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Topic ClosedOdd sound from ’84 320i engine!

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abs66 View Drop Down
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Direct Link To This Post Topic: Odd sound from ’84 320i engine!
    Posted: 08-July-2003 at 04:09
Thanks for the advice guys, much appreciated.

There is one thing I have noticed about the engine that I could do with some advice on.
When I start her hot or cold there is a sound that is like a cross between noisy tappets and an exhaust blowing splutter but this dies down to nothing after about 2 mins of driving and completely dissappears! The sound appears to be coming from the drivers side but like I say dies away before I can identify whats wrong!
Also the idle is very lumpy and when warm drops to about 600rpm. If the revs are lifted to about 900 or 1000rpm the engine is silky smooth like it should be. Can i adjust the tickover on the engine easily, I only ask as try as I might I cant seem to source a haynes manual for this age of car!
Is it normal for these cars to use £25 worth of fuel in 127 miles? I love the way she drives and seems to float along and I would like to keep her as it appears it has been well looked after in the past but like I said I am a novice and dont really know what I am looking for with regards to possible problems any help you guys can give is much appreciated as I am not a rich man! Her indoors sees to that!!
Thanks again
Abs
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Andyboy View Drop Down
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Direct Link To This Post Posted: 08-July-2003 at 19:47
Christ, that's 18 mpg. Something not right there. But around town, an old 320i will get down to that. Is it an auto? The common cause for high fuel consumption is the throttle position switch (TPS). It's on the underside of the throttle body and it fills with oil left in the throttle body by the breather. There's a vacuum throttle damper on one this old - push the rod back into the unit and open the throttle by hand. You should hear a slight 'click'. This is the TPS telling the ECU that the engine is off idle and needs more juice. Some DIY 'experts' raise the idle speed using the throttle stop screw. All you can do is remove the throttle body, take of the switch, prise the back off and wash it out with petrol. Refit it after setting the TPS so that it 'clicks' the instant the throttle is opening. Also pack some grease around the spindle on the throttle body to stop oil getting back into the TPS. Adjust the idle speed using the air speed screw - it's on the inlet manifold above the cam cover.
Unfortunately, these old L Jetronic cars (chrome bumper 320i and 323i) are a nightmare. Leaking vacuum hoses, seized distributors, faulty water temp idle control valves.....aaaaaaargh!
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abs66 View Drop Down
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Direct Link To This Post Posted: 08-July-2003 at 23:16

Thanks Andy.

Is there anywhere I can get pictures of the components you mentioned, I have to admit to being a bit of a novice in this area!!

The temp guage sometimes flickers but tends to settle down. Its a five speed manual and I have been reasonably gentle with the throttle...err well most of the time anyway! I am in the process of replacing all the hoses as I found a petrol hose that was weeping right over the manifold! That could have got interesting. I suspect the vacuum hoses all need changing so I am going to do them aswell. I assume I wont be doing any harm by cleaning all the electonic switches/senders/and other assorted wires and plugs? I want to try and eliminate all the things an amateur can do before taking it to a specialist as my pockets are on the baron side wonger wise!

Your advice is much appreciated by the way. Thanks.

Regards

Abs

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Direct Link To This Post Posted: 09-July-2003 at 21:54
The old Haynes manual (@317 pages) was quite good but don't bother with the new one as it's crap. A Bentley manual is good too.

TPS: It's screwed to the underside of the throttle body, black box the size of a matchbox. And no, you can't remove it without removing the throttle body (4 10mm nuts, easy to drop.....).

THROTTLE DAMPER: This is the thing that looks like a spaceship that acts on the throttle lever - it's next to the brake master cylinder reservoir and it's got a vacuum hose going to it. When the engine is fired up, the rod should pull right back away from the throttle lever.

IDLE SPEED SCREW: Go to the driver's side of the engine bay and you'll see a couple of large bore air pipes going into an alloy bit screwed onto the manifold above the cam cover. Also see the breather pipe where it goes into the cam cover just below it. Look up the 'tube' and you'll see a slotted screw. Turn this to raise or lower the idle speed.

WATER TEMP IDLE CONTROL VALVE: This senses when the engine is cold and lets extra air in. As the coolant heats up, it closes. They corrode and seize over 15 years. See the big air pipe going across the top of the engine from the idle speed screw housing. With the engine cold, clamp this and the engine should almost stall. With the engine hot, it shouldn't do anything. If it stalls when the engine is hot, the valve is stuck open. The valve is down by the starter motor, an alloy H shaped thing. You will not find a good used one!!

The TPS is the common cause of mega mpg though.
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Direct Link To This Post Posted: 09-July-2003 at 21:56
If you live anywhere near Nottingham, bring it over one day and I'll look at it for you. These are so fickle and easy to get wrong, it's quite satisfying to get them running right!
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abs66 View Drop Down
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Direct Link To This Post Posted: 14-July-2003 at 18:41
Thanks for all the advice Andy, it is much appreciated.

I live in Plymouth Devon, so I am a fair distance from you but I have relatives in Hull so pass your way a few times a year! Even if you cast an experienced eye over it that would be a great help just to know where I am looking for probs etc.

Gonna print your advice out and have a look see. Not frightened of getting filthy, just dont want to bugger anything up!! Fingers crossed.

Regards
Abs
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Direct Link To This Post Posted: 24-July-2003 at 16:31
OK Its now pumping fuel all over the exhaust manifold from what I thought was a perished petrol pipe. Replaced the pipe and problem reappeared after two days. Local garage tell me its the cold start sensor where the pipe is attached to.
Does anyone know if this likely? Dont mind paying for repairs if I'm not being ripped off. I'm sure the guy is telling the truth, just could do with hearing other people have had similar problems so to speak. I think I am just being paranoid, but hey, it dosnt do any harm to seak second opinion.

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Abs
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Direct Link To This Post Posted: 25-July-2003 at 18:04
Ignore my last post, it was the cold start sensor and its all fixed now.

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Direct Link To This Post Posted: 04-August-2003 at 21:36
Ok Ignore my last post !!!!!
Its squirting petrol out over the manifold again!! I am now suspicious of the cold start sensor replacement I have paid for!

All the petrol pipe is new and it has new proper petrol pipe clips which I have just re- positioned and tightened, ok so far fingers crossed. Just would like to know is it possible that a cold start sensor could squit out petrol or have I been had over???

Thanx for any advice.

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Abs
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