s70 2.0 NA strange ignition/miss issues Topic is solved

Post by **hausmeister** » 26 Nov 2016, 11:28

No idea. But it has an Siemens ecu. I thougt around 3 Bar ist correct...
I'll Look if I can find the specs.

Haynes Manual says "Regulated fuel pressure 3.03bar" (~44psi)
Shopuld this also be at idle? Then It seems it would be too low.

Post by **hausmeister** » 26 Nov 2016, 13:13

I will take another more detailed look at it tomorrow, pinch return line or disconnect FPR, maybe that will tell me something.

Edit:
according to this post it should be fine: https://www.matthewsvolvosite.com/forums/vie ... 42#p112343

Post by **misha** » 26 Nov 2016, 14:05

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

43.5 psi on 1st prime without starting the engine.Around 30-35 psi at idle and again 43.5psi driving on full throttle.That's for Jetronic,Motronic 4.3 & 4.4.Should be the same for 10valvers.
Me7 have higher spec.

Post by **abscate** » 26 Nov 2016, 18:45

Dig up the primary reference for that fuel pressure. Remember you are diagnosing a subtle problem so even a marginal spec is worth noting.

Post by **hausmeister** » 27 Nov 2016, 06:27

I only found the haynes reference and what misha posted. I will do another check when I have time.

So today I measured some stuff:
Crank sensor: 280 ohm
Camsahft pos. sensor: shows 5v, when running ~2.5 which should be 5 and 0 v alternating.
Air inlet temp sensor: 4kohm (10°C) (it has the temp sens instead of the MAF)
IAC Valve: 8.1 ohm

This seems to indicate everything is likely fine...
While testing the cam sensor I had the voltmeter connected between the connectors, and the engine started on the first try like nothing is wrong.

What is different after the engine runs for 2-3minutes? Temperature ... ?

Post by **hausmeister** » 22 Dec 2016, 05:28

Some days ago I replaced the coolant temp sensor. After I did that it set a code and CEL came on...

Today I was able to read codes. My reader did not like the Fenix ECU, but it could read the "combined instrument" codes, where I got a CI-124 "RPM SIGNAL, SIGNAL FAULT"

The rpm sensor would be the crankcase sensor, not the camshaft position sensor, correct?
I am not 100% sure If I disconnected the sensor sometime during troubleshooting for a short time, but it was definitely connected before and when the code/CEL showed up. As I only measured resistance I think it was with the engine off.

Post by **hausmeister** » 07 Apr 2017, 03:09

Air Intake Temperature Sensor was faulty. Now it runs like new again.