Strange symptoms..

P

phonixp6

New Member
ok so as some of you know i had to swap out my old bw 35 for a secondhand one that was cheap enough and was working, a few miles ago she started to have this symptoms

she will change through all the gears she will pull well in all gears but sometimes at completely different rpm she will just stop revving and stay at that revs even if i engage the kick down it is possible to make her reproduce this by using hard acceleration but it can happen at part throttle cruising at 40-60mph i have tried operating the choke which has no effect so i am assuming it cant be fuel related but that's what i keep coming back to as i have never heard of an auto box doing anything like this. any help you guys can give on the matter would be very much appreciated
 
linkage problem from the accelerator to the carb? I guess the kickdown cable could be catching somewhere???
 
linkage is possible as it is defiantly screwed up i couldn't get it right when i installed the new one i made sure i could get park drive and reverse and just left it don't think its the kick down as that happens at the very end of the throttle travel, i have taken the carb out so that i can see the needles and although one of the carbs is slightly different they both don't look bent although it is possible to make one stick if you push it up at an angle slightly. My next idea is that it might be the coil breaking down at high rpm under load or a possibility that the fuel line is letting in air somewhere causing the electric pump to simply not supply enough fuel i am going to replace the coil and the fuel line on Thursday as the current fuel line setup isn't optimal as its a mass of joined pipes and the fuel pump is in the engine bay so heat in the fuel might be causing unwanted issues if you guys think of anything else please post it here and if anyone knows of someone capable of setting the linkage properly in Suffolk or near please let me know.
 
don't think its the kick down as that happens at the very end of the throttle travel
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sounds not far off right there.

Do you mean it stutters when you're trying to accelerate or that it maintains engine revs? If the first, then carb float chambers, possible coil or fuel. If the latter then that would surely be the linkage between the bulkhead and carb, or the linkage between the 2 carbs sticking...

Rich
 
describing it is difficult i suppose stuttering is as close to it as possible. the problem is it is such a strange symptom that no one has experienced anything like it before.
 
Are you on points or electronic ignition?

If points still I'd have a punt at an intermittantly defective capacitor. Modern (Chinese) ones are prone to this sort of shennanigins. Best solution is to find a really old Lucas one in the bottom of a tool chest....

If that cures it, then go to the next stage and fit electronic ignition!

Elderly plugs can sometimes do this sort of thing as well.

Chris
 
she has already had new points and condenser the plugs all look perfect lovely biscuit color, i thought it might be the fuel pump so just ran her at 4k rpm for 2 min and the fuel filter never lost any fuel so fuel pumps out of the frame now.
 
If you are suffering from loss of power, then it will be engine related.
If you have power or revs, but no motion, then you would be looking at the transmission / drivetrain
Back to basics I think, fuel or spark, if you have checked out all the fuel delivery scenarios, then you now have to look at the delivery of the spark at the plug.
A slow methodical approach I think.

Just reading your first post again, it just points me towards a fuel problem :?
 
the new condenser if not an old lucas one could be the culprit there are plenty of duff ones about.... personally I wouldn't use points. since transistors are cheap and readily available electronic ignition is a no-brainer to me. Rover would've used electronic ignition if it'd been economically viable at the time.
 
DaveHerns said:
just ran her at 4k rpm for 2 min
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I don't think that's a conclusive test for fuel starvation .With no load the fuel consumption is negligible compared with full throttle going uphill
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just stuck a brand new fuel pump on her problem still there, however the piece of nylon plastic that holds the throttle linkage together has snapped and looks very worn i have also noticed that the grommet that is supposed to hold the rear of the shaft in place is missing entirely, i am wondering now if it is the kick down because as i understand it and i am probably wrong is that the linkage adjusts the pressures in the box and severely effects its functions and not just under kick down. After looking in the hanes manual i am not confident that this is as easy to adjust as i thought it would be so i am in need of someone that can sort the problems out i have purchased and fitted new nylon link but have been unable to find a grommet to fit does anyone know of someone that can replace the grommet and adjust the linkage i am in Ipswich in Suffolk so the closer you are the better but am willing to travel a fair distance to get this sorted would also like the selector linkages sorting at the same time. please post the name and number of the people you think may be able to help.
 
I think you just gave us the clue up there! "Just fitted new points and condenser". So that will be a duff condenser causing the agro then! No doubt at all. Find someone who can supply a decent quality one, like SimoonBBC or better still, fit one of his electronic kits. Almost as cheap as points and a capcitor!!

Chris
 
its not the points or condenser as have now tried a working pair as i said i require someone able to adjust the kick down cable i have just got back from a "specialist" that suggested breaking of the small stop block on the cable and then just to wind up the cable till it works? didn't sound right to me as another specialist quoted 75-100 to do the same job!?
 
phonixp6 said:
i require someone able to adjust the kick down cable i have just got back from a "specialist" that suggested breaking of the small stop block on the cable and then just to wind up the cable till it works? didn't sound right to me as another specialist quoted 75-100 to do the same job!?
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The crimp (stop block as you call it) is purely an indicator of where the cable should be set, the problem is that you have no way to know whether it has been correctly set in the first place, and if it's changing up late with the crimp sitting on the top of the outer cable, you won't be able to lower the pressures any further (to lower the shift speeds) without removing it. If it's changing up early, then the position of the crimp is irrelevant as far as adjusting the cable to get the shift speeds correct.
If the kickdown works, then I'd say that the pressures aren't too low, so it shouldn't be upshifting too early, and if you don't have to lift off the throttle to prompt the upshift because it's changing up too late, then the pressures aren't too high either. If all the throttle linkage is in good condition and correctly adjusted, then adjusting the kickdown cable on a roadtest should take no more than an hour at the most, TBH, half an hour should see it sorted.
 
Hello Harveyp6 if I remember correctly you have some experience fixing these boxes :wink: do you have a shop somewhere so that I can come and show you the fault the best I can describe it is that although the gears all work and appear to change at the right time if your heavy with the throttle she gets to a certain rpm and then stutters along at the same rpm even if you engage kick down like i said I think it's time she saw a specialist that knows what I should do be it new valve assembly as one specialist suggested or if it is a governor thing (can't remember what it's called) or something as simple as this cable.
If you can help please post me or pm me your number and the best time to reach you.
 
phonixp6 said:
the best I can describe it is that although the gears all work and appear to change at the right time if your heavy with the throttle she gets to a certain rpm and then stutters along at the same rpm even if you engage kick down
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That still sounds far more likely to be an engine, rather than gearbox, fault.


phonixp6 said:
like i said I think it's time she saw a specialist that knows what I should do be it new valve assembly as one specialist suggested or if it is a governor thing (can't remember what it's called) or something as simple as this cable.
If you can help please post me or pm me your number and the best time to reach you.
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Only very rarely do valve blocks develop problems, and even then it's normally limited to a particular valve which still doesn't necessitate the replacement of the whole block. If you're heavy with the throttle and the pressures are on the high side, then it may be that the engine is faltering because it can't perform at a high enough RPM for it to upshift. If the governor were faulty then it could make the box hang on to gears, and end up causing the same problem as above.

Personally I'd want to be convinced that the engine is working to its optimum before I started pulling the gearbox apart. Yours may be the exception (and there is always one), but problems as you describe have turned out to be the engine rather than the gearbox in pretty much all of the ones I've had dealings with.
 
I am at a loss as to where to look on the engine next. That awful noise came from a warped flex plate it was so slight that I had to have it measured to see it can't remember how many mil it was warped by but wasn't a lot so replaced the thing and she ran fine :)) till now lol
 
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