440 B18U weak performance, bad idle and stalling.

[quickie2]

Hello everybpdy,
I have a volvo 440 with the B18U engine. It has done 17000 km.
Last 12 months:err: I have had problems with the car having overall weak performance, Missfiring at startup and idlespeed reving up and down 600-1100rpm. If I push the throttlepedal fast the engine will die, this is really irritating..

I suspect and airlekage since the idle stabelizes when I pump on the brakepedal once a sec.?!

I have even changed the inlet/exhaust manifold gasket without any improvements. Worst job I ever done!
Please somebody help me, you are my last chance:notworthy:

[Paul240480]

Has yours got an idle control valve? (Not familiar with B18U). If it has give this a go:
http://volvo480.dragons.org.uk/forum/viewtopic.php?t=15569

If this fails, try testing (or simply replace) the coolant temp sensor. It is just below spark plug nearest to dizzy:thumbs_up:

Good luck.

[Clan]

check the vacuum pipes at the rear of the manifold there are two , one goes to the manifold pressure senor near the right windscreen wiper . There should be a brass restrictor in the rubber part of this pipe near the manifold end it can block it has a 1 mm hole through it .
another cause is low fuel pressure due to a worn tank pump .
there could be a problem with the throttle position potentiometer which is part of the throttle body , stored fault codes may help here ...

[quickie2]

Thanks for the answer guys, I have electronic idle control on mine and It's changed to a new one a year a go. The temp sensor is also new.
New plugs
New rotor + distributor.
I have tested with new cables aswell.

I do have a fault code, 4-1-1 on the tps. Looking for a new one, partnr 3437022.
I have checked theese vacuum pipes and exchanged them but there was no restrictor in none of the pipes.:GEEK:

I'm not a proffesional but It feels like an airlekage somewhere, cause when the engine gets hot the engine goes a lot better. And I can hear a sucking noise from inside the car the first sec I push on the gaspedal. Unfortunatly I can't hear this from outside:err:

How can I test the fuelpump?
Thank in advance.

[Paul240480]

Tried carburettor cleaner spray. Leave it ticking over & spray around teh injector seals, inlet manifiold, see if it setlles the engine note for a short period. If yes there's your leak.

Just below the throttle body, have you got a small braided hose, about two or so inches long, joins to a thinner pipe. If yes, twist it. It may look fine but if you wiggle it you may find it has completely perished & is a major source of air leak like mine was.

In the F/O/S wing 'cavity' have you got one of those carbon cannister things? If yes, that has a load of the same braided hose which can also if perished be a source of leak. Mines a 1.7 Turbo, so not sure if yours has these, but worth a check if only to rule out:thumbs_up:

[quickie2]

I've checked theese hoses to the canister and replaced them but still no diffrence. I also checked theese hoses behind the injector unit, they are replaced. I've tested some motor starter gas around the manifold and I can sense some changes in rpm but I've alredy replaced the inlet manifold gasket:hidesbehindsofa: I'm so tired of this ****t now.

I got a bunch of codes now:
4-1-1
1-2-2
1-2-1
1-1-3
3-1-1

I've had 4-1-1 before and I've tested the tps and I know It's bad but the other ones haven't been there before I replaced the gasket?!?
I erased the codes yesterday and we'll see if they are back today..
Thanks for your help, I really appreciate It.

[Paul240480]

That does seem to be a lot of codes LOL. I hope they are 'spurious' after all your work & that the clearing codes works.

One other thought, Lamba Sensor? Have you checked that:

http://volvo480.dragons.org.uk/forum/viewtopic.php?t=14683

I changed mine even after testing. I found it had a regular pattern but not as per spec'. Got it from GSF, & it was a Bosch OEM job. Don't go for aftermarket as you need to splice in the wires & can end up introducing more snags. It can of course be done, depends if unlike me, you are a leccy whizz LOL

Good Luck

[quickie2]

Fortunatlly all codes were gone when I checked yesterday:animal-smiley-085:

But can a bad lambda really give theese symptoms?

Anyway I will check it to so If It's OK.
:car-smiley-004:

[Paul240480]

I was told that it can course quite a few performance related snags.

If it is, say blacked up with carbon, for instance it'll give a duff reading to the ecu, which will then 'compensate'. In this case probably will course the car to run rich, choking up the plugs causing erratic idling, low performance & high fuel consumption.

Good luck.

[quickie2]

the lambda seems Ok. But I'm quite sure I'ts an air leak, the question is where? As I wrote before the idle stabilises when I put my foot on the brake pedal once a second.

[Paul240480]

Okay, have you tried spraying with Carb cleaner as previously mentioned?

These cars can be a real pain on the idling front!

[quickie2]

Yapp, I've tried that and It's hard to notice anything at all. I've read some on other places that point on a worn throttle shaft in the throttle body. This can make air leak in through there. Does anybody of you recognise this?

I am suspecting the carburator foot/gasket. Maybe this one is cracked?