TerrestrialFlyte

I replaced my injectors over the weekend hoping to address fuel dilution in my last two UOA. Upon start up the car runs rough and popped the “Visit Workshop” message on the dash. Foxwell pulls a P0303 code, Misfire Cylinder 3. Is there anything in particular I should be checking to figure it out? I could swap injectors and see if the problem follows it, but curious if there is something easier to check first. Maybe some parameters on the Foxwell or something? Thanks.

Graufuchs

I had this issue years ago with an Audi of mine after an injector issue. I would double check that the injector is seated correctly and sealed (O-rings seated properly) in the injector port. Also check the electrical connection to that injector also.

TerrestrialFlyte

How did you check the electrical connection? That came to mind, but not sure how to do that other than ensuring it’s actually properly plugged in. Couldn’t find anything in the Foxwell, but didn’t look too long.

964hans

Hi,

You can check the electrical connection between DME Unit and injection valve and ignition coil on continuity with a Multimeter.for that you have to disconnect the DME connector and the connector on coil and valve .Also check if there is no connection between the wires and ground.
In the attachment you will some more info concerning P0303

Regards
Hans

TerrestrialFlyte

Thank you. I’m not sure how confident I am playing around with the DME. I guess I need to look for some schematics to determine what pins do what.

Graufuchs

When you clear the code does it come back?

(I was talking about the electrical fitting, ensure its seated correctly)

TerrestrialFlyte

Yes, I cleared it and it returns. It’s under pending codes.

964hans

Why did you replace the injectors anyway?
What does "fuel dilution in my last two UOA" mean? (I 'am Dutch)

TerrestrialFlyte

UOA = Used Oil Analysis. I sent in an oil sample when I changed my oil and the report showed what may be higher higher than expected amount of fuel in the oil. I checked for a vacuum leak to verify unmetered air wasn’t entering the engine and causing the car to add fuel to compensate. No vacuum leaks. So the next step was to replace the injectors since they are 16 years old. The thinking is that they could be leaking or otherwise malfunctioning and too much fuel is bringing injected. Fuel cuts oil and therefore could be increasing wear leading to the onset of borescoring. So I replaced them to see if that would reduce the fuel in my oil.

I’ll have to try and make some time this weekend to troubleshoot.

964hans

Thank you. I 'am learning every day.

Maybe the new injector is broken. The coil resistance should be 10-15 Ohm
Maybe one of the sockets in the connector is pushed back

Thing is that before the swap of the injectors the car was running fine

By the way: did you check your old injectors by applying pressurized air (approx. 5 Bar) and sticking them into some liquid to see if bubbles are produced

Carreralicious

Not related to your injector issue, but was wondering, do you add in a fuel injector cleaner prior to an oil change? Thinking that maybe if you do, that will dilute the oil right before your oil change and hence when you do the UOA, it’ll show that there’s a higher dilution figure than really what’s there. Maybe there wasn’t really an injector problem in the first place?

TerrestrialFlyte

I haven’t ever added injector cleaner, good thought tho.

TerrestrialFlyte

Yeah, car ran fine before the new injectors. If I can find the time this weekend I’ll swap from cylinder 3 to cylinder 1 (since it’s closer) and check connections. That way I can see if the problem follows the injector. If so, then I’ll replace that injector. If not, I’ll take a closer look at the connections.

I have not checked the old injectors other than a visual inspection. I don’t know if I could rig up anything to apply pressure and test them. Not sure if that’s even worth my time/effort.

TerrestrialFlyte

Swapped the injectors from 1 and 3. Start it up clear codes and no codes returned. Still ran rough. Took it out for a 15 minute drive around the neighborhood and about the time I got it up to temp CEL popped up. 4 codes:

P0303 - Cylinder 3 misfire detected
P2195 - O2 sensor signal biased/stuck lean bank 1 sensor 1
P0300 - Random/multiple cylinder misfires detected.
P0304 - Cylinder 4 misfire detected

I guess technically 5 because the cyl 3 code was in there twice. Maybe vacuum leak that just took a few minutes to register as the ECU tried to compensate?

LTFT on bank 1 was went up from like 13 to 18 while I was driving around. Bank 2 was -0.8 to -1.6. STFTs were near 0. Was driving so I don’t remember exactly.

964hans

So the problem is not caused by the Injectors!

My next step would be: check the injector Connecto3 of injector#3.

An another step would be to let the car run with the Injector#3 Connector not connected. I am curious if there will be a difference in running and if (maybe) additional errors pop up