In the beginning...
Was a G that wouldn't rev higher than 4K with foot flat on floor, new-looking but badly fouled plugs and the slowest tickover imaginable causing untold amounts of stalling.
When I first got the car, the accelerator pedal had little or no travel in it & would not go to the floor. It could also be seen that the mounts for the bar joining the pedal to the rest of the throttle linkage had a bit of play in them. However, a few days after the G arrived I finally got to look under the bonnet in the daylight and this was where the problems lay.
Having first changed the plugs (mud in the plug recesses - wonder how that got there :wink: ), I started to look at the linkage. The first thing that was obvious was the linkage on the opposite side of the bulkhead to the pedals was twisted round. Once that had been straightened it was then obvious that the rubber bush on the bulkhead was perishing, so a lot of the pedal travel was being used up in pulling the linkage to the right under acceleration. My good friend Mr. Big Cable Tie sorted this temporarily, allowing me to see where I might have further problems.
Next thing I found was a vacuum capsule by the throttle body going nowhere. Turned out there was a bit of hose near it which had split. Chopped the split end off and re-attached the capsule, seemed a tiny bit smoother on tickover but was still very rich. Looking at what I would call the air bleed screw (arrowed) it seemed very far in, so loosened that a couple of turns and things started to happen - idle speed doubled. Did not run it out too far, only to the start of a point where the idle settled at about 1500rpm.
Looking at the idle speed/throttle stop screw, the first thought was how the @#*% do you get to that! Looks like it is in upside down to be honest, that will get turned around very soon whether it is wrong or not. Anyway, managed to take it back a bit, bringing tickover revs down to about 1100rpm. However, throttle pedal was now having no effect at all. Disconnected last link rod and could be seen that the flap was sticking - actually jamming shut - at idle. Not only that but part of the linkage was now also jamming. Obviously the flap has been getting progressively stickier and linkage bushes had been wearing thinner for some time, so the previous owner(s) had simply upped the idle speed to move the linkage to a point where it would not stick and brought the speed back down again by strangling the bleed screw.
Anyway, played around with it for a bit until I found a relatively sensible spot in the throttle travel where it was sticky but not wedged solid and set idle at that point. Took it out for a road test and wow - what a difference!! Now revs to top end readily and is not chokingly rich at tickover.
So, not what I would call fixed but the parts order is starting to form and that will begin to put it right. Have to say I am getting really excited now as the G comes together. Will keep you all informed!
John
I'm pleased that you have a G, welcome along. I am just checking that you know exactly what the various bits you are altering are doing. The big plastic screw that you called a air bleed screw is actually the idle speed adjustment not the mixture screw. The stop screw that in a carburetor would normally be the idle screw is the stop for the flap in the intake body. Itsounds like you set this fairly well by making the flap move freely. That's what it should do and not touch again. The idle mxture screw is under the air filter cover. I can't describ the location and I don't know how to post pics.When you are looking at the air flap from above, you should be able to see the small screw. The flap that moves in the air flow is what alters the fuel quantity.
Good luck. I've got a manual on that engine which great descriptions on the fuel injection system. Let me know how to post a pic if you want any info.
Roly
. . . Obviously the flap has been getting progressively stickier and linkage bushes had been wearing thinner for some time, so the previous owner(s) had simply upped the idle speed to move the linkage to a point where it would not stick and brought the speed back down again by strangling the bleed screw. . .
It's always the fear of the used car buyer that the previous owner has messed things up. While I certainly share that fear, whenever I have bought a used car I have found the process of forensic analysis sort of exciting.
Best,
- Spalding
Amen to that Spalding :) , love that whole process of taking the new arrival apart bit by bit, then you know it intimately when it goes wrong - though have to say nowadays I try to buy things with a better reputation for longevity!
Happy Christmas to all across the pond,
JG
Captain spalding. Just curious if you are one of the 315 million americans that own one of the 325 million fire arms in cirulation in the states at the moment :shock:
what did you think of g wizz
Captain spalding. Just curious if you are one of the 315 million americans that own one of the 325 million fire arms in cirulation in the states at the moment :shock:
Well, that is certainly an inflammatory question. I'm not sure where those figures are coming from. According to the U.S. Census Bureau, as of July 2004 there were only 293.5 milliion people in the U.S.. I suspect the quoted number of guns is similarly inflated. To answer your question, I do own firearms.
what did you think of g wizz
I loved it. Lots of fun. Thanks very much.
— Spalding
I've got a spud gun and a pair o' gutties, does that count? :twisted:
I've got a spud gun and a pair o' gutties, does that count?
Sure does. At least here. The spud gun is specifically recognized as a dangerous device by the U.S. B.A.T.F.
A chair leg has the same effect on british police.
Rustbucket wrote:I've got a spud gun and a pair o' gutties, does that count?
Sure does. At least here. The spud gun is specifically recognized as a dangerous device by the U.S. B.A.T.F. Is this the ?. Anti Tattie Force :shock: Of course could be classed as biological weapon. Nice one Captian :lol:
A chair leg has the same effect on british police.
Having sat around for a week or so during Christmas & New Year, the truck didn't seem to want to start this morning, so the tools were out again.
Couldn't hear fuel pump kicking in on ignition so cracked the fuel line and there was plenty of petrol getting up front. Checked the cap and rotor and that was all ok, nice and dry but gave it a wipe out and filed the contacts clean just in case. Noticed the earth on the 'spark box' (as someone else has called it - the Bosch module on the n/s inner wing) was well loose, so cleaned the contacts and tightened that up. Pulled out the number three plug, and though it was a bit wet there was plenty of spark once dried so that was ok too.
Once the spark plug had been replaced, I pulled off air filter & complete housing to give max intake, connected up the battery charger/booster so as not to kill the battery during extended turning over and tried to start it in 10 sec bursts with 10/15 secs in between to keep the starter cool.
After 5 or 6 attempts it caught and kicked straight into life. I must have soaked the plugs during previous attempts. Having now fully exposed the very suspect wiring on the starter motor by removing the air intake, I decided to sort that, so knocked off the engine and got the electrics box out.
Stripping back the various coverings, one could immediately see where Billy Bodge had been at work over the years, so took off all the old tape etc, cleaned the wires and redid the connections. Then the whole lot was covered in heatshrink and looked much tidier. That was all reassembled and though I had hoped that it might sort the intermittent starter problem, no such luck unsurprisingly, but it gave me great peace of mind to know that at least the wiring was sorted.
Starting her up once back together & it was REALLY noticeable just how much better the G revved without the air filter, so even though it looked OK, that was obviously knackered too. Left the filter itself out on reassembly and got the dog and the middle daughter on board to do a charity shop run. Without that duff filter, ORL drove like a new vehicle and my mpg has easily doubled as a bare minimum. Last week I did 55 miles on £25 worth of unleaded; this morning it was 45 miles on under a tenner.
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Hi Roly, thanks for the advice and the offer of manual assistance. Might take you up on that.
Only reason I called it an air bleed screw is 'cos it didn't look like it was in contact with the throttle linkage, and my last 528i (1983 vintage) had the same sort of setup, BMW calling it a bleed screw. Anyway, all I was aiming to do today was sort the tickover out, the G will go to a local guy who is good with Bosch systems to be set up when I have serviced it and got some new bits on it to replace the old worn out stuff. He can do the mixture etc, hopefully will be silky smooth after that. It's certainly sounds better now than it did two days ago, so am pleased with that for starters.
Cheers, JG :wink: