GerritD

Hi guys,

yesterday I helped my buddy who has a 928S Euro of 1984 (LH Jetronic 310HP with 2 coils & 2 distributors)
His car won't start anymore and the day before it started without any problem???

We checked the voltage at both coils and they seem to be OK : 12V

But when directly connecting a test spark plug to both coils, no spark detected !!

Where to search for ? Could it be the 2 transistors at the front bumper ?
Or is the ECU completely dead ?

Mrmerlin

first the battery connections and the hot post and 14 pin connector above it.

Then did you make sure the belt for the distributors is good and then the rotors are both pointing at their respective hash marks on the distributor bodies?
this is done with the engine at TDC.

Could the coil wire for each distributor be swapped if so the engine will not fire.
Try swapping the coil wires from each distributor.

Is the crank position sensor good IE not a crumbled connector at the rear of the Valley.
You should see the tach jumping when you crank the engine.

Have you replaced the 4 running relays
fuel pump,
LH,
EZF ,
and ignition

The brains dont usually fail so look at these other things first

Another question to ask is what was the last thing you fixed, this might be a guide

GerritD

* Battery & 14pin connector checked and OK
* Distributor & all spark plug cables has been renewed a while ago. But
I checked spark without connecting to the rotor, so I used a TEST SPARK PLUG directly connected to the coils and NO SPARK AT ALL

* I have no SPARKS on both coils, so it must be an issue with the Ignition
Control

* for the relays :
Fuel pump relay : OK
LH relay :TO BE CHECKED
EZF relay : TO BE CHECKED
ignition relay : TO BE CHECKED

ANy idea at which position the LH,EZH & ignition relays are located ?
How can you check if they are working ? Do they make a sound when switching ?

Mrmerlin

Please read this carefully....

First verify that the timing marks line up at the rotors and the cams and the crank,

No mention of the crank position sensor connection at the back of the valley under the rear of the MAF what is its condition?

Then check for spark, to do that remove one of the plug wires from a spark plug and put a plug in it then ground the electrode crank the engine see if you have spark,
if not then swap the coil wires at the caps. retest.

Your description for checking spark does not make sense to me, so follow my suggestion.^^^^^

the 24 relays in the CE panel can be swapped for 53 relays.

to find a relay chart go to www.928gt.com

on page 2 under tips and links click on fuse charts print one off keep it in the car

RFJ

Listen to Mrmerlin he is correct and your way of checking for spark makes no sense you need to hook to each plug wire or a inductive timing light on each wire to be sure of spark. best to you.

GerritD

I will certainly follow MrMerlin's advice since ignition matters are not my cup of tea and I find the 928's ignition rather complicated compared to a simple non-injection oldtimer...

thanks already and I'll let you know what the outcome was...

Gerrit

John Speake

Check out the WSM which gives a testing routine for the ignition..... there's a test plug near the CE panel.

But the real question is - what work did you do on his car since the last time it started ? Logically the no-start could be associated with some thing you have done.

GerritD

I'll also check WSM....

Sometime ago I removed the complete Fuse-Relay panel to renew all fuses and bad connections
I also checked all fuses and plugs...relays I did not test.

perhaps, just one question : I removed all plugs on the Fuse Panel so that nothing is connected to it but I did this with earth disconnected but with battery still connected (I realized afterwards)

Could this be bad for my ECU ??

John Speake

Hi Gerrit
I assume you mean the earth from CE panel ?

The ECUs fitted to the 84-86 Euros are very rugged, so it is difficult to damage them usually. But of course it is sensible to always disconect battery positive before any dismantling. Of the two ECUs, the EZ-F is the one that fails most. But I would carefully retrace your steps that you made when working on the car since it last started.

GerritD

Indeed John,

I meant the earth of the CE Panel.
That's what I also had in mind because very often any intervention of good running things may cause issues related to this intervention although correct procedures have been applied...but you can never rule out human error :-)

Is there a way to check the EZ-F ?

John Speake

It is difficult to test the EZ-F fully, but the test in the WSM will test the output amplifiers, coils etc.

I would suspect other items before the EZ-F. If you believe after investigating others likely issues it is the problem, then I can test the EZ-F for you and repair it if necessary.

Alan

Congratulations - removing the CE panel with the battery connected qualifies you for Darwin Award !!

Really - don't do it folks...

whenever you are doing any electrical work - disconnect the battery - I do every single time...

In this case the battery is probably not the issue but the dissassebly/reassembly might be. you did reconnect all grounds and all the relays & fuses are in the correct poistions (and are not blown)...

Alan

GerritD

Hi guys, finally the anomaly has been detected : THE CRANK SENSOR WAS FAULTY......
So it had nothing to do with my CE Panel....it was just coincidence....Murphy again :-)

I bought a new sensor (about $ 200) and the V8 beast came alive !

thank you all for your input...it helped me alot

Mrmerlin

Thats great , i hope your friend will enjoy the Euro