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Warm up time and holding the gears
Posted: Mon Mar 14, 2016 3:01 pm
by roosmith
Yep me again, I'm being a pain! Sorry!
The time it takes for my Bongo to run normally and take the correct gears seems to be getting longer. Not sure if it is my perception or if this is correct! It is holding 2 gears down until my engine is at about 75 degrees. It means I can't do much more than 50 miles an hour without it sounding like it's about to expire.
I'm sure it only used to hold the top gear and certainly changed before it hit 75 degrees. Where is the temperature measured, is it gearbox or engine? Do these sensors breakdown gradually or just stop working?
Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 5:45 pm
by Fassi
As i first read this it makes me think there is a problem with the throttle position sensor. With a bit of heat making it work correctly by reducing resistance somewhere. This is an out and out guess by the way and I was at the pub for lunch. The temperature doesn't or shouldn't select gears?
Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 5:48 pm
by Fassi
Have you checked the gearbox oil level?
Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 6:10 pm
by mikeWalsall
Low gearbox temperature stops the gearbox / torque converter going into lockup / top gear ..
Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 8:47 pm
by roosmith
Thanks Mike, I knew I'd read that on here and mine has always done it so I took it as gospel. How does it do it though, how does it know it's warm?
With regards to throttle position sensor, it's not the throttle that is causing an issue, it's the gearbox in a lower gear. Also would mine have one, as I've only come across them on fly by wire systems?
Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 10:06 pm
by Simon Jones
As I recall, it will stay in 4th gear until it gets warm (usually a few minutes) and then it will go into top gear lockup. It does this to ensure the fluids get up to temperature as quick as possible. From your description, it sounds like yours isn't getting out of 3rd gear which is not right. Not entirely sure where it gets it's temperature reading from (engine or gearbox) but it could be a dodgy sensor.
All Bongos have a throttle position sensor (TPS) which is used to tell the gearbox ECU how it's been driven so it knows when to knockdown. In the case of the V6 it also changes the rate at which the fuel is injected. It could be a problem with the TPS but you would not normally expect it to go away when warm, but it's not impossible. I'd certainly start by checking the gearbox ATF level and if you've got no record of it being changed (or it brown and smells of burnt toast), drain the fluid, drop the sump to clean the filter and refil with Dexron 3 fluid.
Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 10:11 pm
by roosmith
Thanks Simon. It's been on the list of nice to do jobs for a while but always been dropped down the list by ones that were essential! It looks in good condition but perhaps I need to just get on with it now and get the oil changed. In theory it's 90k old now.
Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 10:16 pm
by Simon Jones
According to factsheets in the members area, the ATF should be changed every 2 years or 24,000 miles so you may be a tad over

.
http://www.igmaynard.co.uk/bongo/member ... hedule.pdf
http://www.igmaynard.co.uk/bongo/member ... ts/atf.pdf
Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 10:40 pm
by mikeonb4c
Every 2 years! Blimey Charlie i'd thought it was just every 24k miles. I suspect very few have ATF changed that often though now i've been advised i reckon i'd better get it on the to-do list.
Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 10:47 pm
by Bob
Yes, mine is rather overdue.

Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 10:55 pm
by mikeonb4c
Bob wrote:Yes, mine is rather overdue.

Laxative helps I find

Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 11:01 pm
by Bob
mikeonb4c wrote:Bob wrote:Yes, mine is rather overdue.

Laxative helps I find

Micheal...

Re: Warm up time and holding the gears
Posted: Mon Mar 14, 2016 11:30 pm
by cmm303
mikeonb4c wrote:
Every 2 years! Blimey Charlie i'd thought it was just every 24k miles. I suspect very few have ATF changed that often though now i've been advised i reckon i'd better get it on the to-do list.
suspect mine is overdue by 75k miles
Re: Warm up time and holding the gears
Posted: Tue Mar 15, 2016 1:39 am
by Northern Bongolow
check 19-444 on this link, take it out and clean it or check/clean the wiring to it, its an inhibitor switch, which sounds like a temp activated switch.
http://lushprojects.com/bongopartsmk2/c ... o=.html#14
Re: Warm up time and holding the gears
Posted: Tue Mar 15, 2016 6:54 am
by roosmith
Spot on, thanks Northern, missed that exploded diagram when looking at the weekend.