fuel pump cutting out

[charliechalk]

As the title says, I seem to be having trouble with the fuel pump seemingly being switched right off and I have no idea why. The car is an st162 with a red top beams, and it has been doing a few strange things since I did the conversion (still working out the small glitches).

So here's what happens, it drives along fine until it just stops the fuel pump sometimes it seems to reconnect, sometimes it just stays dead. Now there is a click that comes from the front left of the car somewhere (or at least this is where it sounds like it comes from). So I have checked the fuse box, all seems to be well, except that the EFI main and Fan relays are extremely hot, could these be shorting out or is this just normal? It does seem that the thermo fans are quite temperamental as to when they want to come on.

Any help is appreciated on this, the current relay/fuse bits are 22amps for the EFI Main and I think I read 15amps for the Fan No.1. Fuel pump is a Walbro 255. Thermo fans are standard (one is the front mount option but was a standard on similar). All other fuses are in tact, no A/C.

[blakeg]

an alarm installed that you are unware of cutting the fuel circuit ?

[charliechalk]

Have an alarm installed, turned that off as well to see if it made any difference, it didn't seem to.

It's not like it happens straight away, it happens whenever, just driving along at 100 on the freeway, and it stops. If you try and start it up again straight away it'll run for about 10-20 seconds then click and engine dies, if you leave it alone and let it cool it'll drive a bit further, which lead me to believe it might be a current or heat issue?

[Chrisso]

Have a look at your Circuit Opening Relay, check that it's grounding properly and that it's two power feeds aren't shorting somewhere.

[StuC]

that clicking you're hearing is the relay switching. Check for shorts to ground (rubbing etc) check continuity and even resistancec in the wiring. Is the fuse blowing at all? The 20+ year old wiring and the high amperage draw of the Walbro could be putting the system under some large loads.

[CrUZida]

Relays that draw a lot of current tend to get quite hot, especially the metallic ones. I know mine usually get to the point where its almost too hot to hold.

22amps for the EFI relay sounds high? From factory isn't it only a 15A fuse?

Carry a spare one with you, and next time it dies swap it with the spare, see if the car starts up again.

[charliechalk]

Thanks for all the help

Unsure what the factory relay for the Beams is (probably should have checked) but I'll search around and try and dig it up.

It is the standard size for the st162 (the efi fuse is 15amps though), but would the system for the beams be putting more total load on the relay?

The celica is back in storage now so I have plenty of time to redo these things, would switching the fuel pump to a direct switch and its own circuit be a good idea? Would much be involved with doing so?

[Hiro]

The celica is back in storage now so I have plenty of time to redo these things, would switching the fuel pump to a direct switch and its own circuit be a good idea? Would much be involved with doing so?

The whole point of the Circuit Opening Relay is so that it starts when the ignition key is turned, but latches on so that it keeps running and stops if the engine dies. If you run a direct switch, you'd want some kind of switch or relay override that stops the pump if the engine dies (especially if it's a track car) or the car rolls over etc.

[CrUZida]

It depends if its supposed to run a fuel pump ecu (a few of the mid 90's onwards engines do, so I wouldn't be surprised if the BEAMS does).

If it runs a fuel pump ecu then it doesn't actually use a circuit opening relay.

[StuC]

cruzida, now that you mention it i that rings a bell. Charlie, check with Huy

[greywolf]

Similar issue with my car once (not a Beams engine, but a 5S-FE). Engine cutout, relay clicking. Never sorted it out, but my guess would also be a bad ground. Perhaps check out the fuel pump for blockages as well ?

[horse]

beams has COR.

smallish one.

[nF.]

checking the grounds is a good idea, but also confirm that you have a good 12V supply to these relays. i had a whole bunch of trouble with relays not getting enough volts to stay on due to some dodgy wiring. the main relays should be in the kick panel on the passenger side.

switch the car to on and throw a multimeter across the pins.

sometimes immobilises can pull down the voltages to relays even when they aren't immobolised. especially, autobarn installs, etc.