Bongo acting up - help

[cutlass]

stunews if you need - i have PDF-"manual" about this AT and may send for you at "e-mail"......

[Flanners]

The cost of reconditioning a gearbox is circa £2K+ which to me is astronomical and makes it un-economic for many Bongo's. For roughly half the cost I would personally opt for one from a decent Bongo breakers and get someone who is proficient and knows what they are doing to fit it. Could this have been initially an electronic MAF or TB problem, unsure from what you have said as to whether the local spanner could have made things even worse? I would try another gear box with a specialist back here in Blighty that is if you decide to repatriate her.

[cutlass]

I am sorry - £2K????? in russia I may order that AT in Japan and after one month my cargo come in...it be cost apr £300....now £ 1= 77RUB.....https://baza.drom.ru/krasnoyarsk/sell_s ... 14471.html
you do not may order parts in Japan or Korean? I don't understand......

[Flanners]

Yes indeed that is what I would do. Source a box from Japan or a breakers.

[Alacrity]

From the description of the fault it is clear it never was the gearbox. Its a shame I have only just seen this thread. Your description of the the fault in your first post describes perfectly an engine VERY down on power.

I will try to explain. In simplistic terms an auto transmission needs to know two things to work - how fast are you going & how fast do you want to go. Talking in term of electrically controlled transmissions, as we have in the Bongo, the speed is relayed to the transmission computer from a speed sensor on the output of the transmission or transfer box, the 'how fast' is from a potentiometer on the throttle linkage (on the fuel pump in the bongo diesel instance). So assuming everything is running as it should it will change up nice & early on 'normal' in town pull away using (as a for instance only) say 20% throttle opening. If you develop an engine issue & power is way down, to pull away at the same speed you will be using a lot of throttle, so the transmission computer see's, say, 90% throttle opening, you are only doing 10 - 15 mph so it thinks you want to go fast & will hang on to the gears for longer. The problem is that there is no power in the engine so it will never change up until the throttle is released, then it will change up, often to change down again immediately the throttle is pressed again.

Sadly a common mistake mechanics make when diagnosing this sort of problem - "the gearbox is late changing so it must be the gearbox". We see dozens of vehicles for this situation every year here.

[TheLongRoad]

Thanks for sharing this infomation @Alacrity If it ever happens to me I'll be better prepared. Hope original poster can get their Bongo back on the road.

[mikeonb4c]

Brilliant explanation again from a top autobox man. Posts like this should find their way into some sort of factsheet. Thanks Geoff

[Bob]

Post gone astray.

Second try - Thanks Alacrity, top info from a pro.

[TheLongRoad]

I second the factsheet idea.

[Ian]

I'm quite happy to write a factsheet, but it should really be a trouble shooting guide for the gearbox, not just that a single issue. Perhaps Alacrity can send me some relevant information?

[Flanners]

From the description of the fault it is clear it never was the gearbox. Its a shame I have only just seen this thread. Your description of the the fault in your first post describes perfectly an engine VERY down on power.

I will try to explain. In simplistic terms an auto transmission needs to know two things to work - how fast are you going & how fast do you want to go. Talking in term of electrically controlled transmissions, as we have in the Bongo, the speed is relayed to the transmission computer from a speed sensor on the output of the transmission or transfer box, the 'how fast' is from a potentiometer on the throttle linkage (on the fuel pump in the bongo diesel instance). So assuming everything is running as it should it will change up nice & early on 'normal' in town pull away using (as a for instance only) say 20% throttle opening. If you develop an engine issue & power is way down, to pull away at the same speed you will be using a lot of throttle, so the transmission computer see's, say, 90% throttle opening, you are only doing 10 - 15 mph so it thinks you want to go fast & will hang on to the gears for longer. The problem is that there is no power in the engine so it will never change up until the throttle is released, then it will change up, often to change down again immediately the throttle is pressed again.

Sadly a common mistake mechanics make when diagnosing this sort of problem - "the gearbox is late changing so it must be the gearbox". We see dozens of vehicles for this situation every year here.

Sorry to butt in.......so based on the problem you explain what is the probable solution? A new TPS?

This issue crops up all over the Forum and is never really answered to a proven conclusion. It seems to me to be an electronic issue not mechanical.

I have an interest in this as my 2.0 is misbehaving between high tickover speed and the box working correctly or normal tickover speed and the box hanging onto the revs. A new TB was fitted and the problem went away, I then changed the plugs and filter, reset the ECU (not sure why) and it has returned this time normal revs but still holding them when it should have changed up. Does this point to the TPS and can this be tested via a voltmeter to determine if it is faulty?

Several owner's appear have to needlessly shelled out on 'new' gearboxes, changed the fluid etc when that isn't the actual problem

[mikeonb4c]

I'm quite happy to write a factsheet, but it should really be a trouble shooting guide for the gearbox, not just that a single issue. Perhaps Alacrity can send me some relevant information?

Lord knows owners could use a guide written by someone who knows their stuff like Geoff. Maybe he could be enticed with an agreement that his autobox repair company can be given an acknowledgment in the guide. And i suspect he gets fed up with pobbycock and balderdash spouted by self elected experts!

[Bob]

Yep.

[cutlass]

at the diesel motor you can change the position of TPS=to change the shift point AT (now i install 0.62V at the released accelerator pedal)...it is impossible on petrol motor? many tech info about AT you may find into manuals https://www.atsg.us/atsg/ I download it from "torrent"
for next - if you want the gear ratio has varied as you planned - you can use a universal controller AT it allows you to program (from USB) multiple algorithms - winter, city, race, track and etc... for example - ATECU

[Flanners]

Wow that sounds technical, mine has been sorted today!

Codes cleared in ECU which were MAF and TB related. Screw on throttle body was trimmed to obtain proper tickover of circa 850rpm (I think). Just driven 50miles and all is good once again. The problem I was having was between 2000-3000 rpm with a small amount of throttle the gearbox was not changing but the revs rising (felt like slip but wasn't). A gearbox 'specialist' I had a conversation with over the phone (fair enough it was over the phone) in Sussex basically told me on the phone it would be circa £2200 to put right. Thankfully a Bongo Specialist I took the van to said it was electrically related and not mechanical, makes me wonder how many people have had this issue especially on the 2.0 and thrown pots of money at it replacing parts when it just required a tweak?