V6 wont start after cam belt change

[foxuke]

Dear fellow bongo lovers.
I am getting to my wits end with my beloved bongo (bob) as is my mechanic (Mark).

Following a cambelt change which also necessitated new cam shaft seals etc due to fairly major oil leakage the engine will not start.
Mark has typed out everything that he has done so far so I have copied that in below. I have trawled the forum to no avail. I did find a couple of similar posts but there did not seem to be a resolution posted. The engine turns over and over.



Fitted new cambelt with new cam and crank seals.
Then non start rechecked timing all ok checked for fuel at the fuel Rail all ok checked we are getting pulse signal too the petrol injector seems fine gone through all spark system checked leads coil clean dizzy cap fitted new rotor arm and spark plugs check compression all cylinders around 85 to 90 psi which seems far too low rechecked all timing again and all key ways in place on cams and crank checked all pulleys and cam wheels fitted right way and they are.
Redone compression test adding oil too cylinders and cam up too 135 psi better but still low.
Found when turning over spark plugs are wet with fuel yet have a good strong spark.
Plugged in too diagnostics checked fault codes only fault is with one lambda or o2 sensor clear fault and retested fault did not return but car does not start.
We have now swapped crank sensor and pulley whole dizzy unit coolent temp sensors ht leads coil and Coil amplifier but still not starting oh and forgot too say when doing the compression tests also did a cylinder leakage test which confirmed valves all closed but high amount of leakage past the rings in to the sump.
We have checked all fuses in two fuse boxes too.

So over to you lovely experienced people.
Ta
Andy

[Simon Jones]

If you have fuel, air and ignition, it should run, but getting them to occur in the correct order is the critical part. I would be tempted to try some EasyStart sprayed into the pipe above the air box which may allow it to run briefly for a few seconds. I take it all the HT leads are back in the correct order? Was it running fine prior to having the work done? The low compression which rises after oil is added does point to worn piston rings or cylinder bores, but they wont be any different to before the cambelt change so I would put that to one side for now & re-check the timing of the 4 cams as that really is the only thing that has changed, although it sounds like ignition system variables have also come into play.

Whereabouts (roughly) is the garage in case anyone local can pop in to have a look? Good luck with getting this resolved.

[mikeWalsall]

Is the timing 180 degrees out .. ??

[rita]

I would say that the compressions are too Low (dry test), you should get (with a good engine ) about 160/170 PSI.

If the vehicle has been idle for a considerable length of time the HLAs may need to be primed also.

It would also be worthwhile checking the timing against the flywheel marks and your mechanic could also check the TDC position by putting the cam shaft for No1 cylinder on the rock making certain the present timing is not 180 out.


Good Luck.

[foxuke]

Thank you everyone I will forward all this to the mechanic.
It was running perfectly prior to cam belt change.
I should also mention it does have an LPG conversion which when ignition is on is showing correct lights etc.
Garage is in Ringwood.

[Simon Jones]

If you get stuck, I'm in Salisbury so just down road from Ringwood & I've an engine manual. LPG systems will break the signal to the petrol injectors so have potential to prevent it starting, but you say the plugs show signs of petrol so that may not be a problem. If temp sensor is faulty it could try to start on gas which will never work. Normally, it will switch over at 40 degrees C so open/closed circuit sensor could fool LPG ECU to try to use gas rather than petrol. I'd suggest pulling the fuse on the conversion & try again.

[mikeWalsall]

If the plugs are wet the system is injecting petrol .. BUT .. is it getting it at the right time ..??

I have never stripped a Mazda V6 down but you can get the cams (valve timing) set up OK .. but with the rotor pointing the wrong way ie: 180 degrees out .. with the rotor pointing to number four instead of number one ..

On the compression stroke Firing order .. One - Six - Two - Four - Three - Five



As an aside both my Estima and Bongo will start on LPG .. but not drive very well until the engine is warm (Dunno about my Alphard as I haven't tried it .. but it is a Romano system like the Bongo) ..

[foxuke]

Great stuff.

Rita - can you tell me what the flywheel matking look like this was a new one on us.

Thanks

[rita]

Great stuff.

Rita - can you tell me what the flywheel matking look like this was a new one on us.

Thanks

You will need to remove the inspection plate (from inside of vehicle) and the +- TDC data should be stamped onto the fly wheel.

[foxuke]

Hoping to hear somee good news today after all the advice. If not Simon I may take you up on your kind offer. Thanks

[Bob]

Good luck.

[foxuke]

Still no luck
Mark has been trying to look at the flywheel as suggested above.
He is struggling to find the markings. There is a plastic panel in the bell housing but this does not seem to offer access and he has looked were the inspection plate is inside the car but can't see how you can see the flywheel as there is no access through the bell housing there.

If the timing marks on the flywheel are out by 180 degrees then surely the marks on the crank at the other end would be out too??

I do have some images but unable to attach. If you think they will be helpful I can try and find a host for them.

Thank you. xx

[Gasy]

You have to put your pics onto something like photobucket 1st

[Simon Jones]

Info on uploading photos: http://igmaynard.co.uk/bongo/forum/view ... =42&t=9285

[windywatson]

Your low compression readings would/could also indicate that the valves are not shut tight as the pistons are hiting max compression. This would also point to the fact that the timing is not correct, ie valve timing is out. So dispite having checked the timing as you have discribed there must still be a fundimentle error. You have a full compliment of what is needed to run the engine, fuel, spark etc. So as it was a good runner prior to belt change, I would go with all of the other responses & say its a valve timing issue.

By the way have to do the cam seals belt etc on my V6, who did you use to supply the parts?

Best of luck & keep us posted.