weird firing 18i cabby

my 1990 18i 8v gti cabby is weird!! when you remove 1,2 and 4 plug leads engine dies as it should but when you remove 3 it makes no difference, this happened b4 i changed engine now with replacement engine its still doin it, it is sparking on no3 plug and injector is dispensing fuel, any one got any ideas . . . . . . .

Weak spark (loose or damaged No 3 lead)? No compression on No 3? Relative amount of fuel different (do Prowlers injectors test; can be adjusted on the metering head).

This is very much the same problem I have but with cylinder 1.

Can somebody offer more info about testing the injectors flow I'm sure my injectors are fine as they are new aswell!! But I'm concerned about the quantity of fuel being put into the engine

same here - I have got the same problem on cylinder 1. Remove the HT lead and makes little difference to the idle.

Any help will do. Changed the injector cos it was not spraying properly and compression test is OK.

Do a search on "Prowler's injection test" and it should point to a thread on it.

a lad who supposed t know crack on mk1's said its the meterin head recently found out he owned car earlier, said he couldnt sort prob wi it, i said jst fit new DX engine he said shouldnt have DX engine, shows what he knows inside boot on label it says engine code DX what a wanker cost me 300 quid for nowt so be careful of advice a heard ya can adjust metering head but dont do it ya self find an old skool mechanic who knows the KJECTRONIC system supposidly you can adjust it using a emmisions tester, this not to be treated as gospel tho!! other people who have same prob do yous have dodgy start up tick ova meanin it takes few minutes before will idle alone, maybe we have prob with cold start injection on left side of inlet manifold, has elec plug below fuel connection????????…….

???

You don't replace an engine to solve a fuel injection issue - you fix the issue at hand. I always approach the problem solving like this: measure the parameter which it could be (it will only be a certain things), adjust that thing, measure it again. Try to measure things directly, since if you use indirect measuring, it carries with it some assumptions…

If your engine is not firing on one cylinder, it can only be due to 4 things:

- ignition (spark not sparking)
- fuelling (too little, or too much fuel to burn)
- compression
- timing (valves and ignition timing)


Now, you've checked the ignition; the timing is very unlikely since its one cylinder and the other 3 are working; and you say that a compression test has been done too. That only leaves the fuelling. Prowler's injection test will allow you DIRECTLY observe the amount of fuel being delivered by each injector, and the quality of the spray pattern too.

Found some of the problems late last night saying gospel to everyone. Took out the injectors cranked car no fuel but it was running which leads to the cold start injector cracked that off loads of pressure.

Took the top off the air box and the metering head was shut according to the haynes book of crap there should be a 0.10mm gap around the flap and cone in my cae there wasnt. Bent up the little clip anderneath the flap as described in the book of lies refitted everything and cranked over again suprise suprise fuel from the injectors spraying in a nice cone!!!

Reffited every thing got the timimg light out to make sure everything spot on read the book of lies somemore ignition mark should rotate to the rear of the car as the ditributor advances the ignition under accedleration, guess what right through to ful throttle my timing marks stayed in the same place.

22.30 last night in the garage distributor out in peaces in a tray all the weights and springs ceasesd up now trying to find a replacement.

Theory being between a friend and me that previously when it was running we advanced the ignition by hand and the enine zipped up sounded great no misfires as son as the timing was set according to the book of lies it would tick over properly but not rev up start missing hopefuly becasue the distrbutor was not advancing the timing enough!!

Anyone know where i can get a new distributor?