Attessa (?) Pump Always On

[blind_elk]

R32 GTS4, RB25DET, Wolf 3D ECU

Was out and about today, popped into Bunnings for about 15 minutes, came back to the car, starter goes click, click, click. Odd! Back into Bunnings, get a new set of jumper leads, back to the car, alarm doesn't appear to want to de-activate. Gingerly unlock door and open - no siren.

Got a jump from a guy there, started fine, but as soon as the leads are disconnected, engine dies - won't idle, but will run at elevated revs (2k +). Didn't appear to be any more than 12V available, so suspected dead alternator.

Got a mate to bring a battery, car started fine, idled fine, 13.5V.

Got the car home, noticed a pump sound - it sounded like a neighbour had an air compressor going. Disconnected mate's battery - so his wife could have her car back - and the noise stopped. Re-connect battery, noise starts.

I initially thought fuel pump, but on further investigation, I think it's the ATTESSA pump. It's not turning off when the engine is stopped.

Any suggestions how serious this problem is?

[Trex]

Have you been kicking around the footwell at all? There is a single wire connector that runs the pump if it is disconnected. Can't remember if it's yellow and black or not.

[dr phil]

Attesa pump motor relay switches power directly from the battery, so if that relay was stuck on, the ATTESA pump would operate continuously. I'd start by checking that relay, it is in the engine bay, driver side, close to firewall.

[dr phil]

Oh - well that is the location in an R34 anyway, may need to check an R32 manual for location.

[blind_elk]

Not been playing anywhere near the inside of the footwell.

Tried all 3 green relays, no difference.

[blind_elk]

I pulled the fuse, and no longer get the ATTESSA pump activating.

[blind_elk]

Well, that's weird.

Pulled both fuses, connected battery, started car. Both ABS and AWD warning lights. Replaced the underdash fuse, ABS warning light off, got code 19 (whatever that is) at the ATTESSA computer. Replaced the fuse / relay under the bonnet, then stopped the engine. No pump sound!

Restarted the engine, all warning lights off. Stopped engine, no pump sound!

Someone please tell wtf is going on.

[GTSBoy]

Quiet likely that vintage cars such as ours are starting to reach the lifetime limits of electronic components (like electrolytic capacitors) in these control modules. The HICAS CUs have been famously doing odd things for years now. Maybe there is something dying in your ATESSA computer. Giving it a rest might have allowed something to switch off that was being held on by a misbehaving component. Maybe it will stay good now. Maybe it will shit itself again in a few days. Maybe it takes a particular trigger to make it happen and maybe you'll never do that again. Who the f**k knows?

Edited April 6, 2016 by GTSBoy

[jiffo]

I don't see the problem as an electronic one, more likely hydraulic.

If all the hydraulics were working correctly AND the pump stayed on continuously, the relief valve would be screaming, you'd really hear that.

So to me some chunder got stuck under a valve and the pump just kept on pumping, unable to reach cut off pressure.

By giving it a rest, I guess the piece of chunder has either gone further down the pipework/pump or has settled back in the inlet waiting to do this again.

Time will tell.

[blind_elk]

jiffo, it kept on pumping even after the key was removed from the ignition.

The other weird thing was that until immediately before starting the engine, the pump wanted to run when the battery was connected and both fuses in place. Then it all worked fine after starting then stopping the engine.

[jiffo]

Yes the IGN bit is certainly odd.

But if memory serves me these things have a constant 12V feed as well as the IGN for switching.

Will have to dig out the woeful wiring diagrams or perhaps just wait to see if she stays OK.

[blind_elk]

Well, went out last night, got to the destination, stopped engine - bloody pump is still running!!!

Where is the relay that controls the pump? Maybe its faulty - after all, it is over 25 years old.

[Duncan]

its got to be a sticky relay. the attessa ones are both in the boot between the tail lights on the left of the lock

[blind_elk]

Thanks Duncan.

So, I located the relay(s), removed them, hit them with a bigger hammer, left them out of the car for a while, refitted them ....

And haven't had a problem since

[kingtube69]

Thanks Duncan.

So, I located the relay(s), removed them, hit them with a bigger hammer, left them out of the car for a while, refitted them ....

And haven't had a problem since

It might be worth changing them altogether. Relays play up sometimes and they are relatively inexpensive to swap out