v8 3.9i 1990 running problems - help!

[Jos]

Hi,

I bought a hybrid which is based on a 1990 v8 3.9i RRC - totally standrd running gear etc with 100" LR body.

When I first used it off road going up and down steep hill I noticed the power would just die off and throttling it seemed to have no effect. This then started happening occasionally on road, especially going up hill. The engine will make popping noises and feel like it's dying and there won't be any power. Taking it out of gear and revving it helps momentarily and then it feels like it's dying off again. It's come on really bad today and I've limped home at 2 miles and hours with it popping and feeling like it's going to stall. It's worse under load and worse under revs. It seems possibly to have been aggravated by having a full tank of fuel.

Could it be something obvious like a fuel pump? I'm very limited in my mechanical knowledge but what should I be looking at before either a - taking it to a garage, or b - setting fire to it?

I have done a search but nanocom etc is a bit beyond me...

Thanks, Jos

[Bowie69]

No need for Nanocom.....

Try these two first:

Flapper EFI diagnostics: http://forums.lr4x4.com/index.php?showtopi...mp;#entry168690

Hotwire EFI diagnostics : http://forums.lr4x4.com/index.php?showtopic=16476

Being a 3.9 you *SHOULD* be on Hotwire, but with hybrids you never know what you are going to find

Run through that and report back

[manxrover]

Hi,

I bought a hybrid which is based on a 1990 v8 3.9i RRC - totally standrd running gear etc with 100" LR body.

When I first used it off road going up and down steep hill I noticed the power would just die off and throttling it seemed to have no effect. This then started happening occasionally on road, especially going up hill. The engine will make popping noises and feel like it's dying and there won't be any power. Taking it out of gear and revving it helps momentarily and then it feels like it's dying off again. It's come on really bad today and I've limped home at 2 miles and hours with it popping and feeling like it's going to stall. It's worse under load and worse under revs. It seems possibly to have been aggravated by having a full tank of fuel.

Could it be something obvious like a fuel pump? I'm very limited in my mechanical knowledge but what should I be looking at before either a - taking it to a garage, or b - setting fire to it?

I have done a search but nanocom etc is a bit beyond me...

Thanks, Jos

Hi

I had the same problem with my Freelander and it turned out to be the fuel

filter, it got worse and worse until it stopped, we found the fuel filter was almost blocked,

only alowing a small amount of fuel through.

Hope this helps.

Brian

[SteveRK]

If its definitely related to going uphill then that points to a fuel restriction at the tank engine of the fuel system - I would start by removing the pump to check its strainer isnt clogged and looking into the tank to see any obvious signs of crud.

[Jos]

Thanks Guys... I'll start with the fuel delivery (it scares me less than the electrics too)

[RangeyRover]

Thanks Guys... I'll start with the fuel delivery (it scares me less than the electrics too)

And I would add that my rangey does that going round corners with a 1/4 full tank, so +1 for fuel starvation

[jules]

Hi

I had the same problem with my Freelander and it turned out to be the fuel

filter, it got worse and worse until it stopped, we found the fuel filter was almost blocked,

only alowing a small amount of fuel through.

Hope this helps.

Brian

I have had the same with a Classic

one a nother thought dose the engine temp have any affect on what ist doing eg is it better when cold or no difrant hot or cold

[Jos]

I have had the same with a Classic

one a nother thought dose the engine temp have any affect on what ist doing eg is it better when cold or no difrant hot or cold

Don't think engine temp is affecting the problem - will investigate fuel filter as a first

[lansalot]

Check all plug leads are connected and connected correctly as well. I had a couple off on my Defender 3.5, and mistakenly put two of them on wrong way round. Vehicle ran, but was lumpy and under load it (of course) missed terribly, throwing some loud bangs and scaring the boy racers behind me.

[Quagmire]

...Defender 3.5... scaring the boy racers behind me.

That's where boy racers always are when you are in a 3.5 Defender

[Teflon]

That's where boy racers always are when you are in a 3.5 Defender

As other comments, fuel starvation would be on my list, but only after looking at the dizzy.

On load and under acceleration 'pops' would suggest loose vacuum hose, and or malfunctioning advance mechanism.... a spring popped off or a bob-weight 'stuck'.

Have you changed the rotor arm lately by any chance?

But, back to the fueling, filter would definitely be worth looking at, as woudl the pump.... BUT..... making me wonder here, as its a hybrid;

I presume its had the rear overhang hacked of the chassis railes, a defender or home made x-member grafted in and a defendert tub dropped on the back.

Now THAT would suggest that the original Rangie Petrol tank went west with the rear overhang, so, first question, where's your petrol tank, and what does it look like?

Hybrids often get home made tanks wherever they can fit, some, get old series or defender underseat tanks; but either way, next problem is the pump.

Original Rangie pump is an 'in-tank' submerged item, that rins in a 'sump' in the tank, that keeps it 'wet', the return line dumping excess fuel back into the sump.

Lots of Hybrid faults end up being traced to the fuel pump, becouse after all the hard work is done, its a detail that tends not to get too much attension, and gets put together with whatever 'seems' to work.....

So, not MANY hybrids use the OE sub-pump; instead they get something from a scrap-yard, or a generic unit from a motorfactors, that then lives outside the tank, and may or may not be coupled in with filter and properly arranged return line.

If the OE pump IS used, though, iften NOT located in a 'sump', and so it isn't kept ;'wet' like it should, and tilting the thing up-hill, or making the back 'dip' from acceleration, can make the petrol run away from the pump.......

so lots of stuff to have a look at there, before we could possibly give any more ideas.

But check the dizzy first, look for loose vacuum hose from plenum to dizzy, and if thats attached & tight, try sucking on the plennum end and see if it 'holds' vaccum.... if you can carry on sucking, then you probably have a crackered dizzy diagphram.

Next, as said is the advance mech; many people forget that EFi's have these, thinking the ignittion is 'mapped' by the engine ECU.... it isn't plain old fasioned 'contactless' distributor system on the pre-GEMS EFI's, but as the advance mechanism is 'hidden' under the sealed hall effect rotor and pick-up that you see when you take dizzy cap off, a lot of people dont realise its there!

AND the springs are very easily dislidged if you pull the shaft up too far removing the rotor arm..... and that can then jam the mechanism or give any nmumber of 'curiouse' ignition faults; hence one of the first places I'd look.

do need to apply a bit of caution though; the hall effect ignition trigger is sealed to detur DIY fiddling, but it can be taken apart and rebuilt, as long as you are careful setting the senor gap when you put it back together.

A job best done with teh dizzy off the car and on the work-bench, to avoid lost little screws and springs and stuff, and easy enough and safe enough to do as long as you dont crank the engine between takling teh dizzy off and re-fitting, and loose your timing!

Oh, also check the obviouse, like the spark plugs themselves, and the leads.... bit of mud splattered about and you can get all-sorts of faults from partial shorts or loose wires!

[Jos]

Teflon,

Thanks for the comprehensive reply. it's full lenght chassis with RRC tank and pump AFAIK but will check this up.

At the minute it's having the coil anf filter changed so will see if either of those regsiter improvement.

[disco_al]

is th epump making any strange, louder than normal noises? just going through a similar problem with my 3.5 disco, no power under load, pops and bangs etc....but runs fine on LPG.

have changed the cap, arm, leads and plugs as well as the fuel filter. when it happened, i had not long traversed a side slope of about 35 deg ish, and only had 1/4 tank of fuel, and the pump is making a louder than it used to noise.

[BobtailBogey]

IT could be your pump itself al if its making a lot louder noise.

[steve_d]

If this is now a custom setup does the tank have clear breathers?

Steve

[FridgeFreezer]

This can also be caused by the alternator not charging or a bad connection or short on the 12v supply. I've seen both and it causes running so bad that you'd be forgiven for thinking a piston was about to escape.

Alternator brushes get clogged with crud, not enough to make the charge light come on but enough to stop it generating enough volts to charge the battery, which will gradually die causing worse and worse running and eventually a bad loss of power, misfires, flames out of the exhaust as the ignition system struggles to work, and finally stopping.

Problems in the supply cause similar symptoms - I've seen one where the main battery wire connection point has been damaged (on some RR's I believe it's a plastic bobbin bolted to the chassis or bulkhead) causing either a short or open circuit, again the interruptions to the power supply cause the ignition system to struggle and leads to misfires, popping and banging, etc. but can also lead to an electrical fire if there is a short on the battery positive anywhere so check carefully!