A Quickie For Someone

[ccgoose 0]

Well after finding a couple of dead fuses having caused my entire centre console not to get any power, i was a bit confused when i saw this :

 

 

It keeps the fuel pump on permanently......now i'm guessing this would suggest the fuel pump is fooked or there is another issue but for the time being this "quick fix" was implemented.

 

Any thoughts please?

 

Ta

 

H

[gti-si 0]

You sure it keeps it on permanently? The pump is controlled by the relay on the drivers side, or does that bypass it somehow?. That does look like a quick fix for a wiring problem though?

Edited July 5, 2008 by gti-si

[ccgoose 0]

well when i have the ignition on, you can constantly here the fuel pump, obviously until i start the car

[gti-si 0]

That's the fuel pump priming continuously. Mine does this as well, I still haven't located the problem. I couldn't trace a wiring fault and even tried changing pumps with the same effect. Instead of the fuel rail pressurizing it flows straight out of the return, but it runs fine...So from that I have to assume fuel pressure is OK. I think it could be related to the pressure regulator...Or when there is less than a gallon of petrol in the tank?

 

Will confirm when I fill her up (not done it since the conversion)

[t16ryan 1]

Sounds like a tach relay fault, located just near the ECU

[gti-si 0]

Wasn't the case with mine, I'm gti6'd so running a double relay, changed that 3 times and it's still the same. I started the debate a while back about whether the fuel pump feed is cut off by the relay or the pump cut's out when it reaches pressure

 

I'd have to go for the latter, but to check, I think someone with a working prime should set up a multimeter on the pump feed. I'm willing to bet there's still 12v across it when it stops priming

[welshpug 1,675]

sounds more like a fusebox fault, I;ve had to do a similar "fix" as there is a fault internally with the fusebox, where I have power to the fusebox from my Fuel pump relay, but not at the fuse, though the circuit from the fuse to the fuel pump is fine.

 

the pump constantly priming is a separate problem unless its not fed from the Tachy/fuel pump relay, which it looks like it would be the way it has been wired in.

[jonnie205 1]

Yeah i asked teh same question about fuel pump priming and nobody seemed to know whether it cut off at a certain pressure or it a period of time it runs for then stops, the contant priming issue people say is tach relay is often not as replacing the relay makes no difference

[miamistu 1]

Yeah i asked teh same question about fuel pump priming and nobody seemed to know whether it cut off at a certain pressure or it a period of time it runs for then stops, the contant priming issue people say is tach relay is often not as replacing the relay makes no difference

 

I'm pretty sure it's just a short time, rather than a certain pressure. If you measure the plug to the pump without it connected up it will show 12v for a few second then stop.

[gti-si 0]

I'd check but I've only got the one 205 and that primes continuously. I'm gonna go down to my mates later with a multimeter and check it out. I think this question needs to be answered once and for all. I know you've had this before Jonnie, I have and a few others including ccgoose have. I don't think the relay has anything to do with it as like said, when replaced, it makes no difference.

 

I'm going to get a multimeter across the fuel pump feed. If there is still 12v feeding the pump after it's stopped priming, that to me would show that the pump has an internal pressure cut off. That would leave a few possible causes to a constant prime.

 

1. Leak in the fuel system, meaning the system is unable to pressurize

2. Breakdown of the pump itself

3. Problem with the fuel rail, although I'm unsure what that could be, mine flows in through the feed and straight out of the return. I'd need to strip down a rail to see what's going on

 

If however the 12v feed is cutoff when the prime stops, then the problem points to an electrical one such as the relay. It was mentioned on the gti6 that the ECU stops the pump priming, I can't however, see how this would work at all. I just can't see the purpose of a timed prime rather than a pressure rated prime, there'd be no room for anomaly then, such as the pump been run dry and refilled, hence taking alot longer to fill the rail and get rid of any air

[Project205 0]

Ok so I have this same problem (1.6 1991).

 

My car does not have any funny wiring in the fuse box, so my initial thoughts were towards the relay. Checking the pump / replacing the pump would be my second point of call on the basis that it is not making enough pressure. The impeller on the pump could be shot hence the pump continues to prime without ever reaching sufficient pressure.

 

Tell me, do you guys also suffer from a week idle hot and cold? I do.

 

Lets keep this updated, it will be useful for all in future. As has been suggested, could someone with a 'working car', i.e. one that primes then stops priming check the voltage during this cycle at the fuel pump end? This would be most helpful.

[welshpug 1,675]

The impeller on the pump could be shot hence the pump continues to prime without ever reaching sufficient pressure.

 

that would only be the case if there was a pressure sensor in the system, but there isn't one.

[Project205 0]

The voltmeter is coming out to play tonight!

[Project205 0]

Ok so in light of the above, and according to previous posts on this topic, the general concensus is that the fuel pump is on a timed prime cycle. So when I test the voltage of my fuel pump supply plug tonight, I will see a consistant supply, whereas it should be on for just a few seconds. If this is the case, my failure must be down to a broken relay.

 

I shall report my findings.

[Project205 0]

Update on this, the fuel pump is getting supplied with power consistantly whilst the ignition is turned just prior to starting.

 

So anyone got a working relay they want to sell?

Edited August 3, 2008 by Project205

[jonnie205 1]

you will change the relay and it will make no differnence i have seen this problem many times before and it seems its a subject that is not very well known about

[t16ryan 1]

Sounds like a tach relay fault, located just near the ECU

 

Have you not tried a tach relay yet, i have seen this fault a couple of times and both times was the relay,

[welshpug 1,675]

looking at the wiring in the first pic I would check that its been done properly.

 

The fuel pump supply comes in and out on the same 2 wire plug, top right corner of the fusebox, and through Fuse 14 which is the one on the right hand front corner.

[welshpug 1,675]

just looked at the pic again, I can only see 1 wire in that plug (tis obscured a little though)

 

is there an alarm fitted?

[ccgoose 0]

there is an immobiliser fitted yes, looks like there has been others in the past so this could be making matters more complex.....

[Rom 0]

Hmm..

 

Only just seen this topic. Ever since i put my Mi in, my fuel pump runs when the ignition is on too. It doesnt cut off. Ive even wired my stereo to work with no ign as the pump is loud, and nukes the battery

 

Would be nice to know what causes this. Other than a possible faulty tach relay.

The only fault with my car i cant diagnose could maybe related to this.. I hope.. Basically, when the cars hot, and it stalls, (either my bad clutch control in traffic or the rare time it just gets upset and idels funny then stalls) it wont restart. Has to be left for 10 mins or so then its fine. Its only when it stalls, if you turn it off, you can turn it straight back on again.

 

I thought maybe the pump running all the time plays a part, but even if its pumping, the injectors cant fire.. Im at a loss with it really.

[Project205 0]

Miles has kindly sold me a tach relay, so I will try this and report back. It is worth noting that my car has no alarm or immobiliser fitted, it never has had. It is in a secure garage before anyone gets any funny ideas! It will be fitted with security when back in use.

[welshpug 1,675]

there is an immobiliser fitted yes, looks like there has been others in the past so this could be making matters more complex.....

 

 

just checked how your fuel pump is wired in there, it'll be getting power from the wiper circuit not the tachymetric relay, so will be on constant with the ignition.

 

you need to remove that wire and fit a fuse to the slot and see what happens then, it may have been a faulty Tachymetric relay to begin with.

[ccgoose 0]

i put in a fuse and it runs, but drinks petrol something chronic!! Does this point directly at the tachy relay then?

[welshpug 1,675]

that would be an unrelated issue to the wiring IMO!

 

Coolant temp sender or AFM.