S40 (New) Engine 2.0D : Recently broke down and need to fix.

[glegalee]

Good afternoon all, I'm once again hoping to pick your brains with regards to a recent break down situation.

Firstly, here's what happened. I drove my 2005 S40 2.0D SE about 100 miles with no problem. I switched off the engine to unload a bunch of tools for a job, restarted the car, drove it probably 1/4 of a mile to a car park. I had to wait with the engine idling for a couple of minutes while another car moved out of the way. I went to pull away, there was a lack of power from the engine when I pressed the throttle pedal, a message appeared on the screen saying "Engine System Service Required", the engine died and a puff of electrical smoke came from somewhere under the steering wheel. The engine would turn over but would not start again. I pushed the car into a bay and left it all day while I carried out my job. In the evening I came back to it, I always carry a generic OBD2 reader in the car due to previous experiences. There were 5 codes which I left alone (did not delete) and called my recovery service. I had it towed home and there is stayed for just over a week.

I'd arranged to take it to a local diesel/electrical expert repairers in the town where I live, got a mate to trailer it up there and left it with them after telling them the story as detailed above.

They were very puzzled by the fault codes, but eventually found that the throttle pedal was bad as it stank of burnt electronics.

The pedal was replaced for a brand new one but still the car would not start. They then called me to tell me they suspected the High Pressure Fuel Pump and told me that the bill would be in excess of £1K to get and install a new pump (£1K includes the work already carried out and new pedal) At that cost the car is not worth repairing.

I arranged for my mate to come and tow the car home, paid the current bill of £211.20 for pedal and labour (pedal could not be returned to the supplier)

Anyway last night I was having a brainstorm on the issue and was looking at my Volvo wiring diagram for the car, came up with some ideas and went up to the workshop carpark to have a play just in case I could fix it my self and save my mate having to tow it home.

It turns out that Fuse 36 was blown, this is the fuse that supplies power to the throttle pedal and to the ECU on Connector B pin 24. I replaced the 10A fuse and after having to use a jump pack due to flat battery, the engine started much to my amazement!

Thinking that it was fixed I let it warm up and charge the battery for a while then pressed throttle pedal but was met with a slow increase in RPM. It would rev to 3.5K RPM but almost like there's no turbo. I turned off the engine, plugged the OBD2 reader in, erased all codes and tried again, my thinking being that the codes were due to the flat battery and starting issues previously seen. The engine once again started normally but the RPM's still acted the same. At this point I was frozen and wanted to go home.

Today we went up to get the car on the trailer, I started the engine hoping that it would be able to assist the winch whilst being dragged onto the tilt trailer. I pressed the throttle but the engine bogged and died. I tried this again 2 more times but was met with the same cutting out. Anyway I started it again so I could use the power steering and brakes.

We got it home, started it, unloaded it and left it running while we plugged his much more comprehensive OBD2 computer into the car. It was giving 2 codes now

P0101 MAF/VAF A Circuit Range/Perf (Pending)
P0098 IAT sensor 2 circuit high (Current)

I removed the IAT sensor and probed it only to find that it was open circuit and one of the tiny fragile wires was actually severed. I've bought and installed a new IAT sensor and that code has gone away now.

The P0101 code however keeps coming back. I've looked at the MAF sensor, it's not dirty but I'll give it a spray off with MAF cleaner before I reinstall it.

I've read that there's the possibility of a split hose between the MAF sensor and the intake.

How do I go about testing for air leaks on a diesel engine without a smoke machine?
How do I test for Vacuum leaks?
What reading should I be seeing from my MAF sensor connections?

Sorry for the long post but I though it best to tell the entire story so all the information is available to anyone who is willing to offer me any advice on this.

We love our car and aren't ready to part with it just yet

Thank you in advance for your time and help, Greg.

[glegalee]

Update: I have replaced the IAT and MAF sensors and now the engine runs and drives. I have erased the P0098 and P0101 codes and no more have appeared.

Now I have an excessive amount of white smoke coming from the exhaust. It's obviously unused diesel, this is evident from the smell. After the issues I have had with the slow increase in RPM due to bad MAF sensor, is the white smoke likely to be due to excess fuel residue in the exhaust system? Or am I looking at a stuck injector?

Is there a way to test for open injectors without removing them from the engine?

Cheers G.

[IainG]

Hi
There is a test in VIDA that cuts the injectors one at a time and monitors the drop in revs for each.
That would probably work for you?

I think if you actually unplug the injectors to do the same it can cause major problems..

So best to do in VIDA with a DICE.
Iain

[glegalee]

Thanks for the response Iain. I took the car for a spin this evening as we had to go and do the grocery shopping. Thankfully it would appear that my suspicion that the smoke was due to excess fuel in the exhaust as it's cleared now after a good run up at operating temperature.

I'm gonna say the car is now fixed

Cheers G.