bodyart99uk

Good morning all,
I am new to 928 ownership and am currently trying to save an old 1985MY 928S2 (Euro) from the scrapheap! I have a few problems that i would liek your opinions on if possible

After it had sat in a barn for 2 years (before that it sat outside for a further 3!) its now in my possession and the attempts to re-commission the once fantastic car begin.

Having changed all the spark plugs and filters (air oil fuel etc) and putting fresh fuel and injector cleaner through it I have managed to get the car to actually start (the fuel pump relay doesnt energise and has to be bridged but hey at least it runs!!)
It runs reasonably smoothly (not perfect but ok-ish for now) but, and here is where the problems start.... Now and again it will start and run reasonably well and come up to temerature and all is well with the world but most of the time it will start and run reasonably well BUT as the temerature starts to rise (normally just clearing the cold area) it will cutout and absolutely steadfastly refuse to start again until the engine has gone stone cold again! - does anyone have ANY idea where i should be looking for this type of fault??????

Also (and this may be related, i dont know) The car has had an engine change after the timing gear on the original engine failed - the previous owner simply swapped out the engine for anothe 1985my engine) but the engines are slightly different and there are acouple of wires that arenot connected to anything, and i suspect they should be!

Firstly the current engine doesnt have a cambelt tensioner sensor like the original had - i have identified the wire for this so that seems ok BUT there are 2 wires on the top of the engine with female spade connectors that look like they should be connected (the inside of the terminals are clean and corrosion free suggesting they have spent most of thier life hooked up) The wires are located just beside the left bank of cylinders (looking at the engine from the front) and come out of the engine loom just about where the little fuel cannister is thats located on the strut brace. The length of the wires suggests something close by but i cannot find anything nearby to connect them to the wire colours are 1= Red with a green trace, and the other is Lightish green with no trace colour.- does anyone have any idea what these wires are and what they should be connected to???

Finally i have ANOTHER wire thats not connected down near the front grille there is a broken black wire that seems to disappear in behing the left hand driving/fog lights (again looking from the front of the vehicle) and the wire seems like it might be long enough to go to the small front water resevoir mounted near the headlights themselves. Does anyone know what this wire might be for? were the front headlight washer jets on a 928 heated perhaps??

The list of problems wih the car is long and extensive (mostly electrical i think) but any help on the above would be greatly appreciated, Hopefully one of the experts here on Rennlists can help point me int he right direction.

i look forward to eharinf from you
many thanks in anticipation
Stewart

WallyP

First thing - you need the factory shop manuals. You can get a marvelous set of 928 tech info CD's from Jim Morehouse - a huge amount of tech info, including the manuals. Jim's email is jim928ATptd.net - change AT to @

I would start with standard troubleshooting techniques - trying to split possibilities in half as quickly as possible.

First - fire or fuel? When it quits, either check for spark from the coils or from a plug wire. BE CAREFUL - the 928 ignition system is VERY powerful, and can hurt you! You can also try spraying starting fluid into the air cleaner - if it fires, the problem is fuel, if not, probably ignition.

Once you have split the problem into fuel or fire, you can start looking for temperature or time related problems.

One possibility is the crank position sensor, located in the top of the bellhousing.

You have probably found one of your problems. The two wires should be plugged into the Temp II sensor on top of the water crossover. The sensor housing contains two temp sensors, one for the fuel injection ECU and one for the ignition ECU. These sensors tell the ECU's the coolant temp, which changes the air/fuel ratio and the ignition timing.

A black wire on a 928 is normally a power wire. There aren't too many solid black wires.

BTW - standard description depends upon left/right being from the driver's viewpoint. The steering wheel on USA cars is always on the left. The fender on the other side is always the right fender...

SteveG

Bodyart: Your first post, so welcome, glad you are saving an '85 Euro. I would suggest you learn to post pictures as soon as possible. It makes the communication clearer and hence diagnosing tons faster esp on something like this.

Mike Frye

Hey how's it going Stewart?

Welcome and congrats. Refurbing a 928 is a blessing and a curse. Good luck!
As Wally said, the two wires coming out of the 'loom' or harness are probably supposed to go to the Temp II sensor. There should be a sensor on the top of the water bridge (the thing that the radiator hose comes out of).

I think it would be good to determine what engine you have in there. You said it's been swapped, I guess it's most likely (since you're in Europe) that it was swapped with a Euro '85, but if it's a US '85 it would be different and that might account for the wiring mismatch.

There should be a set of serial numbers stamped on the block right up top, I think there's a flat spot near where the oil filler neck goes in, or maybe near the water bridge. I know you can see it if you look around near there and clean off any flat spots.

Once you get that you can post it and someone will be able to give you the info on what engine it is.

86'928S MeteorGrey

Welcome to the tank. Become a Rennlist member as soon as possible. It's the best $20 you will ever spend on your shark. Looking forward to more info and pictures.

bodyart99uk

Thanks for the replies all,
I dont think the wires are the temp 2 sensor since this is present and connected with a plug connector rather than 2 individual wires - these wires must be for something else. I am told the engine came from anothe UK 1985 model but will get teh engine number and check froim there.

Good advice re spark/fuel i will install a set of HT testers i have which will at least show if a spark is present on at least 4 of the cylinders (i only have a set of 4)

I managed to download a set of factory manuals so will be working through thoses soon(ish).

One suggestion that has been put to me is that it might be MAF failure causing the problems - before i satrt to strip it out does that sound feasable/realistic????

membership only $20? sounds like a bargain, best get onto it right away

Thanks for all your comments it really is appreciated

bodyart99uk

Thanks for all the replies your help is most welcome!

I am still working thru them all but in the meantime i was asked for picture re the extra wires - well here they are (hopefully!) as you will see the 2 wires i cant figure ou what they are for - one of the wires seems to go down to a little round "thing" near the headlight - the red/green wire is electrically connected to the bottom post of the two - not figured out where the green wire goes, or where the other post of the round thing goes - does anyone know what it is?? and does it help figure out where these wires on the block should be connected??
Hopefully one of you experts can help me out here
thanks in advance!
Stewart

John Speake

Sounds like your enine is from an 84 MY S2. The two spare wires could have gone to an inlet temperature sensor switch which was introduced in MY 85. The switch is fitted to the inlet runner of CYl #2. Do you have that sensor ?

bodyart99uk

Thanks for the quick reply John, Its entirely possible the engine is from a 1984 MY as here in the UK registration letters only changed once a year and it was possible for a 1984 MY and a 1985MY to recieve the same registration marker. I dont know if i have the sensor (but will have a look fairly soon and post the findings here) if its NOT present - could that be the cause of the poor running/cutting out as engine warms issues i am currently having??? I am supposed to be getting the original engine shipped to me for spares over the next couple of weeks so if i dont have it, and its on the original engine i could probably get it swapped over
kind regards
Stewart

John Speake

The switch is about 30mm diameter, but hidden on the most vertical part of the runner , facing inwards to the centre of the "Vee".

bodyart99uk

Thanks John, I will have a look as soon as possible and post the results.
I suspect the switch will indeed be missing - presumably if i get the swich and intake from the old engine i can just swap it out and connect up??

Do you think this might be the cause of the engine cutting out as it warms and refusing to restart until cold or is this just an additional problem i nee dto deal with? (this deinately appears a "fuel issue" as the cylinders still spark when cranking). Incidently it did once (Just the once!) fully warm up before it cut out and then went back to the usual cutting out as it starts to warm

any thanks in anticipation
Stewart

Ps just watched the mythbusters 928 show which aired inthe UK -what a sacrilidge to chop up a perfectly good landshark!

John Speake

The "spare wires" if they go where I think, won't be having any effect on your running issue. Suggest you swap out fuel pump, LH and EZK relays for good type 53 or equivalent. The EZK relay is probably the fuse tester one, but you can substitute a 53 for fault finding. The fuel pump relay is the most heavily loaded of the three, and usually the first one to fail.