Engine Problem with 3.5EFI Rangie

More than likely, from the sounds of it. Possibly the ecu temp sender throwing a wobbly or a bad connection to it?

Could also be the ignition module on the side of the dizzy, they can do weird things when they get old as they lead a hard life in that hot, vibrating home of theirs!

No s*1t, sherlock! Remember to also factor in replacement of the pump or the carbs'll just flood, and also the fact that the cam is a different profile and simply fitting carbs will result in incorrect fuelling.

Chicken! LOL.

Badger. B.H.Engineering. Rover V8 engine specialists.

OK - just got it home. On starting it up it was running with what felt like a 3-5 cylinder misfire which cleared once the engine got hot, although it was still blasting black smoke while running and was hunting quite a lot when idle.

As a quick test I had my wife rev it up and down the range while I pulled the vacuum tube off the top of the plenum (the advance/retard pipe) and there was a grand total of zippo difference to the running of the engine at any rev range.

It's also got an interesting mechanical clatter from the backend which I thought was exhaust popping until I heard it mixed with a tinny rattling noise.

I see this taking much work.

P.

Hi

I have a similar problem - 1987 RRC Vogue 3.5EFI

Driven 'around town' and on light throttle openings = excellent driving. Fuel consumption = 17.5mph (round-town) - which I thought was generally OK. BUT - on the open road perhaps with a gentle up-incline - push on the accelerator and power falls off - engine 'popping' 'mis-firing' power drops until it is necessary to change down!!!! Then get to back to 'light' throttle openings. Done all the obvious things including spark plugs of 1 higher in heat range. My analysis so far is that on light throttle the vacuum advance is keeping the spark when/where it wants to be. OR some problem with the air-flap thing which causes excess fuel injection. Any hints/clues would be appreciated as I don't believe it taking things apart on a 'just-in-case' basis.

David Christchurch, New Zealand.

Had a similar prob. with my '86 RR a few weeks ago. (Well, if finally died and needed fixing...)

I'd been chasing the problem for months - changed throttle pot, dizzy, temp sensors, etc.) with little improvement.

The culprit? The ECU!, oh yes, that little silver box under the drivers seat.

Have you access to a known 'good' one? - most independant dealers have one squirreled away for diagnostic use. When I replaced mine, the car ran better than it'd ever done!

Cost me £350 for a genuine Lucas re-manufactured one. I've heard some pretty dire stories (from several sources) about having them repaired, so I went with a genuine one.

Hope this helps.

Horse

It also sounds similar to the problem I had with the 101, which turned out to be an inlet manifold leak. What is it like when cold - does the problem get worse as the engine warms up?

Could also be fuel starvation - if you are getting a backfire that would suggest it is running too lean at higher throttle. Possible causes there would be dicky fuel pump, blocked line, blocked filter etc etc.

Agreed. Could also be (lean wise) faulty PCV valve or leaky diaphragm in the brake booster. If you want help/opinion a bit closer to home (Auckland, and get to Chch from time to time) email me (unmunge as per sig) or phone me on (027) 473-2631 during sociable daylight hours.

My first candidate would be the fuel pump/system. This sounds like classic fuel starvation problems. When was the fuel filter last changed ? If you don't have a suitable pressure gauge to measure the fuel rail pressure this can be difficult to diagnose without changing the pump. You could divert the fuel return pipe and see if fuel is still being returned when the engine starts missing. If the fuel return dries up then the pump isn't delivering enough pressure/fuel.

Other than chacking for leaks, check the throttle position sensor ( throttle pot) and the air flow meter output. These are easy to check with a multimeter. If you haven't got a manual that tells you how too carry out the checks let me know and I'll p0ost a description.

On the ignition side, is it throttle position or rpm dependant ? If it's rpm dependant then maybe the mechanical advance weights are seized.

cheers

Dave W.

Had my ECU from the EFi RRC I once owned repaird by the company below, the engine was overfuling all the time, black smoke and running rough, sotty plugs etc. This cured the fault, but can't remember how much they charged.

ECUs are actually very reliable Lucas 4cu sometimes suffer with dry joints more usually a relay or wireing or a sensor is at fault If the ecu plug has been taken off check sockets not bent in socket shroud more stuff on site see below

I think I'll check the ECU connections tomorrow. I'm not going near the insides of one as even though I suspect the 4CU on this thing to be a very crude piece of electronics I also suspect it's very easy to make the condition worse.

P.

Took this rangie to my local Nationwide autocentre who took a look and said "We think it's the air mass sensor, but we can't test it"

Took it to my local Franchised Non Franchise Specialist (go figure - owned by a franchise, staffed by the same guys, doesn't actually have a franchise itself and costs half as much)

They took it to bits, bridged out various sensors under the bonnet which made no difference to the running and suggested it was probably an ECU fault, but they didn't have a good 4CU to test against.

So, I go prodding around to figure out how difficult the ECU would be to replace (not very as it turns out) and accidentally dislodge the multiplug from it. Plug it back in and get in the car.

It's not misfiring. It's not hunting, it's not blowing vast clouds of smoke.

Could it really all have just been a connector fault into the ECU? Would be nice if it was, but I'd have hoped that somebody else would have checked that.

P.