V6 wont start after cam belt change

[foxuke]

Did you try dynamic timing with a strobe light - that would confirm both timing and spark are OK?

Doesn't the engine have to be ticking over to get the right revs to check it this way?

[mikeWalsall]

No .. with the pick up attached to number one plug lead .. in a dull light .. if you strobe the 'tipexed' timing marks on the crank pulley .. by just cranking the engine over .. a good battery powered strobe should 'freeze' the rotating crank timing marks OK .. this will give you a 'static' (basic) timing ..

I do not have V6 workshop manual .. but some manuals do give specific timing data (degrees) at certain RPM to check the advance / retard is within a set range .. although with today computer controlled units there is little point as most parameters are pre set anyway ....

[Simon Jones]

A few notes from my visit to look at Andy's Bongo. This is not an exhaustive list of the checks / work done over the past 8 or so weeks, just what I can remember:

- The cambelt timing has been checked & rechecked numerous times by at least two mechanics who have worked on dozens of V6 Bongos.
- The camshaft pulleys have been removed and checked to ensure the marks are in the correct place & the pulleys are on the correct bank
- The following have been swapped from Andy's Bongo to another: HT leads, dizzy cap, rotor arm, distributor, HT coil, igniter, crankshaft pulley & crank position sensor. They all worked fine on the other Bongo. A swap was done the other way round i.e. bits from working Bongo fitted to Andy's and it won't start.
- New plugs & rotor arm fitted.
- The distributor is driven directly from the end of one of the camshafts so no worm drive & no possibility that it can be fitted 180 degrees out.
- HT lead order checked & rechecked
- King lead cleaned of some corrosion inside the coil output
- Healthy sparks seen on all the plugs
- The fuel feed from tank has been disconnected & there is plenty of pressure from the pump.
- The petrol is quite fresh and a sample has been given a simple flammability test
- Leaky fuel line replaced
- It has a Prins LPG conversion which has not been fitted to the highest standards (loose wiring, powered by leisure battery!, etc). This sits in series with the petrol injectors so they can be switched off when running on gas. The LPG ECU has been disconnected to ensure any internal faults are not affecting the rest of the vehicle. The connections to the injectors have been remade & the signals to the injectors tested.
- Petrol is getting into the cylinders & the plugs come out wet after being turned over for a while
- EasiStart has been sprayed directly into the inlet manifold with the butterfly valve open. There is no sign of life when it turns over.
- All under-bonnet & internal fuses checked
- There is an immobiliser fitted. With it armed, there are no lights on the dash & the starter will not operate. With it deactivated, they all light up & starter works.
- ECU & temperature gauge sensors checked/swapped
- Compression test has been done & this shows all cylinders are lower than expected at around 85 psi. This has been compared to a running Bongo which is around 100. It should be between 140 & 196 psi, so while it's very low, it's unlikely to have changed from when the engine was last running.
- Tests were carried out to check the leakage past the rings and into the inlet & exhaust manifolds. This showed no obvious leak that would be the case if the valves were not closing at the correct time.
- Timing checked statically by putting no. 1 to TDC on compression stroke & checking rotor arm is pointing to no. 1 HT lead.
- Dynamic timing needs to be carried out with engine running at between 500 & 900 RPM but of course its only turning over on the starter. The distributor position looks the same as mine so is close enough to at least get a bang or splutter, but it's doesn't get that far.
- It was noted that there was some coolant (rusty coloured) found in a well in the casting under the n/s cam cover. This is outside of the head but inside the cam cover in the area where the spark plugs go. There are no coolant pipes in the area that could have leaked & no sign that is has come from within the engine either. This is a weird thing to have happened & appears unrelated to the non-starting.
- The hydraulic lifters have been seen to be doing their thing and the valves are opening & closing as expected.
- The engine shows signs of having run hot as some of the plastic components (cable conduit, mounting clips, etc) are brittle or broken. It's possible some of the wiring inside may have also been affected.
- At a point some time back while in the same garage for an MOT, a load knocking noise was heard from the bottom end. An oil change was done & there were no nasty bits & it has run fine for quite some time since then. When the engine is spun over on the starter, it does take around 30 secs for the oil light to go out. Considering the engine is not running to build the pressure up, so that's probably nothing to be overly concerned about.
- Andy has spoken to the previous owner who advised there were no similar problems. The only thing that did happen once is the engine cut out after a dunking in wet weather. This is not unheard of & I believe is caused by the crankshaft sensor getting damp. After a short period to dry out, the problem went away.
- There is one strange thing: when the engine had not been turned over for a number of hours, when trying to start it, there appears to be a sign that it has a brief attempt to run for a second or so. The cranking speed increases & it sounds like there could be some combustion. Try it again straight after & there is nothing.
- The mechanic has got the engine manual & followed many of the fault-finding steps & also attempted to read the fault codes, but there are none apparent.


The only things I've suggested he does next is:

1) call Allan in Plymouth as he is one of the most knowledgeable guys when it comes to the V6. This is planned for tomorrow.
2) remove the engine ECU to check for any visual signs of problems & unplug/re-plug all the connections a few times to ensure the pins are clean & making good contact.

There have been two similar instances reported on the forum of failing to start after cambelt replaced, but unfortunately, the people concerned never updated the threads with the outcome (good or bad).

http://igmaynard.co.uk/bongo/forum/view ... start+Belt
http://igmaynard.co.uk/bongo/forum/view ... start+Belt

So over to you good folk for further discussion

[kingrollo]

Really hope it gets sorted - good luck

[mikeWalsall]

A very exhaustive list checked of there ..

Like Simon said .. given the low compression and his other observations the engine does not seem in pristine condition .. My V6 is an instant starter .. but on the very rare occasion it as not .. my oil light goes out on the first spin of the starter motor ..

BUT .. back to the problem engine .. Was the belt changed just as a routine service measure .. or was it part of some other 'troubles' ..??

Was it was running OK prior to the belt change .. if so unless something 100% coincidental as cropped up .. if the valve / ignition timing is set right it's really weird to why it's not firing up ..

When I rebuild an engine (mostly bike / TAG engines know days..!!) I usually prime the bores with petrol down the plug hole(s) as it generally guarantees an instant fire up .. but as these plugs are coming out wet (I assume with petrol) and there is a good spark at the sparky .. at the right time (?) .. the valve timing set right (?) .. then even with "poor" compression it should fire up ..

[teenmal]

This is an obvious problem......

Compression test has been done & this shows all cylinders are lower than expected at around 85 psi. This has been compared to a running Bongo which is around 100. It should be between 140 & 196 psi,

Has the mechanic in fact checked the HLAs.

Some times engines needed a bit of heat to restart after a long stand or after the head etc was removed , this was often achieved by towing the vehicle to create heat, or spinning the engine very fast.

[g8dhe]

The one problem we had on the V6 was the HT leads, when I first checked the spark with the plug out side the engine it looked fine, but what was happening was that when the plug was screwed in the deep hole the HT lead was tracking to the bore of the hole which of course it couldn't do when outside for testing, only careful inspection of the lead itself showed up the tracking after being cleaned, there had been at least 4 leads like this;

[rita]

1) call Allan in Plymouth as he is one of the most knowledgeable guys when it comes to the V6.

I have a sneaky feeling what he is going to suggest.

[Simon Jones]

This is an obvious problem......

Compression test has been done & this shows all cylinders are lower than expected at around 85 psi. This has been compared to a running Bongo which is around 100. It should be between 140 & 196 psi,

Has the mechanic in fact checked the HLAs.

Some times engines needed a bit of heat to restart after a long stand or after the head etc was removed , this was often achieved by towing the vehicle to create heat, or spinning the engine very fast.

The hydraulic lifter are functioning and valves seen to be operating. When the cylinders are pressurised there is no sign of leakage into inlet & exhaust manifolds, or getting past the rings. Unfortunately, the option of tow start is not feasible as its an auto. My V6 can left standing for over 3 months & it will start fine so there is nothing to suggest the lifters should require re-priming.

The cambelt was replaced as routine maintenance and the seals were required too as quite leaky. The original belt was badly contaminated.

1) call Allan in Plymouth as he is one of the most knowledgeable guys when it comes to the V6.

I have a sneaky feeling what he is going to suggest.

Feel free to share the wisdom - that is the point of this thread

[cmm303]

Is the mixture right? Maybe this could explain the initial brief splutter?

Apologies in advance, I'm posting thoughts, not solutions, in total ignorance of the fuel injection system. (Last time I stripped an engine it had carburettors - no starting handle - but either unchoked or flooded it wouldn't show any signs of life when cold.) With the system being electronically controlled, could some part of it have been distrurbed or damaged? Is there a way of temporarily fudging/forcing a cold start set up?

[mikeWalsall]

An injection system does not have a choke .. temperature senders tell the ECU to inject faster / more fuel and adjust accordingly ..

Petrol down the spark plug hole .. or some (addictive (??) easy start, usually provides extra starting fuel ..

On a rare, reluctantly to start motor bike, I have heated the spark plugs up on the gas stove and fitted them back in the engine while still hot ..!!

Now what would I do if it was my Bongo (or any motor) ..??

I like to think logically .. if something as gone pear shaped .. why .. what as been done since the engine (or what ever) worked OK ..??

Then back track over past the work .. in this case it appears ‘only’ the cam belt change caused the none starting problem .. so remove I,t and go through a ‘text book’ re fit .. Checking belt hydraulic tensioner / rollers .. all timing marks allied to compression stoke / rotor pointing to No 1 firing in dizzy cap match .. as the cam seals have been changed .. are the woodruff keys still located in the cam shaft .................??

[blobber]

Any info on the outcome of this problem yet?

[teenmal]

Any info on the outcome of this problem yet?

The last time I heard of a similar problem to this one it took the "Bongo Specialist" Nine Weeks to sort it out/fix it.

Time yet.

[Simon Jones]

What was the resolution in that instance?

[teenmal]

What was the resolution in that instance?

HLAs. Hydraulic Lash Adjusters.