JBGold07

As Mr M mentioned earlier. Also put a fine eye over the throttle position sensor plug and wires to the sensor. Its close to the oil filler cap. If those wires touch something they shouldnt. No start

ramcram

Yes, I have more resistance than I should at Temp sensor II but not enough to stop it from starting.
Thinking of spark plugs, when I do the trigger test as per the Porsche book, [page attached] I get a beautiful 4mm spark form the coils but if I then reconnect the computers and crank the starter over, I don't get a spark at all?
So if it's not sparking at the coil, then it won't even get to the plugs?

ramcram

Had another go at trouble shooting yesterday after a detailed study of how to use my oscilloscope.
retested wires 7&19 on the EZF plug and got the attached readout. Perfect wave form and great voltage readout.
Connected it back up, pulled of LH coil wire and attached the spark plug with a 4mm gap to test for spark, hit the key and it fired up on 4 cylinders?
Connected up the LH coil again and it's running perfectly?
Wriggle the CEB and the engine stops. Narrowed that down to wriggling the wire at the back of the CEB behind the LH relay. With the CEB out, every thing looks great though. More testing to do?

Mrmerlin

might be time for some deoxit 100 spray

docmirror

This is where things get tricky. You have an intermittent open circuit from the pick for the relay to ground. If you're sure the first time it was only running on 4 of 8, I think this might be in the ground plane? As I recall, but don't have my wiring diagram right now, the two groups of injectors have a slightly different ground return. If one of them is intermittent to ground, you'll only get 4 running.

You can use an ohmmeter on contact points while you wiggle various wires. This is where an analog meter is useful because you can see trends much better. But - use what you have, and check the pins on the relay sockets carefully. As noted, they are known to get pushed back into the housing when the connector latch bends, and the pin goes back. You've got it down to an area, just plug through with the ohmmeter, and watch for changes as you wiggle stuff.

John Speake

The test connectors for each output ignition amplifiers are above the CE panel - make sure they are connected OK and not trapped or damaged.

ramcram

Thanks guys, it all helps.
I have already used Deoxit twin pack with the 2 little bottles with brushes in them.
It started on 4 cylinders because we had the left coil wire out of the distributor and on a plug with a 4mm gap to test for spark, as the Porsche test outlines but we tried it on crank. Luckily it stalled pretty well straight away. We were taken by surprize as this was the first time it had started in weeks. When we had reconnected the left coil, and it ran beautifully, we started wriggling things and it would stop each time but not in the same place? This made me suspicious of looms or CEB connectoinsbut it narrowed down to the top RH corner of the CEB. It is out now but trying to remove the grey wires on the back it difficult. The brass male pin seem to come out before the female spade on the wire. The little lock clip is very tricky to pull out.
John, we have played with the trigger wire plugs allready! One had a broken plug and we replaced it.
That's when we discovered that the Australian cars, for reasons no one can explain, have a 100mm link from the trigger wires to the computer. This link is a crossover. If you replace the plug and lay the link wires out nice and straight, well you have a few days of fun trying to work out why it fires all funny annd won't start!

ramcram

Update;
The CEB is perfect. I have 4 CEBs here counting this one and the other 3 all have been messed with but this one is 'as new'. We went all over it with my Fluke 88VA, wriggling and pulling but no faults.
Put it back in the car after lining up all the loom connectors where they lay naturally without any load and started the engine without issues.
With the engine running, we pulled and wriggled every wire in every loom plug, every relay and every fuse. Not even a stutter, smooth as silk.
Pre refitting the CEB, we did find a wire in plug 'W' [significant to this issue] that had been opened and soldered up. This soldered joint looked '****ty' and came apart with a tug, so we resoldered it properly.
So we plan a road trip to test it. The rego has expired, so I think I can borrow some 'Trade plates' to allow me to take it on the road, followed by the trusty Skoda with a tow rope. Fortunately, from my house we can drive out into the country without going through any traffic lights, just a bit hilly for the first bit which might make towing home fun!

ramcram

Test start again today, sweet.

SteveG

Hopefully you got it. Cudos.

I just have to ask, why one black wire from each distributor to plugs? Other 3 are red. I'm not sayin this is racist, . . . just the way you do things downunder I guess.

ramcram

No matter what rout we tried with the supplied set, we couldn't get them to lie nicely as they should, so I had the long ones made up at the local Bosch shop. He only had black.
All the others were then moved forward one.
The 5.0 litre S has that 'loop' at each plug which uses quite a bit of length, even though this set was supposed to be for my model.

ramcram

Started first time yesterday to drive it out of the shed while painting the 'project' under body.
it stood out in the cold all day, started fine and went back in. Great if it keeps up. Still waiting for a chance to give it a good big road test.

ramcram

Car has been starting faultlessly for weeks now, just waiting for time and good weather to take it out on the road.
Yesterday all systems go, weather great, time to rumble, Skoda Superb and driver ready with tow rope just in case . . . battery flat!
One hour later, turn the key and she purrs like a kitten, so off we go.
Stoped to fill up with 98RON fuel, drive about 10km and stop for a snack [late lunch] and take off again.
Into some pretty windy, hilly country now. Long windy downhill, overrun with brakes on and engine cuts out instantly!
Into neutral, turn the key and she fires up straight away and she's off again.
Drive for about 20km more, pull over for direction choice discussion, pull out onto the road and the engine cuts out instantly again. No coughing or spluttering, just cuts out. All roadside assist, they arrive 30 mins later, turn the key and she starts up perfectly again.
All the way home no problem at al???

SteveG

Uhmm, you say the battery was flat and one hour later you are on the road. I'm hoping that was a new batt, not the result of a jump pack device??

If it is the latter, you may have fried whatever you fixed. Whatever the history, or order of events, I would not use that or any fast charge on these systems, unless the batt is out of the car.

Also want to know why it was flat in the first place??

ramcram

Car wasn't registered, so it sat in the shed. I start it from time to time to see if it will start. I let it run for a while. It had stood for a while untouched, I kept telling myself to put the battery maintainer on but kept forgetting. Then my mate popped up and said "let's take it out and test it NOW while he has time and the weather if fine. Guess what? Why didn't you have the maintainer hooked up? I use a 'Calibre' Charger which first does a polarity check, then a battery check [if it fails, the charger just beeps and flashes a fault light] , then a soft start which pulses the voltage and amperage, then a bulk charge, then absorption, then analysis, then boost and finally it goes into float mode.
I truth the battery is probably in 'time on' because it was in the car when I bought it at the beginning of 2013. Its history I know not. However, it behaves well when the car is used as it should be.