JUST replaced these last week when he had the car. NGK TR6 plugs.

So I’ve almost narrowed it down to a few things. My compression test kit just got here today. Going to perform that this weekend

Here are my findings so far:
- All 8 spark plugs are new (same ones from initial replacement)
- coils are new, tested spark with each one.
- Fuel injectors are good, fuel is also getting into bank 1 (evidence on the spark plugs)
- verified power and ground to the fuel injector connectors with a power probe. Each connector was getting 12v and good ground.
- replaced both bank 1/2 o2 sensors before the cats
- tested alternator for shits and giggles. That’s fine.
- reset the KAM with SCT tuner after all of that. No change.

After letting the car run to get up to temp. The driver side (bank 2) high flow cat gets up to 400 Fahrenheit. Bank 1 cat is only 150 degrees.

What I haven’t ruled out:
Compression test - is this a low probability considering all 4 cylinders on bank 1 appear to be misfiring?

ECU issues - who knows, current ECU was a refurb.

Fuel pressure - the fuel pressure test kit I got didn’t have the right adapter. So I will be looking at this again if compression test is good.

Oh also forgot. Seemed like bank 2 short term fuel trim kept spiking up to +20%. Car is definitely running rich