TVR Chimaera fuel pump

ged · Post by **ged** » Fri Jun 12, 2009 9:48 am

Hi All,

I'm having an electrical problem with a TVR fuel pump.
The problem started a while ago. When you switch on the ignition the fuel pump runs for a few seconds as is normal but every now & again the fuel pump refuses to start. Initially I changed the relays which cured it for a while but intermittantly the problem recurs. I have found by (with the ignition on) unplugging both relays & then refitting them so that they arc it kick starts the pump into life. I have made sure all electrical connections to the pump are OK. My question is could the pump itself be sticking & by arcing the relay I am creating a power surge which kicks starts the pump? I do have a spare pump which I will fit but I just wanted to know if anyone has experienced a similar problem.

I'd be grateful of any input.

Ged.

ChrisJC · Post by **ChrisJC** » Fri Jun 12, 2009 11:49 am

What engine management system have you got, as it probably controls the fuel pump.

Chris.

ian.stewart · Post by **ian.stewart** » Fri Jun 12, 2009 12:28 pm

when you replaced the relay, what power rating was the relay???

r2d2hp · Post by **r2d2hp** » Fri Jun 12, 2009 12:47 pm

Have you a multimeter, check the feed to the pump in the failed condition. If you see 12v its going to be the pump.

ged · Post by **ged** » Fri Jun 12, 2009 2:23 pm

Hi All,

Thanks for your replies.

Let me state first of all my knowledge of fuel injection systems is nil.

Chris it's got the Hotwire injection system.

Ian the replacement was a 30amp bosch as originally fitted.

r2d2hp Yes I've got a multimeter but I haven't checked for power at the pump. It's played up about half a dozen times in the last 2 years & usually when your in a rush to go somewhere. Next time it happens I'll get Susan to use the van so I can check.

A bit more history on it. The first time it happened I called an auto electrician who was baffled with the problem. After that I managed to talk to a TVR specialist who told me to change the relays as they are a common fault. The thing is you can here the relays working & I've even tried the old ones when it is running ok & they work. Is it possible that it may be an intermittent immobiliser problem? It's got me stumped!

Ged

Ian Anderson · Post by **Ian Anderson** » Fri Jun 12, 2009 3:04 pm

Ged

Check the Black White wire that feeds from coil / dizzy to the air flow meter. If the contacts on this are "iffy" you could be chasing your tail

What should happen is
1) Turn on Ignition
2) Fuel pump will run for 3 seconds to prime system
3) Pump will then stop until the signal that the engine is turning is received (This comes from the wire to air flow meter)
4) The pump should immediately start again as soom as the airflow meter sees the "pulse"

This then means if you crash and rupture pipes etc the pump will stop pumping once engine stops

Ian

ged · Post by **ged** » Fri Jun 12, 2009 3:26 pm

Thanks Ian Anderson,

I'll check that when Susan gets home.

Ged.

r2d2hp · Post by **r2d2hp** » Fri Jun 12, 2009 3:46 pm

Hi Ged,

Another simple option. A length 2 core cable (speaker cable) with a small lamp or led connected one end that you can place in the cockpit. The other end connect across the pump.

You can tell at a glance then if power is getting to the pump from inside the car.

ged · Post by **ged** » Sat Jun 13, 2009 7:57 am

Hi Ian Anderson,

I checked & cleaned the contacts on the B/W wire but after doing so (out of curiosity) I left it disconnected & tried the ignition. The fuel pump still primed so I don't think this is the cause of the problem. But please keep forwarding your ideas.

Hi r2d2hp,

Good idea mate. I'll also add an on/off switch.

Ged.

Ian Anderson · Post by **Ian Anderson** » Sat Jun 13, 2009 10:08 am

Ged

My understanding is it will run for 3 seconds when you switch the ignition on - after that the circuit is turned off.

Once the engine is cranked there are "pulse" to the Ecu via that wire that then turn the relay back on again

So reading your post that is exactly what I would expect it to do.

So then try

Turn it on
Pump primes
Pump stops

Without the BW wire connected and dizzy center wire out crank it over
The pump should not start working again

Reconnect the BW wire and crank again (No Dizzy / coil wire still) and get 3 seconds of pump then it will turn off again.

If that works then I would presume your pump electrics are fine.

They are rotor vane pumps so could something have jammed the pump? Bit of rut from tank etc? But then I would think it would blow the fuse instead.

cheers
Ian

ged · Post by **ged** » Sat Jun 13, 2009 10:49 am

Hi Ian,

Sorry maybe I didn't explain clearly. The problem is when you switch on the ignition, normally as you say you can here the pump prime. When it decides to play up the pump doesn't prime. This happens occasionally. Sometimes it will do it twice in a week & then be ok for three months. It will crank over alright but you know it won't start because no fuel is getting through. If I remove the relays with the ignition on & refit them so that they arc, the pump primes & all is ok until the next time it decides to throw a wobbler. The car only has 23000 on the clock & Susan uses it as her daily runner (about 100 miles a week).

I really appreciate all advice as I find not being able to permanently fix it very frustrating.

Ged.

Ian Anderson · Post by **Ian Anderson** » Sat Jun 13, 2009 3:55 pm

Hi Ged

Where are the relays etc fitted in the Chim?

Could it be that damp is managing to get into the contacts / wiring and upsetting the contact / flow of elastictrickery?

Got me scratching my head now - Probably time for Ramon to come to the party - his knowledge is amazing

Ian

ged · Post by **ged** » Sat Jun 13, 2009 4:39 pm

Hi Ian,

They're in the passenger side footwell above the battery & even after heavy rain there's no sign of water getting in. Good thought anyway.

Ged.

Ian Anderson · Post by **Ian Anderson** » Sat Jun 13, 2009 8:40 pm

Condensation from the Cold Aircon?

Ian

ged · Post by **ged** » Sun Jun 14, 2009 3:49 pm

Hi Ian,

All the plugs look new & shiny but after thinking some more I'm going to recheck the pump earth. That's if she'll leave the car at home for long enough. I don't know why but she would rather drive the Chimaera than my Escort diesel van.

Regards Ged.