98 v70r no spark ISO quick tips and guidelines

yellow92gixxer · Post by **yellow92gixxer** » 04 Aug 2016, 01:00

So here I am, back in the volvo community. As a prior owner of an 855 turbo, I had almost literally a gem of a v70r dropped in my lap. Saw it sitting in a tow yard around november 2014, it disappeared and then I found it again in my cousins driveway because he's a mechanic and does side jobs in his driveway. Cut to today. The owner as well as my cousin have given up and handed it over to me just about free, lol.

What ive been told is that they did timing belt and found it to be one tooth off on timing, compression test they said it has good compression, swapped out both cam and crank sensors, did find a crank sensor on floorboard. Basically they are convinced its an ecu issue, which I am not. I have a feeling it may have something to do with alarm or immobilizer system. I'm just not sure if either of those systems would cut power to the coil causing no spark. It does crank.

Things I've noticed that may play a role.
Not sure if key is original or a copy purchased to unlock doors and such
Key sometimes spins in ignition switch without engaging ( have to fiddle with it to engage the starter)

By no means am I asking for you guys to do all my work for me, however I seem to have a hard time in these forums when it comes to searching for specifics. I downloaded( so far) 2 pdf files from this site for anti theft and central lock systems. I didn't see a description of the modules/relays in the schematics as to what they run. My adobe was acting up a bit.

I'm trying to find my volt meter so I have no test results on sensors or anything as such. Just trying to establish a list so when I do find it I can hit the ground running. It's been 3 years since I worked on my 855 and I've forgotten so much it's kinda frustrating. Anyways, thanks in advance for any help and I will be picking your brains until I get this car on the road.

Post by **Ozark Lee** » 04 Aug 2016, 06:48

The '98 doesn't use a chipped key so, unless the hazard lights are flashing when you try to start I doubt it is the immobilzer. On the 850s the immobilizer killed the starter circuit and I think the '98 70 series did the same thing. On the 99+ cars it does kill the ignition but it has the chipped key.

The usual suspect with no spark is the cam position sensor. It doesn't always set a code when it fails completely. Less common is the coil itself but it has been known to happen. The ECU failing is very rare indeed but not impossible. If the car has been parked for a long time it wouldn't hurt to remove the ECU and TCU and spray the edge connectors with electrical contact cleaner.

...Lee

yellow92gixxer · Post by **yellow92gixxer** » 04 Aug 2016, 19:30

Ah yes, the coil. forgot about that one too. lol I keep running different scenarios through my head in hopes of jogging my memory or having some ideas pop up as to all possible culprits. One thing that popped into my head today was some sort of ignition system wiring diagram so I can figure out the ignition process and what components go where and do what. I found a post that had a link to a pdf file on volvo wiring diagrams . com but its for 99 v70. How useful will this be for me? Its a service manual.

Also another thing I forgot to mention is that the serpentine belt setup has not been reinstalled but is in the car. I wonder if that may also play into these problems. I happen to have an ecu I came across years ago out of I believe a 97 r that I plugged in just out of curiosity and of course nothing happened. I know theyre different but I was hoping and assuming if nothing else the engine management side of it would be similar enough for it to start and verify an ecu problem.

Lee, thank you for the response. I'm asking all these questions because I'm gonna probably end up bringing my meter from work home and try and test a few things this weekend. I'm kinda stuck because of house projects I need to get done but I'm also super anxious to be back in a volvo again.

Post by **Ozark Lee** » 04 Aug 2016, 20:02

The '99 v70 wiring diagrams are useless for you. In '99 they completely switched everything in the engine management system (ME7 ECU, coil packs instead of a coil and distributor setup, electronic throttle module, CAN bus communications and so on). The '98 is very much the same under the hood as the 850s. The volvowiringdiagrams.com site should have a couple of files for the '98 S/V/C series but, like everything else there, the pagination is all messed up. Grab a '97 850 schematic as well for ECU and ignition related things, it is the same.

...Lee

Post by **scot850** » 04 Aug 2016, 23:31

There is another point worth considering and it stems from your point on the key issue. The ignition lock may be a problem if the key spins. Don't recall having this on a 98 though, but had it on a later car with a brand new key from Volvo cut to the car. The old keys were (are) fine. Key or lock mechanism may be worn, or it may just be the electrical portion of the key is bad.

Last issue is the PNP switch not registering the car being in park. Have you tried starting it in neutral?

Neil.

yellow92gixxer · Post by **yellow92gixxer** » 04 Aug 2016, 23:57

Neil,

It does crank in neutral as well as park. I'm gonna go through all the sensors and clean them as well as the ecu and etm contacts and while I'm at it the pnp switch. I'll have my fluke from work and be able to diagnose more definitively my sensors and switches.

Thank you.