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starting problems


max

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Hello got a bit of a strange problem sometimes my car doesnt want to start straight away.

Sometimes i turn the key and can leave it cranking till the battery dies and it wont even try and fire but if i turn the key off and on to crank a few times it will fire.

Other times i turn the key and it fires straight up.

Tempreture has no effect on whether its going to start or not.

Once started it runs perfectly but i could turn it off after running and it could either fire or not its a very strange problem bothe triggers go green on cranking and get good stable cranking rpm .

I originally had the setup on a 8 valve cvh engine that used to start up perfect everytime i then swaped to a 16 valve focus rs engine that is a zetec engine.

the loom and all components haven't changed so dont think the fault lies in any of them.

The cam only has one trigger point on it is there any setting to alter the angle of the angle like the crank sensor does.

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i would say its spark as after turning it over for a while with out it firing when i turn the key off and on to crank again a get a back fire so the spark returns and there must be unburnt fuel present

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Working on it being spark then we need to confirm that the coils still have power to them while cranking.

You can also do a spark test to check they will fire after a period of not starting.

It could be the cam sync is not quite being picked up so maybe try a lower arming voltage at cranking speed.

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ok i will play with arming voltage around cranking also when i do ignition test it always works.

i will check if coils have power at cranking id be suprised if not as it sometimes starts so that would indicated a wiring problem or ecu intermittent problem and i get zero problems once started. i will try altering the arming voltage around the 0 and 1000 boxes to see if that helps.

thanks for the help

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at the moment 0 is set to 0.5 and 1000 is set to 1.0 im going to try 0.2 in the zero section and 0.6 in the 1000 section.

ive never messed with these settings before what are the effects of these numbers so i can see if im going the right way as in what will happen if set to high and what will happen if set to low. 8-)

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  • 2 weeks later...

been having a play and for some reason it doesn't want to pick the cam sensor/trigger 2 up.

it finds trigger 1 as soon as i turn the key and as soon as it starts it finds trigger 2 that's obviously why its not starting consistently.

what settings can i play with to try and get it working on cranking its a factory sensor with no adjustment but as i say works fine once strted

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Seems to be better if i press the throttle while cranking.

So would that indicate to much cranking fuel its strange as sometimes it starts fine and other times not id have thought if it was to much fuel it would be like it all the time

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It could be the trigger 2 is just borderline for voltage and the open throttle allows the engine to crank a pit faster.

In turn giving a slight stronger signal.

If you are running a 0.2 for the arming voltage already then the next option is to see if you can close up the sensor to tooth gap. THis will help give a bigger voltage.

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Hi Max,

with the laptop hooked up and VTS open can you hold the throttle at say a constant 3% and start the engine , if not try a constant 5%.

A lot of these types of starting issues are to do with closed throttle air bypass being insufficient.

We need to rule this out.

Also have a look at your plugs if they are black and sooted they will induce starting issues.

If you think you have flooded the engine while trying to start, hold the throttle WIDE OPEN (FULL) throttle and crank, this will shut the engine down and can also help the engine start in some conditions.

Regards

Dave.

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hello i've fitted various new cam sensors with the mounting tab lathed down to close the gap as its a factory standard cam sensor mounted in a ford zetec head and has zero adjustability.

there seems to be nothing that help it. it either starts or it doesn't regardless if your holding the throttle open or not.

when cranking i can watch the runtime screen crank goes green straight away cam does nothing when its not going to start and the engine just turns over without even trying to fire when its going to start it also goes green with in a second or two then fires in to life so ruled out plugs.

there is no consistency with the fault to be able to track it down it can fire from cold straight away it can also fire from warm straight away but at the same time you could have to crank it 5 or 6 times in both situations to get it to start.

once started it picks the cam sensor up fine with no trigger errors

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  • 1 month later...
Hi Max,

with the laptop hooked up and VTS open can you hold the throttle at say a constant 3% and start the engine , if not try a constant 5%.

A lot of these types of starting issues are to do with closed throttle air bypass being insufficient.

We need to rule this out.

Also have a look at your plugs if they are black and sooted they will induce starting issues.

If you think you have flooded the engine while trying to start, hold the throttle WIDE OPEN (FULL) throttle and crank, this will shut the engine down and can also help the engine start in some conditions.

Regards

Dave.

i have recently swapped coils which has helped the starting problem and if i now hold the throttle open slightly it has more chance of starting up so it seems the problem is as described above.

is there any way to get over this problem many thanks

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  • 2 weeks later...

Hi Max,

you need to disable any idle control that your engine uses.

You will then need to adjust the throttle blade stop screw if fitted so that the engine idles at your desired idle speed or just below it.

Remember to recalibrate the TPS after adjusting the stop screw as this will change the closed throttle voltage.

Then re enable your idle control and test your starting, you will more than likely need to make small changes to the idle control parameters to lower the idle speed as it will probably idle higher than it used too with more air blade gap.

This may not require any adjustment if using closed loop idle speed control.

You may need to alter cranking fuel numbers etc to make up for the extra air.

Are you using pre start enrichment triggered from ignition on or cranking.

Using these will aid starting dramatically when setup correctly.

Regards

Dave.

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  • 6 years later...

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