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General => The garage => Topic started by: ians on 03 March 2012, 14:17

Title: mk2 8v fuel issue?
Post by: ians on 03 March 2012, 14:17
ok so its a 1990 golf gti 8v digi. was running well then stopped running after what sounded like misfiring under load, I'm getting spark, air and fuel to the injector rail, but should the plugs be getting wet if I'm pumping the accelerator peddle? because mine is not so I'm thinking that the injectors are not working? anyway to check at all? it cranks over but does not even try to fire up both the fuel pumps are priming and like i said i have fuel to the injector rail. I've also looked at the timing and its spot on.

Any help as I really need the car for work  :sad:
Title: Re: mk2 8v fuel issue?
Post by: AlexMozza on 03 March 2012, 21:50
One way to check if the injectors are working is to take them out still attached to the rail. Crank the engine and it should spray fuel out of the injectors.
Just dont stand to close as it is highly atomised and the fuel can cut you very badly :o
Title: Re: mk2 8v fuel issue?
Post by: Wayne on 03 March 2012, 23:49
One way to check if the injectors are working is to take them out still attached to the rail. Crank the engine and it should spray fuel out of the injectors.
Just dont stand to close as it is highly atomised and the fuel can cut you very badly :o

I would not recommend that  :shocked: that could end in tears.
Title: Re: mk2 8v fuel issue?
Post by: ians on 04 March 2012, 07:08
i've heard of people checking this way...didnt know it could cut tho  :shocked:
Title: Re: mk2 8v fuel issue?
Post by: Wayne on 04 March 2012, 09:53
i've heard of people checking this way...didnt know it could cut tho  :shocked:

The bigger worry is petrol being sprayed everywhere, one spark and boom
Title: Re: mk2 8v fuel issue?
Post by: clipperjay on 04 March 2012, 14:29
In the good old days we took one out then stuck them in big jam jars to collect any spray its to check pattern rather than leave it pissing fuel everywhere!
You can wrap a cloth at the top of the jar or cut recess into the lids, its visual notes more than anything.

Title: Re: mk2 8v fuel issue?
Post by: ians on 04 March 2012, 14:58
In the good old days we took one out then stuck them in big jam jars to collect any spray its to check pattern rather than leave it pissing fuel everywhere!
You can wrap a cloth at the top of the jar or cut recess into the lids, its visual notes more than anything.



that sounds like a good idea, I went out to check but cant figure out how to get the electrical clip iff the rail? I didnt want to force it I tried squeezing it and tried to prize out the retaining thing too...any ideas?
Title: Re: mk2 8v fuel issue?
Post by: clipperjay on 04 March 2012, 15:02
It should come out check there is no hex bolts on the main body of the whole unit you might just need to give it a good pull of the retaining clips failing that try taking the clips off aswell?
TBH I can't remember all I do remember it came out okay?
 
Is it metal or plastic?
Title: Re: mk2 8v fuel issue?
Post by: AlexMozza on 04 March 2012, 23:31
i've heard of people checking this way...didnt know it could cut tho  :shocked:

The bigger worry is petrol being sprayed everywhere, one spark and boom

How about a Picoscope?
Could it detect the injector pulses?
Title: Re: mk2 8v fuel issue?
Post by: AlexMozza on 04 March 2012, 23:33
i've heard of people checking this way...didnt know it could cut tho  :shocked:

Diesel is worse, at around 1500Psi, It can cut through bone, fingers, directly into the blood....
Title: Re: mk2 8v fuel issue?
Post by: ians on 05 March 2012, 09:09
i've heard of people checking this way...didnt know it could cut tho  :shocked:

Diesel is worse, at around 1500Psi, It can cut through bone, fingers, directly into the blood....

ouch that made me cringe  :sad: where would I get one of the scope things to detect the pulse?  :smiley:
Title: Re: mk2 8v fuel issue?
Post by: AlexMozza on 05 March 2012, 13:07
http://www.picotech.com/picoscope-oscilloscope-software.html (http://www.picotech.com/picoscope-oscilloscope-software.html)

They are very expensive, but i think you can rent them?
Title: Re: mk2 8v fuel issue?
Post by: ians on 05 March 2012, 14:55
hmm I'm going to take them out as a complete unit and test in bottles as suggested. is it possible to clean the injectors at all?
thanks for your help so far  :wink:
Title: Re: mk2 8v fuel issue?
Post by: AlexMozza on 05 March 2012, 15:39
Yes, you can get a fuel additive that does it. Otherwise for a real clean you need to send them off  to a specialist. However you might find that getting them cleaned etc could be nearly as much a new set :/
Title: Re: mk2 8v fuel issue?
Post by: ians on 05 March 2012, 15:49
oh right thanks for that, were i get a set I've had a look around but cant find any i'm probably being dim tho, did a night shift last night :sick:
Title: Re: mk2 8v fuel issue?
Post by: ians on 05 March 2012, 15:52
found these but mines a 1990

http://www.gti-bits.co.uk/carbsinjectors.htm

heritage do em but only says kjet?
Title: Re: mk2 8v fuel issue?
Post by: clipperjay on 05 March 2012, 16:02
You can take the injectors off and send them for servicing mate as for diesels atomising the fuel you own a 8V petrol  :wink: