newbie e34 owner with possible fuel problems :(

[Baz25099081]

Hi fellow Bimmer owners :) . I've managed to buy a mint '94 100% original 520i ,( Pics to follow as soon as I can sort :). This car is in unbelieveable condition and tugged at my heart strings as soon as I saw it. ( I have to confess to being a previous merc owner but I've found a new love :) . It does have one niggling issue tho. It's very hard to start. When running if you try to accelerate too quickly from tickover she will try to cut out and stall. There is a sucking sound from around the air inlet manifold as she tries to stall but I've done the old carb cleaner around the lot trick and no leaks were found :( . My first point of attack was going to be the fuel pump but i cant find it and I cant find a workshop manual for it anywhere. Haynes manuals stop at '91 and start again at '96 ?????????? Please help as she looks stunning on my drive but should be out on the road :)

[Baz25099081]

I think I'll try changing the injector seals first. Can anyone give me a quick heads up on how to do it please :)

[632 Regal]

You need to score a Bently E34 manual to get ideas how to work on these things. You may have the infamous intake gasket leak syndrome going on, really doubt its the injector seals at this point. You will have a gasket between the throttle body housing and intake, also where the intake bolts to the head. Sometimes the leak is underneath and the carb cleaner trick will fool you but all you need is a real small leak to mess things up.

[Baz25099081]

Thanks Regal. The previous owner threw quite abit of money at the problem changing sensors and stuff in a garage but didnt cure it. I'm thinking of taking the inlet manifold off and changing all the gaskets just so that I can rule that out of the equation. I dont want to have to do all the gaskets twice tho so can the injector seals be done without taking the inlet manifold off a second time and damaging the new gaskets ?

[Baz25099081]

Just noticed something that may be of use. I've just noticed that when you try to rev from idle that the inlet manifold distorts slightly ???? Should the engine really be sucking that hard on the manifold ? Hmmmmmmm........

[Baz25099081]

Can somebody tell me what this is please ? ITs ticking like mad even after I've removed the keys from the ignition and I have to disconnect it to make it stop !

[Tiger]

First thing first... get fuel pressure reading... when car is off... when car is running... and after it shuts off... and 15 minutes later.

Sounds like a fuel pump problem.

[Baz25099081]

Had an auto tuner guy check out the fault codes. Only 2 came up. Temp sensor isnt changing and rpm sensor. The rpm sensor wont go away. I've changed the crank shaft sensor but its still there ??? Any idea's. He confirmed no leaks at the inlet manifold. There is however a constant sucking noise from the dashboard. It's not from the engine compartment and definately from the dash. Sounds like a hiss from a stereo but there isnt one fitted. The clocks have been changed at some point as I have the old ones with the car but could this have something to do with the hiss/sucking noise. I managed to sit in another 520 today and his didnt hiss/suck ??????

[whiskychaser]

Maybe post what codes you are getting?
With regard to the hissing, have you got a small bore pipe from the inlet manifold or T'd off the brake booster hose? It would go into the bulkhead near the heater pipes. If so its part of the ventilation system and connects to a valve affair behind the panel above your feet. If it has come off it could sound like the noise is coming from the dash. I've only ever seen one on a 535i but if you have it and its disconnected, its a source of vacuum leak you dont need.

[Baz25099081]

Whiskey chaser you are top of my christmas card list ! There is a small bore pipe from the inlet manifold to the bulk head. It's definately not healthy and is perishing cos if you rub it your hand turns black. I cant seem to find it in the car tho ? The hiss is definately in the car not the engine bay. Trying to remove the glove box as we speak :) .

[Baz25099081]

Whiskey Chaser. I've removed everything from the passenger footwell and the point of entry for the pipe. ( I really hope it'll all go back together :( ) This is definatly the source of the hissing as if i disconnect the pipe the hissing stops !!!! If I block where it enters the inlet manifold it seems to run better to :) Do we know where it goes tho. It seems to go up into the dash around the drivers side. Is it a full dash out job or can I get to it from the drivers side footwell. I'm getting scared now cos theres more dash in the boot than in the car ! There's a bottle of whiskey in it for you if we can sort it !!!!!! :)

[whiskychaser]

Stop taking bits off :D Like I said, its above YOUR feet, not the passenger side. I'm sure it terminates behind the panel that holds the chime or 'bong' speaker. There will be a grille cut out for the bong and you might even have another one for this sensor affair. Either way, that panel is easy to remove to have a look.

If push comes to shove, just block it off at the manifold end. Apart from annoying you and making your engine run badly, its not doing much now so you are not going to miss it are you?:)

[Baz25099081]

DOH ! Realised as I was taking the drivers side off what they were !!!! There are two air vents in BOTH panels !!! One drivers side and one passenger side. They are sucking air in so fast that they are making the hiss. Anyone know what they are ???? They have electrical connections at the vents to ????? If there is a fault with them its either whatever is controlling them electrically or the one way valve that they are connected to at the inlet manifold. Anybody know what this is ???????
On the plus side, I can strip both footwells in about 10 mins and I've fixed my loose glovebox ! :)

[whiskychaser]

I think they may be temperature sensors and work like this: Air from inside the car is drawn through them by the vacuum from the engine. Depending how hot/cold it is, the signal goes up the wires and is an input to adjust the heating/fresh air. So its not the wires controlling the sensors, its the other way round. The one-way valve may be tired and too much air is being dragged into the engine from inside the car.
Somebody will correct me if I am wrong

[Baz25099081]

Sounds good to me Whiskey :) Damn Haynes for not making a manual for it ! Need to change the valve and see if it makes a diffrence :( . There has to be something not right cos they suck on your hand if you try to cover them. I'm pretty sure that isnt right:)

[whiskychaser]

Haynes is only good if you have a wonky table leg. Did my brother's Renault over the weekend and it didnt even get the fan belt drive run right:)
Bentleys is your best bet. I just had a look and didnt see what you want in it. Some reading material for you: Free File Hosting Made Simple - MediaFire (http://www.mediafire.com/?ijviizbkk26be)
Put your vin in realoem and see what you come up with though.

[ss2115]

Can somebody tell me what this is please ? ITs ticking like mad even after I've removed the keys from the ignition and I have to disconnect it to make it stop !

Its the valve in line with the charcoal canister - part of the fuel evaporative system.
Under certain circumstances, its supposed to open to allow vacuum in the inlet manifold to dry out vapours captured by the carbon in the charcoal canister so that it can saturate up new fuel fumes next time you stop. The ECU compensates for the opening of the valve while the engine is running.

It shouldn't be ticking if the ignition is off as it shouldn't have any power going to it to my knowledge.

[genphreak]

Check the pipe that goes to the fuel pressure regulator as well, its under the manifold at the far end and goes to the FPR on the Fuel rail. Be careful, teh connetors on the manifold are plastic and can break. They perish regularly, require small hands to change and cause the car to drive very poorly as the FPR doesn't know what pressure is inside the manifold.