The V8 Owners Forum -

Well I am replacing my worn out carb V8 with an efi unit, the only question I need an answer to is can the flow meter be mounted at any angle? I have repositoned mine and its at 90 degrees to the original way. Its the flapper type as it has a flapper type arrangement in it, I guess thats why its called flapper then?

Should be fine.

Chris.

Super thanks Chris.

Okay all is and running BUT, she starts great and tickover seems ok, a bit lumpy maybe, but when its warmed up and you blip the throttle it almost dies and back fires a bit or down into the sxhaust.

Does this sound like a dodgy water temp sender? I seem to have two on the inlet manifold, or could it be something worse?

When I tested the engine dry to see if she stated after putting in the wiring it seemed to be fine revved really well. but this was only done for about 30 seconds as there was no coolant in.

mikeinatruck wrote:---- starts great and tickover seems ok, a bit lumpy maybe, but when its warmed up and you blip the throttle it almost dies and back fires a bit or down into the sxhaust.

Hello Mike,

Choice of two mixture control problems, running rich or running lean.

Could be the temp sensor failed or with open circuit connections creating a too rich mixture, but:

Because of the backfiring as you describe it, its more likely to be an uncontrollable weak mixture as a result of a rogue air leaks into the plenum chamber.

You can read all about temp sensor and plenum air leak detection from the essays in the following index:

http://www.vintagemodelairplane.com/pag ... nts01.html

There are several other possibilities, but best to go with the usual suspects first.

Pulled the ram base and plenum chamber today cleaned up all faces and refitted, but still no joy, strangely its worse than yesterday? I think its very rich so much so cylinders 2 and 4 are wahing out and not firing, confirmed spark and compression.

I have noticedthat when I first started it up you could hear the fuel pump go under loadonce pressure was up but not now..... If the fuel pressure reg is duff the way I understand the system it would over fuel.

The engine was stood in a RRC for a year in a garden so I would not be suprised to see things failing now its running.

I have checked continuity through the loom to the water temp sender and checked millivoltage on the potentiometer, all appears good.

Its the first time I have really played with efi bit of disel specialist myself, at a bit of a loss now.....

What you need is the proper Land Rover EFi diagnostics manual. I have scanned it in, but it's huge. I'll see if I can do something with it.

Chris.

Chris I have sent you a PM

UPDATE:
Stuck a pressure gauge on it today using the cold start pipe off the rail, at ignition on my gauge shows mid 35ppsi (have to use a compression gauge but thescale reads ok) on start up the pressure never goes below 32 at tickover. I am thinking the regulator has failed so I am ordering another from my local landy spares for 40 quid, wont do any harm anyway.

Q. Underneath my regulator is a grey plastic device with two wires coming out of it, can anyone tell me what that is?

That pressure sounds OK. It should vary with manifold vacuum.

The grey thing with two wires & a pipe going to the back of the plenum is the overrun shutoff valve. It shuts off the coil -ve into the ECU under overrun conditions, thus saving fuel. The two wires can be connected together and the unit bypassed if it's faulty, but if it were faulty, the engine simply wouldn't run.

Chris.

Hello Mike - a few observations.

mikeinatruck wrote:Pulled the ram base and plenum chamber today cleaned up all faces and refitted, but still no joy, strangely its worse than yesterday? I think its very rich so much so cylinders 2 and 4 are washing out and not firing, confirmed spark and compression.

If two cylinders are washing out that would indicate that the two respective injectors are weeping or even stuck open. Obviously its running, albeit only just, on six pots, so what is the state of the other spark plugs? Sooty, Wet, Dry? That will give vital clues as to how the rest of the Efi system is performing.

mikeinatruck wrote:I have noticedthat when I first started it up you could hear the fuel pump go under loadonce pressure was up but not now

That change in behaviour would indicate that there is an open injector or return line, so whilst the pressure remains up there is a continuous flow going somewhere so the pump shows no sign of being loaded.

mikeinatruck wrote:If the fuel pressure reg is duff the way I understand the system it would over fuel.

Not necessarily, it would depend upon the failure mode. If stuck shut, then yes, if stuck open, then no.

The clues thus far do not seem to point initially to a duff regulator. Look for the other things mentioned first.

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Moving on, the cause of such behaviour could indicate a couple of issues.

# the injectors are simply gummed up and need a good clean. Injector cleaner in the fuel might do the job, but pulling the injectors for cleaning/service wont go amiss. Read about that in my injector essay.

# Crud in the fuel has somehow reached the pintles indicating breached fuel filter and injector basket filters. Possible but not common, unless sometime previously injectors (sans filter baskets) have been fitted.

Fuel tank crud is very common these days (possibly due to fuel additives intended to keep engines clean, actually stripping crud from ancient fuel tanks also) so you may have to purge the whole fuel supply system.

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Finally, because your transplant has been sitting around a while you will almost certainly be looking at further problems as time passes.

For the record, the majority of routine Rover Efi system faults are due to rogue air leaks followed closely by wiring/connector problems.

Next on the list is filth and crud contaminating fuel flow components, the breather system, idle air galleries and throttle plate.

After that you are into component failure.

Not surprising, because contrary to popular belief, nearly all the Rover Efi system components are pretty bulletproof with perhaps two exceptions.

The throttle pot and the coolant temperature sensor, both of which will cause overfuelling in their common failure modes..

The other plugs where all a bit sooty, not really bad but as though it had been on choke or a long time, stuck open injectors thats a good train of thought, did not think they could stick open, if I unplug them and run it a bit they should dry out unless the injectors are stuck open?

I know that as its been standing other things will crop up from time to time but I expect that. As for cud in the tank I know thats clean as it was cleaned not long back and I did double check prior to instlling the pump.

What sort of money are injectors? If they do prove to be stuck I may well just change the lot for peace of mind.

Thanks for your advice its appreciated, I'm a two stroke diesel man normally LOL

There is a cleaning service offered on e-bay.


http://cgi.ebay.co.uk/ULTRASONIC-FUEL-I ... 240%3A1318


Kevin.

Fitted a new fuel pressure regulator today, I can now here the fuel pump load up almost to the point you think its going to stall, but she still runs pants if at all, missing and very rich. I stripped out the injectors to check for leakage and blew them out with an ai line, still no joy.

I have ordered a new dizzy for 83 quid www.simonbbc.com i am changing that as when I got the engine I pulled the rotor arm off and the top half of the dizy fell to bits so I had to rebuild it. basically its a change it and see scenario now.

I need to check resistance through the injectors via the loom next.

Oh well fingers crossed.

mikeinatruck wrote:Fitted a new fuel pressure regulator today, I can now here the fuel pump load up almost to the point you think its going to stall, but she still runs pants if at all, missing and very rich.

Check the fuel pressure again, it must not exceed 36 psi and not below 26 psi.

If the pressure is very high that would indicate a blocked return line thus result in overfuelling.

Otherwise, running rich for sure, means you should soon be getting down to electrical component testing as suggested.

mikeinatruck wrote:I stripped out the injectors to check for leakage and blew them out with an air line, still no joy

Did you energise the injectors with a 3 volt supply to allow any crud to be blown through?

New dizzy arrived today from www.simonbbc.com but made no difference arg!. four cylinders are not firing, I have resistance checked all the injectors 8.5 ohms and checked throttle potentimeter, going to check air flow meter now, i am starting to think something has broke electronically and is causing a massive overfuel, as the four cylinders not firing where washed out.

On the pside when I put this engine in I was very vague about how it all worked, learning lots now though. LOL

update:
Well at a last gasp I changed the spark plugs and it runs now, it looks like the wrong plugs may have been in the engine somehow, I now have a set of resistor plugs in and thats made a big difference.

I have now got the emmisions down to 2% CO.

Still some tweaking to do as its not happy getting the throttle blipped.

Mu book says timing should be 5-7 degrees BTDC that sound about right?