Missing on one cylinder

stinkypaul · Post by **stinkypaul** » Sat Jun 13, 2020 11:36 pm

Car hasn't been used much during lockdown, but I've used it once a week or fortnight, and it's been fine.
I drove somewhere this week and it started running on three cylinders.
I'm trying to diagnose the fault at home now.
Seems to be running on three cylinders. Removing the plug lead on cylinder 1 does not change the engine note. Removing it from the others does.
Cylinder 1 does seem to be kind of running though???

I have spark (of some kind at least)
I can smell unburnt fuel coming out of the exhaust and cylinder 1 smells of fuel with the plug removed.
I've had a screwdriver on the injectors, they all sound the same.
Ran a compression tester and all cylinders have the same pressure.
Checked timing belt and timing, both seem fine.
Replaced plug and plug lead with spare ones, same problem.
No engine codes
Cleaned the the dizzy cap and arm, needed doing but hasn't helped.

Could the coil do this, or the ICM maybe?

Anything else worth checking?

Thanks

Paul

Post by **vanzep** » Sun Jun 14, 2020 2:19 am

dizzy could be coil or icm but youd best take it off and take it apart and have a look if ok then move onto, ht leads,check for bad fuel and check there are no coolant leaks, also look for any water in the car look in passenger footwell at ecu
good news the compression test is good so you know its fixable/ worth doing

ive been having problems with the washers jets suddenly not working so l got all worried about the electrics and possible issues until i checked the connections at the washer jet pumps and it was obvious loads of corrosion - scraped that off and now im fairly sure the pumps will go on for another 30 years

many times ive worried about the car and it has always turned out to be something basic and simple or the dizzy. hope this helps

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sun Jun 14, 2020 6:16 pm

Coil and arm would be common to all cylinders.

If you've changed the plug and lead on that cylinder, I would try a new distributor cap next - they can break down and start leaking current instead of insulating it and keeping it in the terminal.

If it's not that, then I think you need to look into the injector.

Scott560 · Post by **Scott560** » Mon Jun 15, 2020 10:32 am

worth checking the spark plug/swapping.

I know people don't like swapping parts, but if you don't know when the cap/arm were last done, i'd do those first.

Its unlikely to be a fault elsewhere. if injector 1 sounds like its ticking, then it could be blocked? try tapping it whilst the engine is running and giving the loom a wiggle also just incase the sound you hear isn't from that injector.

stinkypaul · Post by **stinkypaul** » Mon Jun 15, 2020 10:38 am

thanks for all the responses. After getting into it a bit further, the distributor is not doing well. Seized on rotor arm, stiff shaft (bearings might be iffy), and cracked wiring (which blew my last engine up :/). So I'm doing some distributor surgery, or maybe another distributor.
I'll see how it is after that.

Scott560 · Post by **Scott560** » Mon Jun 15, 2020 10:42 am

As an FYI - the arm is retained by a screw, you might need to turn the engine over to get access to it to remove.

stinkypaul · Post by **stinkypaul** » Mon Jun 15, 2020 2:04 pm

Thanks. I hate that screw, it's always tight. This time it was seized, I had to cut the rotor arm to get it out :/ also the metal ring in the rotor arm was rusted on the shaft. Maybe I need a new gasket as well.

Scott560 · Post by **Scott560** » Mon Jun 15, 2020 2:42 pm

yeah, a new cap is under 20quid and you get a new seal with it i recall (blue print one anyway).

Ended up using some loctite on that screw on mine - last time i didnt, it came loose and ground a hole in the 'flash shield' or whatever you want to call it, and filled the dizzy cap up with plastic dust (caused no issue mind).

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Jun 16, 2020 5:18 pm

Scott560 wrote: ↑
Mon Jun 15, 2020 10:32 am
worth checking the spark plug/swapping.

He did say he'd already swapped them with a spare.

stinkypaul wrote: ↑
Mon Jun 15, 2020 2:04 pm
Thanks. I hate that screw, it's always tight.

With you on that - the rotor arm screw is a total sod on this series of distributors.

Strange as it sounds... Knackered bearings in the distributor could be causing it to miss on a cylinder, actually - if it's spinning slightly out of round and increasing the gap between the arm and the cap contact, for that cylinder.

Post by **vanzep** » Tue Jun 16, 2020 11:20 pm

glad youre well on the way to getting it sorted.
ive found that you need to take the dizzy off to work on it properly and then its wd40 onto the screw and finding the right screwdriver but yeah ive had trouble with that screw many times - how the hell does it get rusty normally everything else has a fine misting of oil on it......

i bought a new dizzy from motortronic/ultra spark on ebay sure they do ones for 5th gen as well wasnt cheap but it does make a difference - i had already spent money on fixing the old dizzy, new cap ,coil, rotor arm, (old)new module - it worked ok but just not as good as a new one.