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Petronus

1990 1.9 fuel pump

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Petronus

I'm getting no power to the fuel pump on my 1990 1.9 gti. The car was running fine last time a started it about 4 months ago.

The fuse is okay and the fuel pump relay is about 7 years old but the car has done less than 300 miles since it was fitted. You can hear it clicking when the ignition is switched on.

I don't know if it related but i've found a three cable brown connecting block in the engine bay which isn't connected to anything.

It comes from the gearbox very close to the flywheel on the back of the engine/ gearbox and seems to want to head up towards the distributer cap area of the engine. I've got the car up on a lift and can't find where its meant to connect.

I've checked the wiring diagram and several sensors connect to the fuel pump relay so I guess this could be related, or is it just a redundant wire?

Any advice would be welcome.

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Richard309Sri XU5JA 205GTi

I thought that the fuel pump was activated by the tach. relay? And the tach relay is "energised" as soon as the key moves into engine running position(2). 

 

So the pump then comes on when the key is at engine running position(2), and stay on whilst key position is at three(3) - starter motor engaged to start engine. 

 

(I mean that I move key on once(1) and then I can use the radio; then again and that is engine running position(2) I mean. then to start would be the third position(3) which springs back into two,have to hold to keep starter turning. say position 0 is off). 

 

Or have I got that totally wrong? 

I will look up the wiring diagrams in the Haynes and the French Tech manual to check. 

 

If I am right I don't think the brown connector is associated. 

 

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welshpug

it'll be the diagnostic engine speed sensor, not used by the engine management in a car with jetronic.

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petert

Is the car Motronic or Jetronic?

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Petronus

I think it's Jetronic as there is no wire connected to the central position in the plug on the Air Flow Meter

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Richard309Sri XU5JA 205GTi

if its jetronic then I personally think the first thing to check is the tach. relay. 

the pin that feeds the fuel pump number 8 on this picture. otherwise it must be the wiring in between that and the fuel pump. seem to label the fuel pump 112 on this 

 

I think this or similar is shown on the general LE2 jetronic schematics in the Haynes 205 manuals also.   

I think on the phase 1 models the tach relay in the engine bay in phase 2 its under the steering wheel/side 

near the ECU 

 

20210913_200905 - Copy.jpg

Edited by Richard309Sri XU5JA 205GTi

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DamirGTI

Do you have a spark ? does the ignition work ?

 

As for the fuel pump , with an piece of wire bridge fuel pump/tacho relay socket - connect/bridge pin 30 and 87 , that should power up the fuel pump if the wiring is good (12v + ground) , further (if the pump works) if you want to start it up without relay - connect/bridge pin 30 , 87 and 87b .

 

.. also , ignition barrel might be playing up , try to wiggle the key a bit ... oxidized or broken off fuel pump earth (it's at the back , accesses from the boot on the RH side next to the RH light you'll see earthing bock)

 

D

Edited by DamirGTI

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petert

Definitely sounds like Tachymetric relay if Jetronic. Regardless, start tracing wire 76. It goes from the fuel pump, to the fuse, then on to the tachymetric relay.

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Petronus

I bridged the relay and the pump works.

I'll get a new one ordered

Thanks for all your help

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welshpug

worth popping the cover off, could be an easy fix of a broken or dry solder joint, you can tell which area to look for by whether the relay clicks and gives no power or doesn't click at all.

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Richard309Sri XU5JA 205GTi

that's great :) 

 

I just found my old diagnosis socket you were referring to - if any one reads back the thread it looks like 

this picture out the car. I thought it was grey - weird memory loss LoL yeah so in the motronic something like this was included in the whole engine management system 

 

so 'my' diagram photo posted was right - they just turned the picture 90 degrees clockwise 

from the diagram so 76 goes to the fuel pump from what they call pin 8 but it is right. 

sorry 112 is the ignition coil i didn't notice they rotated the picture. 

 

20210914_180933[1].jpg

Edited by Richard309Sri XU5JA 205GTi

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Richard309Sri XU5JA 205GTi
22 hours ago, welshpug said:

worth popping the cover off, could be an easy fix of a broken or dry solder joint, you can tell which area to look for by whether the relay clicks and gives no power or doesn't click at all

yeah for sure - I didn't realise they were 30-50 quid each. 

 

great article on it in the general guides, with the pin numbers etc in detail by @DamirGTI

 

 

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DamirGTI

Indeed , pricey nowadays for the new ones yes ... but there's a lot of 80's/90's cars which had the same type relay , so second hand used is optional too .

I've an Opel/Vauxhall GSI used scrappy picked up relay on my 205 for good +15 years now .. still works . 

 

New ones , there's also some other part No's for the same relay type for other car brands/makes which parts catalogues usually doesn't list directly , obviously cheaper (as/if you don't ask/search for "GTI" item only) .. can't remember now which ones specifically , i did some research about while ago .

 

Easily reparable too as said , if you're handy with soldering iron , handling resistors , diodes etc. everything can be replaced/repaired .. or if happened to know someone who repairs household appliances it'll be easy job for them .

 

D

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SRDT

The relay is indeed very basic inside with big components so you really don't need much soldering skills.

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