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just fitted EFI and it wont run......... help!


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Posted

Right then, a friend has just spent 2 days removing the carbs etc off my 3.5 V8 and fitting it with EFI.

We have 2 complete EFI kits both bought as good running systems....... basicly it wont run now, and as he has no internet he's sent a txt of the issues.

Fitted EFI.

Turn the key and it will run for a few seconds then stop and wont pick up. Touch the throttle and it will stop. Tried known working air flow meters, ECUs and relays.... no change. Tested for fuel and its there.

The RR has got an EFI fuel pump fitted.

Any ideas where to start please??

Posted

Hotwire or Falpper

Please post up a lengthly blow by blow account of how and what you fitted plus some pucs etc.

Should be something simple, but need to know what you have done exactly :)

Are you sure you have the wiring right, Main powerr (big One) 12v feed when ign on, fuel pump, and then cranking.

If you have the 12V feed on crank live only that could do what your saying above ?

Nige

Posted

What EFI system are we talking here? AFMs suggests probably not Megasquirt (although it can). Hotwire? Flapper? One of the newer LR systems? Another aftermarket system?

I'd hazard a guess from what you've said that we're talking either Hotwire or Flapper Lucas EFI, but even those two are significantly different!

Posted

i will try and get Si online 2moro to say what he has done........ so please check back 2moro.

Posted

Hello gelf,

From your limited description of the system, IF its a flapper - its running on from the fuel supplied by the cold start injector but when cranking stops so the engine stops because the connection from coil negative to pin 1 of ecu via a 6800 ohm trigger resistor is missing.

check the temporary cct digram here

http://www.vintagemodelairplane.com/pages/.../Circuit01.html

more info on the trigger resistor and its function, here:

http://www.vintagemodelairplane.com/pages/.../Trigger01.html

If its NOT a flapper, I'll go directly to jail and not collect 200 quid.

Posted
Right then, a friend has just spent 2 days removing the carbs etc off my 3.5 V8 and fitting it with EFI.

We have 2 complete EFI kits both bought as good running systems....... basicly it wont run now, and as he has no internet he's sent a txt of the issues.

Fitted EFI.

Turn the key and it will run for a few seconds then stop and wont pick up. Touch the throttle and it will stop. Tried known working air flow meters, ECUs and relays.... no change. Tested for fuel and its there.

The RR has got an EFI fuel pump fitted.

Any ideas where to start please??

at the front of the inlet manifold there is two sensors, 1 is thermotime the other thermosumthing else :ph34r: try swaping the plugs around on those, mine did the same and it was that, the one controls the choke so obviously wont start with out it.

hope that helps.

hamish

Posted
at the front of the inlet manifold there is two sensors, 1 is thermotime the other thermosumthing else :ph34r: try swaping the plugs around on those, mine did the same and it was that, the one controls the choke so obviously wont start with out it.

hope that helps.

hamish

Not quite - the thermotime switch (the bigger of the two) controls the 9th injector on the side of the plenum which kicks in for cold starts and sprays fuel over the tops of the intake trumpets, although it should start & run fine without it - mine spent most of its life disconnected before being removed entirely.

Posted

Sounds like classic symptoms of not having the coil feed back to the ECU connected -on Hotwire this comes out of the AFM multiplug and should go to the negative side of the coil -pretty sure it's the same on flapper.

Posted
Not quite - the thermotime switch (the bigger of the two) controls the 9th injector on the side of the plenum which kicks in for cold starts and sprays fuel over the tops of the intake trumpets, although it should start & run fine without it - mine spent most of its life disconnected before being removed entirely.

i was nearly there...worth a go ha.

Posted

At long last I got around to looking at this problem today! & in the rush of getting the job done yes I overlooked the above mentioned connection to the ignition coil! :o

After said wire was connected it started instantly!

Cheers Guys! ;)

Posted

runs really well now.............. only the temp gauge only runs at just under 1/4 on the gauge now, would sit at half way all day when it was on carbs.

dont think there is an air lock, bottom rad hose is cooler than the top one, and the temp sender was swap when the EFI went on.

so should an EFI engine run cooler? i wouldnt have thought so....... :huh:

Posted

Well done!

No reason for it to run cooler TBH, both mine sit just under the halfway mark.

When you say you swapped the senders... you mean you have the sender from the carb setup on the EFI engine now? If so that makes sense, sorry if I am being dim...

One thing, did you change the thermostat when the EFI gubbins were off the engine? Much easier... but probably a bit late now! :(

Posted

Wasn't thinking different, although someone could have had a 74C one in there as opposed to an 88C, I was more thinking that the one currently installed is getting a bit old and slow...

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