1992 S2 avant non start.

[John.]

Had a half hour today to help a mate with his S2 estate....it doesn't start.
Engine turns over but no feed to fuel pump, the relay has been replaced and still the same. Prior to the non start situation, when last run the rev counter was sticking at 2000rpm and half the dash lights weren't working, I doubt this is related but thought I'd mention it?
Checked for battery voltage at pin 30 of fuel pump relay.......ok.....so bridged pins 30 and 87 but still no feed at pump. Fuse 13 intact but no voltage here when cranking. Gave pump a direct feed, pump runs and draws 6 amps......so cranked engine but still it doesn't fire up.
There's battery voltage at injectors, wasn't able to check for switching when cranking.
The battery has been charged and engine turns over fast enough.
Before I trawl through wiring diagrams and posts on this here good forum.....anyone any thoughts.

One spanner in the works is that it has a Sigma immobiliser, the control unit for it is behind the dash as seen when we replaced the heater matrix. I haven't checked for coil switching/HT spark and as mentioned injector switching.

Thanks in advance.

John.

[Vorsprung durch Technik]

Could very well be the Hall sensor other know as the G40 sensor on the front of the Head behind the pulley.

[John.]

Could very well be the Hall sensor other know as the G40 sensor on the front of the Head behind the pulley.

Cheers Mark.
I did mention that to him after he replaced the pump relay to no avail.....it's a good shout. Although the no feed to pump after bridging pins 30 and 87 makes me think there's a fuse box issue?......I was really hoping for it to fire up after supplying a feed!!.....no such luck.
Went to the car today with no tools other than what he had in his plumber's tool box!

[Vorsprung durch Technik]

The G40 sensor does the same as the 2.6 V6 hall sensor in that if it fails the ecu won't trigger the fuel pump or fire injectors. The ecu recognises the fault and shuts the vital systems down needed for a start.

Have you pulled the codes?

Just seen your reply ok no tools. Plumber leads me to Jacks old car.

[John.]

The G40 sensor does the same as the 2.6 V6 hall sensor in that if it fails the ecu won't trigger the fuel pump or fire injectors. The ecu recognises the fault and shuts the vital systems down needed for a start.

Have you pulled the codes?

Just seen your reply ok no tools. Plumber leads me to Jacks old car.

No codes, Aye K15RNA

[Error404]

If the ECU isn't energising the fuel pump relay then it would likely suggest a trigger sensor error of some sort, either G40 hall sensor as VDT suggests or the G28 engine speed or G4 reference sensor.
You'll need a scope to check the last two as they are VR sensors, but in my experience they rarely go wrong. The false RPM signal might be a symptom of a bad engine speed signal.
Have you pulled the codes yet? Timing pin on the flywheel if also worth a check if you remove the crank sensor block.

Of course it could be an immobiliser issue of some sort - pull the cover of the fuel pump relay and manually activate it - it should run. If not then trace the immobiliser and see if it has interrupted the fuel pump circuit.

It also sounds like you have some electrical greminlins - if the car has been stood for some time then have a look at earth points etc, both to the chassis and the engine.

Have a look at this sticky: https://www.s2forum.com/forum/techni...does-not-start

[twoqu]

If you could verify that there is power at the injectors when cranking that might help. With ign on the holding relay in the ecu supplies power. When the ecu is happy that the engine is being spun fast enough, the ecu signals the fuel pump relay to take over. So if it disappears that might suggest the immo interupting it.
It does seem that immobolizers like to use that circuit!
Don't forget that basically the fuel is controlled by the flywheel sensor whilst the spark is via the crank and camshaft sensors.

[John.]

Problem I have is the car's not that close to where I am !! The owner isn't shy at chucking money at it and is ok with the spanners, maybe not so with electrics..........so maybe him fitting a new cam sensor is the way to go for now.

Chen Yang Technologies in Germany ??......ok for this sensor?

[twoqu]

The cam sensor does not influence the fuel system as far as I am aware.
The only thing thats troubling is the comment about bridging the relay plate unless either you bridged the wrong 87 (there are 2) or you are actually not making contact with the terminal. They are quite deep so I normally butcher a spade connector to insert so I have enough depth. You could check that by continuity with fuse 13.
If there was somebody to help, I would pop the top off one of the relays and get somebody to crank and see if the contacts close.
Essentailly the sequence is as above, engine spins, ecu is happy, grounds the fpr, power to fuel pump/injectors/other sensors.
Could introduce some easy start into the induction. If it fires at least you know its fuelling rather than sparks!

[Mikes2]

no point guessing until you've pulled the codes. Let me know if you need assistance as I'm not that far away

[John.]

The only thing thats troubling is the comment about bridging the relay plate unless either you bridged the wrong 87 (there are 2) or you are actually not making contact with the terminal. They are quite deep so I normally butcher a spade connector to insert so I have enough depth....

Was a concern of mine too, bridged the two largest connections, 30 and 87.......87a was a smaller connection.

[John.]

no point guessing until you've pulled the codes. Let me know if you need assistance as I'm not that far away

Thanks Mike, codes will get pulled.

[John.]

Regarding the cam sensor, would I be correct in thinking the Bosch part no. is 0 232 101 020 ??

Was looking at links from one of the "sticky topics" regards getting a sensor.........

https://hiem.com/hall-effect-switches/

http://www.efiexpress.com/catalog/pr...products_id=95

http://www.hallsensors.de/Hall-Vane.htm

https://www.jaycar.com.au/hkz-101-ha...duced/p/ZD1900

Anyone dealt with any of the above???........I'm thinking there must be someone closer to home!


This one from our friend at Opie Oils....... https://www.ebay.co.uk/itm/Bosch-Cam...YAAOSw5JJZkcCh
.........but although it came up when searching for 0 232 101 020 it states Bosch no. as 0 232 101 021

[Vorsprung durch Technik]

The opie oils one although not cheap is plug and play for convenience if it's correct. I seam to remember the the Professor mentioning these sensors bought like the first 4 in your list as being a very cheap alternative.

This link shows the same 2 different bosch part nos although suggest the same, plus cross references to S6 S4 etc, so your link should be good and cheaper.

BOSCH Camshaft Position Sensor Fits AUDI 100 80 Avant A6 Coupe 2.2L 1991-1997

[twoqu]

Was a concern of mine too, bridged the two largest connections, 30 and 87.......87a was a smaller connection.

I would check continuity between the relay plate 87 to Fuse 13. The relays either not being switched or its not reaching Fuse 13/fuel pump. Either could be the immo I guess.
I haven't tried it personally but I would think one of those LED test lights would work on the hall sender to see if it was outputting a signal. That would save unnecessary expense/work. Others have made test tools. I'll find the link!
http://www.efiexpress.com/catalog/ar...articles_id=11
I don't think its the issue but you could eliminate it.