V6 Bongo with LPG conversion will NOT start

[jdf71]

I have a 1997 2.5 V6 with a professional Landirenzo Omegas LPG conversion that will not start.

The story goes . . .

I noticed a small oil leak one day, went to the garage who said the front crankshaft oil seal needs replacing. While this was being done decided to change the cambelt and also turned out both auxiallary drive belt tensioners need replacing. The parts were located (and that's a whole separate story) and this work was done but since then the garage have not been able to start her up! There was never even a hint of a starting problem prior to this.

The mechanic has now been scratching his head for over a week. He's checked, double & triple checked all the mechanical work done. He's checked that there is a strong spark and fuel available for starting (fuel pump working, pressure in fuel lines). We've both spoken, independantly, to 2 LPG specialists who have both said its unlikely that the LPG system is the cause of the starting failure because the sytem starts on petrol and should do even with an LPG fault.

The mechanic has run out of ideas. An auto-electician was called in. He took one look and said "not touching it"! (Hasn't got any diagnostic software and couldn't find any information on the V6 Bongo).

I've searched the forums but cannot find anything similar to this problem. Help please! Anyone with any ideas or experience with something similar?

(The Bongo is in west Cornwall.)

Thanks!

[kawasaki kid]

Hi, If the only the crankshaft oil seal and timing belt have been disturbed - the crankshaft pulley must have been removed - has the pulley been put back on in the wrong position and the timing been put out - I take it the engine is turning over but not catching - or has a sensor been disconnected and it hasn`t been noticed.

[mister munkey]

Welcome to the forum JDF, sorry its under difficult circumstances but you've come to the right place. Its quite rare for a techie problem not to be resolved on here, albeit sometimes slower than you'd like.

It sounds like all the bases have been covered but theres always that elusive obvious one!

Theres a fountain of V6 knowledge on here & a few savvy LPGers that may well be able to point you in the right direction.

Chin Up.

[The Great Pretender]

As you have a spark and fuel pressure It sounds like the injectors are not opening.

[lpgimports]

Hi

I would agree unlikely to be LPG system related, but however try this.

90% of LPG systems will default to run on petrol only even in event that the LPG computer(ECU) is not even powered, however a couple don't and just require the LPG (ECU) to be powered to enable this.

Does the LPG control switch light up on the normal manner when ignition turned on? Likely to indicate on petrol or on petrol wanting to go to LPG etc depending on which type of switch fitted, all are a little different but generally the same kind of thing.

If the LPG switch is behaving as it did before its highly unlikley to have anything to do with it. If its not lit up as normal, then arround the battery there will be a fuse for it find this and check replace if neccesary. If LPG now lights up try starting it.

I would think the issue is more likely to be mechanical or electrical in the area where the vehicle has been worked on. Have they tried actually squirting some fuel into the inlet manifold and seeing it it fires? Fuel pump and fuel pressure are all find but you actually need to have fuel going into the manifold. If it fires on fuel in the manifold then somehting is stopping the injectors firing, they can check this by removing a plug from one of the injectors and testing for a pulse on the negative pole of the injector wiring, if they are unsure then it will be the wire that is differently coloured on each injector, the possitive is the same colour on each injector. If they have no pulse then they need to check why...

I would be looking at Crank position sensor, or plug or wiring to it.

We had a MX5 a while ago with very similar symptoms and it turned out to be the cam position sensor, I can't recall where this is on a Bongo may be on the back of the engine rather than front, but if at the front then check its connected undamaged no bent pins or snapped wiring.

They could have the timing completely out but hard to see how a proper garage could get it so far out it wouldnt run, not uncommon to get a cam a tooth out and it run lumpy and then they have to check and try again..


Paul

[jdf71]

Thanks to all who have responded so quickly with positive comments.

Hi
Does the LPG control switch light up on the normal manner when ignition turned on? Likely to indicate on petrol or on petrol wanting to go to LPG etc depending on which type of switch fitted, all are a little different but generally the same kind of thing.
If the LPG switch is behaving as it did before its highly unlikley to have anything to do with it. If its not lit up as normal, then arround the battery there will be a fuse for it find this and check replace if neccesary. If LPG now lights up try starting it.
Paul

Yes, the lights all flash/ behave as before and do not flash in the manner to indicate a fault.

I would think the issue is more likely to be mechanical or electrical in the area where the vehicle has been worked on. Have they tried actually squirting some fuel into the inlet manifold and seeing it it fires? Fuel pump and fuel pressure are all find but you actually need to have fuel going into the manifold. If it fires on fuel in the manifold then somehting is stopping the injectors firing, they can check this by removing a plug from one of the injectors and testing for a pulse on the negative pole of the injector wiring, if they are unsure then it will be the wire that is differently coloured on each injector, the possitive is the same colour on each injector. If they have no pulse then they need to check why...
I would be looking at Crank position sensor, or plug or wiring to it.
We had a MX5 a while ago with very similar symptoms and it turned out to be the cam position sensor, I can't recall where this is on a Bongo may be on the back of the engine rather than front, but if at the front then check its connected undamaged no bent pins or snapped wiring.
They could have the timing completely out but hard to see how a proper garage could get it so far out it wouldnt run, not uncommon to get a cam a tooth out and it run lumpy and then they have to check and try again..
Paul

I don't pretend to know much about engine parts and how they function so please bear with me!

The mechanic has discussed some of what you have said with me. He says there is fuel getting to the manifold and he has also tried squirting in some starting liquid and the Bongo still will not fire. Apparently, first thing in the morning the engine fires once when the key is turned then nothing on subsequent attempts. He also say the injectors are pulsing.

Like you, the mechanic thought the crank position sensor a likely place to look but he says its fitted correctly (and will only go on one way), though I suppose it could be damaged.

Your point re. the MX5 cam position sensor sounds like it could be relevant, I'll definitely pass it on. Would something like this cause a fault code though? Apparently there are no readable fault codes.
The mechanic has checked and rechecked the timing, it was marked when it came off and he has managed to get the right technical diagram too, so he doesn't think that has anything to do with problem.

John

[munroman]

May be a silly question, but does the Bongo have any sort of alarm/immobiliser?

The fact it fires up at all shows that the timing is most likely correct and there is a spark, so if it doesn't restart then maybe an immobiliser kicks in?

Just a thought, I hope you get your Bongo back soon!

[lpgimports]

Hi

If it is pulsing the injectors and it has fuel pressure and it has a good spark at the plugs (check more than one) then it is sounding more like a incorrect timing issue and it must be out a long way.

The firing in the morning is interesting though, has he pulled the plugs are are they dry or wet, dry would indicate no fuel wet that fuel is getting into cylinders and pulsing and fuel pressure are all ok.

Checking all plugs for spark is due to the distributor cap rotor being a bit fragile and they need to be removed to do the cambelt and sometimes crack or the centre pin gets lost. (unlikley as mechanic says it has a spark?)

Obvious one but the firing order is correct?

The fault we had with MX5 had one mechanic give up on it had two auto electricians swear it was the ecu so had the ecu sent off checked and came back perfect, I pulled a cam sensor from another mx5 and stuck that on and instantly started. No fault codes at all, though it had run perfectly when you squirted petrol in the inlet manifold.

I would

Check plugs are dry.. if so give it a good squirt with brake cleaner or easy start whilst cranking it up the air intake pipe if it has a spark then it will fire and try and very likley start, if not then look more at ignition system firing order and cambelt and cam timing.

[Simon Jones]

Hi
Obvious one but the firing order is correct?

Worth checking the obvious. The first car I had was a 2 cylinder Fiat 126. The owner was selling it as a non-runner so I got it cheap. Guess what - he'd accidentally swapped the 2 HT leads over & that was why it didn't start

[foxuke]

Hello Everyone
I have been searching the forum as I have a very similar problem to this one.
Did this ever get resolved? If so I would really like to know the answer.

Currently cutting and pasting all this for my mechanic!
Ta

[Simon Jones]

What are your symptoms, what happened prior to the problem occurring and what has been done to diagnose and rectify it?

[mikeWalsall]

Ummm.. the original posters problem was five years ago (and he only ever made two posts) .. be hopes he sussed it out a long time ago ..!!

Like Simon says a bit of history with your own problems may help others to help you trouble shoot it ..