Problems outta nowhere 04 Disco 2 4.6l

[Sintonics]

My coolant reservoir had a crack in it and my serp belt was looking bad, so I replaced both and also the small 1/4 inch hose from reservoir. Went to crank and was sputtering, then outta nowhere shut off. Serp belt is right. Fanned the gas and got it cleared up so went around the block. It died on me. I fanned the gas and stopped and started it back home. M and S are flashing while hill decent assist stays on plus check engine is always on since o2 sensors were unplugged. I got the codes cleared and the M S LIGHTS are staying off but can't get it to crank and run right at all without fanning gas just to keep it running...

[Les Parker]

And why did you disconnect the O2 Sensors? They could be the source of your problems.

[Sintonics]

No they have been unplugged for well over 2 years. The exhaust is straight pipe no converters and one muffler. Had new coil packs put on in April, with new plugs and plug wires. I've checked most wires around the areas I worked on and no grounding or shorts. All fuses are fine and I have a new mass air flow sensor which I double checked and is properly installed. It seems as tho it's choking when I give it gas, Boggs down, then shuts off, but eventually it will roughly idle. But yesterday I couldn't get it to fire up. Starter works and engine turns over, oils clean. Has 120,000 miles on it.

[Sintonics]

I worked on it again today, wouldn't crank but had raw gas smell, ran OBD and got P0123. Throttle/Pedal Position Sensor/Switch "A" Circuit High Input, multiple misfires -3,4,6,& 8.

[mearstrae]

With the O2 sensors disconnected, how does the computer figure out how much fuel the injectors should be adding? I can't remember right now how it affects the fuel mixture, but it will either go full lean or full rich, either of which isn't good. I've heard of folks adding a resistor to the mass airflow sensor to fool the computer into thinking the O2 sensors were in place. Odd situation.

'99 Disco II
'95 R.R.C. Lwb (Gone...)
'76 Series III Hybrid 109
'70 Rover 3500S

[Sintonics]

I'll check that out, I'm thinking now that there was damage done from the coolant tank cracking and spraying hot coolant everywhere. I'm slowly tracking back from that area. Actually when when changed the exhaust over our gas mileage was much much better. Didn't see any loss of power and I travel 18 hours every year up the coast with maybe three gas stops. Maybe it is confused but I didn't change anything but the coolant tank, a few hoses, and serp belt then this started happening. When I got down the road. Weird.

[mearstrae]

Now that I've looked back over this post, I've decided to think about what happened first, 'Coolant leak from cracked reservoir.' The last time I had a cracked overflow tank it was because the head gasket had blown and over pressurized the system. And.. the resultant blast of coolant can't be good for electrics. Also, the great mileage might be down to the injectors running lean. Good for mileage, but bad for engines when it's too lean.

[Sintonics]

Wouldn't a blown head gasket turn the oil white milky?

[mearstrae]

Not always, it depends on where the gasket blows out. It could blow to the outside air, the oil return (causing cloudy oil), or the cooling jackets. Sometimes they only blow out between combustion chambers.

[Sintonics]

Ok wow, I didn't know that. Are there any visual symptoms to that? Or just motor giving up? I did check my oil, is clean but smells like gas... Idk what that means but I did get it to idle a lil bit ago, with misfires. Cylinder 8,6,&2 this time. Then just like you said over pressurized hose let go and sprayed on the exhaust. So I kinda just want to yank the entire engine out and use it to prop my feet up on when I'm taking ****. I'm very frustrated. And I hate plastic. And I hate all the sensors and electronics. MAF!

[Sintonics]

This is the first modern vehicle I've owned. I've put a lot of time in it to be let down over and over. I always loved land rover and when I finally got this one I fell in love even more. I've taken this baby up hills and across mountains through NC. Thru creeks and rivers. Mud holes. Towed friends and had fun but this motor needs so much attention. I stay in the FL Keys. This is where it keeps giving me trouble. Flat ground and maybe drive 20 miles a week until April when I take it up to NC for a few weeks to have a little fun in it. I had an old cherokee before this that had a bullet proof engine but everything else fell apart. Now I've got a super sensitive engine with everything else being bullet proof.

[mearstrae]

Yes, having had a couple of these over the years, they are a demanding mistress. Maint. costs are a little high to keep them running, but even higher if they aren't looked after. My Range Rover Classic had a blown gasket that pressurized the system, it ran good up until it quit. These new cars have all these electronics that have to be kept working or the whole thing goes up in smoke (or steam in your case). You can't just unhook things like in the old days, everything is there for a reason. I love my '76 Series III 109 (and my Rover 3500S), they have a carb. and four hose on the engine, and I know where they all go. My wiring has six fuses.

[Sintonics]

Well thank you for your help, I'm gonna have a land rover tech look over it but I'm sure you nailed it. Just keeping my fingers crossed. Gonna look for something simple like what you got. Something I can crawl in beside the engine and shut the hood. :) I'll have it fixed and back how it should be. Too much in it to not. Maybe keep it up in the Carolina's for farm and fun. Thx again.

[mearstrae]

I love opening the bonnet on my '70 Rover 3500S or my '76 Series III and seeing the ground all the way around. Good luck with your project.

[Sintonics]

You were correct with the head gasket, I had exhaust leaking into the coolant and over pressurizing the system. I'm tearing parts out and working my way to the head gaskets. Now another question comes to when I start piecing this thing back together. Is it possible to convert to carbs? I'm sure it is but are their parts for this engine to do so? Cause I know it's gonna change the air manifold and where hoses go and a lot of things but is there a kit out there for this 4.6? I looked a jeg's but only saw a ford 4.6 conversion kit. I feel I can benefit better with my set up if I have carbs. I'll lose here and there but I don't care. Oh and I have never seen a more stupid place to mount coil packs... What the hell were they thinking?

[mearstrae]

Both Offenhauser and Edelbrock make 4bbl manifolds for Rover V-8's (they are also listed as being for Buick 215's). I have one of each, and like the Edelbrock better, my '70 3500s (it's a car...) has the Edelbrock and my '76 Series III has the Offy. You'll be in dark territory as far as ignition goes, I don't know what mods might be needed to get things sparking correctly. [Oh, and while I'm thinking about your head gasket, there were problems with the 4.6 with cracked bolt holes in the upper side of the blocks, this caused it to seem like a blown gasket, even after new gaskets were installed (and the heads straightened...). Saw this happen on a friend's '03, solved the problem with industrial block sealer.] Anyway, to put a distributor into a newer 4.6 you'd need the front parts from an older distributor equip't engine, including the cam shaft and possibly the crank, to allow for the older distributor drive system.

[Sintonics]

Ive been online researching like a maniac, a guy told me to look into HEI Distributer, and another said the fuel pump will need to be changed as well. "Stand alone HEI Distributor. While your at it get rid of EGR and pollution pump. Beef up that intake manifold because it needs a new one anyway and gasket match everything." Is exactly what I was told. I will definitely look into those carbs, but basically I would be bailing on all sensors and attempting to simplify the whole damn system. I have problems every 3 months with this thing. Mostly with the electronics. I'll also look for the Cracks you were talking about. I also found oil cooler leak in the little box the hoses run too so that will have to be replaced. Found a lot of parts with yellow dots. Salvaged. I feel like I bought a lemon but I keep finding people with same issues and irritation. Maybe they were all lemons. :) I'm gonna figure this out and turn her into a peach.

[mearstrae]

The present fuel pump is between 35 to 40 psi and a carb only needs between 4 and 6psi. I used a Coil-in-cap distributor on my '95 Range Rover Classic, it came from 'heidizzy' on Ebay, I liked it because the ones for Buicks are shorter overall and cause clearance troubles on the intake manifold and sometimes the water pump housing. The reason the cam, and possibly the crank, need to be changed is that the oil pump drive is different. The older engines had the oil pump drive at the lower side of the distributor drive, and there's no provision on newer motors to put that drive gear on the cam. possibly the best thing to do is find an older 4.6 with a distributor drive and just put on the carb/intake and a Carter fuel pump. Yes, the electronics on these things is usually the biggest trouble. I also just don't understand the use of so many relays, why not just use 30amp switches and better wire?

[Sintonics]

There is just so much in so many places, it's insane! I am down to a few bolts to expose the heads. I'll put up a photo later if it lets me. I am a little worried to what I may find. But the lifters and camshaft look spot on. It was actually beautiful to me to see it all. I'm just trying to make it more simple by attempting this. The computer shuts me down if a fly turd gets swallowed by the air intake. Like I say I want an engine that will run. Not limp around the whole time. Four days after I bought it the check engine light came on and is still on to this day. I've put 10,000 miles on it in 2 1/2 years. It broke down 4 times to where it wouldn't move. Stranded by the comp. I can't take it. But I know it capability. The diff lock is intoxicating. I've never seen anything that big and heavy go str8 up a wet grassy hill and not even leave a mark that it ever went up the hill. I luv it's soul, but it's brain damaged. It's like having a mom that's scared to let you play football. You have all the capability to play but instead your in a soccer field because the ECU is deciding your pushing the motor a little too hard, or uh oh a sensor suddenly went bad somewhere, better stop!

[mearstrae]

The problem with having so many things depending on the ECU, is that changing anything at all is a giant pain. The engine and transmission both depending on sensors. The best would be a carbed engine with a manual transmission. Oh, and I saw that on the 4.6 (and other Bosch engines) the cam is shorter, while the crank is longer. There was a company doing 5.0 land Rover high performance engines with carbs, I can't find the info presently, maybe a web search for Buick/Rover V-8 would bring something useful to light.