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

[bobthecabbage]

Originally Posted by Dirty Diesel

I've just checked it after having the car running for a minute at most, after replacing the rear discs and pads, and funnily enough it still has a vacuum problem. Has a slight vacuum, but not much. The shut off valve only moves slightly.

Would that be why the car boosts when it's been running for a while, but doesn't boost 100% when it's just been starting/not run long?

Probably!

I think the black cannister has some sort of spring loaded bellows inside it (something to provide a vacuum after the engine is switched off), so potentially that could have a hole in it causing the vacuum loss.

Does the open port on the solenoid for the shut off valve have vacuum when the car is running?

[Baffler]

Originally Posted by Dirty Diesel

I've just checked it after having the car running for a minute at most, after replacing the rear discs and pads, and funnily enough it still has a vacuum problem. Has a slight vacuum, but not much. The shut off valve only moves slightly.

Would that be why the car boosts when it's been running for a while, but doesn't boost 100% when it's just been starting/not run long?

Located under the black vacuum chamber is a solenoid which activates the shut off valve. Remove this solenoid, clean it with carb cleaner and once dried out get some PTFE spray in there (WD40 & 3in1 do a dry PTFE range). Do the same with the boost control valve (N75) on the bulkhead and ensure all rubber hoses going to both valves are in good nick. Secure them with small cable ties if needs be. Let us know if there's any improvement!

[Dirty Diesel]

Originally Posted by AndyV7o

You need a vacuum gauge to really tell mate.

I'm taking the car with me to work tomorrow. Gonna get the scan tool to read some codes from the car and see what I get back, in case anything new has popped up. Plus there's a couple of blokes there who are fimiliar with the F9Q engines, so I'm gonna see I can get them to look it over and see what they think.

Hopefully we should have a definite answer tomorrow. Or at least be closer to solving the vacuum issue

[Dirty Diesel]

Originally Posted by bobthecabbage

Probably!

I think the black cannister has some sort of spring loaded bellows inside it (something to provide a vacuum after the engine is switched off), so potentially that could have a hole in it causing the vacuum loss.

Does the open port on the solenoid for the shut off valve have vacuum when the car is running?

I took it to work yesterday, got one of the lads to look over them. Luckily he was a master tech at Renau and knows these engines well, and after reading the codes, the MAF sensor fault code has appeared again! He said to try a genuine Volvo MAF. Recommended trying one of a car from a scrap yard and see whether that works.

He thought it was the new maf being dodgy. When he removed the pipe going to the actuator, the actuator arm did move back to a resting position, like it would if it was under vacuum, then when he put the pipe back on, it rose back up again. Yet the car still runs like a sack of spuds.

Still confused about it to be honest. Would be nice to be able to pick up a parts car! But alas, the street is cramped enough as is.

[AndyV7o]

Pattern part mafs are a minefield... Lots of dodgy stuff, you can get a decent one, but the odds of getting a bad one are high.
So yeah, a genuine one would be required to eliminate definitively.

[Dirty Diesel]

Originally Posted by AndyV7o

Pattern part mafs are a minefield... Lots of dodgy stuff, you can get a decent one, but the odds of getting a bad one are high.
So yeah, a genuine one would be required to eliminate definitively.

I purposely went for an OE Quality part from Euro's because of this haha. Got a Delphi sensor. Guess it'll be best to go for a genuine Volvo one. I was gonna check the part number from my old sensor, against the new one, just incase i got one that was for the D4192T4 instead of mine (D4192T3), but I've seen Gatos post on here showing that the part numbers for the MAF sensors for both engines were the same, so that kinda eliminates that pretty much.

Plus the heavens have opened for most of the weekend so I'm screwed

[AndyV7o]

Delphi ought to be ok tbh...
Then again, ecp can turn out some questionable budget ****, might not be delphi but chinese **** that ecp have a license to sell using the name, or, there have been cases of counterfeit stuff from ecp...

[Reynard]

Not sure if this is relevant to the original thread but had a good experience with MAF sensors recently that went like this:-

Have 2 V40's 1.9Ds First one, reliable and used for the last 5 years and another one been stood for 12 months that is waiting to replace the original

The one that had been parked up developed an issue when I went to move it a while ago.....blue smoke.....no power

Read the codes and one showed the MAF. Thought it a good idea, take the one off the reliable car and put it on the problem car. No improvement.

Put the "good" MAF back onto the reliable car and that resulted in the same problem as the other car..... blue smoke and no power.

The Fix was to disconnect the battery overnight, let the ECU forget all about it. Next day, no issue. On start up, the car checks everything from scratch including the MAF which is fine so hey presto.

Although you can erase codes and think the ECU will underhand, sometimes it refuses to forget so will still give a problem. Disconnecting and clearing it's memory seems to fix it.

[AndyV7o]

Very good point!
If batt hasnt been disconnected after replacement, the ecu may think,its still working with a faulty unit. Let it forget and learn from scratch...

[Dirty Diesel]

Originally Posted by Reynard

Not sure if this is relevant to the original thread but had a good experience with MAF sensors recently that went like this:-

Have 2 V40's 1.9Ds First one, reliable and used for the last 5 years and another one been stood for 12 months that is waiting to replace the original

The one that had been parked up developed an issue when I went to move it a while ago.....blue smoke.....no power

Read the codes and one showed the MAF. Thought it a good idea, take the one off the reliable car and put it on the problem car. No improvement.

Put the "good" MAF back onto the reliable car and that resulted in the same problem as the other car..... blue smoke and no power.

The Fix was to disconnect the battery overnight, let the ECU forget all about it. Next day, no issue. On start up, the car checks everything from scratch including the MAF which is fine so hey presto.

Although you can erase codes and think the ECU will underhand, sometimes it refuses to forget so will still give a problem. Disconnecting and clearing it's memory seems to fix it.

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?