Non starting 1.7 - 1971, Djet ..... Options

[Bibble]

Hello all, looking for some help with a 1.7 from 1971, running Djet. Apologies for the length of the post but thought it helpful to give some background and an overview.

The car has been off the road for a couple of years having attention to tin worm in the corners and jacking points. It ran ok if very rich prior to coming off the road so tended to cut out once it was warm as you decelerated but it restarted easily enough

As I started to pull the car together I thought it wise to get things as clean as I could to try and overcome the rich running as above. I have the correct ecu fitted which has been tested and checked as good. I had the injectors tested and cleaned (correct yellow ones) The MPS is a NOS one good vacuum.

When I first tried to restart the car there were some fuel leaks from the pipes around the engine bay, and it seemed like from the pump itself, but crucially for this tale the pump was pushing fuel around the loop in the engine, past all of the injector take off points and back to the tank. I had a spare pump so swapped it with the one in the car. (But have subsequently swapped back) as the spare one once fitted did not pump fuel around the loop, but buzzed away quite happily.

The fuel pump/s pump fine when attached direct to a battery, pressure still a little high at mid 30s.  When attached to the cars wiring both do their 1.5 seconds initial buzz and then stop. When measured, the voltage from the fuel pump plug connector is around 11.80v. When cranking the voltage drops to and fluctuates around 10v. But putting the fuel pump connection back to the pump and cranking it there is no fuel pushing around the loop in the engine, no pressure when tested as against the 30s when direct wired.  Fuel pressure tested at the take off point on the injector rail.

I thought I Ishtar also have a problem with the FI points in the distributor but using a Noid light, I’m getting pulses at all 4 of the white injection connection points. I haven’t taken a jet out to check that fuel is actually coming out as yet. I have checked and am getting a spark at all 4 plugs. 

There is no sense of firing even when direct wiring the fuel pump so fuel is flowing around the loop, the pulses should be kicking fuel out and the spark should be there but no firing. I presume therefore that the fuel pump actually wired to the vehicles system and pumping fuel (and not direct wired to a battery via clamps) is part of the Djet functioning and then getting a fire, otherwise as it it has fuel, it has spark, it has a Fi pulse, nothing has been changed in terms of points position, valve timing etc since it last ran so why wouldn’t it? even a horribly rough cough and splutter would do! 

I have checked the fuses on the relay board swapped out the relays with the headlight ones - seem good with the lights operating fine, cleaned up all of the connections on the relay board, cleaned the FI earths on the engine block but cannot get the fuel flowing. What am I missing! (IMG:style_emoticons/default/confused24.gif)

Would appreciate any thoughts.

Best wishes

Jonathan

[Bibble]

Thanks for the link Rob, presumably the spec of the pump needs to be around the 28- 30 range pressure range?

On swapping the Bosch 3 port pumps out, the original leaking but delivering pump serial number ends in 0011, the non leaking pump 3005. Are they both appropriate for a Djet system for a 1971 car? The 3005 seems to work ok but hasn’t got the oomph to push the fuel round ? Or is it just an internal failure that means it’s dropping its output?

Thanks again

Jonathan

[BeatNavy]

Thanks for the link Rob, presumably the spec of the pump needs to be around the 28- 30 range pressure range?

On swapping the Bosch 3 port pumps out, the original leaking but delivering pump serial number ends in 0011, the non leaking pump 3005. Are they both appropriate for a Djet system for a 1971 car? The 3005 seems to work ok but hasn’t got the oomph to push the fuel round ? Or is it just an internal failure that means it’s dropping its output?

Don't know what's wrong with your existing fuel pumps. Don't see a reference to p/n 0011, but 005 is definitely a Bosch fuel pump for our cars. More info here: https://members.rennlist.com/pbanders/DJetParts.htm

If you go with an aftermarket FI fuel pump they are all going to be rated to at least 3 bar (~45 psi). You definitely need to check / adjust your pressure to D-Jet's happy place of ~28-30. Likely it will still be there but worth checking.