Second opinion needed

[muddydigger]

My 97 Disco is running like a bag of carp. Its chugging and has no power on slight inclines. It continues to chug for a little after it levels out. if I put the boot in it still chugs but not a sever as letting it go into a higher gear ( auto).
My first thoughts were fuel filter which I changed and no change, My next thought is coil break down under load.
Any other suggestions before I replace the coil?

[RaginRover]

timing and or vacuum advance ?

Tom

[muddydigger]

still running like poo, changed plugs, leads and coil. Vacume advance seems to be ok.
Runs well untilit sees a hill.
Run well at idel and standing still and revs freely no chugging until it comes back down, slight chug( miss) .

[RaginRover]

still running like poo, changed plugs, leads and coil. Vacume advance seems to be ok.
Runs well untilit sees a hill.
Run well at idel and standing still and revs freely no chugging until it comes back down, slight chug( miss) .

Have you checked the timing and verified that TDC is actually TDC

Tom

[RaginRover]

Sent a Pm but will post it here too for the other blokes to see what they think.

Gday mate,
Righto reading through your reply maybe its the vacume advance. I did try yo suck on it but but by christ its hard, it hardly moves at all. In fact putting pressure on it witha pair of liers its hard to move.
And sucking on it it definatly wont move the plate in the dizzy. As I said it was loose and I tightnd it up. Seeing, as I live on a very dusty road Im thinking aload of sh!t has gotton inside and clogged it up!

Anyays i ll get a new vacume advance unit today and try that.

The timmings never been touched scince I had it.

Im not too comvinced on it either. When i start the car it sits and purrs like a kittten and sits on about 750 rpm. If timming was an issue surley it wouldnt run that well ??

Also when I do drive it it relly wants to go the power is definatly there but somehting is holding her back. when there is no hill it really moves.
But its really drinking the fuel, by the sounds off it beacause it cant advance the engine??

I would think it is the advance, - it should be easy to move with minimal effort - I would swap it out - last time I did they were like $66 exchange, carb'n'gas in Brisbane does mail order takes a deposit until you send the oldie back.

If you think about it - at idle there is no load on the motor - I always had trouble tuning lpg by hand because you can't really get it all sorted at idle. As you accelerate and put load on the vehicle (i.e. a hill) the motor creates vacuum under acceleration and advances the timing to suit - yours does not.

Don't touch the timing - swap out the advance.

Tom

[muddydigger]

New vacume advance unit put in today... No diffrence!!
Any other ideas??
The bloke i bought the unit from said maybe the valves. He recons there is a few in with gummed up valves?

What do you guys recon??

[Marty1]

Can you keep up high revs for a period of time, even with no load,
or does it stave out?
Not getting enough high fuel flow?

[muddydigger]

Revs at 3000 Rpm as long as you want! no change in note, doesnt slack off.
Does start to chug as you increase the revs slowley at about 2000 rpm, but is slight and hardley noticible, but definate when decreasing the revs.
It has enough power to get up slight hills its just when you back off a little its starts chugging and wont recover from It. Over fueling??
I duno a bomb is next.
Timming is spot on.

[LincolnBlack]

Just putting it out there... What about the fuel pump?

If the problem is only going up hills, perhaps the pump can't keep the juice heading up front?

[muddydigger]

Anything is worth ago.
Pulled the fuel pump out seems to deliver good pressure although I cant measure the fuel flow.

Interestingly tough when I disconected the fuel lines , the return line was bone dry but fuel to motro was wet!

May be the fuel isnt getting back and over fueling the line Guessing I dont know..

Any suggestions?

[RaginRover]

you could disconnect both ends and blow it out with air.

How many ks has it done and when was the pump last replaced ?

Tom

[muddydigger]

you could disconnect both ends and blow it out with air.

How many ks has it done and when was the pump last replaced ?

Tom

I did blow them out but no diffrence

Its done 153000 klms.

[RaginRover]

mine needed a fuel pump at nearly exactly 150,000km

But I don't know if that means you should rush out and get one, my symptoms were a lot more fuel pump like

Tom

[DL]

Muddy,

You should have some fuel in the return line, especially at idle. Sounds like the pump (had similar probs with a RRC). Ideally you'd borrow another pump and see if that fixes it.

DL

[RaginRover]

Muddy,

You should have some fuel in the return line, especially at idle. Sounds like the pump (had similar probs with a RRC). Ideally you'd borrow another pump and see if that fixes it.

DL

his pump will be in the tank - lot of pain for a loaner but worth not spending the money especially when he has put all the other stuff in there.

I know the pump I got was $180 (fair few years ago now 3 or 4) and it was the same as a VR commodore from memory with a different connector - I crimped a GM connector on the RR wires and I was away

Tom

[RaginRover]

One thing I meant to say - does the fuel rail regulator have the vacuum hose plugged into the manifold or is it all perished and cracked, and, do the discos have the valve like the p38 on the fuel rail so you can check the fuel pressure ?

Tom

[DL]

Hi,

The mention of problems when going up a hill is carbon copy with the prob I had with mine, which turned out to be the fuel pump.

cheers, DL

[Reddo]

Yup

only probs with Disco Dave were fuel pump and dist advance unit - both at the same time. Same symptoms as described. 380 dollars later, all gooood:)

[muddydigger]

All fixed now.
It was the inlet valves, they had become sticky with carbon deposits.
Fuel pump was tested just before hand to be sure ans was fine.

Appantly this is a common problum with 3.9 discos, especially thoose that are not pushed hard, and driven easy.

The fix, was two bottles of fuel injector cleaner sucked through the vacume advance unit( I think thats where he put it) and reved the ring out of it till it had sucked one bottle dry, the second one he put on then drove it hard and kept it it low gears.
then changed the oil and filter.

good as new!!! maybe better.

So now I definatley got a good excuse to hammer it 4wding

[Scouse]

Good result .

[Reddo]

....oh and yes, that happened to Disco Dave too - oil change to Castrol magnatech and some goooood thrashing, and now all good. Occasional lazy lifter but....

Good outcome for you at least no major cost.

[Philip A]

The problem with 3.9s etc is not inlet valves but exhaust valves coking.
You will be VERY lucky if the cleaner is a long term fix as most of the cleaner burns in the combustion chamber.
The only real fix is to take off the heads and decoke them
It often happens to cars that are babied to much. Loadup a trailer and take it up a range under load.
Regards Philip A

[muddydigger]

The problem with 3.9s etc is not inlet valves but exhaust valves coking.
You will be VERY lucky if the cleaner is a long term fix as most of the cleaner burns in the combustion chamber.
The only real fix is to take off the heads and decoke them
It often happens to cars that are babied to much. Loadup a trailer and take it up a range under load.
Regards Philip A

I will be doing this soon. I have to take My Rover sedan to Bundy fro my father in law to give it a bare metal respray, so it will get a good work out then. Got to put the tow bar on though. had it sitting arround for a while and havent been bothered to fit it

[460cixy]

sounds like the subaru engine cleaner we use. easts the carbon and shit out od subarus there bad for it. use it alot on falcons too

[muddydigger]

I dont beleive it, its doing it again But now its worse. It has all the simtoms as before but now chugs on level roads. still plenty of go there but a rough idel and chugging all the time.

had nealy a week of good driving and its back!

so now ive started stripping the motor down to take the heads off.

Ive got all the tappet covers off and the plenham chamber is off too.

I cant beleive the crap in there. Its full of it. Every thing is black gritty carbon.

Ill get the fuel injectors sonically cleaned whilst I have them off.


Quote
Philip A wrote:
The problem with 3.9s etc is not inlet valves but exhaust valves coking.
You will be VERY lucky if the cleaner is a long term fix as most of the cleaner burns in the combustion chamber.
The only real fix is to take off the heads and decoke them
It often happens to cars that are babied to much. Loadup a trailer and take it up a range under load.
Regards Philip A

End quote


looks like you were on the money!! do you ever get sick off being right

let you know how I go.

[chimpboy]

It often happens to cars that are babied to much.

Time for you to get some dirty marks on that clean driving history I reckon Mr Digger

You could have tried the old "Italian tune-up" before stripping the motor, but I guess it's better to get it right and know you've got it right.

[RangingRover]

You could have tried the old "Italian tune-up" before stripping the motor, but I guess it's better to get it right and know you've got it right.

As I'm fairly sure muddydigger will tell you, having now seen inside his motor, once 'sticky valves' has started to occur, there is NO way you will clean it just by caning it around - the amount of gunk has to be seen to be believed. Just another reason to do very regular oil changes!

Incidentally, usually sticky valves present very similarly to an intake manifold air leak - give it death up a hill, then pull up to idle somewhere and it will hunt like crazy, and be badly down on power. The way to differentiate is to pour water along the sides of the valley, and listen for a change in idle (normally increases by a few hundred rpm). If it does idle up, its more than likely the intake manifold, if not chances are its time to pull the heads off. Obviously you could take your oil cap and/or flame trap off and see how much gunk is down in the rocker cover for some encouragement....

[muddydigger]

You could have tried the old "Italian tune-up" before stripping the motor, but I guess it's better to get it right and know you've got it right.

As I'm fairly sure muddydigger will tell you, having now seen inside his motor, once 'sticky valves' has started to occur, there is NO way you will clean it just by caning it around - the amount of gunk has to be seen to be believed. Just another reason to do very regular oil changes!

Incidentally, usually sticky valves present very similarly to an intake manifold air leak - give it death up a hill, then pull up to idle somewhere and it will hunt like crazy, and be badly down on power. The way to differentiate is to pour water along the sides of the valley, and listen for a change in idle (normally increases by a few hundred rpm). If it does idle up, its more than likely the intake manifold, if not chances are its time to pull the heads off. Obviously you could take your oil cap and/or flame trap off and see how much gunk is down in the rocker cover for some encouragement....

There is absalutly no way this crap will blow off, its backed on crap Im suprised the engine ws running at all.
I ll take a photo tommorow so you see.
Anyways whilst the heads are off I ve decided to have them sent to a performance shop. tey are going to port the heads ( but not polish, they say polishing will loose the touque ) and redo the valves.

He has told me that the carbon build up isnt a result of being babied at all its a result of recirculated gasses from the EGR valve Read- anti polution stuff. Sure giving a hard time will reduce this but by no means is it a cure the only cure is to blank the EGR recirculating the gasses into the engine.

He will be porting the heads fitting slightly bigger valves, machining the surfaceses and supplying a set of extractors to capitalise on the head work $2200.

So Ill take the whole muffler off and take the extractors and remaining muffler bits to my mate to rebuild the muffler with a bigger muffler say about 2 to 2 1/2 inch system.


Ive got a few picturs allready before and will put up the after shots aswell.

[Britswed]

It was a valve problem and you need to buy the modefied valves to fix the problem

Mal

[muddydigger]

So this photo shoud give an idea as to how much sh1t was in the engine