94 q45 misfire, no codes, after new injectors and ks'

[Ccdiesel]

As the title states I am at a loss now. I had 4 bad injectors, all 8 were replaced along with knock sensors. It sounds almost the same but is not throwing a code. Rough idle, misfire, are the main symptoms and no power.

Should I mess with diagnosing spark? Or try to find a consult? Or will that help at all?

[OwnerCS]

Where are you located?

When two of my injectors failed, I purchased a diagnostic product named ECUTalk and downloaded software that allowed me to shut off cylinders one-by-one while the car was running to find confirm the cylinders that were missing.

The issue could be coil-over-plug (COP) related or something else like MAF or IACV.

The cost of ECUTalk might be less than paying for a consult diagnostic. If I had the same situation, I would take out my ECUTalk software and try to find the cylinders that when shut off show no change to engine running. If I could pinpoint the cylinders, I would look to swapping the coils to see if the problem moves with the coil to a new cylinder.

I see ECUTalk is now being sold in the US by a company named NISMOTRONIC.

Maybe some other members can offer their advice as well.

[db_autotek]

Is the problem worse or better after replacing the injectors? You're definitely not getting either fuel or spark to at least one cylinder, probably two if it's that dramatic.

[Ccdiesel]

I will look into the ecu talk but I found a reasonably priced consult though. If all cylinders are firing I wouldn't think a MAF could cause that rough of an idle.

It doesn't seem any better or worse, which is weird considering I've been in a q with one bad injector and it ran the same.

[goody90q45]

As the title states I am at a loss now. I had 4 bad injectors, all 8 were replaced along with knock sensors. It sounds almost the same but is not throwing a code. Rough idle, misfire, are the main symptoms and no power.......

Could one of the replacement injectors not be seated properly and leaking fuel past the lower o-ring? Any white or black smoke coming out of the exhaust pipe? A fuel pressure check (hook up the gauge, turn off the engine, look for quick drop in pressure) would tell you if this is the problem.

[Ccdiesel]

Thanks I am thinking it could still be an injector, they were deastchwerks new 370cc injectors. Maybe they weren't all firing, I haven't had a chance to run it yet. I'll let you know what it is

[Q451990]

In two instances on my old Q I had spark plugs that were fouled badly after an injector failure - causing the misfire to persist even after replacing the injectors. I was able to clean or replace them and get everything up and running correctly again after that.

[db_autotek]

In two instances on my old Q I had spark plugs that were fouled badly after an injector failure - causing the misfire to persist even after replacing the injectors. I was able to clean or replace them and get everything up and running correctly again after that.

Yes this! That's the main reason why I just replaced all my plugs. Two of them were totally fouled beyond belief, from the two failed injectors. You should replace or at least remove and inspect /clean your plugs any time you have a injector(s) failure. It should really be mandatory.

Cylinder 1 and 2 plugs looked like Santa Clause's a** after sliding down 2 billion chimneys lol:

[Q451990]

That's what they looked like. This was a long time ago, but I think I cleaned them with a toothbrush and some gasoline enough to get them firing... then the normal combustion cleaned them the rest of the way. If you have an air compressor, I would recommend going the route the FSM recommends and getting one of those sand cleaners. Harbor Freight has them for about $15... or just replace the set with the factory recommended NGK plugs since you're that far in.

Heath