ignition help

[Big Dave]

Just another quick check,
Check that the main earth lead that connects from the back of the engine to the bulkhead is tight. This can lead to intermittent challenges.....

 

[Andy H]

Bit the bullet and ordered a new ignition switch from Porsche £35 +vodka and tonic (vat)
not too bad I thought for a dealer part, will find out if its the real "fix" on wednesday when it arrives

 

[xenon]

Andy - sounds like you're getting to the bottom of it but it's easy to make a hard-wire link to bypass the DME relay if it ever gives you grief. Good thing to carry around in the glovebox.
Make a wire to link terminals 87 & 87b and then to 30 (i.e. all linked)

 

[Andy H]

ORIGINAL: xenon

Andy - sounds like you're getting to the bottom of it but it's easy to make a hard-wire link to bypass the DME relay if it ever gives you grief. Good thing to carry around in the glovebox.
Make a wire to link terminals 87 & 87b and then to 30 (i.e. all linked)

Thanks for the tip Ian,
I will be making an emergency 'get you home' kit for the car as I find out these things , probably end up with a boot full , but better than being stranded.
A friend works for VAG and is cross referencing all the relay part numbers etc to see if theres a possible source for spares from there,
I need to get a manual and wiring diagrams, I hate wasting time stabbing in the dark for faults.
I do fully intend to get fully aquainted with all the mechanical/electrical components in the very near future.
Fortunately dont need to worry about bodywork as Ive been building show cars for years for some top magazines /customers, but the S2 will stay white (as long as I stay out of my custom colours cabinet).

Andy

 

[xenon]

The original Porsche factory manuals are available for download (pdf) from various sources, including full wiring schematics. I can send you them if you can't find 'em.

 

[Andy H]

that would be great ![]
Save a lot of time mucking about.
Downloaded a parts manual last night, but couldn,t find any wiring diagrams

 

[xenon]

Available on Rick's site here: http://www.cannell.co.uk/Manuals.htm

 

[Andy H]

Cheers Ian,
spot on!

 

[sawood12]

ORIGINAL: JamesO

The reference and crankshaft position sensors are next to each other at the top of the bellhousing. The connectors should be both mounted at the back of the cam tower.
They are variable reluctance sensors one "reads" the teeth of the starter ring gear and the next one picks up a stud on the flywheel.
Following this link may be helpfull :- http://www.clarks-garage.com/shop-manual/ign-02.htm

Slight correction, the Reference and Speed sensors are positioned next to eachother just off the 12 o'clock position on top of the bell housing. They are both the same sensor so are interchangeable and a brand new one costs around £75. The sensors mount on a bracket which bolts onto the bell housing. There are two nuts: one to fix the bracket onto the bell housing (which can work loose over time) and the second to position the height of the sensor relative to the flywheel (you don't want to mess with this one). When I had my intermittent starting issues I bit the bullet and bought a new sensor but when I went to replace it I immediately noticed the reference sensor was loose. I tightened it up and all has been well ever since.

The crank sensor is located somewhere else on the engine - low down I think and is a bit of a pig to get to. THis was the next thing on my list of sensors to check if the problem was not the Reference sensor.

 

[Fen]

Actually I don't think that's the same for the S2 Scott. The S2 I believe uses a true Hall sensor for one function (not that I know exactly what is different about that [&:]) whereas the Turbo uses two identical pickups

 

[JamesO]

Much better description but I'm sure those two sensors are the only ones that relate to the crank on an eight valve car (I don't think the turbo has one extra).
They are a bitch to work on though, I once made the massively stupid error of fitting an engine then noticing the sensors complete with bracket still on the shelf

The sixteen valve engine sat in my garage has one sensor on a 60 tooth wheel on the crank and a sensor on the cam

 

[Fen]

[] i didn't read the last of Scott's post. You are right the Turbo has only the 2 sensors in the bellhousing. One "reads" the teeth on the ring gear (speed) and the other a couple of grub screws in the edge of the flywheel (reference). There is no true reference sensor measuring half rpm speed (usually on the camshaft) so the sensor (and hence the ECU) only sees crank position and can't differentiate between compression and exhaust stroke. If the plug fires is purely down the the rotor arm.

 

[Andy H]

ORIGINAL: JamesO

Much better description but I'm sure those two sensors are the only ones that relate to the crank on an eight valve car (I don't think the turbo has one extra).
They are a bitch to work on though, I once made the massively stupid error of fitting an engine then noticing the sensors complete with bracket still on the shelf

The sixteen valve engine sat in my garage has one sensor on a 60 tooth wheel on the crank and a sensor on the cam

After checking mine tonight, mines seems to be the same, I can only see 1 sensor at the rear on the bell housing.
Made a test rig set up at work today to bypass the ignition, and tried it tonight.
Fired first time every time YEEEEEEESSSSSS!!!!!!!
Hopefully not being over confident here ,but its looking good.
New ignition switch arrives from the Porsche centre on Wednesday, the true test ,, fingers crossed.

Incidentally, tried to download the chassis section from the link that was posted and it was a no go!.
Anyone else tried and failed to get this section, it is a monster file to be fair
Got everything else printed off, (there goes another rain forest [8|])

Andy

 

[JamesO]

Oops should have noticed it was an s2 from the start! I had trouble downloading that file too, it took a few tries and it worked in the end.

 

[Andy H]

Well fitted the new ignition switch tonight and...........................all seems well in the world again ![]
Absolute pig to fit, working blind and back to front ,but its done and working
The kind gents even gave me a new tax disc holder for free and trade discount ,, so im well chuffed.
Big thanks to all for help and suggestions.

Andy.