98 V70AWD Missing on 4,5,random - replaced plugs,,wires,cap,

[erikv11]

I have also only used Bougicord, but over at Volvospeed there has been long term success with Kingsborne 8 mm wires.

[abscate]

after exhaustive diagnostic, the ECU appears to be bad. Was told to look for a replacement. Have a separate post on that here - https://www.matthewsvolvosite.com/forums ... =1&t=69789

wondering what other years / models I can pull one from.

Did they monitor ECU signals for the injectors and detect anomalies here? If you can get these waveforms for reference, that would be great.

[Andrew Vanis]

after exhaustive diagnostic, the ECU appears to be bad. Was told to look for a replacement. Have a separate post on that here - https://www.matthewsvolvosite.com/forums ... =1&t=69789

wondering what other years / models I can pull one from.

Did they monitor ECU signals for the injectors and detect anomalies here? If you can get these waveforms for reference, that would be great.

and from this other thread - https://www.matthewsvolvosite.com/forums ... 78#p365878

I think it was Timmy (professional mechanic) that share an acronym that basically stated when they don't have a clue, they tell you ECU....

It is a long, tortuous path of diagnosis before you settle on an ECU as the problem. We probably have seen 2-3 ECU solutions here on this forum, in history - and those were usually because someone Fubarred it.

From the other thread, I recall that you had a cylinder 4 or 5 miss that was code indicated. Have you tried moving plugs and injectors to see if the miss moves?

Also, if its ECU, it would have to be fuel injector signals to make a cylinder miss consistently - any data here?

The mechanic is a Master Volvo Mechanic. Started at dealership, then biggest independent in town before starting his own shop.

I don't think he went injector signals but he did swap plugs, wires, cap, rotor, Idle control unit, MAF, fuel pressure, and I'm sure some other stuff before getting a substitute ECU and calling me that I should start looking for a replacement.

BTW - that diagnosis seem likely. I after-the-fact recall hooking up the battery backwards when replacing my TPS and testing the car with the battery out of the vehicle and connected by jumper cables so I didn't have to reassemble the thing to verify TPS adjustment - Bonehead move on my part connecting the jumper cables to the wrong terminals.

And the cool thing is that he's charges only $50 for all of this diagnostic and I'm nor required to buy the parts there - so I trust the guy.


****side story o this mechanic, I recently had a MAF go bad, stalled me in town when I was in my suit getting my daughter to school.

I AAA towed to his shop, diagnosed in 15 minutes, put in a loaner MAF - Said BOSH was the only choice there and gave me reasons why the others tend not to work - had a chance to buy one from him at 40% margin (nice when you can have that kind of conversation with your mechanic).

Found one for $130 shipped to me, asked him, he said "yeah, my deal is $50 on the diagnostic. No need to buy the MAF from me. They cost me about $180 but that vendor gets them to me when I need them, I can warranty through them easily and I don't have to shop the internet so I can spend my time fixing cars. Use the one I lent you until your's arrives and return it then."

Instead of the $50 he asked, I happily paid him $100. He got $100 for 15 minutes and a MAF loaner and my continued trust.

http://themasterstouch.qwestoffice.net/

[abscate]

Thanks Andrew...reversing polarity ...ouch. That is one of the few ways you can fry your ECU.

I have the same relationship with my indie....he knows I like to use my brand of parts, and is happy to install what I bring. I always offer to pay his markup and he always declines.

I got 3/4 the way through new struts and springs when I broke my compressor, so he came in on Saturday to do the last one for me.

I wonder if your 4-5 cylinders are even the culprit..thinking about it, the ECU probably detects a miss and then assigns it by the CPS...if the clocks and timing in the ECU are fried, all assignment bets are off.