qt500 not starting

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Permalink Reply by Alex on October 10, 2010 at 8:16

Hi.

This is almost impossible to diagnose with the info you have given us.

Not starting when hot often indicates a Rich Fuel Mixture.
Does it start really easily when it's cold ?

What Color were the old plugs. they should be light brown / Tan coloured.
Dark brown again indicates a rich fuel Mixture.

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Permalink Reply by jamie gardner on October 10, 2010 at 9:00

hi alex tan colour when cold takes a long time to start it fires but just dosent go yestaday i had to jump it as the battery went low and its got a new battery and also when its going along you get up to 60.and dosent want to any faster its only been playing up for 3 weeks before it was going well

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Permalink Reply by Jordan on October 14, 2010 at 23:32

Hi,

I remember from the days of my Funtech 50 that it was the ignition coil that caused a similar problem to this. Of course, they are totally different vehicles and operate totally differently - the QT500 may not even have an igntiion coil, but Im sure Alex will be kind enough to offer his views.

Good Luck,

Jordan

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Permalink Reply by Roger on October 16, 2010 at 15:35

Assume engine turns over OK, so not starter motor or battery. When it fires does it struggle to pick up revs to idle speed. If so could be fuel system, try a new fuel filter, Mann - MUH/WK 613, Crosland 6805.

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Permalink Reply by jamie gardner on October 16, 2010 at 18:58

hi roger i took the fuel filter off but it didnt make any differance but today it was turning and firing but wouldnt start but then i touched the injecter leads wiring and turned the key and it started was amazed but there is something wrong as when you rev car up it missis i beat like its miss firing.

Roger said:

Assume engine turns over OK, so not starter motor or battery. When it fires does it struggle to pick up revs to idle speed. If so could be fuel system, try a new fuel filter, Mann - MUH/WK 613, Crosland 6805.

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Permalink Reply by Roger on October 17, 2010 at 10:35

Sorry if I am teaching you to suck eggs, is your miss fire at 5150 rpm? If it is, that is the engine restriction! Its designed like that. Other than that, it looks like you have found the problem with the injector wiring or connections. Having changed your plugs you are probably familar with disconnecting the injector connections, I disconnect mine to give better access to the plugs. They are held in place with a wire clip. Might be worth checking they are secure, watch the clip it can jump off and disappear!
Engine workshop manual is available @ http://service.lombardinigroup.it/english/man_index_gb.htm your engine is LGW 523 MPI at bottom of list.

Hope this helps Roger.

jamie gardner said:

hi roger i took the fuel filter off but it didnt make any differance but today it was turning and firing but wouldnt start but then i touched the injecter leads wiring and turned the key and it started was amazed but there is something wrong as when you rev car up it missis i beat like its miss firing.

Roger said:

Assume engine turns over OK, so not starter motor or battery. When it fires does it struggle to pick up revs to idle speed. If so could be fuel system, try a new fuel filter, Mann - MUH/WK 613, Crosland 6805.

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Permalink Reply by jamie gardner on October 17, 2010 at 19:33

cheers roger thanks for your help

Roger said:

Sorry if I am teaching you to suck eggs, is your miss fire at 5150 rpm? If it is, that is the engine restriction! Its designed like that. Other than that, it looks like you have found the problem with the injector wiring or connections. Having changed your plugs you are probably familar with disconnecting the injector connections, I disconnect mine to give better access to the plugs. They are held in place with a wire clip. Might be worth checking they are secure, watch the clip it can jump off and disappear!
Engine workshop manual is available @ http://service.lombardinigroup.it/english/man_index_gb.htm your engine is LGW 523 MPI at bottom of list.

Hope this helps Roger.

jamie gardner said:

hi roger i took the fuel filter off but it didnt make any differance but today it was turning and firing but wouldnt start but then i touched the injecter leads wiring and turned the key and it started was amazed but there is something wrong as when you rev car up it missis i beat like its miss firing.

Roger said:

Assume engine turns over OK, so not starter motor or battery. When it fires does it struggle to pick up revs to idle speed. If so could be fuel system, try a new fuel filter, Mann - MUH/WK 613, Crosland 6805.

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Permalink Reply by Alex on October 17, 2010 at 22:40

Hi.

I have to agree, it sounds like a Fuel Problem.

Saying that - it could be a Lamda sensor gone AWOL.
I don't have a fun 500 so take this as generic advice.

Check the Lamda sensor, It's in the Exhaust. (I presume there is one)
There are instructions on the web, this site has good basic info.
http://www.autodiagnos.com/fileadmin/assets/en/downloads/pdf/techni...

You could also disconnect it - see if anything changes..... If it's not working, take it out, If it won't move ( very likely) heat the surrounding area up with a blow lamp.
Soak it in petrol for a few hours
Let it dry and re install it.
There are plenty of aftermarket sensors available, again look on the web or Cunninghams can supply a genuine one.

If it's getting really Hot it could be the Ignition pickup sensors.
No idea where these are on the fun 500, but they rarely fail.

Just some thoughts / Ideas.

Alex

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Permalink Reply by jamie gardner on October 18, 2010 at 20:30

ill try anything thanks 4 info ill let you know if it works....

Alex said:

Hi.

I have to agree, it sounds like a Fuel Problem.

Saying that - it could be a Lamda sensor gone AWOL.
I don't have a fun 500 so take this as generic advice.

Check the Lamda sensor, It's in the Exhaust. (I presume there is one)
There are instructions on the web, this site has good basic info.
http://www.autodiagnos.com/fileadmin/assets/en/downloads/pdf/techni...

You could also disconnect it - see if anything changes..... If it's not working, take it out, If it won't move ( very likely) heat the surrounding area up with a blow lamp.
Soak it in petrol for a few hours
Let it dry and re install it.
There are plenty of aftermarket sensors available, again look on the web or Cunninghams can supply a genuine one.

If it's getting really Hot it could be the Ignition pickup sensors.
No idea where these are on the fun 500, but they rarely fail.

Just some thoughts / Ideas.

Alex

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Permalink Reply by Roger on October 19, 2010 at 20:31

If you have a sensor problem (sensor not connected) your engine will go into limp home mode, see engine manual. it will have fixed revs of 2000rpm!
Regards Roger.

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Permalink Reply by Alex on October 29, 2010 at 23:16

Hi jamie

Did you find the problem ?

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Permalink Reply by jamie gardner on October 30, 2010 at 22:07

hi alex not sorted starts better but wont go over 60 miles an hour something not right ill have to take it to a lombardini garage get a diagnostic test on it it ticks over normal thanks for all your help i let you no the outcome...

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