V40 1.9D won't rev freely and puffs blue smoke

[AndyV7o]

5 mins should suffice mate, just enough for anything which might have stored power to run down fully.

[Dirty Diesel]

Originally Posted by AndyV7o

5 mins should suffice mate, just enough for anything which might have stored power to run down fully.

Oh okay! I'll go do that. Hopefully we're onto something.

[Dirty Diesel]

Originally Posted by AndyV7o

5 mins should suffice mate, just enough for anything which might have stored power to run down fully.

Just tried it, still seems to smoke upon revving. I'll have to try more again tonight or tomorrow. Busy man you see haha. Hopefully something's changed

[bobthecabbage]

Before you get too carried away, maybe have a really close look at the wiring and connector for the MAF.

What was the actual maf code and fault description?

Its a shame that euro car parts doesn't seem to sell the genuine maf any more. I'm not sure they are still in production? Mine was a siemens VDO and I think I found it using the part number of the old one. There are loads of people who list 'genuine' mafs and the part numbers but it needs to say 'genuine siemens vdo' original part or something like that.

I'm not saying your new one is faulty, maybe its fine and the wiring or connector is at fault. You can find guides on how to test MAFs on youtube etc.

The maf I got from Euro car parts came in a 'renault genuine parts' box so don't forget to try a renault dealer if you are going to go genuine. If you've got the part number they should be able to match it for you. It could be cheaper than volvo!

[AndyV7o]

^^^^ That.

[Reynard]

Mine didn't reset after leaving it for a short time. Disconnected overnight and it was fine next day accept for the radio code.

[aldred309uk]

Originally Posted by Dirty Diesel

Disconnecting the battery fixed it?! Wow, I nevee would have thought that. So should I disconnect the battery this morning and then plug her back in, say tonight or tomorrow morning and see what happens?

Find the radio code first!!!

[Dirty Diesel]

Originally Posted by bobthecabbage

Before you get too carried away, maybe have a really close look at the wiring and connector for the MAF.

What was the actual maf code and fault description?

Its a shame that euro car parts doesn't seem to sell the genuine maf any more. I'm not sure they are still in production? Mine was a siemens VDO and I think I found it using the part number of the old one. There are loads of people who list 'genuine' mafs and the part numbers but it needs to say 'genuine siemens vdo' original part or something like that.

I'm not saying your new one is faulty, maybe its fine and the wiring or connector is at fault. You can find guides on how to test MAFs on youtube etc.

The maf I got from Euro car parts came in a 'renault genuine parts' box so don't forget to try a renault dealer if you are going to go genuine. If you've got the part number they should be able to match it for you. It could be cheaper than volvo!

Here's the code i got from the scanner:

"1806 Mass Air Flow (MAF) Sensor. Faulty Signal" that was from a Snap-On Solus Ultra if that helps at all.

I've been on a few pages for testing 1.9D MAF's, but with there being two extra wires for the IAT (Intake Air Temperature), I'm really not sure which wires are what. I have learned that wires #3 and #4 are for the MAF, and that wire #1 is for the IAT, but after that I don't know. I don't know what exact readings I'd be looking for, or whether I'm able to test them, as their doesn't seem to be anywhere to stick a pin in the back of the connector to check for "running" voltages.

I did find a YT video where you can see whether your MAF is fine by simply unplugging it when the engine is running. If it cuts out, the MAF is fine, if it doesn't, you've got a problem basically. Mine just ran on no differently after unplugging it.

Unplugging the battery didn't seem to do anything either, even after leaving it for a few hours. And to anyone who was wondering: I do have the radio code, don't worry. With my car having an aftermarket head unit fitted by the previous owner, it doesn't require the radio code after any time that I've disconnected the battery.

Thing is, I doubt that the MAF itself is a dud, because it actually did improve the power, just not the economy or smoke output. I am getting a slight vacuum; the shut off valve does move down slowly, then return slowly after shutting off the engine. Doesn't seem to go down fully though, and is very sluggish to move. Any ideas?

[DNCJ]

Originally Posted by Dirty Diesel

Here's the code i got from the scanner:

"1806 Mass Air Flow (MAF) Sensor. Faulty Signal" that was from a Snap-On Solus Ultra if that helps at all.

I've been on a few pages for testing 1.9D MAF's, but with there being two extra wires for the IAT (Intake Air Temperature), I'm really not sure which wires are what. I have learned that wires #3 and #4 are for the MAF, and that wire #1 is for the IAT, but after that I don't know. I don't know what exact readings I'd be looking for, or whether I'm able to test them, as their doesn't seem to be anywhere to stick a pin in the back of the connector to check for "running" voltages.

I did find a YT video where you can see whether your MAF is fine by simply unplugging it when the engine is running. If it cuts out, the MAF is fine, if it doesn't, you've got a problem basically. Mine just ran on no differently after unplugging it.

Unplugging the battery didn't seem to do anything either, even after leaving it for a few hours. And to anyone who was wondering: I do have the radio code, don't worry. With my car having an aftermarket head unit fitted by the previous owner, it doesn't require the radio code after any time that I've disconnected the battery.

Thing is, I doubt that the MAF itself is a dud, because it actually did improve the power, just not the economy or smoke output. I am getting a slight vacuum; the shut off valve does move down slowly, then return slowly after shutting off the engine. Doesn't seem to go down fully though, and is very sluggish to move. Any ideas?

I had a similiar problem with my v40 1.9 , i was on the freeway running about 120km/h with the ac on, and suddenly no power , had to turn the ac off and go about 80kmh/h with the pedal fully pressed to get home, i noticed the Throttle Body was leaking a bit,bought a new one from Renault p/n 8200843370, this just stopped the leak, still no power,
no engine light warning on the dash, the mechanic plugged the obd machine and the error was the MAF Sensor, so I bought a original one (siemens)on a scrap yard, and the result was a slight increase of power , but still was very slugish , to enter on a roundabout was a nightmare.
After that bought a map sensor but no luck , then bought a new maf sensor from LUCAS on EBAY and the car was the same, unplugged the battery for 2 days, and was slight better, but still had lack of power under 2000rpms.
Unplugged again for another 2 days , and voilá fully power again, still don´t know what solved the problem, i think the ECU has to adjust to the maf, but i´m not sure.
Prior to this i followed the guide from Biotoxic, and cleaned the EGR,
this went wrong because after cleaning , the turbo didn´t work at any revs,
found out was the Boost pressur Valve (p/n 30618057 ), bought a new one and problem solved.

Just sharing my exprience hoping to help with this problem.
Sorry for my English

[Baffler]

Originally Posted by Dirty Diesel

Thing is, I doubt that the MAF itself is a dud, because it actually did improve the power, just not the economy or smoke output. I am getting a slight vacuum; the shut off valve does move down slowly, then return slowly after shutting off the engine. Doesn't seem to go down fully though, and is very sluggish to move. Any ideas?

The shut off throttle body could be distorted, it's plastic after all, hence the slow movement of the butterfly valve. Try disconnect the rubber vacuum hose going to the actuator on the side of the throttle body and push the plunger down with your thumb. When released it should spring back into the open position. If the butterfly valve is sticking closed you'll need to replace the assembly. A half closed valve would cause insufficient air flow and in effect incorrect air to fuel mixture (low power/smoking).

The MAF meter must be a Siemens P/N 5WK9632 (Volvo P/N 30887504)...anything else cannot be trusted.