LeonLewis

Hi,

I have a starting problem with my 928 1981 Euro Automatic,

The engine cranks but there is no spark at all.

This happened around the time of very heavy rain and floods. The car was outside at that time. and there was water half way up the wheel.

Immediately after the floods it worked fine for a few weeks and then no start..
After a week or so of trying to start it it did randomly start again and I drove it for a few days and then I didnt use it for around a week and then no start at all.. Before the no start, perhaps before the floods (Cannot remember) I noticed something which had never happened before, which was the engine cut out at low revs just after starting, but then drove fine afterwards.. This happened on 1 or 2 occasions just before the no start problem..

For the last 10 days The car has been garaged and still no start

I have done the following:

- Checked Fuse 22
- Checked cut out automatic transmission Relay
- Replaced Battery
- Checked resistors to Ignition coil (Checked before and after and voltage is normal)
- Replaced Ignition Coil
- Checked ignition coil - distributor cable
- Replaced Distributor Cap
- Replaced Distributor Arm
- Checked spark leads
- Dried out distributor with a hair dryer..
- Checked green cable.. Visually looks good, fairly new.. Also checked for voltage and I get a reading of a few volts coming from the distributor (I talked with 928intl who said this would normally indicate a functional distributor)..
- Pulled out ignition module and the Checked resistance of sensor system as per workshop manual between terminals 7 & 31d. Checks out.. ok


From my trouble shooting the only thing that can be left to replace is the distributor and the ignition module. Is there anything else I missed? Also does any1 know how to test the the ignition module or the distributor before buying a new 1?


Many thanks

Leon

GlenL

So by "no spark" you mean that you've checked for that with a timing light?

LeonLewis

No, I pulled out a spark plug cable, then instead of pulling out the old spark plug, I put a new one in. And then grounded and checked..

The ignition coil was also checked for spark by my mechanic, but no spark either

soontobered84

Did you check for power at the resistors on the drivers side engine compartment?

LeonLewis

yes resistors checked out ok

GlenL

The ignition system is really simple with the most common fault being the green wire. A timing light is very useful for this and would be a good addition to your tools.

I'd look at power to the spark control (silver) box.

Can you tell if the fuel pump is coming on when you're cranking it? A pin to that relay will go high-and-low if the spark box is sensing the distributor correctly.

LeonLewis

Glen,

Can you tell me more about this timing light. Where can i buy one (Can you post a link)? How do I use it to test the green wire?

There is 11.8 volts going to the spark box, already checked that

I can smell fuel when cranking the engine, so I assume that the fuel pump is working, however I have not done any further checks... So if the fuel pump is operating, that means the spark plug box is working ok?

GlenL

The timing light looks at the spark plug wires and wire from the coil. Available all over. Just google "timing light."

The fuel pump relay does two things. When the car is turned on it runs the pump for a couple of seconds to pressurize the system. After that it runs the pump only when the spark box sends it a toggling (high-low-high-etc) signal. That way the pump cuts off when the engine stops. This is another way to check if the box is working. You probably can't hear the pump when the engine is cranking but if you smell a lot of gas then it likely is.

Maybe the wire from the spark box to the coil is shorted or open.

LeonLewis

Ok Glen thanks for your help, i will check the line from the spark box to the ignition coil and report back

davek9

OP just as an FYI, you do not need an expensive timing light for testing the presents of High Voltage Spark.
A cheep HF test tool works just fine.

http://www.harborfreight.com/catalog...q=timing+light

LeonLewis

I checked continuity from the spark box to the ignition coil and there is continuity. I don't know how to check if the line is shorted. Im thinking of going ahead and buying a new spark box...
Any tips? Is there a replacement part or do I have to buy a used one?

A local french website is showing this:
http://www.oscaro.com/appareil-de-co...08-16308-932-p

I wouldnt consider buying this as its 500 eur but i thought i may be able to get it cheaper somehwere.. But I dont see how it would work anyway as the connections dont look correct..

GlenL

Where are you located? That's a lot of money. Check eBay or 928 International for a used, correct part.

Then again, I believe that ignition problems are, in the end, traced to the green wire like 80% of the time and everything else the small remaining fraction.

I'd put a voltmeter on the lead to the coil and compare the levels in on and cranking in both DC and AC modes. Look for DC changes and, especially, an AC reading. I'm not sure what the voltages would be. If both readings are consistent then it'll point to the box, green wire or the Hall effect pick-up in the distributor itself.

LeonLewis

Thanks for the info,

I am located in France

i pulled out the green wire and aesthetically looks good, looks around 10-15 years old.. I also pulled out from the distributor side and all connections look ok and not corroded.

Perhaps even if it looks ok, there could be a problem internally, so perhaps I will replace this first if you say it accounts for the majority of non start cases..

I read on a website just now that the spark box can break if there is a faulty alternator.. My alternator is new, however im wandering if it got flooded with the floods and created a voltage spike which broke the spark box.. All theoretical, I suppose I wont know until I have changed out one bit of a time.. This is going to get expensive..

Mrmerlin

before you swap out the spark box, can you please answer a few questions.
did you inspect the CE panel ?
IE did you spray deoxit 100 on front and back of the panel and remove the relays and fuses?

NOTE the CE panel can get wet either from the flood waters or from water dripping onto it from the blower box? was the floor wet>?

LeonLewis

Hey

Yes I inspected it and could not see any sign of humidity.

I have not sprayed anything.

I have only removed and replaced the automatic gear relay and fuse 22. The others I have not touched

The floor was not wet (At least I didnt notice it)

Thats interesting to know about the blower,

P.S FYI during the flood there was water half way up the wheel.. Therefore I believe it was not sufficiently high to get into the car.. Although this does not of course mean that some humidity made its way in..