Jerking motion under light load??! please help

Jerking motion under light load??! please help

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StuRo

Original Poster:

138 posts

118 months

Saturday 15th November 2014
quotequote all
So I've just had a new radiator fitted and all seems well there...

But the original problem it went to the garage for was the idling problem (coasting up to lights etc. it would fluctuate between 3-400 and 1000rpm).

I thought it was an LPG issue but the garage thought not (leading me to think they were just blaming the car rather than their lpg installation)...

...any way, not diagnosed it yet but suffice to say it's definitely not LPG specific... I've driven it on petrol only today and it's now very jerky under very light throttle (not related to revs, but throttle position i think)

Anyone had similar or any ideas as to what this might be? check engine light comes on and beeps at me (quite a bit!)

Sticky throttle body maybe? could it be a misfire? I'm scared to drive it now in case i damage something!

Thanks in advance for any suggestions.

Xpuffin

9,209 posts

204 months

Saturday 15th November 2014
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Take apart and spray the throttle body connector. Try that, if no fix its prob the TB itself.

007 VXR

64,187 posts

186 months

Saturday 15th November 2014
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Sounds like TB to me too, had this on mine before.

StuRo

Original Poster:

138 posts

118 months

Saturday 15th November 2014
quotequote all
Ok, thanks guys. I'll try it tomorrow in the light. I'll post the results on here!

KMud

2,924 posts

155 months

Saturday 15th November 2014
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It's throwing an engine warning light - get a code reader on it.

stigmundfreud

22,454 posts

209 months

Sunday 16th November 2014
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KMud said:
It's throwing an engine warning light - get a code reader on it.
What he said, I got one of these following a post on here: http://www.ebay.co.uk/itm/U380-Diagnostic-Scanner-...

that isn't the link to the item I bought but it is the same model

StuRo

Original Poster:

138 posts

118 months

Sunday 16th November 2014
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I did try this:

http://www.ebay.com/itm/WiFi-Bluetooth-ELM327-Auto...

...with the Torque OBD app for android but it doesn't seem to come up with anything? (I maybe have it set up wrong?!) Sounds like some guys on here have used it and found that it works though? :S

StuRo

Original Poster:

138 posts

118 months

Sunday 16th November 2014
quotequote all
So.. had a look today (as much as i could get at... some of the LPG kit gets in the way of the engine cover which i imagine is because they couldn't fit it underneath and I didn't wanna mess with it)

looks like the pulley near the MAF sensor has been rubbing on one of the connectors! so probably a bad connection there... could that be the reason? i imagine I'm not the only one this has happened to? (it looks like one of the wires from the 3 pin connector has been disconnected)

managed to get a look inside the TB, looks pretty clean, can't see any evidence to suggest it as the cause... then again i couldn't get access to remove it and have a proper look (and I have very little exp here!).

Still can't get any sense out of the OBD app either...


stigmundfreud

22,454 posts

209 months

Sunday 16th November 2014
quotequote all
AS st as it sounds its hardly surprising to hear of yet another LPG conversion having issues and leaving the owner high and dry stuck beteen an installer that claims their work is perfect and a car with a CEL light.

stevieturbo

17,229 posts

246 months

Sunday 16th November 2014
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It is unfortunate that many LPG installers really are clueless. I hear few stories of genuinely good quality conversions, but quite a few of shoddy ones !

As for generic OBD readers, they are hit and miss. Some will work, some wont, but also bare in mind even those that do work will just give a generic OBD based code, which isnt always correct or specific enough to the problem compared to a dealer level code reader

If nothing else they are handy for clearing most codes though, and as a novelty

Still worth having if you can find one that works with your vehicle even if it may not always be accurate.

KMud

2,924 posts

155 months

Sunday 16th November 2014
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Anyone with a flashscan or similar near South Yorks? Even if the codes aren't helpful/present, a quick bit of logging should be helpful...

StuRo

Original Poster:

138 posts

118 months

Sunday 16th November 2014
quotequote all
I took her out for a little spin a couple of hours ago and she seemed to behave (idling ok/no jerkyness)... but the light still came on... and I'm not sure that all of the power was there when i booted it...

That pulley had definitely been chewing on the connector though... wires exposed... one looked like it was completely severed... surely there's a good chance that's the cause? (or is it just a red herring?)

I feel like all I do on here is post problems! I'm such a leech! (apologies for that tongue out)

Hopefully I'll be able to help someone else out soon!

stigmundfreud

22,454 posts

209 months

Sunday 16th November 2014
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Stu without meaning to sound insulting (not that it ever really stops me) if you have a CEL light on wtf are you doing booting it? I mean seriously I never understand why when people have CEL's they drive them as normal up until the thread "how much is an engine rebuild"

Stu, the cars fked, that light is telling you to drive careful, drive very short distance and get it to someone that can read the codes. As you are in South Yorkshire your official dealership is limited to fk all so you need a code reader or someone that can read the codes for you - such as the AA or RAC if you have home start get them out to diagnose it. Or you can pay an autospark to read most codes.

StuRo

Original Poster:

138 posts

118 months

Sunday 16th November 2014
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Ps.. I saw a very nice silver vxr in Bawtry (Doncaster) this morning... looked very well looked after... biggrin

StuRo

Original Poster:

138 posts

118 months

Sunday 16th November 2014
quotequote all
stigmundfreud said:
Stu without meaning to sound insulting (not that it ever really stops me) if you have a CEL light on wtf are you doing booting it? I mean seriously I never understand why when people have CEL's they drive them as normal up until the thread "how much is an engine rebuild"

Stu, the cars fked, that light is telling you to drive careful, drive very short distance and get it to someone that can read the codes. As you are in South Yorkshire your official dealership is limited to fk all so you need a code reader or someone that can read the codes for you - such as the AA or RAC if you have home start get them out to diagnose it. Or you can pay an autospark to read most codes.
Duly noted. Will get it read pronto.

stigmundfreud

22,454 posts

209 months

Sunday 16th November 2014
quotequote all
it should be ok but seriously, that orange light has been ignored to the detriment of some members - just thinking about your wallet

StuRo

Original Poster:

138 posts

118 months

Sunday 16th November 2014
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Thanks mate. I think I needed a dose of tough love anyway hehe

StuRo

Original Poster:

138 posts

118 months

Sunday 16th November 2014
quotequote all
Just to add...had another look with Torque pro and it claims there are no faults... ?! I'll get it read at a garage... confused

Behold81

2,931 posts

168 months

Sunday 16th November 2014
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Are you checking while the light is on??? Som errors don't log as the clear themselves. Check with torque while the light is on. If that's not picking it then a better reader is needed.

As to the wire can to trace it to another end to test continuity?


StuRo

Original Poster:

138 posts

118 months

Sunday 16th November 2014
quotequote all
Behold81 said:
Are you checking while the light is on??? Som errors don't log as the clear themselves. Check with torque while the light is on. If that's not picking it then a better reader is needed.

As to the wire can to trace it to another end to test continuity?
Yeah. I started it up, light came on, then scanned and nothing came up... so there's a bit of miscommunication there.
looks like some proper equipment is required!