Help please. I'm giving it one last go!

[Mkengineering]

As some of you guys know I've got a black Manual 850 t5.

It's got the problem of not being fuel efficient! Now I know these cars aren't mpg gods. But my car is giving me 5 to 10mpg! It use to give me at least 26mpg around town and on a long run I would be in the 30s!

Not only have I seen a huge decrease in mpg, ive noticed the car chucks out a mixture of black smoke and white smoke? Black smoke mainly comes out when you stamp on the pedal.

Anyway I've noticed also the Idle is now at 1k and sometimes jumps up to 1300-1500 revs, holds it's for a few seconds then drops down to 1k?

Couldn't see any boost leaks and I've checked a few times.

So things that I've changed

Spark plugs
Genuine temp sensor
Genuine thermostat
Genuine fuel relay
Genuine fuel filter
Genuine oil filter
5w40 silkolene ester oil
Genuine dizzy
Genuine rotar cap
Gsf car parts ht leads
Bosch tps sensor .

When I bought the car it was on a Rica map which I then swapped over to shemtek map.

The following I upgraded to run the shemtek ECU;

3inch snaab intake
4inch AEM filter
540i BMW housing
New Bosch standard maf prob( Volvo genuine 850)
Decat

So to summarise;

My car seems to be over fuelling giving me 5 to 10 mpg.
Lots of white smoke and black smoke once you put load on.

I've done what I can and I dont know if iv missed anything?

Just need help here

[Mkengineering]

Someone must have some idea??

[ksmi]

Originally Posted by Mkengineering

Someone must have some idea??

Revert back to bog standard settings/parts?????? Volvo knows best??????



Regards,Keith.

[taiwan740]

Originally Posted by Mkengineering

As some of you guys know I've got a black Manual 850 t5.

It's got the problem of not being fuel efficient! Now I know these cars aren't mpg gods. But my car is giving me 5 to 10mpg! It use to give me at least 26mpg around town and on a long run I would be in the 30s!

Not only have I seen a huge decrease in mpg, ive noticed the car chucks out a mixture of black smoke and white smoke? Black smoke mainly comes out when you stamp on the pedal.

Anyway I've noticed also the Idle is now at 1k and sometimes jumps up to 1300-1500 revs, holds it's for a few seconds then drops down to 1k?

Couldn't see any boost leaks and I've checked a few times.

So things that I've changed

Spark plugs
Genuine temp sensor
Genuine thermostat
Genuine fuel relay
Genuine fuel filter
Genuine oil filter
5w40 silkolene ester oil
Genuine dizzy
Genuine rotar cap
Gsf car parts ht leads
Bosch tps sensor .

When I bought the car it was on a Rica map which I then swapped over to shemtek map.

The following I upgraded to run the shemtek ECU;

3inch snaab intake
4inch AEM filter
540i BMW housing
New Bosch standard maf prob( Volvo genuine 850)
Decat

So to summarise;

My car seems to be over fuelling giving me 5 to 10 mpg.
Lots of white smoke and black smoke once you put load on.

I've done what I can and I dont know if iv missed anything?

Just need help here

Try unplugging the oxygen sensor - classic Volvo hunting-at-idle cause

[taiwan740]

Plug has a red top that you have to lever up with a screwdriver or something, located in the gap behind the air filter housing, down by the gearbox

[taiwan740]

Failing that, other things to look at that you haven't already listed -

Leak going to the Idle Air Control valve? Or just **** IAC?

[taiwan740]

just adding posts so I can get over 30 post count for the ol' DM function, y'know

[Shinsplintz 101]

Did Shem map the car, or did you chuck in a mapped ECU from another car? Does your spec exactly match the other car? If not your asking for trouble.


Have you checked the oil to see if it smells of fuel? If it does then you have bore wash - too much fuel vs air in the head washing the bores clean & diluting your oil - are you running standard injectors? Or weak spark not igniting the fuel could also be a contributing factor. Borewash would help explain the smoke on WOT, although some may be coming from the turbo if it hasnt been replaced, seals weaken & they start burning oil.

Personally I'd stop driving the car. Put the induction set up back to standard & drop in a standard ECU. Then try again.

GSF HT leads - bougicord? If not get some. OEM all the way on ignition system.

[Mkengineering]

The shemtek map I believe was just off the shelf map for it yo take the 3.5 maf housing.

Injector wise I'm running blue injectors. I've ordered some new standard injectors and hoping to revert back to standard.

The idle control valve could be ****ed as ive cleaned it a few times.

Priced up a new idle control valve and its over £300!!!!

[taiwan740]

Originally Posted by Mkengineering

Priced up a new idle control valve and its over £300!!!!

I paid £400 for the whole car m9 lol