pa402 0 Posted August 13, 2007 Having been sat for a week or so my 1.9 decided not to start at the weekend. With my limited mechanical knowledge it appears that there is no fuel getting to the spark plugs (they were dry when I removed them). Therefore i'm guessing its an issue with my fuel pump. My questions are: Should you be able to hear the fuel pump when attempting to start the engine? Where's the fuel pump relay located? Is there anything else I should check? Cheers Paul Share this post Link to post Share on other sites
jim21070 2 Posted August 13, 2007 (edited) Hi Paul, The Tachometric Relay (often spelt Tachymetric and known as the tachy relay) is a prime suspect here. It controls the operation of the pump and injectors and only runs the pump when engine rotation is detected. It is all for safety to ensure if you crash the fuel will instantly cut. It is mounted up under the dash on the drivers side near the ECU. It looks like a vastly overgrown normal relay and has a lot of pins. The usual problem with them is dry joints on the PCB inside and often they can be successfully repaired. To test if it is the pump or relay, hot-wire the pump direct to the battery (via a temporary fuse) and see if the pump runs. On first turning on the ignition, I hear my pump run briefly. I believe the tachometric relay incorporates a function to run the pump initially on innition on the prime and pressurise the system. A voltmeter across the fuel pump supply terminals will also confirm what is going on. Edited August 13, 2007 by jim21070 Share this post Link to post Share on other sites
jackherer 543 Posted August 13, 2007 Tachometric Relay (often spelt Tachymetric and known as the tachy relay) I looked into this and 'tachymetric' is correct, like 'tachycardia'. I too used to think 'tachometric' was correct based on 'tachometer' (i.e. rev counter) but its not Share this post Link to post Share on other sites
jim21070 2 Posted August 13, 2007 I looked into this and 'tachymetric' is correct, like 'tachycardia'. I too used to think 'tachometric' was correct based on 'tachometer' (i.e. rev counter) but its not Thanks. I shall now try to erase Tachometric from my mind Share this post Link to post Share on other sites
pa402 0 Posted August 13, 2007 Cheers. Will go investigating later in the week. What do you mean by using a temporary fuse? Would connecting a wire from the battery to the terminal (incorporating a normal fuse - what amp?) be good enough. I really should go buy a volt meter!! Paul Share this post Link to post Share on other sites
Blish10 0 Posted August 13, 2007 Hi Paul Ive got a fuel pump going spare if you need it. For a small fee of course Share this post Link to post Share on other sites
jim21070 2 Posted August 13, 2007 What do you mean by using a temporary fuse? Would connecting a wire from the battery to the terminal (incorporating a normal fuse - what amp?) be good enough. I really should go buy a volt meter!! Paul Sorry Paul What I meant was the temporary wire you use to see if the fuel pump runs should be fused for safety just in case your pump is duff or you accidentially cause a short-circuit. A 10 or 15A fuse will be fine. A multimeter will rather useful for checking things although a little test lamp (a sidelight bulb with a couple of long leads) will do fine as a substitute. I still have a little screwdriver with a bulb inside it and it is a really useful little thing. Not seen them on sale now for donkeys years. Share this post Link to post Share on other sites
pa402 0 Posted August 14, 2007 Think I used to have one of those screwdrivers, no idea where it is now though. Will be interested in the fuel pump if thats where the problem lies. I'll be in touch. Paul Share this post Link to post Share on other sites
pa402 0 Posted August 15, 2007 Ok its not the fuel pump but the relay, which has started working again since I took the casing off. Anyone know where I can get a new one from that doesn't cost £50!! Paul Share this post Link to post Share on other sites
jim205GTI 3 Posted August 15, 2007 I think i might have my old one lying around somewhere, so if i can find it you can have that un as i don't need it anymore . I'll have a look later Share this post Link to post Share on other sites
jim21070 2 Posted August 16, 2007 Ok its not the fuel pump but the relay, which has started working again since I took the casing off. Anyone know where I can get a new one from that doesn't cost £50!! Paul Paul, Open it up and resolder all the joints around the relay. They run quite warm and suffer from dry joints after a few years. Given the cost of a replacement and their rarity in scrappies, it is worth a try. Nothing ventued, nothing gained as it were. You know yours is basically functional so it is worth a go. The cover usually comes off quite easily, often just two clips at the base that can be released with a small screwdriver. Some are sealed at the base with a softish silicone-like compound and these are harder to get into. Share this post Link to post Share on other sites
pa402 0 Posted August 16, 2007 I've had it apart, and looked at the joints and there is one that appears to have parted company with the board. Which could explain, why it has started to work again. But it does look like its been re-soldered before. I'll pop a post up here to see if anyone has a spare as I dont trust this one. Paul Share this post Link to post Share on other sites
jim21070 2 Posted August 16, 2007 I've had it apart, and looked at the joints and there is one that appears to have parted company with the board. Which could explain, why it has started to work again. But it does look like its been re-soldered before. I'll pop a post up here to see if anyone has a spare as I dont trust this one. Paul No worries Paul, just repair the damage with a bit of stiff wire as a bridge across the damaged printed circuit. It'll be as good as new again then Share this post Link to post Share on other sites
