Help please

[2L mk2]

I need help or suggestions...

I have a mk2 running Digi injection. a 2L audi 3a block, an early soild lifter head with standard euro gti cam...

I can not seem to get the car running right..
problems are: Pinging, backfire through exhaust, and surgeing/jumping when theres not much throtle applied. and an extreme loss in power.

I've played with the timing (retarded till pinging stopped and that made the car run worse, power etc...) changed dissy's, changed knock sensor, changed temp sender, have checked vac lines,checked exhaust for leaks .. and looked over most other things I could think of..

the car is still drivable, but lacks power (sick of getting beaten by bloody commodores)hehe, uses too much fuel, and pings still when very hot...

what else can I do... I don't really understand how all the electrics work (timing being advanced etc..) but something must not be working..

any help from anyone would be good..

thanks Scott

[ausgolfer]

Might have done this already but have you checked the cam timing? could be a tooth or two out.

[2L mk2]

yeah thats been done.. I'm goin to check over everything again... just looking for other things I may not have thought of...

Scott

[86gti]

dont know how the distributor gear looks like in them, if it'll only go in one way or it has teeth on it...but sounds like a timing problem.....sounds silly but....plug leads in right sequence???.....
but yea first thourghts were same as ausgolfer....valve timing....

[roccodingo]

changed knock sensor,

Are you using a VW knock box ?? if so you use a distributor without vacuum or mechanical advance, the box does ALL the timing adjustments..

Make sure you have the vacuum line connected for it also..

[h100vw]

Confirm that the indicated TDC is actually correct. The crank pulley can spin a bit if the bolt comes loose. I have had it myself. The car runs really flat depending on how far out the timing has got.

My mate 2 litre 16V mk2 would pink it's head off with more than a tickle of throttle until we spotted the bolt loose and the pulley stripped of it's key.

Use a screwdriver through the plug hole so you can see it go over TDC as you rotate the crank. Make sure you don't get the screwdriver jammed in there though.

The rotor arm should point to #1 plug lead if you take the cap off. There is also a notch in the dissy body under the dust cap. I fcuked that up initially on Robins 16V conversion and it wouldn't run.

Can't remember about the cam timing but it'll be in a Haynes somewhere.
Gavin

[2L mk2]

Thanks for all the reply's guys..

Im haveing a look at it again on the w/end so I'll keep you all posted on my progress...

this combo was running fine with my old hydro head on it. and a different/larger cam..

Btw what is a knock box?? I've just got a factory knock sensor on it.

Scott

[Bora Sport]

Why did you change heads and has it only been running poorly since the head was changed?

[Bora Sport]

I was wondering Scott are you also known as Barty and is this my old GTi? I actually went to bed tonight and before I could drift off I was thinking about this problem. Initially I was wondering what injectors you were running and whether the O rings were leaking and letting in air. Then I was thinking that it sounded more like a timing issue as mentioned above.

I recall that there is a water temperature sensor on Mk 2's and if it is stuffed then the computer won't advance the timing and the engine runs really flat. I can't recall the details but its one of the sensors on the bakelite water outlet on the head.

Now I am going back a few years now but I recall that there was a test you could do. I think you disconnected the sensor and then started the car. With a timing light you rev the engine to 3000rpm and from (a very poor) memory you then reconnect the plug onto the sensor and the computer should advance the timing by 15 degrees.

I remember Chad's first Mk2 had the problem and it would run and idle etc. but it just didn't want to rev out. heaps of people charged him heaps of money for injector cleans etc. but eventually after some research we changed the sensor and presto, Bobs your Aunty's live in lover.

[2L mk2]

Hey yes thats me...

and its chad's old car..

I changed heads becuase one of my valves broke in half.. and this head came up and was already reco'd etc.. and was told it would have been fine etc..

I'm still not convinced the injectors fit this head properly.. I have replaced the temp sensor before.. maybe it's gone again...

do you remeber the size/type etc of the cam you put in the car or what chip you put in???

Cheers Scott