97 S70 2.5 Turbo MAF Problem

[DaveyUK]

Hi there, first post here but been lurking for a while! About 3 months ago I bought a 1997 S70 2.5 turbo. Up until recently I have been using it daily without a single problem. Unfortunately about 2 weeks ago it cut out and refused to start. Disconnected the MAF sensor and it idled (a bit roughly) Purchased a new non genuine MAF hoping I might get lucky but no luck just same result. Swallowed the cost and ordered a genuine new Bosch part instead. Again exact same issue, car really struggled to start, idled very lumpy or cut out with also a very bad smell from what I'm guessing is the air/fuel mixture being right out. Was just hoping that I was just very unlucky and had another duff part. Sent that back for another replacement Bosch sensor. Tried it tonight and once again my problem is still there! Now it seems the previous owner has messed with the wiring at some point because the MAF plug on the cars side had at some point been cut off for some reason then reattached. I have checked the connections and they all seem ok, just to make sure I redone all the joints with insulated crimps and tested the plug for continuity, all seemed fine. Secondly, I have a warning light on the dash. Plugged my basic generic OBD scanner into it and got a P0103 fault back. Cleared the code but it instantly came back. I'm really at my wits end with this and not sure where to go from here! Any advice or tips would be great.
Thanks guys

Dave

[Dangerous Dave]

Sounds like the wiring is bad somewhere from the MAF (including the connector) to the ecu. Probably beat to check back to the ecu connector with a multi meter and a wiring diagram for the connector. If you search for moronic 4.4 connector ponout you should be able to find a diagram.

[DaveyUK]

Thanks for the tip mate, I'm off work tomorrow so just going to spend the day troubleshooting and checking all the wiring. There's nothing else I can really think of it being.
Cheers

[Dangerous Dave]

Also check the intake system for big leaks (pressureise the intake system after the turbo somehow).

Also best to go over everything to make sure all the vacuum pipes are ok, etc. A mini stage 0 as such

[DaveyUK]

Bit of an update, spent all day checking and re-checking. No leaks or splits in any pipes that I can see and I unplugged the ECU and tested the cabling from the MAF plug back. All seemed fine and continuity was good. Was about to give up and as a last resort I removed the IAC valve, cleaned it and also gave the throttle body a clean while I was down there. It just about started but once started idled fine. Took it for a good blast and went ok, doesn't quite pull quite as hard as before and I still got the P0103 error, I clear it and it just comes straight back. It also hesitates to start and won't start without a bit of throttle. Once started, idles fine and does not cut out or hunt around. So at the moment it's drivable and about 90% there. I just need to see why that error code keeps coming back and why it's a hard starter. Seems odd that cleaning the throttle body and IAC valve has nearly completely fixed it. Would it be worth replacing these parts?

[Dangerous Dave]

Found this thread with the same problem:
http://volvospeed.com/vs_forum/topic...h-p0103/page-2

Did you pressurise the intake system to check for leaks? They can hide in places you can't see like the bottom intercooler hose.

If the ecu was unplugged then the memory will have been reset so this could explain why it was better after unplugging the ecu for a bit.

Oh and Welcome to the forum!!