Alfa Romeo Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
22 Posts
Discussion Starter #1 (Edited)
Hello, first post :)
I've bought a 1999 156 v6 not long ago and when I bought it it seemed slightly down on power (I've owned a 156 v6 before) but since the engine was running evenly and the rest of the car was OK and it was £1600 I bought it anyway.

The slight power loss hasn't got any better, and it sometimes appears to have flatspots appearing around 3000-4000rpm. It's hard to say if it gets better at higher revs. There's too much traffic where I live to go and study the engines performance. The idle is also poor. Because I paid so little for the car, and it's still quicker than a 2L I've been putting up with this, but now it's beginning to bug me because I now there is at least 5% more power hiding in the engine somewhere.

I've joined this forum and read some posts which look related and they point to the MAF. Some people have horrendous problems and mine aren't severe at all. People who haven't driven the v6 before might not even notice. I've unplugged the MAF and taken it for a blast on the local motorway and it does pull smoother, maybe slightly more powerful, difficult to tell.

I'm going to order a new MAF sensor, a vauxhall 0 281 002 180, since it's supposed fit. In the meantime I'd like to run with the MAF unplugged.

Is this sensible?

Since the engine runs fine without it (apart from the low rough idle which shakes the car) I can't imagine I'm doing any damage to the engine. I expect I'm just running lean or rich in different circumstances. Maybe this will fill my engine with soot? Am I wrong?

On another issue, I have had one power loss episode on a motorway when I was overtaking a truck in the heavy rain. Sudden powerloss at 3000 rpm, I only just managed to overtake the truck! The engine was running like some of the cylinders weren't firing properly. The idle was incredibly rough. I thought this might be moisture related so I revved the **** out of it until it cleared and was on my way again after a few minutes.

I happened to be on my way to Alfaman who did a diagnostic and the only fault was intermittent knocking which is likely unrelated and no big deal.

Anyway, my main question is about running with the MAF unplugged.
thanks
 

·
Registered
Joined
·
426 Posts
Welcome to AO Ewan.

MAF is probably the correct diagnosis. When mine failed it the injection warning light came on. The engine ran OK upto 5K rpm but then just stopped revving.

You can run with the MAF unplugged until you get the new one fitted.

Is that Vauxhall part the same as for the Alfa V6??
 
1

·
Guest
Joined
·
0 Posts
I have a vauxhall one in my V6 part no 0 281 002 180, you just get the sensor no housing so you have to transfer them, however for £32.99 i didnt mind the 10 minutes taken..

:thumbs:
 

·
Registered
Joined
·
426 Posts
I have a vauxhall one in my V6 part no 0 281 002 180, you just get the sensor no housing so you have to transfer them, however for £32.99 i didnt mind the 10 minutes taken..
I'll remember that for next time.:rolleyes:
 

·
Registered
Joined
·
1,109 Posts
Spray the maff with carb cleaner then rinse it under warm water then leave it to dry. Dont touch the element inside with a cotton bud or anything they are too delicate to risk it thats why i use carb cleaner it does a top job of cleaning the maf. Give that a go it could save you a few quid.
 

·
Registered
Joined
·
9,912 Posts
Spray the maff with carb cleaner then rinse it under warm water then leave it to dry. Dont touch the element inside with a cotton bud or anything they are too delicate to risk it thats why i use carb cleaner it does a top job of cleaning the maf. Give that a go it could save you a few quid.
no need to rinse with water carb cleaner evaporates away:thumbs:
 

·
Registered
Joined
·
22 Posts
Discussion Starter #8
Carb cleaner huh? That might be a top tip. I've already ordered the part though so it'll likely turn up tomorrow. I could try the carb cleaner trick but then I'll be spending money on a can of that. However in the name of science it might be a good experiment to try before putting in the new sensor to see if it makes a difference. I don't know if I'll be patient enough to wait for the cleaner to evaporate off though. I suppose you need to leave it for a bit for the carb cleaner to do it's thing? Dissolve the muck etc.
 

·
Registered
Joined
·
1,109 Posts
Carb cleaner huh? That might be a top tip. I've already ordered the part though so it'll likely turn up tomorrow. I could try the carb cleaner trick but then I'll be spending money on a can of that. However in the name of science it might be a good experiment to try before putting in the new sensor to see if it makes a difference. I don't know if I'll be patient enough to wait for the cleaner to evaporate off though. I suppose you need to leave it for a bit for the carb cleaner to do it's thing? Dissolve the muck etc.
Nah. Just spray it on and watch the gunk drip off dry it with your other halfs hair dryer, plug it back in and see the difference.
 

·
Registered
Joined
·
22 Posts
Discussion Starter #10
Update:
I ran for a couple of weeks without the sensor. No harm done. I put the new sensor in yesterday morning but I noticed the seal between the sensor pipe and the air filter was pretty crap. It was a plastic on plastic seal, maybe there was supposed to be a rubber seal in there?
I took it for a spin and the engine was definately smoother but I got a strange sudden torque loss at about 3500 rpm. Nothing magor, the car was still pulling, but it was nonetheless noticable.
A mate of mine suggested that warm air from the engine bay may be getting sucked in through the bad seal, so I went round to his and we glued and sealed over where the leak might have been.
We unplugged the battery to reset the ECU and then went for a spin.

Everything appears to be working fine now.
So the crap seal against the air filter may have been part of the problem.
 

·
Registered
Joined
·
9,912 Posts
Update:
I ran for a couple of weeks without the sensor. No harm done. I put the new sensor in yesterday morning but I noticed the seal between the sensor pipe and the air filter was pretty crap. It was a plastic on plastic seal, maybe there was supposed to be a rubber seal in there?
I took it for a spin and the engine was definately smoother but I got a strange sudden torque loss at about 3500 rpm. Nothing magor, the car was still pulling, but it was nonetheless noticable.
A mate of mine suggested that warm air from the engine bay may be getting sucked in through the bad seal, so I went round to his and we glued and sealed over where the leak might have been.
We unplugged the battery to reset the ECU and then went for a spin.

Everything appears to be working fine now.
So the crap seal against the air filter may have been part of the problem.
nowt todo with seal to air box
did you check corrugated rubber pipe to throttle body that usually splits
 

·
Registered
Joined
·
562 Posts
If all the rubber connectors of the intake runners are OK (wich is nearly impossible taking the age of the car into account) and the intake pipe is ok too, the first check the sensor seal.
If it doesn't help unplug the Lambda Sensor and see if there's any difference (faulty lambda will cause a bad idle for instance).
 
1 - 13 of 13 Posts
Top