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Second and Third plug not firing

Just had a look down the oil filler cap and there is traces of white mayo...... its going to be the head gasket [:eek:][:(][:eek:]

I was advised not to go with Victor Reinz gaskets when i changed mine but i'd already bought it so fitted it, looks like that might have come back to haunt me.

I'll be going to Porsche in the morning an buy directly from them i thinks.
 
That's not unusual this time of year (the mayo), even more so if the engine wont run for long, I would be very surprised if it is the headgasket.
 
I agree, mayo on the filler cap at this time of year is not unusual. Plus... there are several ways a head gasket can fail - water to oil, combustion chamber to water, combustion chamber to oil, combustion chamber to combustion chamber... If it were oil to water, so to cause mayo, it wouldn't cause it to run rich... Indeed I seem to recall the plugs on a car with headgasket problems to the waterways tend to be grey... But I'll bow to the more knowledgeable on that. I must admit from what you have told us now, and the further checks you have don, my money would be on the ECU (because I believe it works on pairs of plugs/injectors with a final amplifier per pair before th outside world) or the two middle cylinders are red-herring, and it is the airflow meter causing it to run stupidly rich, actually, scrub that, my money is on the ECU!
 
ah man..... i'm so confused as to what to do next.

Granted the mechanic hasn't seen the car and is only going off a conversation on the phone so it could well not be the head gasket. Finding an ECU to swap over and try on mine is going to be hard work. I did try and source one earlier this year when i had a fueling issue which ended up being the DME and ended up having to get one from the states. I've since sold that on as the ECU wasn't the problem.

Any suggestions on how i could try a different ECU quickly, I doubt my mechanic has one laying around and i don't know anyone with a 944 locally. [&o]

I just mentioned to the missus that the head gasket may have gone and on seeing how down i was she just agreed to get the car looked at and fixed as i look so miserable.


 
The ECU is the DME: DME stands for digital motor electronics and its Boschs name for their ECU. The DME relay is so-named because it powers the DME and on receiving a control signal from the DME, it powers the fuel pump.

Incorrectly mixing up their names is probably going to cause confusion for you when you speak to others.

You can use a later (ie series two 944, which is metal and plastic) DME, but make sure that you get the airflow meter and injectors to go with it.
 
Just had a look on ebay and PIE performance do have an ECU matching mine.

hmmm might have to give them a call tomorrow.

What would cause the ECU to fail though Tref?

the theory that the two cylinders not firing are the ones next to each other, 2 and 3, does make sense because there's been a breach in the gasket or a crack has occurred.
 
I think you're chasing a fault, replacing parts that might be perfectly good.

Where are you? There must be a decent indie somewhere nearby?
 

ORIGINAL: pauljmcnulty

I think you're chasing a fault, replacing parts that might be perfectly good.

Where are you? There must be a decent indie somewhere nearby?
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I'm in SE London mate, I've got a chap named graham at Elite Motors who I use and spoke to, I think I'm going to have a bit the bullet and get him to fully diagnose it. He understands I've got house costs coming out my ears and tax etc to be paid so hopefully he will go easy on me. He's always been very honest with work done in the past and his rates are reasonable.
 
Good decision, I think it's better to get it diagnosed than to change parts at random, often ending up with a huge total bill and no better off!

I'd check whatever they suggest here, as with more info it might become clearer.
 
I would agree Paul, I wouldn't suggest buying an ECU, but if there is a known ok running car you can borrow one from... Swapping a part to prove or eliminate it from the diagnosis is the cheapest yet surest way of determining a problem isn't it? Why does an ECU fail? Same reason as any other part - they are all "mean time until failure" devices. They are all going to wear out and/or fail sooner or later, we can only use them in the meantime. At some point there has to be a change between just good enough to work and not good enough anymore, such a miniscule difference, but that is the difference between you car running or not! That is the way I look at every component.
 

ORIGINAL: Asiangunner

Simon,

I have tried a brand new DME and it made no difference mate.
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A DME or a DME relay Ranjit? I think that we're talking at crossed purposes here. [:D]
 
A compression and leakdown test on the engine as well chemical coolant test should tell you volumes about the condition of the head gasket.

I suspect the problem could be as simple as your injectors being completely gummed up and could probably do with ultrasonic cleaning, new baskets and flow testing..

At this time of year some mayo in the filler neck is not unusual.

Victor Reinz make the 944 gaskets for Porsche, they are not a problem and if yours has been replaced recently, I doubt there is a problem with yours, they are usually good for about 10 to 15 years

It should be quite simple to get to the bottom of the issue and I doubt it is the DME, but it could be.
 
Clarks Garage has lots of useful testing procedures for things like the AFM, TPS and other sensors that might be worth a look before giving up. Most of it is pretty straight forward if you can work a multimeter.
 

ORIGINAL: Indi9xx

A compression and leakdown test on the engine as well chemical coolant test should tell you volumes about the condition of the head gasket.

I suspect the problem could be as simple as your injectors being completely gummed up and could probably do with ultrasonic cleaning, new baskets and flow testing..

At this time of year some mayo in the filler neck is not unusual.

Victor Reinz make the 944 gaskets for Porsche, they are not a problem and if yours has been replaced recently, I doubt there is a problem with yours, they are usually good for about 10 to 15 years

It should be quite simple to get to the bottom of the issue and I doubt it is the DME, but it could be.
Click to expand...


Thanks for the reply mate, the car at my indie now. On a old invoice from when i had my head gasket done there is a note of corrosion on the head and between me and the mechanic we vaguely recall a conversation about the head and the fact there was corrosion on it.
I'm just waiting for the mechanic to get the head off and have a good look. If we remember correctly the corrosion was too close to an edge to have it welded but i will have a better idea of that over the next couple of days.

I've already started looking around for a replacement head should i need it if my head can't be welded, how much should i be looking to pay? £100-150?

I will get my injector new seals and hats etc once all this is done.
 
Popped in to the shop yesterday, the head is off at the machiners and needs welding in three places, there was corrosion to the head, I did suggest buying a different head but mechanic felt I could just be buy a whole new load of unknown issues. I'll try and get pics up.
 
Spoke to the mechanic today, heads welded and back on. Cars firing on all four cylinders but there is a problem reving now, they are going to investigate..... More money I fear....
 
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