gearbox sensor overheat?

Technical questions and answers about the Mazda Bongo

Moderators: Doone, westonwarrior

Post Reply
Four Oaks Bookworm
Bongonaut
Posts: 60
Joined: Mon Aug 03, 2009 9:47 pm
Location: W Midlands

gearbox sensor overheat?

Post by Four Oaks Bookworm » Wed Jun 03, 2020 9:43 am

In the recent hot spell, we have an occasional issue with gear changing, where the selector seems to hunt around for the correct gear and has difficulty finding it. It's sometimes almost as if one of the cylinders is missing a beat, causing the sensor to think that another change up is necessary. Other circumstances:

Idling is even and normal, no issue with cold start
Fault occurs between 1500 and 2000 revs, usually around 4th gear 30-40mph
Usually when reapplying the throttle (gently though) to climb gentle gradients
No hold light (or any other light)
Always when engine is warm, and outside temperature is very hot
Other than that, it's really only intermitttent

Any advice welcome as always!
Thanks
User avatar
Northern Bongolow
Supreme Being
Posts: 7713
Joined: Mon Mar 15, 2010 11:33 pm
Location: AKA Vanessa

Re: gearbox sensor overheat?

Post by Northern Bongolow » Wed Jun 03, 2020 7:06 pm

Petrol or diesel.😷
rita
Supreme Being
Posts: 3284
Joined: Tue Sep 15, 2009 7:11 pm

Re: gearbox sensor overheat?

Post by rita » Wed Jun 03, 2020 7:52 pm

Northern Bongolow wrote: Wed Jun 03, 2020 7:06 pm Petrol or diesel.😷
Diesel...
Four Oaks Bookworm
Bongonaut
Posts: 60
Joined: Mon Aug 03, 2009 9:47 pm
Location: W Midlands

Re: gearbox sensor overheat?

Post by Four Oaks Bookworm » Thu Jun 04, 2020 5:36 pm

Yes, Diesel
User avatar
Northern Bongolow
Supreme Being
Posts: 7713
Joined: Mon Mar 15, 2010 11:33 pm
Location: AKA Vanessa

Re: gearbox sensor overheat?

Post by Northern Bongolow » Fri Jun 05, 2020 12:19 pm

Without any fault codes and the description you give I would be looking at the turbo or pipework to it, you state it happens around where the turbo starts to spool up and add boost.
Could be fuel filter (both). Or small dia pipe on inlet manifold elbow to pump top advance diaphragm blocked with oil or off.
What year is the diesel.
Four Oaks Bookworm
Bongonaut
Posts: 60
Joined: Mon Aug 03, 2009 9:47 pm
Location: W Midlands

Re: gearbox sensor overheat?

Post by Four Oaks Bookworm » Thu Jun 11, 2020 5:48 pm

Fuel filters were cleaned the week before this started (by a bongo specialist), so I don't think it can be those. It's a 1996 model (P reg)

If it's the turbo, wouldn't that mean very sluggish pulling away in low gears as well though? There's no problem with performance off a standing start and it goes through the gears fine from 0 / cold. It's just when it's hot (weather) and warm (engine). Kickdown works fine for overtaking and there's plenty of boost then still. Will get the pipes/inlet checked over though, thanks!
Post Reply

Return to “Techie Stuff”