s70 2.0 NA strange ignition/miss issues Topic is solved

[Clemens]

Had exactly the same problem on my 854 2.5 10v. New plugs cured that although the old ones only had a few thousand ks on them.

[hausmeister]

Strange. mine are also fairly new. I will replace them.

Edit:
Replaced them today. The old ones look fine to me.

[hausmeister]

No difference with new Volvo Spark plugs.

I finally got the refurbished injectors today, will swap these next.

[hausmeister]

I recently had a complete no start... nearly drained the whole battery... then it did start fine after I waited a bit. I'm starting to think it might be the fuel pump relay. Already ordered one, will replace it next. It is just so hard to troubleshoot because I cannot replicate it reliably.
Maybe there are multiple issues at play.

[Clemens]

It could also be the Alarm / key sensor ring. If it Fails you have no start. don´t know if they had them in 98 or started in 99.
Try resoldering the fuel relay. or get a used one from Autoteile Schmied. If it deosn´t start the next time tfy to see if there is pressure at the scharder valve. if it is, it´s most probably not the relay or the pump. do you ever drive it on the Autobahn? Should help against crud buildup. It halps on my 854 commuter if it starts to misbehave after weeks of Kindergarten short trips.

[hausmeister]

It drives absolutely fine on the autobahn.
Problem is when this happens I'm mostly somewhere away from home, and it is cold, dark and late... not ideal situation for troubleshooting. And I can't replicate it, so I have to drive it to see if it works or not (also takes time).. for now I switched to my T5-R, at least until I replace the relay.

I don't think it is the immobilizer.. it wants to run and you can hear it firing a few single times.

Yes Schmied.. too far away, and I did not have good luck with parts from them. What I got was nearly worse then what I wanted to replace... I'd rather buy a new one.

[Clemens]

if it has a serious no start try having someone hammer on the fuel tank with a large Piece of Wood or something. if that fires it up your fuel pump is going south.

hope you get that sorted out, it´s awful not being able to trust a car. I´m driving my R in winter as well, I feel bad for it, but then at least it is driven frequently.

[hausmeister]

Thx for the tip.
I'm not worried about my T5-R (it is not very pretty), but in Winter it is simply overpowered and also the AC does not work which means it is hard to defog the windows

[hausmeister]

This is just so frustrating.
Today I had time for some trobleshooting.

- Replaced Fuel Pump relay
- took out all the spark plugs and checked them; yes they all spark
- measured fuel pressure at rail, seems to be fine. (you can see it in the video)
- swapped out the ignition cables with some spares, but no change.

So, I'm at a loss. I think It has to be some sensor/electrical issue. I will try to measure some of the sensors I know...
And Like I said, It does not happen always, mostly when the car runs 1-3 minutes and then you turn it off and try to start again.

It doesn't have codes set, so I can't check that either. Will link in the video when it is uploaded, maybe you guys can tell something from it.

https://www.youtube.com/watch?v=8VTNGpy9eNw

[abscate]

Whats spec for fuel pressure at idle? I don't think 35 psi is high enough. Its 50 psi for my 1999 with ME7