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Help. Sound like a single cylinder missing.

eyecandy993

Well-known member
Joined
22 Jan 2010
Messages
486
Hi all, I hope you can give me some ideas on what to expect.
I've been away from the forum and my '94 C2 was garaged from May 2012 till March this year because of health reasons. I am on the mend now but unfortunately not my flat six.

I had to garage the porker since May 2012. It must have had a sixth tank full of petrol than. Took it out first time again in late March 2013 when I filled up with new petrol after a run with the old to diminish further the left over old petrol. Was not initially aware of any engine abnormalities first run but than I became aware of regular missing in not more than one cylinder with a perceptible high frequency shudder proportional to rpm and especially noticeable when going uphill (not too steep) in higher gears (eg 4th gear). Sounds more like a VW Beetle at times of acceleration with possibly some loss of the usual power.

I usually take it for service across the pond to Sicily where I bought it from. They offer a good helpful service and they see a lot of 993's unlike here in Malta where the 993 population totals 3 cars! I am reluctant to get it seen to here. Doubt even if the local dealer can access the OBD I.

My primary diagnostic possibilities are 1) Single fouled or non firing plug in one cylinder, 2) fouled or non performing fuel injector - but would expect a greater sound change and lower power, old fuel on the other hand could have lead to this, 3) a faulty valve closure or valve guide in one cylinder 4) faulty high tension lead to one plug.

No smoke coming out of the exhaust but POSSIBLY an increased smell of petrol. My main concern is that the local OPC may have never seen a 993. I know for a fact that a foul running 964 could not be put right over here but the defect was nailed by my guy in Sicily. My physical recovery and the possibility of a catastrophic engine breakdown preclude me from getting to Sicily this year.

Any other diagnostic things I can do before going to discuss options with the local OPC?

Thanks for any input.
 
Eyecandy.....just doing a quick bump for you.....I cannot be of help but I am sure there is someone here abouts that can....good luck and I am glad your health is on the up.
 
One thing to check is the distributor, if the belt goes and one dizzy is stuck firing it can cause odd issues, just an idea.
 
I don't think we are ignoring you - it sounds like you have the usual suspects covered, and it's very difficult to diagnose over a keyboard.

Can't you drive it to the ferry, and get it picked-up by trailer from the italian-end?
 
Julian Weston said:
One thing to check is the distributor, if the belt goes and one dizzy is stuck firing it can cause odd issues, just an idea.

If you notice a loss of power, then Julian's suggestion sounds the most likely, i.e. half of the sparkies are not firing :dont know:
 
I had a cylinder go a few years ago and turned out to be the ECU.....
 
Thanks. Am considering taking it by ferry and than trailing it. It is definitely a single cylinder missing so do not think it is the belt drive of the second alternator that has gone. The Missing is quite subtle that is why I suspect a single plug in one cylinder. Have to have some ideas to discuss with local OPC before being convinced they know what they are talking about. If it's the ECU, Ugh :sad:
 
My initial thoughts were a coil or distributor belt etc.

Have you tried pressing all the plug leads into position in case there is a poor connection? Personally I cant see it being a spark plug since there are two plugs per pot.

Try running it on a single distributor and see it if starts on one. That way you can at least eliminate that problem.

If ECU is suspected I'd try cleaning the plug contacts first to see if that helps.

It could also be a dirty/fouled injector if you suspect poor petrol.

Have you got an OBC reader as that may identify the fault
 
Zingari said:
My initial thoughts were a coil or distributor belt etc.

Have you tried pressing all the plug leads into position in case there is a poor connection? Personally I cant see it being a spark plug since there are two plugs per pot.

Try running it on a single distributor and see it if starts on one. That way you can at least eliminate that problem.

If ECU is suspected I'd try cleaning the plug contacts first to see if that helps.

It could also be a dirty/fouled injector if you suspect poor petrol.

Have you got an OBC reader as that may identify the fault

Thanks OC,

Will try pressing the plugs at the distributor and coils but going to the individual plugs is out of the question as I would not attempt to dismantle anything in the 993. My most adventurous auto mechanic problem solving was that I took apart a BMW E30 carburetor and found stuck needles after it failed to start.

Yes there are two plugs per pot but - an here it is speculation - I would think that if one plug in one cylinder was not firing there can be a perceptible though subtle shudder unlike both plugs in one pot which seems unlikely to happen. If I can exclude a misfiring plug than it has to be a fouled injector from the use of some of last year's fuel. I HAVE ONLY 76000 KM on the clock.
 
Took out the old girl out for a drive, I wanted to discuss issue with a friend but the problem seemed to have gone away. SO most likely cause was some gunk from one year old fuel in one injector or some corrosion on one contact for the distributor rotor. Hope it will not recur.

Deviating from the tread, ordered some service spares and 10 Liters Mobil 1 0W-40 from UK to be delivered to shipping hub in Essex for forwarding to Malta but companies would not accept credit card unless delivery address was same as that of credit card. Hopefully will be resolved by sending bank transfer. Everything is twice the price here in Malta. Got a pair of rear Michelin Pilot sports 17's from Germany at €420 the pair including shipping. The local Michelin agent quoted €470 EACH and a 12 weeks wait! :x
 
If you pay for my ticket I'll source all your stuff and bring it to you :thumb:

I haven't been to Valletta since 1989 - are there still Hillman Hunters racing around as Taxis?
 
OC, no Hilman Hunters.
EC, where oin the island do you live?
Where do you get it into 6th?
LOL

Ive stayed at the MBH many times.
Stutts
 
I see you have ordered 0/40 mobil 1......I would have thought with your warmer climate 5/40 would be the better choice......I use Mobil 5/40 over here in the UK.....but of course I could be totally wrong......that usually is the norm for me.....:)

p.s. I have read somewhere that 0/40 oils are not the best for the 993 anyway ..... :dont know:

p.p.s. I have my coat in hand ready to head for the door...... :D
 
orangecurry said:
If you pay for my ticket I'll source all your stuff and bring it to you :thumb:

I haven't been to Valletta since 1989 - are there still Hillman Hunters racing around as Taxis?

No we've moved up. All sorts of taxis now but the standard taxi cab in 1989 was probably the Mercedes W123 and 124. Still loads of old British and Italian makes still being used as daily drives by old owners though many are now coveted by very enthusiastic and resourceful Classic car enthusiasts.

The average age of passenger cars here is 14 years due to high registration taxes which have only been partially replaced with a horrendous circulation fee. If I had imported my 993 after 01/01/2009 my annual circulation fee would have been €1500. As I imported before that date it comes to €510 but the registration tax and VAT on that tax cost me €31000. Yes I could have bought another 993 or a Caymen with that money. We only live once and even that almost came to an unscheduled exit.
 
stuttgartmetal said:
OC, no Hilman Hunters.
EC, where oin the island do you live?
Where do you get it into 6th?
LOL

Ive stayed at the MBH many times.
Stutts

I hail from the centre of the Island - Mosta. Roads have since been upgraded around the MB Hotel. True, do not use 6th much but shifting 3rd and 4th to accelerate for a few hundred yards between speed cameras and bends is fun.

If you ever visit again PM me. Hope I'll remain in good health till then. Was in the UK from July to November last year for health reasons. Wished to meet some of you from the forum but was never as well as I wished to be while still there.
 

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