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2001 C70 T5 Stalls and Rough idle

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

perkunas
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Year and Model: C70 T5 2001
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perkunas

Re: 2001 C70 T5 Stalls and Rough idle

Post by perkunas » Mon Oct 31, 2016 8:43 am

The no-start issue seems to have been solved by unplugging and re-plugging the antenna ring. We'll see how it holds up during cold weather.
Though I think it might be useful to others that it appears the immobilizer kicks in several seconds after the ignition is first set. That means, if you immediately try to start the engine, it will fire up and then stall. If you listen to the fuel pump to prime and then start, the time required for the immobilizer to be triggered will pass and you will get a crank but no start situation.

The rough idle issue is a bit more interesting. I went ahead and replaced the spark plugs with Bosch FR7DPP+24. I was thinking the car was going to have some old Volvo OEM plugs, but what I found inside the engine was really so much worse. I'm surprised it ran at all. The plugs were really not that tight too, just above hand tight. What the hell was the previous owner thinking? I regret not doing this earlier. Car feels so much better now, like day and night. Take a look at this garbage that I found in my car (the gap can be measured with a ruler and is somwhere around 2 mm):
Image

Some googling shows that the Bosch FGR line of plugs fits a lot of performance engines, i.e. E36 M3 and some Porsches. I guess it's good for n/a engines, maybe not ideal for turbo Volvo, especially when they're way beyond their service life.

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abscate
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abscate

Re: 2001 C70 T5 Stalls and Rough idle

Post by abscate » Mon Oct 31, 2016 6:30 pm

Nice - Ill claim one Vikinghorn for the plugs lead...

The immobilizer does cut the engine out after a second or two - I didn't know if you wait it will do a full no-start
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perkunas
Posts: 45
Joined: Sat Nov 16, 2013 2:25 pm
Year and Model: C70 T5 2001
Location: Lithuania
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perkunas

Re: 2001 C70 T5 Stalls and Rough idle

Post by perkunas » Mon Oct 31, 2016 10:41 pm

I think the immobilizer just cuts out the ignition several seconds after the key is turned if it doesn't get a RFID read from the key, regardless whether the engine is running or not. Though I am still not sure what the flashing red light in the middle of the dashboard meant.

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