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Hi guys,

was driving the mx last weekend about 100km from home when she decided to cough & splutter for about a km & then died, anyway towed her home & started working on her, found the woodruff key broken between the harmonic balancer & the timing belt cog, fixed that & still would not start, checked for spark, fuel pressure & all seams well, tried using the spare key, changed crank angle sensor & coils, still nothing, checked the green relay & it opperates, timing belt has not jumped (checked that 3 times including if it has after market cams & needed to be dialed in) no go....pulled the piggy back computer & larger injectors out & put new plugs in her just in case, no luck.... im really lost

she started once since she died, but was very laggy on throttle, when trying to start she backfires & try's to run but sounds like the leads are around the wrong way or timing is out.....

im thinking of checking cam sensor next, but want to know if it could cause these problems, also im told that temp sensors can play up but ive only experienced rough idle & so forth with a faulty one, not killing an engine...

it looks like a fault has come up but am unsure how to test or check it as they have that silly mazda only fit diagnostics plug....


any ideas guys?

do nb's have ignition modules? im told the coils have built in modules but am unsure

does any one know if a cam sensor could cause this?

should i be checking my computer for damage? does anyone know how to check fault codes or where i can buy the plug? (its not odb2 if it was i have a cable & could have run a scan)

anything else i may have missed?

any help would be much appreciated

thanks Zoran

p.s its a 98 nb incase you didnt know..

Yes, it could be caused by a CAS fault.
Yes, the coils have builtin igniters

Have you done a leak-down or compression test to determine if you have dropped a valve (you've checked just about everything else)

I know you said you had fuel pressure, but I would have said pump first up.

Try clearing the ECU codes (disconnect battery, foot on brake 30 sec with ign on, turn ign off and reconnect battery)
It could be that the chopper plate has progressivly moved and the ECU has adjusted to suit the move. Now the chopper is in the right place (it is isn't it?) the ECU would need to relearn.

Crank Angle Sensor clearance is important to.

Bazz

As you mention it does sound like timing, I would double check that the timing is not out when you replaced the belt.

Try checking that your harmonic balancer is still indicating top dead centre correctly . It may be miles out.

After my pulley boss slipped on the crank nose I put a dowel down the no1 spark plug hole, turned the crank back and forth a bit and put a new TDC mark on the pulley.

,,, and if you take that a step further you should also check that your timing belt drive pulley on the crank is lined up with TDC too. Otherwise the valve timing could be way out.

Woo wrote:Yes, it could be caused by a CAS fault.
Yes, the coils have builtin igniters

Have you done a leak-down or compression test to determine if you have dropped a valve (you've checked just about everything else)

Crank Angle Sensor clearance is important to.

Bazz

Hey Bazz

Also did a compression test ( I knew i forgot something last night) motor is not great but has plenty to keep it going....
(thats my next project a nice motor for it)

What should the Crank angle sensor clearence be? ive got mine set on about 2-4mm.......

the harmonic balancer & boss is at tdc & also turns straight (no wobble)

i'll try clearing the ecu now,

thanks for your help so far guys

will let you know if clearing the ecu helps if not might have another look at the timing

0.5 - 1.5 mm clearance
Also worthwhile to check that the chopper plate pins are running through the centreline of the sensor. The chopper plate can go on backwards but it wont trigger the sensor.

Woo wrote: The chopper plate can go on backwards but it wont trigger the sensor.

BINGO

checked that & it was on back to front........

it started first pop...

this is something to remember if you ever have to pull your harmonic balancer appart.....

thanks for your help guys....

small unmarked, non-sequencial bills thanks

Nah, only jokin, glad you got it sorted

Bazz

You should've kept it stock!

Hot Rodders wrote:You should've kept it stock!

theres already enough stock ones Rod ;)

maybe you should join the party that way you can go fast enough to not have to worry about washing your car so much

hehehe

hope things have picked up for you mate, have to catch up soon

Beleive it or not Bazz, we checked it about the same time you posted it & after we walked in the house found your reply....

if only you did it a few hours before i wouldnt have rechecked the bloody timing belt

ah well all going now...

now for more mods

thanks again guys

sprx3 wrote:if only you did it a few hours before i wouldnt have rechecked the bloody timing belt

In my first post I asked "Now the chopper is in the right place (it is isn't it?)"
You may of missed the importance of what I was trying to say there. Sorry, at least when it comes to doing the next belt change you'll be an expert