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Bad Ignition Coil?

Help, Advice and DIY Tutorials on Volvo's P80 platform cars -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, including 850 R, 850 T-5R, 850 T-5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

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VolvoTurbo850
Posts: 405
Joined: 26 April 2010
Year and Model: 1994 850 (T5)
Location: Toronto, Canada
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Re: Bad Ignition Coil?

Post by VolvoTurbo850 »

Never had a 97 but these cars do not always though codes for the component that is bad in my experience from 96 back.

I would suggest you start with the simplest thing and work from there.

I agree that the distributor cap and the rotor be replaced first and see what happens there. It is odd that number 3 is not acting but does not always mean that it is the cap either.

If you pull off the maf sensor it is usually to test if the car is running better without it. In your case it just dies right?

I have saved about 8 coils from scrapped cars I had and yet have to use one on any of the cars I currently own. In general these are pretty dependable.

Cam sensors are less dependable on higher mileage cars as well as MAF sensors.

When was the last time you replaced the timing belt by the way?

The Fleet

2001 V70 (NA) 2.5
1999 C70 Conv. Turbo 2.3 HPT
1998 S70 Turbo (T5) SE
1994 850 Turbo (T5)
1980 Corvette (Corvolvo)

Previous Possessions: (4) 240's, (1) 740, (9) 850's, (5) 70 Series
Projects on the go: NONE... Yet!

kcjones
Posts: 116
Joined: 15 March 2011
Year and Model: 1997 855 GLT 200k :)
Location: Littleton, CO

Post by kcjones »

Thank you for your inputs, guys. I'm glad to have found help with this after beating my head against the wall.

Glencoe: My driving is usually hwy/city mixed. I can get up to 24 if I baby it through the whole tank. Also, the only reason I don't suspect injectors is because of the manner in which the car is running and the fact that 4/5 injectors going bad simultaneously would liquefy my brain :shock:

PKC: I think you may be right. I'm working on a replacement. Updates to be had.

VT850: It is still a possibility that cap/rotor could be culprit, even though I'd like to think Bosch can outlast 9,000 miles. Car does die when MAF is pulled. From what I remember, timing belt was done just before I bought it around 120k.

Side note: Coil did not help. My ability to diagnose is still sub-par :(

jblackburn
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Year and Model: 1998 S70 T5
Location: Alexandria, VA
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Post by jblackburn »

Cam/crank sensors do NOT always throw codes.

Measure the resistance on the crank sensor (should be between 250-500 ohms). The crankshaft sensor is located just above the transmission housing; the camshaft position sensor is in a housing just behind the distributor cap on the engine block. Pin 1 to 3 of the camshaft sensor should read 12.5 V, 1 to 2 should read <5 V, and pin 1 should ohm out 0 resistance to ground.
'98 S70 T5
2016 Chevy Cruze Premier


A learning experience is one of those things that says, "You know that thing you just did? Don't do that."

mercuic: Long live the tractor motor!

kcjones
Posts: 116
Joined: 15 March 2011
Year and Model: 1997 855 GLT 200k :)
Location: Littleton, CO

Post by kcjones »

Crank sensor: 350 Ohms

Cam sensor: Pins 1+2 - 12.2 V
Pin 2 to Ground - 0.18
Pin 1 to Ground - ???

Chilton told me to try pin 2 to ground (instead of 1 to 2 as you had suggested). I tried both, and got 0.18

I couldn't get a resistance from pin 1 to ground. I use a Fluke 77 for all my testing, not sure if it has ever read "0" on resistance.

To speculate, pin 2 seems awful low. I assume <5 means somewhere in 3-4 range....... I sure hope I'm not replacing wiring any time soon.......

I really don't have the $120 to blow on a cam sensor, especially if it doesn't solve my "8 misfire codes-a-day" issue.

I know something is wrong, but only because the stupid CEL is yelling at me all the time. Other than that, I haven't a clue what it wants. I don't want to replace part after part if I don't have to. Contrary, I think I'll stop for cap and rotor tomorrow. JIC.

kcjones
Posts: 116
Joined: 15 March 2011
Year and Model: 1997 855 GLT 200k :)
Location: Littleton, CO

Post by kcjones »

So my cam sensor has some power. Any great way to tell if it works?

kcjones
Posts: 116
Joined: 15 March 2011
Year and Model: 1997 855 GLT 200k :)
Location: Littleton, CO

Post by kcjones »

Well, I must've jiggled something right while playing with the volt meter; no codes today :D

Hope it holds up.

kcjones
Posts: 116
Joined: 15 March 2011
Year and Model: 1997 855 GLT 200k :)
Location: Littleton, CO

Post by kcjones »

No dice. 4 more. Cyl 1,4,5, and multi. Cam sensor: $140 shipped. FML

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