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stu2002 
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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 Topic: Fuel or Ignition?
Posted: 08-October-2003 at 09:40 |
Dear All
I have a rather perplexing problem which I hope someone may be able to shed some light on. The symptoms are:
1) Severe juddering upon light acceleration or deceleration
2) Lumpy-ish idle
3) Unwillingness to idle from cold
4) Under hard acceleration the symptoms dissappear
The problem can happen in any gear and at any speed. I've replaced the entire ignition system (apart from the distributor itself, which I've stripped & cleaned) and replaced the fuel line, fuel filter, cleaned & stripped the fuel pump & carb all with no effect. She starts 'on the button' every time, so I'm sure the timing/points/plugs must be OK, also looked for air leaks - none found.
I'm very nearly at my wits end - any help would be very much appreciated.
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 08-October-2003 at 11:31 |
Forgot to mention - my rev counter has also gone haywire! Swings wildly back and forth from 0 to 8000 rpm very often. Not related to engine speed I hasten to add.
Could this be related???
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alistair.rodger
Advanced Newbie
Joined: 16-May-2003
Location: United Kingdom
Status: Offline
Points: 22
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Posted: 08-October-2003 at 17:16 |
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Somebody mentioned to me a possible reason. If your engine mounts are a bit wobbly and you have a direct driven accelerator (i.e. bit of steel rod, and not a cable), what can happen is the movement of the engine changes the rate of acceleration. Just an idea worth mentioning.
I personally would try disconecting the rev counter wire from the distributor. That is the one which does not stop the car when removed. And possibly test the capacitor.
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 09-October-2003 at 09:23 |
Alistair,
Thanks for your suggestions, I'll certainly look into it but I think I'm going to give in and let someone 'grown up' sort it out.
Think I'd better check down the back of the sofa for some money first!?!
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Russell
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 26
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Posted: 11-October-2003 at 01:24 |
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Wot car you got? sounds like ignition , with the tach doing wierd stuff... sure you got the right plugs? mine ran like that with W6DC Bosch plugs (std 2002, 8.6cr bit (!) smoky!). W8's sorted it out fine.
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 13-October-2003 at 13:49 |
It's a std '74 2002 (single carb job). I'm running W6DC's but I've got some W8's on the way, also a bit smokey (valve stem seals - as usual).
Surely the plugs don't affect the tacho, do they?
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Russell
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 26
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Posted: 14-October-2003 at 00:00 |
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You wouldn't necessarily think so but the tacho is basically a spark counter so misfires can make 'em do lots of odd stuff! If yours starts pinking with W8's try W7's , but it should be ok unless the timing's too advanced.
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 14-October-2003 at 08:10 |
Will be fitting the W8's tonight.......fingers crossed.
I'm also lacking the manifold heat shield, perhaps the plugs are overheating??? Having some trouble finding one but I've heard that the heat shield from an E21 will fit with minor modification?
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Russell
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 26
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Posted: 14-October-2003 at 23:14 |
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How long have you had the car? The heat shield has two purposes, Firstly as a heat shield and second is for a warm air intake to reduce carb icing in cold weather. if you have no carb icing problem, the best heat shield solution is an E30 318i exhaust manifold gasket which has the heat shield as an extension of the gasket. I cant say about the adaptability of an E21 heat shield but they are quite different in appearance and the pipe comes off vertically, not horizontally. Mines been fine without one for the last 3 years.
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 15-October-2003 at 08:20 |
Had the car for 7 years now. Never had the heat shield & never had any carb icing problems, guess I'm just clutching at straws in desperation.
Fitted the W8's last night, also did the points & condensor while I was at it. Result - no difference, but it did sort out the tacho problem!
Really stumped as to what to try next, apart from throwing some more money at it.
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alistair.rodger
Advanced Newbie
Joined: 16-May-2003
Location: United Kingdom
Status: Offline
Points: 22
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Posted: 15-October-2003 at 09:17 |
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Try swapping the carb.
Has anybody got a "known working carb" to try a swap. I had two but gave them away.
If I still had it I would lend it to you to try. Sorry about that. I shouldn't expect you to have to spend more than £10 for one??
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 17-October-2003 at 15:58 |
Have taken the carb out again and stripped & cleaned it for the 4th time!! Will replace it tonight and keep my fingers crossed, but I'm not going to hold my breath.
My feeling is also that it must be the carb but for the life of me I can't find anything wrong with it.
Will let you know on Monday how it went. Have a good weekend all.
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 20-October-2003 at 13:53 |
No joy with the carb, problem still there. I seem to be swaying back toward the distributor/timing. Don't know why, nothing seems to make sense anymore!!
I think I'll take it to my local garage and get them to hook it up to their Crypton to see if it's OK or not.
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alistair.rodger
Advanced Newbie
Joined: 16-May-2003
Location: United Kingdom
Status: Offline
Points: 22
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Posted: 20-October-2003 at 14:13 |
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If the carb is worn, no amount of cleaning will replace the worn bits. Are you going to Donnington this weekend if so perhaps a trial carb could be arrainged to eliminate that as a problem.
Sorry if this sounds a bit rude, emails always do. But if somebody else in the club can help you it would make your membership all that more worth while.
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--
alistair, white '02, blue roof
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 20-October-2003 at 15:55 |
No rudeness detected. I agree it would be very good to try a carb swap.
Wasn't intending to go to Donington but it could be possible with some diary juggling. It's a BMW Drivers Club event isn't it? I'm not a member, only of the BMWCC. Although I don't suppose it makes any difference.
I don't think the carb is worn, maybe just badly adjusted. The carb is about 5 years old and I do around 3k miles per year. The throttle spindle seems to be a snug fit, i.e. very little play.
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alistair.rodger
Advanced Newbie
Joined: 16-May-2003
Location: United Kingdom
Status: Offline
Points: 22
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Posted: 20-October-2003 at 17:26 |
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I spoke to Fay @ Jaymic as I gave them an old carb. Fay said it might have gone off for referb after all it is theirs to do what they want with. But I haven't heard back yet.
For donnington see;
http://www.bmw2002.co.uk/events.htm
Even if Jaymic have thrown out the carb or spent money on it, there is a parts stall @ donnington anyway.
I believe a pinto weber carb is a good replacement. see
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=2437214110&category=21654
£61 looks a little steep to me, but that is about 2 hours of a mechanics time ;-)
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=34202&item=2438238247
I haven't suffered "throttle spindle wobble" myself but am a firm believer in the whole sale swapping of parts when you can get them for next to nothing and with so many ringers out there this should be possible.
What can be more fun than playing with a car and paying little for being able to do so.
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alistair, white '02, blue roof
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qsela
Newbie
Joined: 04-August-2003
Location: Finland
Status: Offline
Points: 8
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Posted: 21-October-2003 at 12:14 |
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You didn't mention which kind of ignition do you have. Usually these rev counter problems are caused by (what the h**l is it?) "ignition control box". I've had 2 broken boxes in my previous cars (non-BMW) and the spark and rev counter probems were solved by replacing this box. Maybe this is worth to try?
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 22-October-2003 at 15:29 |
Just standard ignition with points & condensor i.e. no electronics. Sorted the rev counter by fitting a diiferent temperature spark plug.
I'm beginning to suspect that the vacuum advance unit is duff. I tried sucking on the pipe and it was very difficult to get any movement of the plate. This could possibly cause a 'misfire' under 'no load' conditions???
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medlow
Groupie
Joined: 28-July-2003
Location: United Kingdom
Status: Offline
Points: 97
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Posted: 21-November-2003 at 19:16 |
Stu2002... have you found a fix for the:
1) Severe juddering upon light acceleration or deceleration
2) Lumpy-ish idle
3) Unwillingness to idle from cold
4) Under hard acceleration the symptoms dissappear
I have a e30 320i with exact same problems!!!! I have been unable to fix, I have had the whole injection and fuel, airflow and ecu checked out to no gain in performance, compression on all six is fine.. I have cleaned out the ICV and AFM.. is it a misfire?? the only thing I havent checked is HT leads.
I know yours is carb but I was still hoping you had some advice. Anyone, please I am getting desparate, a gorgours, mint condition 320i Conv needs your help! I am reluctant to let BMW at it.. cash a bit tight as it coming up to xmas..
James.
----------------------
1990 320i Conv.
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stu2002
Newbie
Joined: 07-October-2003
Location: United Kingdom
Status: Offline
Points: 35
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Posted: 24-November-2003 at 11:54 |
James
Unfortunately I haven't fixed the problem. You name it and I've replaced it. As your e30 is a very different beast to the 02 I would be reluctant to suggest anything.
Sorry I can't be of more help. Good luck.
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Fuel or Ignition?