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mt · Posted: Mon Dec 11, 2006 2:56 pm Post subject: P4 - Misfire

My P4 is misfiring badly, sounded like it was firing on 1 cylinder when i tried to start it this morning. Managed to get it running after a few goes at which point it felt like it was running on 2 cylinders up to 3k-ish revs, and then on 3 cylinders above that. Ran it for a bit to warm it up then it felt like 3 cylinders below 3k revs and fine above. Took it down the road, got to the roundabout and it felt like it had dropped back down to 2 cylinders, coaxed it back home where i struggled to get back into my drive, it simply wouldn't rev under load.
Thought it might be a water thing as the rain was torrential, so left it for a couple of minutes then started it again and it felt like 3 cylinders up to about 2k revs where there'd seem to be a click and it would fire on all 4.
Then left it for about 10 minutes, fired it up and it revved fine, but loads of white smoke out the back and i think it smells like it's running rich. Gently ran it down the shops for some WD40 (to replace my amazing dissapearing can), seemed fine, got back, loads of white smoke. Blipped the throttle, engine backfired Shocked

but still running.

I'm totally confused as to what's causing this. Any ideas?

More info:
Engine seems to be up to temp but there's very little heat coming through the heater, so maybe the thermostat is screwed and affecting a temp sensor somewhere, but i don't think this would matter on start up.
Think the thermo is screwed though as there was noticably less heat from the heater at the weekend and last weekend i started the engine to warm up in a car park while i waited for someone, no heat even when the engine was up to temp, drove 100 metres down the road and full heat.

For the last month or so it's seemed to be starting on 3 cylinders the firing on all 4 after a minute or so, figured it was just water on one of the leads/plugs etc and has been quite consistant.
There's no cat and hence no Lambda sensor.

Leads/caps felt dry to touch, dizzy cap/rotor arm were dry inside but the arm and the terminals looked very worn, strange as i changed them last year. Will change em later but i don't think it's this causing the prob.

stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

hi
check your oil and water for residues - sounds like head gasket failure
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mt · Posted: Mon Dec 11, 2006 3:54 pm Post subject:

tvatavuk · Posted: Mon Dec 11, 2006 4:08 pm Post subject:

Hi.

Some 33is have black ruber cap that covers whole 1 end of coil/ spark generator(bobine), if should protect from spaying water but it is ideal for acumulating water so you end up with small pool inside of it.

0. Unplug cables 1 by 1 at distributor.
While doing it you can find out which 1-2 cyl foul, if you disconenct cable and engine turns or runs same you got it Smile

1. Check that problematic cables have spark at plug end.
2. If they do, check for spark on spark plug by unscrewing it.

After all this you'll surely have black deposits on spark from all extra fuel.

If thermo is realy screwed? car has been running rich for a while so you might want to clean all 4 spark plugs.

Reasons for heater not heating enough in cabin can be few :
0. Thermo
- coolant is not hot enough
- no coolant going at heater
1. Not enough coolant flow
1.1 heater blockage
- outer tree leafes
- inside calc acumulated in pipes
- small leakage on it
1.2 coolant pump not pumping enough
- coolant pump belt slipage
- something obstructs roatation of coolant pump belt
- coolant pump propeler not rotating (broken shaft) or leafes broken
2. not enough coolant in coolant system
- leakage somewhere in system
- air in coolant system

Regards
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Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

mt · Posted: Mon Dec 11, 2006 5:45 pm Post subject:

Cheers for that Tino, time for some more investigation i think!
Have to admit i didn't check the main ht lead or the coil (what you call a bobine) to see if they were damp, i think i'll use a water dispersant tonight and whether that makes a difference for the morning.

Will investigate the heater problem more too. Do you know if hot water will be passed to the heater matrix if the thermostat is shut?

paulhide · Posted: Mon Dec 11, 2006 7:49 pm Post subject:

Our thermostats tend to remain open when they fail so that the radiator is permanently in play and the engine has more difficulty reaching operating temperature. Heater matrix shouldn't be affected by the thermostat.
If at some point when the car has been left for a while the engine won't turn over you know you've got a cylinder full of water from a failed head gasket. Remove plugs (fun on a 16v engine) turn over engine and see if water is expelled anywhere.
First port of call though is to check leads, plugs, rotor arm and distributor cap and connections to coil.
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tvatavuk · Posted: Mon Dec 11, 2006 7:53 pm Post subject:

AFAIR thermostat only opens/closes big pipe going into radiator meaning it blocks water from going to->through->out of radiator.
Heater is connected to internal circuit (lower part of themostat) which I thnik runs freely.

Yeah coil is the name I've been searching for Smile

Deposits on spark plugs can tell you if there is coolant in cyls.
Thre was this story (probably for jokes section) when someone had fitted DTM style exhaust end pipes to his 155 end box and it was a lot of fun on rainy days because rain would fill in rear box.

Some new exhaust boxes have smal holes in them to let condesate drain out, others don't so you need to realy heat up mid and rear boxes for all condensed water to evapourate. This shouldnt concern you to much as it mostly concernes cars with catalytic converters as those make plenty of water or in case on low qual fuel sulfic acid.

Chhers
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Tino Vatavuk
Little black dress which replaced Alfa Romeo 33 S 16v Permanent 4 GMo

mt · Posted: Mon Dec 11, 2006 7:53 pm Post subject:

paulhide · Posted: Mon Dec 11, 2006 7:59 pm Post subject:

Very old spark plug leads can become porous.
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mt · Posted: Mon Dec 11, 2006 8:12 pm Post subject:

paulhide · Posted: Tue Dec 12, 2006 11:14 am Post subject:

A garage can do an extremely quick hydrocarbon test in your header tank to make sure it isn't head gasket failure. Check rotor arm and cap.
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Bellamachinna · Posted: Tue Dec 12, 2006 6:47 pm Post subject:

Hi...

Seems that your car has the same symptoms that mine also has.

On mine, it only starts mysfiring during the winter.
During spring & summer the car behaves itself, but when the nights get colder, the mysfire appears.

I tried everyhing. I changed the AFM, the plugs (by the way, my engine doesnt like Golden Lodge plugs, because they got soaked in petrol. I have to use the NGK because they seem to be more powerful to "dry" themselves).
I also changed plug leads (original ones, and very expensives), distributor cap, rotor arm...

On each change, the car seemed to improve, but it only lasted for a week or two...
I also suspected head gasket failure, but my oil doesnt show any traces of water, and it doesnt "drink" a drop of oil. Also, the coolant is clean, and doesnt desapear...

Also, at a steady engine speed, i can feel the engine mysfiring, because theres a slight drop in RPM.
From 1000 to 2000 RPm, the engine coughs, and is impossible to maintain it there. It`s annoying in traffic, because i have to get the Rpm beyond 2000 rpm, just to get going... Under that, and the engine shaks, and eventually stalls...

Next try will be the injectors. I`ve arranged a set, and sent them to be cleaned.
Fingers crossed

All the best
P.Camilo
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mt · Posted: Tue Dec 12, 2006 7:13 pm Post subject:

Scott Sander · Posted: Tue Dec 12, 2006 8:28 pm Post subject:

Hi,

If you have lost your coolant and suspect a head gasket problem, before starting it you should remove the plugs to check that you don't have a cylinder full of water.

If your coolant is in the cylinder you could cause your engine to hydraulic lock if you try to start it.
http://www.prepsparkplugs.com/hydrofact.htm

Has the oil level (or should that be oil/water level) increased?
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Scott Sander
'91 Alfa 33 Boxer 16V Monza - Awesome
http://www.sanderfamily.com

stedee · Alfa 33 Joined: 02 May 2006 Posts: 364 Location: brighouse

headgaskets when gone dont necessarily leak water into the oil they can just leak into the cylinder chamber hence the white smoke, that is why i originally said headgasket failure
and if the cylinder does fill up with water you can seriously damage the engine ie bent conrods.
you could try taking the plugs out and turning it over to see if water does come out one or two of the cylinders.
i`m sorry for u if it is headgasket - pain in the arse with the boxer engine.
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