As many have probably read already, I've been through hell and back sorting out issues with one of my ABF swaps. I'm now getting close to the finish line, though, as after replacing ECU relay #30 it runs pretty well. It's still missing on #1, though, and pretty much only when cold - after 10 mins of driving the miss has largely gone. Power does seem a bit off, even once warmed up, though. Occasionally after over 30mins of driving, the miss does tend to come back and power drops off a bit more Compression is strong and cap, leads, rotor, crank sensor, coolant sensor, TPS, 02 sensor etc have ALL been replaced I've also tried swapping the injectors to find a fault here, but this achieved nothing either. Is is worth trying a different dissy? I cannot describe how desperate I am to sort this car once and for all - this has been ongoing for months There are no fault codes either...
does it look like a fuel or spark issue , do you think ? Hardly a dodgey plug? Or compression being down a wee bit on that cylinder? how are the ABF tappets adjusted?
My next step is to remove #1 plug and put the spark tester on when cold and see if it fires... It's strange, though: it sounds like it runs on 3cyls for a couple of minutes after start-up when idling, but as soon as I touch the throttle, it'll rev cleanly up off idle. Taking off when cold will get a miss at about 3k RPM, though, which I believe is just on #1 as this is the only fouling plug... ABF tappets are hydraulic... I'm doubting a carbon build-up on the valves or anything like this, though, as the head was only recently rebuilt and all seems to be working ok once warm. Very strange issue. All I can suspect now is the dissy, or perhaps even the hall sensor, but I'm reluctant to spend even MORE money P.S. I've tried replacing plugs, so no trouble there
If it's only missing on No.1 , it surely isn't the hall sensor . Can you rotate the dizzy far enough so that no 1 plug fires through a different pin , hence ruling out either the dizzy or the cylinder? Sorry if I'm talking boll0cks , just I'm not familiar with 16v distributor arangements. Did you swap the plug leads around?
have you pulled the plug leads of whilst the engine is running? are plug gaps ok? take all the plugs out, fit to lead and crank see if there is a spark. (away from fuel!!) resisitance of leads if you can check and compare with others. what qulity leads? silicone grease can be used on top of the plug to stop spark going along ceramic (possibilty)
Unfortunately, the ABF dissy is fixed in place, unlike earlier 16vs. I've tried swapping the leads around as well, but had no joy! The leads are brand new OE Beru, so no quality issues, plugs are also fine too! I'll put a spark tester on #1 tonight and see if it fires when cold at idle speed (it certainly sounds like it isn't). So sick of this car
Have you tested for combustion gases in the coolant - either by sniffing, or with a block tester kit? If it's leaking between the chamber and a waterway, that can cause lumpy running when cold.
Take the plug out put it on the lead and turn it over if it sprks then its not lead/plug related then check connection at the injector rail . If you rev the car dose it catch at all ?
I'd try pm'ing rj, or wait until he comes along, hell tell you how to trace the problem. The only problem my 9a and abf on kjets have is too much hammering is killikng my crankshaft keyways and pulleys! Something you may never experience at this rate! Stick at it tho a 2.0 16v mk2 is pretty cool when working, though I think I need a 20vt in it now..
If the spark is weak/yellow in colour, then under compression there may be no spark at all. You need a good, strong, blue spark. When a spark plug fires under compression, the quality of the spark will be very different from when it fires under ambient pressure. Barometric (air) pressure at sea level is approximately 30 lbs. per square inch. If cylinder compression is 75 psi (measured with a compression gauge), this is actually 75 psi greater than ambient pressure because the compression gauge is zeroed at ambient pressure. It is much more difficult for a spark to jump the gap under higher pressure, because higher pressure makes the air a better insulator. Quote kindly loaned from: http://www.splitdorfreg.com/Blancard/magproblems.html
If you rev it when cold, it picks up #1 and revs smoothly, but under load it'll miss when cold and then gradually clear up once the engine warms up (still feels under-powered, though). I'm pretty sure it has to be ignition related, as there's unburnt fuel getting dumped out the exhaust during cold starts (chances are my new 02 is stuffed by now). I think even rubjonny is stumped with this one too [:^(]
I hope it's something simpler and easier to fix, but I had the same problem on an engine which was down to a gasket leak between combustion and coolant. Have a sniff in the header tank. When I took the head off there was a chunk missing under the fire ring.
Yeah, I'm really mystified by this in general, as this used to be a very strong engine Sniff test was also passed without problems, so the mystery continues!! I'm going to pull the dissy cap off tonight and have a look at this, as it's only been on the car for about 1000kms. This will also be a chance to check for play in the dissy. I'm wondering if this will ever be fixed
If you've already tried swapping injectors, have you checked the contacts between the fuel rail and injectors.
Check the vac pipe for FPR. Think this comes out by number 1 cylinder. if this has a small hole in it will let air in and No 1 cylinder will run lean,giving a misfire. Also check the vacuum pipe for the servo. Sometimes the rubber sections of this gets small holes in and gives the same symptoms. Had it on a MK3 1.8 Golf Cabriolet,drove me potty Gavin
Ok, so I just started the car after a days and it started first time (as usual). Pulling #1 lead makes no difference at all (as expected) and #1 plug is wet even with the lead connected, so it's certainly not fuel related. In saying all this, spark is actually pretty weak on all cylinders - hardly visible even. #1 doesn't look to have any spark at all. Revving the car cold is a bit lumpy, but it does clear up with more throttle and revs. The weak spark perhaps explains the lack of power, even once warmed up. Next step - shall I try a coil? Other than coil, what about coil wiring? I'm just curious as to why potential coil problems mainly affect cold starting - I've normally experienced the opposite in the past, where heat affects the coil... Plus, why is #1 cylinder the worst!?! I've also checked the dissy for play and it's fine. The cap and rotor look perfect and show no signs of trouble either. REALLY appreciate everyone's help
