Skag 0 Posted July 24, 2020 Hi, new to the forum but always been a VW nut lucky enough to have received a project car for me and my son to work on unfortunately it’s not been on the road for 8 years and stopped running a month ago There is no power feeding to the fuel pump, if I manually put voltage to it it works changed today fuel pump relay and ecu relay and wondering what to do next, any help or guidance would be appreciated as I’m now sticking my in educated head in wiring diagrams. thanks. Quote Share this post Link to post Share on other sites
1xshaunx1 27 Posted July 24, 2020 10 minutes ago, Skag said: Hi, new to the forum but always been a VW nut lucky enough to have received a project car for me and my son to work on unfortunately it’s not been on the road for 8 years and stopped running a month ago There is no power feeding to the fuel pump, if I manually put voltage to it it works changed today fuel pump relay and ecu relay and wondering what to do next, any help or guidance would be appreciated as I’m now sticking my in educated head in wiring diagrams. thanks. Is the relay clicking and supplying power at the fuse box or still dead there. welcome by the way Quote Share this post Link to post Share on other sites
fendervg 33 Posted July 24, 2020 You'll want to check the fuel pump wires to the boot for continuity to make sure the continuity is there, but chances are there is no power coming from the fuel pump relay. This is switched by the ECU when it sees the engine is turning, but it's possible to use a short wire/paper clip or test lead to bridge the fuel pump relay - this would be my first test. The diagram on the side of the realy will show what pins to bridge. The ECU sees the crank sensor and hall sender signals when the starter is run, and then trips the relay. Quote Share this post Link to post Share on other sites
seanl82 23 Posted July 24, 2020 24 minutes ago, fendervg said: You'll want to check the fuel pump wires to the boot for continuity to make sure the continuity is there, but chances are there is no power coming from the fuel pump relay. This is switched by the ECU when it sees the engine is turning, but it's possible to use a short wire/paper clip or test lead to bridge the fuel pump relay - this would be my first test. The diagram on the side of the realy will show what pins to bridge. The ECU sees the crank sensor and hall sender signals when the starter is run, and then trips the relay. Is this correct? The fuel pump relay energises before the engine cranks. Same with the ECU relay. If you remove the fuse box cover, just put your finger on the casing of relays 67 or 167, & 108. You'll feel it ping as it energises so you'll know that power is attempting to be supplied there. Quote Share this post Link to post Share on other sites
fendervg 33 Posted July 24, 2020 7 minutes ago, seanl82 said: Is this correct? The fuel pump relay energises before the engine cranks. Same with the ECU relay. If you remove the fuse box cover, just put your finger on the casing of relays 67 or 167, & 108. You'll feel it ping as it energises so you'll know that power is attempting to be supplied there. Not sure, but that's what I've seen from my testing and observations on my car - the VR6 doesn't prime in the same way as an 8v or 16v, where you can clearly hear the pump running with the ignition on. It's a safety feature anyway, so that when the engine stops turning the fuel is cut - otherwise the fuel would still be flowing with ignition on. I'm open to corrections though, but the signal definitely comes from the ECU, not ignition, so it must be checking for other input before it switches the relay. Another thing to check is any alarm/immobiliser as most of them cut into the starter and fuel pump circuits - so if there is any fitted, this is worth investigating. Quote Share this post Link to post Share on other sites
Skag 0 Posted July 24, 2020 Thank you for the responses and appreciated Would it be worth checking the crankshaft sensor itself, as this would not allow the fuel pump to prime if inoperative? Sorry for silly questions, not a techy chap normally get my kids to help me! Quote Share this post Link to post Share on other sites
fendervg 33 Posted July 24, 2020 (edited) I'd try and jumper the fuel pump relay slot directly first - if it starts like that you know the wiring back to the pump is ok. If it doesn't then look for power to the really and why it's not being triggered. There's a few on here who know this stuff inside out, so hopefully one of them will be along soon to help out.... Edited July 24, 2020 by fendervg Quote Share this post Link to post Share on other sites
Dox 23 Posted July 24, 2020 Faulty crank sensor gives no spark and no fuel injected (dry plugs after cranking). try a different key? 1 Quote Share this post Link to post Share on other sites
Skag 0 Posted July 24, 2020 Thank you for the reply Dox Does the key of a 93 VR have an immobiliser build in, looks like a normal style key ? Okay best place to order a sensor? Quote Share this post Link to post Share on other sites
fendervg 33 Posted July 25, 2020 AFAIK only the later 94/95 cars fitted with a coil pack had a factory immobiliser linked to the key - does your 93 have a distributor? But there may be an after marked one fitted. Crank position sensor you could try VW, TPS, VW Heritage or there are usually plenty on eBay. Quote Share this post Link to post Share on other sites
