A forum for Bongo fans and owners
https://www.igmaynard.co.uk/bongo/forum/
https://www.igmaynard.co.uk/bongo/forum/viewtopic.php?t=41685
With the bike that is probably because you were then cruising along much closer to peak torque revs which are usually quite high on bikes.Velocette wrote:Very generally speaking low revs in high gear doesn't necessarily mean maximum economy. If the engine is designed to cruise at higher revs it will not be working efficiently, a bigger throttle opening will be needed and more of the fuel will go through the engine unburned. This seems to bear out in the results I got from my manual car and motor bike when I switched to 3rd gear in 30mph zones instead of top when I had points on my license and didn't want any more. I wasn't really going much slower. just that it is easier to stick to 30 by ear that way. My fuel consumption was no worse, possibly better.
This thread is very useful by the way and explains a lot. My Bongo does not seem happy if I feather the throttle, and I have to use hold if I am doing a steady 40 or 50 or if I am behind slow traffic or it hunts and "unlocks" I think. If I can just put my boot down and do my own speed it is much better. I do have some transient problems with the gearbox because the hold light flashes sometimes usually preceded by delayed changes jerky changes and hunting. It is going into ADS to be checked,
Sounds fairly normal to me. In the cold weather you have to travel some distance before 4th will come in then a bit further before lockup. Is the engine running at the right temp? We sometime have cars in here with no 4th or lockup where the problem turns out to be a faulty thermostat in the engine (stuck open) not allowing the engine to get hot enough to allow 4th to be commanded.Darkstar wrote:ive been having concerns lately, as the box did not seem to go into top gear and would be reving at 3000rpm at 60mph until about a few miles up the road i did a forum search and thought i read this was normal in the cold weather, went for a drive tonight ambiant temp was 14' and it changed up as soon as i got up to about 40-50mph.
i hope that things were ok??
I've been wondering for some while how this 'commanding' is carried out.Alacrity wrote: Sounds fairly normal to me. In the cold weather you have to travel some distance before 4th will come in then a bit further before lockup. Is the engine running at the right temp? We sometime have cars in here with no 4th or lockup where the problem turns out to be a faulty thermostat in the engine (stuck open) not allowing the engine to get hot enough to allow 4th to be commanded.
I am not sure this would work with the 2000 > trans as I believe the lockup is regulated as opposed to straight forward on/off, although I am not 100% on this as I haven't seen one in the flesh so to speak.
- think of the acceleration! 
Update ADS have replaced the throttle potentiometer and it has transformed the car, it changes up almost inperceptibly at low speeds without any revving or delay, haven't tried it out of town yet but will tomorrow.Velocette wrote:Very generally speaking low revs in high gear doesn't necessarily mean maximum economy. If the engine is designed to cruise at higher revs it will not be working efficiently, a bigger throttle opening will be needed and more of the fuel will go through the engine unburned. This seems to bear out in the results I got from my manual car and motor bike when I switched to 3rd gear in 30mph zones instead of top when I had points on my license and didn't want any more. I wasn't really going much slower. just that it is easier to stick to 30 by ear that way. My fuel consumption was no worse, possibly better.
This thread is very useful by the way and explains a lot. My Bongo does not seem happy if I feather the throttle, and I have to use hold if I am doing a steady 40 or 50 or if I am behind slow traffic or it hunts and "unlocks" I think. If I can just put my boot down and do my own speed it is much better. I do have some transient problems with the gearbox because the hold light flashes sometimes usually preceded by delayed changes jerky changes and hunting. It is going into ADS to be checked,
A belated post in reply to this, but one big issue with the Bongo I think is that the turbo doesn't seem to do a lot below 40mph and I wonder if you would in fact be forever changing down due to lack of engine torque in top. On the other hand, my Bongo does seem to stay in the lower gears up to higher revs than I think it really needs to.Diplomat wrote: I drive mine most of the time with well below average gross weight and cannot see that I would be straining such a torquey engine in a high gear even down to about 30-35 MPH.
Frank
There is some adjust-ability, the throttle pot on top of the fuel pump can be moved around a little bit (I forget which way) but it simply fools the gearbox into thinking that less throttle is being applied than actually is. This means you can apply a little more throttle before it drops out of the lock-up, ideal for inclines.Diplomat wrote:
I've been wondering for some while how this 'commanding' is carried out.
Would it be possible to:
Fool it into locking up at a lower road speed?
Deter it from coming out of lock up so easily?
Manually control the lock up range?
There sure would be a big demand for an aftermarket accessory that could provide these functions.
I drive mine most of the time with well below average gross weight and cannot see that I would be straining such a torquey engine in a high gear even down to about 30-35 MPH.
Frank
I think potentiometer denotes the type of sensor so yes it is a TPS but possibly all (non Bongo) TPS's are not pots. The fact is a pot suggests that it has an anologue function rather than open closed half etc' .mikeonb4c wrote:A belated post in reply to this, but one big issue with the Bongo I think is that the turbo doesn't seem to do a lot below 40mph and I wonder if you would in fact be forever changing down due to lack of engine torque in top. On the other hand, my Bongo does seem to stay in the lower gears up to higher revs than I think it really needs to.Diplomat wrote: I drive mine most of the time with well below average gross weight and cannot see that I would be straining such a torquey engine in a high gear even down to about 30-35 MPH.
Frank
Velocette - is the throttle potentiometer different from the throttle position sensor, or are they the same thing? What was cost of replacing it, if it isn't rude to ask? I keep thinking that as Bongos get older, there must be an increasing number of components whose performance may deteriorate but without completely failing. Where replacement is cheap (thermostats and water pumps are two much discussed examples), ther is perahps a case for replacing them even if the Bongo 'appears' to be running normally (but how can you know what is normal unless you drive other similar Bongos, or else fit a replacmenet part like you did, whereupon the difference before and after was striking)
Thanks for that - price seems about right for TPS from a distant memory of dandywarhol discussing his on here a long time ago. Expensive little buggers that's for sure!Velocette wrote:I think potentiometer denotes the type of sensor so yes it is a TPS but possibly all (non Bongo) TPS's are not pots. The fact is a pot suggests that it has an anologue function rather than open closed half etc' .mikeonb4c wrote:A belated post in reply to this, but one big issue with the Bongo I think is that the turbo doesn't seem to do a lot below 40mph and I wonder if you would in fact be forever changing down due to lack of engine torque in top. On the other hand, my Bongo does seem to stay in the lower gears up to higher revs than I think it really needs to.Diplomat wrote: I drive mine most of the time with well below average gross weight and cannot see that I would be straining such a torquey engine in a high gear even down to about 30-35 MPH.
Frank
Velocette - is the throttle potentiometer different from the throttle position sensor, or are they the same thing? What was cost of replacing it, if it isn't rude to ask? I keep thinking that as Bongos get older, there must be an increasing number of components whose performance may deteriorate but without completely failing. Where replacement is cheap (thermostats and water pumps are two much discussed examples), ther is perahps a case for replacing them even if the Bongo 'appears' to be running normally (but how can you know what is normal unless you drive other similar Bongos, or else fit a replacmenet part like you did, whereupon the difference before and after was striking)
ADS charged £175.00 incl labour using a second hand part. New ones were £175 +VAT on Flea Bay.
I could do that now. I wouldn't have got to the end of our road before!bigdaddycain wrote:The amount of throttle application affects when and where the box changes up or down as a generalisation. For example, i managed a trip from Wigan to Cornwall without exceeding 2500 RPM through deft throttle use.