Misfires out of nowhere

[Varak]

I didn't take a look underneath, but all of the wiring leading to each coil has been retaped with new electrical tape as well as the thicker wire from which those wires separate from that extends down the back of the engine.

According to the service adviser, they had completely pulled out the harness in order to test the entire thing to find the open circuits. They then reinstalled it and recinched it into place.

[Eli]

I guess the compression test checked out within range, but did they happen to give you the numbers?

Originally Posted by Varak

I didn't take a look underneath, but all of the wiring leading to each coil has been retaped with new electrical tape as well as the thicker wire from which those wires separate from that extends down the back of the engine.

According to the service adviser, they had completely pulled out the harness in order to test the entire thing to find the open circuits. They then reinstalled it and recinched it into place.

I wouldn't do that for $300. Sounds like a pretty good deal really...

[RedJellyBean]

Originally Posted by Varak

Don't have a picture, will see if I can spot it tomorrow. Here is what they described it as.

Performed Open/Short procedure from coil to PCM and found open in ground wire and one power wire.
Inspected wire harness and found and fixed the two open sections of wire.

This was after they:

Tested spark plug
Tested resistance of ignition coil
Tested Injector with noid light and hds
Performed compression test on all cylinders

For this they charged me 3 hours of labor and $360.

You did fine - honestly, you did just fine.

[Varak]

Originally Posted by Eli

I guess the compression test checked out within range, but did they happen to give you the numbers?



I wouldn't do that for $300. Sounds like a pretty good deal really...

Compression was listed as 128PSI.

I was more miffed at them doing all the mechanical testing first after I told them it was almost assuredly electrical since the car run perfectly 99% of the time. Guess they have to follow their procedures, though.

When the service adviser came back to inform me of the progress(or lack thereof), it was obvious that he had not been told about what I said about the electrical angle. And on the service sheet, none of the details I gave the initial person was there, just "misiring" and "Engine light on" basically. That was what irritated me.

[Eli]

Hmm.. 128PSI is the minimum acceptable, so I doubt that's what it means. It should be listed something like 180-185-175 or something, if it were the actual numbers.

And yeah, understandable.

[Varak]

Originally Posted by Eli

Hmm.. 128PSI is the minimum acceptable, so I doubt that's what it means. It should be listed something like 180-185-175 or something, if it were the actual numbers.

And yeah, understandable.

They only listed the single number, though they said that they performed the test on all cylinders. Guess I should contact them to confirm. Here is what was listed on the paperwork.

Diag and Repair Injector harness connectors

Current DTC is P0303: misfire cylinder #3, spark plug condition and gap is good 1.1mm. Tested resistance of ignition coil number 3; coil good. Tested injector number 3 with NOID light and HDS; tested good. Performed compression test on all cylinders; compression is 128psi which meets the standard specifications. Perform open/short procedure from coil to PCM. Found open in ground wire and one power wire. Inspected wire harness found the two open sections of wire, perform wire repairs and perform open/short procedure. No opens for coil #3, cleared codes and test drove vehicle. no codes detected at this time.

[Eli]

Hmm. Interesting. That does make it sound like they read 128PSI, but again that is very low . I'd be shocked if you could get good fuel economy at all with numbers that low, and your car would be utterly gutless.

[Varak]

The car is definitely somewhat gutless and my mileage has dropped 5-10% from when I first got it. It is starting to use a bit of oil as well, maybe a third of a quart in the 5-7K miles between oil changes.

My driving conditions are about the worst possible, I think. 30-60K miles/year, 90% of which is stop and go traffic in the Phoenix heat.

Any tips on what I can do to prevent further deterioration?

Just hit 272K miles on it.

[Eli]

Have you been having your oil analyzed?

The last analysis you posted was great, so that's somewhat surprising.

I say you should check the compression numbers yourself if you're curious, to be sure.

[Varak]

I've not had the oil analyzed since then. I am changing the oil soon and will have it analyzed again.

I don't think I have the tools to do the compression tests myself, but I may have my regular mechanic do it the next time I am in (need to have some stuff done anyway).