20 replies to this topic

[bradderz]

think i have fixed the problem. i was checking to see if a certain cylinder is misfiring by taking each lead off one at a time while engine was running to see if anything changes. the 2nd spark plug wasnt firing, swap the leads over, still the 2nd spark plug not firing, swapped the spark plugs over and then the 2nd cylinder was firing. so it must be the spark plug right? bought some new spark plug, just waiting for the engine to cool down to see if it has fixed, thingers crossed. how comes nobody suggested the ignition systems? has anyone seen this happen with spark plugs before, not working when cold and then working when warmed up?

Edited by bradderz, 02 November 2010 - 08:07 AM.

[minimat]

I don't think my heater works,i just live with it because as sprocket says it turns of when the engine is warm anyway.

[Knuckles]

Cold running (rather than cold starting) problems that disappear when warm to hot can also be attributed to the manifold heater or PTC heater as it sometimes called. Check that the fat brown wire is attached to the spade terminal on the base of the manifold (directly under the manifold if you were looking down at the throttle from the top( the underside of the silver knobly bit at the bottom of the inside of the manifold, under the throttle disc)). It is fairly common for this connection to be burnt, loose, or even disconnected. Also check the relay pack large connector for similar scorching/ burning of the same wire (brown/ blue? from memory) as well as the circuit track on the inside of the relay pack. If this all looks fine, it could be that the heater itself is faulty. The heater should read an ohm value between the spade terminal and the manifold somwhere in the 100's depending on the temperature. If there is infinity ohm resistance with a cold heater, the heater is faulty.

I have this random blue/red wire down the back of the throttle housing not connected to anything.....
is this the spade connector that connects to the ptc heater under the housing ?

[AVV IT]

has anyone seen this happen with spark plugs before, not working when cold and then working when warmed up?

Yes my car used to misfire like crazy when cold, but things improved to drivable when warm. Turned out to be some kind of intermittent problem with spark plug number 4 when cold, so I replaced the rouge spark plug and things improved considerably but were still not perfect. I have since discovered that my car heater matrix was completely clogged up and there was therefore no water flow around the heater pipe circuit. As my heated inlet manifold is also plumbed into the heater circuit the manifold wasn't getting heated either, since flushing and clearing the system (and now with warm water flowing everywhere) the car seems to run a lot better when cold!

[Sprocket]

Cold running (rather than cold starting) problems that disappear when warm to hot can also be attributed to the manifold heater or PTC heater as it sometimes called. Check that the fat brown wire is attached to the spade terminal on the base of the manifold (directly under the manifold if you were looking down at the throttle from the top( the underside of the silver knobly bit at the bottom of the inside of the manifold, under the throttle disc)). It is fairly common for this connection to be burnt, loose, or even disconnected. Also check the relay pack large connector for similar scorching/ burning of the same wire (brown/ blue? from memory) as well as the circuit track on the inside of the relay pack. If this all looks fine, it could be that the heater itself is faulty. The heater should read an ohm value between the spade terminal and the manifold somwhere in the 100's depending on the temperature. If there is infinity ohm resistance with a cold heater, the heater is faulty.

I have this random blue/red wire down the back of the throttle housing not connected to anything.....
is this the spade connector that connects to the ptc heater under the housing ?

EDIT That'll be the one I was right, The heater is indeed a heavy Brown/ Blue wire. The Blue/ Red is for the oxygen sensor heater. so if its not connected to Lambda sensor, that will be causing you problems

Edited by Sprocket, 05 November 2010 - 05:20 PM.

[kjwithers]

I know this is an old thread, but I think my PTC heater has failed, I've got an awful flat spot when cold and checked all vac lines etc. I've checked the resistance of the PTC and measures 10ohm. A previous post on a different heater measured 2 ohm. Does this mean mine has failed or have I measured it wrong?