GolfGTIforum.co.uk
Model specific boards => Golf mk3 => Topic started by: valver3g on 17 January 2011, 16:46
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got a problem, abf engine, mk3 16v. was driving along one day and the car started spluttering and popping so pulled over. wouldnt start again. the cat was glowing orange and thought it may be a baffle from the cat blocking the flow. so had the exhaust off but all was fine. put it down to an overfueling problem. changed the crank speed sensor which stopped the strong fuel smell when turning it over.
but now there s no spark......... so i changed the coil, rotor plugs and leads, still nothing.i took off the distibutor to check that and accidently snapped off the connection for the hall sender. so replaced it with a KR.chcked it with diagnostics andf had two fault codes, one 'immobiliser preventing engine start' and 'air flow sensor' so deleted the codes but they havent came back since trying to start for days. ive matched a dizzy cap from a 8v gti at the scrapyard the KR dizzy and the rotor is new for an abf dizzy, but ive checked the clearances and theyre all good. there is a spark from the coil through the king lead to the dizzy. yet no spark at the spark plugs. could this be something to do with the KR dizzy having more than 1 slot for ignition reference? or the previously deleted immobiliser fault code?
the fuel pump is priming and all relays are good. i held the rotor inside the cap whilst a mate turned it over and there is a strong ark between the rotor and the dizzy cap contacts?
so im getting sick!
can anyone shed some light on this GTI with and STI? cheers
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cranckshaft position sensor
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thats what i meant by the crank speed sensor, ive changed it. cheers though
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potentially the wrong dizzy position. Check the leads are in the corect firing order too.
Otherwise possibilities are:
Lambda
Immobiliser (doesn't always raise a fault code)
Coolant temp sensor maybe but wouldn't have thought so.
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yeah leads are in the correct firing order from the cap, checked and double checked. ive tried the dizzy at every possibe position with the adjustable slots, it tries to fire at certain points but just splutters on and doesnt fire. but ive heard that the ignition timing on the abf is electronically adjusted anyway so im not sure this would make a difference. by lambda do you mean in the cat? and would this not have brought up a code? ive disconnected the battery overnight because i heard that resets the immobiliser?is this true? cheers.
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kr dizzy is wrong for abf, but disconnect the hall sensor plug and car will still run though so try that next. 4 triggerwindow dizzy will certainly throw the ecu out of whack though i dunno if it will just ignore the signal or prevent it from firing. either way pull the hall sensor plug for now.
the above wouldnt stop the spark getting from cap to the leads though so possibly you have a missmatch between cap and rotor arm. the 90spec mk2 & mk3 gti cap is different to the mk2 16v one. i would put the old dizzy back on with the proper cap and leads see where that gets you.
you may be able to swap the hall sensor out of kr dizzy into abf dizzy, but its a bit of a slag to strip them down tho.
does the pump prime when you turn key 1 click, and can you hear it running as the car is cranking over on starter?
edit: its not the factory immobiliser kicking in, as that will allow the car to fire then cut the ignition. pulling the battery -ve wont do bugger all to it either. ignore the above, if engine isnt firing due to factory immobiliser it will log a fault.
its aftermarket immobilisers you want to worry about, these coudl do all kinds of odd things.
oh, and could be coil have heard of em sparking to king lead but not being strong enough to fire at the plugs. was the one you tried known good?
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You mentioned that when you held rotor arm inside dizzy cap there is a strong spark to the dizzy contacts. I would check the rotor arm very carefully ,even it is brand new ( is it a genuine item ?) There are lots of stories of poor quality rotor arm copies that can fail from first use - hairline cracks in the plastic end up shorting the coil output to earth thru the dizzy shaft. Also the plastic can have poor insulation properties and end up 'tracking' to earth This might be why you are getting a spark thru to the dizzy cap with the rotor arm off the dizzy.
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i suspected it may be a different cap so im waiting on a mk2 16v cap. i had suspected that the 4 window trigger may f#!k up the firing so i will try and swap the spindle and trigger window from the abf dizzt to the KR and see if that works.im waiting on a new abf dizzy so when that arrives hopefully the problem will be solved. the rotor arm was from halfrauds so cant see it being 'genuine' i think it was halfrauds own!. so il get a gen vw one. il try unplugging the dizzy.
the fuel pump primes when the key is turned for sure, can hear it whining. its got an aftermarket cobra alarm but i disconnected it well before this happened because it was doing strange things!
nah the coil is brand new, because i suspected that too but the coil is spot on, il try the nakered original dizzy unplugged to see if that gets me a spark.
cheers for the advice ill let you know what the problem was if i manage to get it going
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buy bits from gsf or avs, they stock bosch/beru which is oem quality.
dont bother stripping the dizzy, just fit the abf one back on and leave the plug off, it will still work fine even if disconnected.
or if you DO strip the dizzy, simply swap hall sensor from kr dizzy into your oldf abf dizzy to fix it! strippign trigger window tho is not easy on these you need to hammer the pin out of the base of the dizzy,. but if you do that the whole thing comes apart, hence why i say jkust swap the hall sensor over as its only held on with 3 screws once trigger window is out :)
but like i said just disconnect the plug on the kr dizzy and try again, that'll rule out the dizzy. i dont think its that anyway, i think its down to rotor arm and dizzy cap, as even if 4 window was causing problems it wouldnt stop the spark making it to the plugs
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well, got the replacement dizzy (ABF) brand new cap and bosch rotor STILL no spark at the plugs, tried it with the dizzy unplkugged too, so that rules that out. the battery is low but tried jumping it from me mates car, but it will turn and turn fast enough to get compression i think :undecided: but then will just stop with a clunk and all the clocks reset as if its jus randomly lost power completely, and then the oil light flashes???! it just seems like the power is going elseswhere. could that be a bad earth? ive notived that theres only one bolt holding the coil to the bulkhead there should be two, is the coil earthed to the bulkhead?
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no its earthed via brown wire, and the spark leads. check the gearbox earth is ok, it runs to a stud on the end of the rear engine-> box mount.
hasve you plugged it into vag-com yet, also check the measuring blocks. does fuel pump prime with ignition then continue to run as its cranking over. try a known good coil as well. are you sure the leads are good, mate of mine had new beru leads but a couple of em broke within a month or so
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oh, :angry: well i bought a fault code reader that claims to do exactly what vag com can do and it did have two codes, one immobiliser preventing engine start and air temp sensor + or something similar and i cleared them but they have came back. measuring blocks? sorry i dont know what they are? yeah fuel pump primes i can hear it and checked on the injector rail to see if there continues to be pressure by taking out the black plug type thing well this one is literally brand new from a place i trust. as for the leads ive tried a set i got off a ibiza at the scrappy AND the original set that were perfect before all this sh!t happened still no spark.ill check the gearbox earth, does that earth the starter?
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i think you now have 2 issues, first it seems you are loosing power to the starter, probably due to the battery being knackered. 2nd you are now seeing engine start blocked by the immobiliser. read the immobiliser fault codes, this will tell you why the immob is kicking in.
the measuring blocks are an advanced feature of VAG-COM, which some cheaper code readers wont have. VAG-COM is the software you install on a laptop to use with the usb/serial vag-com cables. what you can do with this is check the sensor inputs to the ecu, like ecu temp, inlet temp, throttle position etc. :)
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sory that was a typing error :laugh:, i meant the codes have NOT came back. the reader cost me 90 quid and yeah u can check and adjust the measuring values of each sensor, but i havent tried it yet.
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Right, spent two days checking everything over the other day and traced the sparking problem to the ECU, seems the + and - on the coil have shorted and popped a diode in the ecu!? so got a 24p 4002 diode from maplins and soldered it in, spark sorted. however it still didnt want to start it wants to, spluters, then runs slowly on what sounds like 1 cylinder. so checked the timimg AGAIN, spot on, so removed the injector rail and turned the engine over, all sensors are plugged in and its only injecting on cylinders 1 and 3 :huh: wierd, is this normal before ignition or is there something else wrong?! cAN ANYONE HELP!? could it be a dodgy oxy sensor?
cheers
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sounds to me like more has gone on the ecu than just that diode. buy a new one mate, just make sure its the right one to match your car, i.e. pre or post 96. early ones dont ahve the immobilser, late ones do. though you can run non-immob ecu on late car, cant do it other way round without adding in all the immob stuff. if you have vag-com you can match another immob ecu to your car easily
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do you by any chance have a wiring diagram for the digifant 3.2 ecu? just il try and fix this one if i can coz il have to fanny on with a new immobiliser and set of keys and could end up being a tad more expensive than a few ecu components.
cheers
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sure do:
http://vwtech.no-ip.info/downloads/g3abfecu.pdf
you dont need to touch keys or immob when swapping an ecu, just use vag-com to code the immob box to the new ecu. takes all of 5 seconds :)
edit: like this, but as it says near the bottom need to select 'immobiliser' not 'instruments'
http://www.ross-tech.com/vag-com/cars/immobilizer2.html
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cheers
im gona have another look at it this weekend n replace the ecu relay and fuel pump relay just incase.