Bongo Breakdown (Paris)

[moesymoe]

Howdy folks! Love the forum!

Unfortunately, I'm reaching out in a time of need. Walter(2.5 v6 '99 Bongo) just threw his first proper wobbly on a motorway just outside Paris, at the start of our 10 day European adventure en route from cherbourg to chablis and beyond (switz was the idea but that appears increasingly unlikely).

Anyway, no apparent issues for the first 4 hour stint of the motorway journey. Then, when re-entering the autoroute, coming up to speed at 40mph on the way to 60, felt a shudder and then there was no response from the accelerator. Got to the hard shoulder, Walter restarted when retried after 2 mins and held at idle, but when put into drive with foot on brake, he couldn't hold a rev and cut out. He has since been able to drive for short distances <2k without issue.

Now, with help of tow truck mechanic, couple of issues found:
- cooling fan not working. Part appears v difficult to source.
- 'membrane sensor' not working. The one under the gearshift on the driver side. The mechanic is suggesting to make a temporary repair to bypass this sensor.

On the cooling fan, I think that this was a pre existing issue. Am I correct that a faulty cooling fan on the front may not present an obvious issue when motorway driving as the air intake would be sufficient to cool the engine?
And therefore, am I correct to assume we may be able to proceed cautiously, paying close attention to the temperature gauge? Or is this a serious issue that needs to be resolved before proceeding anywhere?

For additional context, my home mechanic, in Dublin, Ireland, had just replaced timing belt last week, along with the distributor cap, rotor arm and all ht leads. Is it possible that they didn't rebuild the engine correctly and left a loose connection?

My mechanic in Ireland suggested over the phone that an issue with the crank sensor may be the reason for the stall/cut out on the motorway. Does this seem likely or any other alternative suggestions for a root cause to investigates?

Feeling very much at sea on mainland Europe. Any and all help from the fantastic Bongo family very much appreciated in this time of need.

[nth]

What is a membrane sensor?
Was it showing any symptoms of overheating? temp gauge sitting ok? Loss of coolant?

[g8dhe]

Oh, not so good to hear
Not sure about the "membrane sensor" or even what's being referred to without a picture or part #.
The cooling fans are operated via a relay by the ECU from signals from the engine temperature sensor (2-wire one) at the front, there is also another sensor (single wire) which feeds the temperature gauge on the dashboard - the dashboard gauge is "dumbed" down so that it normally sits at 11:00 position until its VERY hot.
Given that it has just had a service, then its quite possible that something has been disturbed or not re-connected.
So many faults will give you similar symptoms as you have suffered, it really needs more serious diagnosing to be able to pinpoint the actual fault, otherwise your in to replacing items randomly until something cures it, this can be expensive

[moesymoe]

Thanks for the replies! So just up update: One step forward, two steps back.

Helpful Mazda mechanic replaced the front fan motor and bypassed the air intake membrane/sensor (see pic) that was previously glue repaired and faulty(apparently). He thought this membrane sensor had caused the original issue so sent us on our way.

The issue is not fixed unfortunately:
After 15 mins of city driving, same issue happened again just as we entered the motorway trying to go from 40mph/2k revs up to 60mph. Once I put the foot down, it felt like it slipped a gear, gave a couple of chunks, and then no power to accelerator. It re-engaged at about 20mph, and then lost it shortly after and limped to the side.

After giving it some time to cool down, it starts ok again, and runs for a few mins at ~20k but is cutting out now at much lower revs, sometimes just when I lift my foot off the accelerator.

Any and all suggestions/advice is very welcome. Trying to limp to a campsite now....

[g8dhe]

Ah I believe that is the Variable Resonance Intake System (VRIS) shutter valve operated by the vacuum system. There is a diaphragm (Membrane ?) that pulls a rod to adjust the engine air intake mechanisms.

[Ian]

The part number for the shutter valve is J50320150A.

[nth]

OK I would have called that a swirl flap actuator. I dont know if this one defaults to a normally open or normally closed state but you could try disconnecting & blanking the vacuum pipe then physically jamming it either fully open or closed (depending on which way around it operates). Secure the arm/rod with cable ties or tie back with wire etc.

[windywatson]

Have owned 2 V6 Bongos I have rearly ever heard the cooling fans run. Certantly not on a regularly basis. Only heard if the ambieant temprature was very high & I'd been stuck in stationary or slow moving for long periods. Was the van actually showing signs of overheating?
Having had the cambelts changed on both of my vans & knowing that it takes care to ensure that all is correctly reassembled, (one having been replaced 1 tooth out on the belt) I would be looking at all of the recent work carried out. Was the garage doing the cambelt change familiar with the correct method to bleed the coolant system? As hopefully you will have had the water pump done as part of the belt change. Even if the pump was not done, coolant hoses have to be disconnected in order to do the belt change. You could have an air lock in the cooling system causing over heat problems.

[moesymoe]

Thanks again for all the replies.

We still haven't been able to find the cause of the problem and feel like we have come to a dead end here in France.

Just to update, there appears to be two scenarios where the issue appears:
1. As per the original issue, on the motorway, putting the engine under pressure to go from 40mph to 60mph, feels like it misses getting in to gear, gives a couple of shudders, and then no power to accelerator. I noticed the hold light flashing, and was subsequently able to get the fault code '12' using the BF factsheet, which I think is Throttle Position Sensor, based on the factsheet but this was for 96, whereas mine is 99 so may be out of date. This scenario has only happened twice.

2. After 30 minutes or so of easy driving from cold. Seems to be after I have stopped temporarily, or after a three point turn, the engine will just cut out when gently accelerating or decelerating. This also is what happens after the motorway scenario above when trying to limp home. The hold light doesn't flash in this scenario.

So the first scenario with the hold light flashing, suggests possible issue with the gear box and/or the throttle position sensor. But then the second scenario seems to be simply temperature related.

The french mazda mechanic isn't convinced the throttle position sensor is the issue and is trying to get confirmation from Mazda Europe on the code before investigating further. He is also unwilling to do anything with the gearbox so he seems to be out of ideas. I can't find any auto gearbox specialist here either and based on some conversations with helpful Dunnings specialists in the UK, the symptoms could well be gearbox related but impossible to diagnose over the phone without them having van there, understandably.

So we are currently deciding between getting a tow back to Cherbourg for the ferry this Sunday or to try to limp back, 350k, on non-motorway roads, getting as far as we can before it cuts out and then letting it cool down. Not sure how much further damage we are risking or how far we can actually get with this approach.

Given it appears temperature related and the temp gauge doesn't really work, are there any other overheating signs to watch out for to hopefully try to avoid doing further significant damage?

Any further input/suggestions very welcome.

[Flanners]

If it was me and I hoped to repair it without possibly causing more damage/terminal failure and even more ££££s; I would bite the bullet and get a full lift/recovery back to the Port, especially if you have no real idea of the temperature the engine is operating at.

Have you had a play around with the TPS and altered it's position?

viewtopic.php?t=45757

[willow2u]

had a similar problem with vivaro van turned out it was the crank sensor all the symptons seemed to be more of a fuelling problem wouldnt hurt to try one in there even if its one of another motor so long as the air gap is reasonably close and it goes in the hole

[Bongolia]

Think I would go with Flanners suggestion.
Basically you need fuel and ignition, faults you describe could be either or both. The garage should be able to easily check out the TPS with a multi meter, not rocket science TPS usually totally fail or develop a flat spot that you can push past by pressing the acc pedal further down and generally not temp related. Crank sensors tend to give indications of failure then quickly fail easily checked. Igniton amplfier or as Mazda term ignitor pack, in or around distributor,(dunno where but usually in distributor) on the other hand give symptoms you describe.
But as I said without knowing what checks the mex have done or components eliminated its a wild card.
So maybe the best bet would be to get it dragged back to a guy who works on Bongos unless you can find one there?
Did you get the manifold issue sorted?