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paulhide · Posted: Sat Nov 23, 2013 5:38 pm Post subject:

Yep, I've been getting quite intimate with the wiring, pulling out all the alarm wires under the dash and rewiring. Just one earth wire to reconnect before chucking the thing, then seeing if it's made any difference tomorrow.
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eagle3 · Alfa 33 Joined: 11 Nov 2007 Posts: 402 Location: France

Are you sure the fuel pump starts pumping as soon as you crank the engine?

If you can't hear it get someone to go under the back and make sure.
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paulhide · Posted: Sun Nov 24, 2013 9:51 am Post subject:

I put the pump on permanently by putting a wire between two of the contacts where the pump relay would sit. So it comes on with ignition. Unless the relay then uses another contact when the engine is running??
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paulhide · Posted: Sun Nov 24, 2013 1:00 pm Post subject:

Removing the alarm has made no difference except the starter turns over better now. (The immobiliser part of the alarm was bypassing the starter exciter wire, which I've now reconnected)

Maybe I will hardwire the pump somewhere other than the relay as there are also red wires going into the relay base and maybe they do something.

Beginning to consider Ian's initial suggestion.
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RFlower · Posted: Sun Nov 24, 2013 1:43 pm Post subject:

Do be careful where you connect your "live bulb wire" and any other jumper wires.
You could accidentally connect to an output on the ECU that doesn't like 12 volts put into it!
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Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

paulhide · Posted: Sun Nov 24, 2013 2:57 pm Post subject:

Yes, thanks. Replaced the ECU afterwards just in case and to see if there was any difference.

Had previously replaced flywheel sensor with another secondhand one and all the previous shorts cleared except for the odd flicker of the indicators on the dash.
I have got spark, but the fuel pump is just not priming, so I am assuming flywheel sensor is okay, but something else is causing the problem. Have tried replacing the fuel pump relay and ignition relay with spares to no avail.

Fuel pump wiring all works from the fuel-pump-relay-base back to the pump.

So what does that leave??

Wiring from flywheel sensor to ignition relay to ECU to pump relay??

There are two red wires going to base of Pump relay - I need to work out what they do/where they come from.
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RFlower · Posted: Sun Nov 24, 2013 3:27 pm Post subject:

I had a starting problem with my VW (which has a Bosch Jetronic system similar to that used on the 1.7ie), which turned out to be caused by no "engine running" signal arriving at the ECU.
This signal comes via a white wire on the -ive terminal of the coil, I think it may also supply the tachometer. I had good sparks, but the spade connector to the coil terminal for the wire to the ECU was corroded and a bit of cleaning immediately solved the problem.
I don't know what system your car has, but it may be worth checking the coil connections.
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eagle3 · Alfa 33 Joined: 11 Nov 2007 Posts: 402 Location: France

paulhide · Posted: Sun Nov 24, 2013 5:27 pm Post subject:

One of the things I did earlier today was replace the spade connection on one of these wires as it looked a bit knackered, but to no avail.
Maybe I should replace the other one too, although it didn't look as bad.

Interesting idea, thanks.

I've got compression and spark and I've live-wired the pump to work, but the engine won't fire - I can only see that injectors aren't working or timing is way out. I wonder if this white coil wire would also stop the injectors working.
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LoneWolf33 · Posted: Sun Nov 24, 2013 8:38 pm Post subject:

Hi Paul,

In case of Motronic the (thicker) white wire is driven by the ECU.
At the coil - terminal there's a branching towards the tachometer (thin white whire).
The unlike the Jetronic, the "running signal" is provided by the flywheel sensor in your case.

You can try introduce starter spray into the intake manifold. If the engine
fires up for a few moments after that, then it's gonna be a fuel supply problem.

P.S.: Have you tried pushing the car in 5th (with the pump relay installed) while the ignition is on?
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lee16v · Posted: Sun Nov 24, 2013 9:01 pm Post subject:

Removing a plug after cranking will tell you if the fuel is arriving Paul, i.e, wet and smelling of petrol. Have you double checked the plug leads are on in order.

paulhide · Posted: Mon Nov 25, 2013 8:29 am Post subject:

I assume flywheel sensor is working as I have a spark?

Yes, have checked and double checked plug lead order, which doesn't account for why pump isn't working anyway.

Running out of ideas. Could also put a bulb across injector terminal and see if it lights up Question

I am assuming wires to pump relay are pink/white-live grey-earth and two reds-switch from either ignition relay or ECU

There are loads of leads coming from ignition relay base - I've no idea what they all are.
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RFlower · Posted: Mon Nov 25, 2013 9:18 am Post subject:

You should really be checking what you're doing on the wiring diagram.

I don't think you're going to get anywhere fast by randomly checking things, you have to do troubleshooting methodically.

I don't think you will see a bulb light up across the injector terminals, as the pulses are very short. You might also overload the circuit by using a bulb.

It's possible your system is different, but on mine there is a positive feed to one injector terminal (when ignition is on) and the wire to the ECU earths the other terminal to fire it.

So check for +ive on one injector wire with ignition on.

I check my injectors by removing them, reconnecting the wires, and putting them in a transparent container (plastic jam jar) and observing the spray pattern, but I don't know if they are accessible enough to do this on the 16v.
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paulhide · Posted: Mon Nov 25, 2013 10:41 am Post subject:

Thanks for your help, I was hoping someone might let me know if the bulb across the injectors was a bad idea.

Yes I am trying to do things methodically.

Now I think I've narrowed things down wiring diagrams will be the way to go, if I can understand them. (I think things are down to ECU/pump relay/ignition relay/injectors)

Will check plugs for petrol in case it is noticeable and look for a +ve feed on the injector wiring.

Failing that I will put the injectors in jam jars.
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LoneWolf33 · Posted: Mon Nov 25, 2013 11:29 am Post subject:

Hi,

Until you have spark it is quite sure that the the signal from the flywheel sensor is reaches the ECU.

The injectors have ignition activated +12V supply on one terminal, the other terminal is connected to the ECU.

Bulbs less than 5W could be used for testing, but as mentioned the injection pulses simply too short
to get useful results. Actually it would require an oscilloscope.

The operation of the injectors can be tested with the actuator test feature of the Motronic unit.
Connecting the injector valves one-by-one you should hear
continuous audible clicking. If all four injectors produce "clicking" sound,
then it points towards fuel supply.

The injectors can be activated "manually" as well by using crocodile clips on their terminals in order to
apply 12V to them (not for sustained periods).
There's a small "+" mark in the yellow plastic connector neck which identifies the positive feed.
The other is the - terminal.
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paulhide · Posted: Tue Nov 26, 2013 9:58 am Post subject:

Okay, I've studied the wiring diagrams, which hasn't made much difference except for one thing:

I've got wiring going to connectors G133a and b which then go to the INJECTION CONTROL UNIT (S1) This is not the same as the ECU (S11)

My question is does anyone know where this injection control unit is located and what does it look like

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LoneWolf33 · Posted: Tue Nov 26, 2013 10:38 am Post subject:

Hi,

The "injection control unit" referred as S1(-S5) is used in the Jetronic system.
Are you sure that the drawing applies for the Motronic version?
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RFlower · Posted: Tue Nov 26, 2013 10:39 am Post subject:

Sorry, I can't help with information on the Injection Control Unit, but there should be location diagrams for the various components somewhere in the manual.

There might also be a table of electrical circuit checks to make from the ECU or the Injection Control Unit.
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Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

eagle3 · Alfa 33 Joined: 11 Nov 2007 Posts: 402 Location: France

In my french rta CP 090.3 (Haynes manual sort of) there's a wiring diagram for 16V ignition/injection.

From the coil you have one of the two white wires going to connector 1 on G99a and the green and black going to connector 2 on G99a.

The other white wire goes to connector 1 on S11(Central Commande Motronic). This unit has 35 connectors on the plug so I don't think you can confuse it with anything else.

There's fuse holder G4(described as reserve fuse holder - not sure what that means) between the battery and the fuel pump relay. The fuse is rated at 15A. That might have blown if you're hot-wiring the pump.
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paulhide · Posted: Tue Nov 26, 2013 12:57 pm Post subject:

Hi eagle3, yes I am using those wiring diagrams.

Yes the coil is fed by the ECU (S11) with another white wire going to the dash display. Considering I am getting an intermittant indicator display on the dash illuminating for no reason I am wondering whether there is a short with the second white wire.

Reserve (or flying) fuse holder (G4) is next to the relay and fine (though someone has put a 30amp fuse there - was there a previous problem??)

I can't find any explanations on any wiring diagrams of what/where the Injector control unit (S1) is. Difficult to follow wiring through looms, but it looks like it should have a pink and a pink/white wire going to it.
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eagle3 · Alfa 33 Joined: 11 Nov 2007 Posts: 402 Location: France

Never a good idea to overate a fuse. You end up melting wires not designed to carry that amperage..

And shouldn't the two wires(white, green and black) from the coil go to the ignition module? Maybe not directly. I don't know.
B is white(Bianco) and VN is green and black(Verde Negro) er I think.
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paulhide · Posted: Tue Nov 26, 2013 1:50 pm Post subject:

Coil is powered from ECU white wire.

Green/black wire is earth at G99a

2nd white wire goes to G99a (provide signal for rev counter??)

Is G99a part of fuse box?

Totally agree about fuse strengths.
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eagle3 · Alfa 33 Joined: 11 Nov 2007 Posts: 402 Location: France

G99a is described as (in french)

Branchement Tableau Moteur A. Not really sure what that means.

There is also a Branchement Tableau Moteur B, C, D and E.(G99b > G99e)

So just a connector possibly? Don't think it's anything to do with fuse box.
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paulhide · Posted: Tue Nov 26, 2013 7:10 pm Post subject:

Pretty sure they are the connectors into the back of the fuse box.

Should have some time tomorrow afternoon hopefully.

Alex Poulter is sending me spare flywheel sensor, relays and ECU to check and I have found a spare wiring LOOM, so I can replace the whole lot if need be.
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eagle3 · Alfa 33 Joined: 11 Nov 2007 Posts: 402 Location: France

Just one thing. You say the green and black wire from the coil is negative. Are you sure about that? I'm trying to figure it out but I'm not convinced it is at the moment.
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