Northern924
New member
Geoff, sorry but I had to laugh that soudns like something from inside a fortune cookie [
]Ignition has me stumped
- Thread starter Northern924
- Start date
Geoff, sorry but I had to laugh that soudns like something from inside a fortune cookie [
]
Northern924
New member
I have had the plugs out and checked them along with all the leads direct to the coil to make sure I was getting a spark from each one.
Its just strange that the car was running smoothly, all be it with the intermittent cutting out, and then nothing..
Geoff, sorry but I had to laugh that soudns like something from inside a fortune cookie [
] Ah, so
peanut
Active member
something is not right here.
if you have a spark at the end of all of your spark plug leads and the plugs are all good then your plugs and bores must be drenched in fuel .!
you must be able to smell it and see the ends of the plugs wet.
if that were the case you would at least get the occasional fireing or misfire ,even if the timing was compltly wrong.
Are you sure you have both fuel on the plugs and a spark when you turn it over ?
if you have a spark at the end of all of your spark plug leads and the plugs are all good then your plugs and bores must be drenched in fuel .!
you must be able to smell it and see the ends of the plugs wet.
if that were the case you would at least get the occasional fireing or misfire ,even if the timing was compltly wrong.
Are you sure you have both fuel on the plugs and a spark when you turn it over ?
Northern924
New member
When I say the leads and plugs are good, thats when they are connected direct to the coil, you can certainly smell the fuel when no.1 plug is out to check for a spark, it all falls down when I connect up the whole system, that why i was asking about the chain of events once the coil has fired. managed to get hold of a spare TIU which should be hear by the end of the week.
jr2015
New member
Hi, you seem to have given the ignition system a good seeing to, might it be the fuel pressssure regulator on the fuel rail failing and flooding the engine? You can check this by fitting a pressure meter to the nose of the fuel rail and checking the pressure therein ( be careful if you unscrew the union on the rail as its got a spring behind it). It should be about 2 bars at tickover .
jr
jr
924nutter
PCGB Member
We await the outcome of the "new" TIU, as I can see how changing the unit will make the spark that arrives at the cap come out the other side, because when my igntion module went U/S it sparked beautifully but about 80 degress too late. The engine would barely run and sometime briefly fire up backwards due to the unburnt fuel. Then for days on end it would be good, then just when you needed it, it let go again. Yours may have failed so badly the spark is coming so late that it can't arc across to the segment.
By the way, if the resistance of the individual leads is around 6.7k ohms don't you think 1.4k is a bit low for a lead about half the length of no.4?
By the way, if the resistance of the individual leads is around 6.7k ohms don't you think 1.4k is a bit low for a lead about half the length of no.4?
924nutter
PCGB Member
On this model 924 the only connection the fuel pump relay has with the igntion circuit is a feed from T1 on the coil to T16 ( I I RC) of the relay which disables the relay as a safety device if the coil signal drops out, for cutting pump feed in a 'stalled engine and ingnition on condition', preventing fuel from being pumped unnecessarily. In an accident, for example, with the driver disabled in some way and unable to cut the ignition, the pump would otherwise continue to feed, and you can use your own imagination as to how life threatening that would be if a fuel pipe ruptured in the engine bay spraying out fuel at 3 or 4 bar. Earlier models had a connection routed through the air metering unit via a terminal on the side of the casting which enabled the relay as soon as the flap lifted (i.e.engine sucking) and broke the connection.
Northern924
New member
I was thinking that, thats why I asked, it does seem really low, but with a HT lead connected to it and a plug on the end, it still transfers a strong spark from the coil, see what joys the TIU brings, and if I get it firing again, first thing I'll be buying after that is a new set of HT's, plugs are only 4 months old, so at least then the whole ignition system will have had an overhaul [8|]
peanut
Active member
I still don't understand how you can have both a spark and fuel and not get some sort of ignition. ? you must be getting at least the occasional cough splutter or misfire .!
This is important. If you are not.. and you definitly have fuel on the plugs then either you have no spark or you cannot be getting a spark at the right timing.
Have you connected everything up then connect No 1 HT lead to a spare plug and earthed it on the engine and turned it over ? do you get a strong spark then ?
If you remove No1 spark plug when you do this you should be able to see the spark co-incide with No 1 piston coming up on the compression stroke which will give you a rough timing check
its rather frustrating not getting the full picture.
ps be very careful disconnecting the fuel rail as it is under considerable pressure and would cause serious damage if it caught you in the face or eyes.
This is important. If you are not.. and you definitly have fuel on the plugs then either you have no spark or you cannot be getting a spark at the right timing.
Have you connected everything up then connect No 1 HT lead to a spare plug and earthed it on the engine and turned it over ? do you get a strong spark then ?
If you remove No1 spark plug when you do this you should be able to see the spark co-incide with No 1 piston coming up on the compression stroke which will give you a rough timing check
its rather frustrating not getting the full picture.
ps be very careful disconnecting the fuel rail as it is under considerable pressure and would cause serious damage if it caught you in the face or eyes.
924nutter
PCGB Member
Peanut, on the 924 N/A it is possible to have a spark and fuel and still no cough or splutter. I speak from the bitter experience of a long afternoon in the compay carpark with a portable generator, a spark and gradually increasing mixture setting until I was getting a near hydraulic lock there was so much fuel. The only conclusion I could draw was that that a capacitor/ transistor combination within the module was allowing the spark to fire too soon or too weakly to set light to the fuel and make the engine run. What I do know for certain is that going from immobile to running as sweet as a die was achieved by changing the ignition module for a brand new one (£314 plus vat) without any other adjustments having been made.
mr brightside
New member
wow this is turning into quite a fixathon isn't it!! if your transistor ignition module doesn't fix the problem then here are 2 more ideas for the melting pot.
put it all together and have an assistant turn the engine over in the pitch black of a country lane or something, if your HT side is arcing off to ground somewhere you will see it clearly.
also if water has got into your fuel tank it will play holy hell with the metering head and they're not fixable, on Mk1 Golfs water gets in through rusted filler necks.
put it all together and have an assistant turn the engine over in the pitch black of a country lane or something, if your HT side is arcing off to ground somewhere you will see it clearly.
also if water has got into your fuel tank it will play holy hell with the metering head and they're not fixable, on Mk1 Golfs water gets in through rusted filler necks.
Northern924
New member
Been driving me mad not being able to do anything, but the TIU should be here on Tuesday, so will have to wait til then.
Thankfully live in the middle of nowhere so dark country lane is right outside my front door []
Thankfully live in the middle of nowhere so dark country lane is right outside my front door [
]
I don't know what a TIU is but if it is the same as a ECU there was one on ebay yesterday standing at £30 with a 'Buy Out' price of £40.
peanut
Active member
yes this is the one complete unknown. I don't know of any way you can substitute the ignition module except with another one,although there must be a way to test it. (not much help when you are stuck out in the wilds without tools and test gear)
We'll just have to wait until Tuesday I guess for the next installment.!
better than Sky+ this thread lol[
]
Northern924
New member
All these thre letter acronyms, starting to confuse me as well [8D]
ICU & TIU are one in the same, as nutter has said on the older 2.0ltr n/a its the big grey Bosch box on the N/S inner wing, the Unipart one on eBay is for the S if I'm not mistaken.
Sods law though, I just missed out on the correct one on ebay, forgot about the auction yesterday and it sold for £5.51!!
ICU & TIU are one in the same, as nutter has said on the older 2.0ltr n/a its the big grey Bosch box on the N/S inner wing, the Unipart one on eBay is for the S if I'm not mistaken.
Sods law though, I just missed out on the correct one on ebay, forgot about the auction yesterday and it sold for £5.51!!
ORIGINAL: 924nutter
The ICU is the igniton control unit and guess what, that's what it does. The ECU is the Engine control unit which on the 924S controls fuelling, and thus mixture as well as the ignition.
I knew you didn't understand the question[
I understood that he quoted it as a 'TIU' that's what I didn't understand but then I don't claim to be a Technical Advisor. The thing on ebay was the usual alloy box that sits on the nears side inner front wing.
But what do I know?[8|]
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