Hello All,

I joined the rover family a few weeks ago when I bought a cheap 1999 Disco 2 so I would have a 'work truck' (yes, my wife and I both thought a cheap pickup would be more useful... but the allure of a rover won us both over). Here it is with our dog:




It was definitely an impulse buy and I bought it with what I thought was a cylinder 6 misfire. Turns out there are several misfires and some O2 issues but that's a different post for when I have more time and money. It has so far been slow but reliable. It spews oil all over the driveway and does an embarrassing honk on startup, but it has been a blast so far and has hauled everything we have needed it to.

Currently I'm attempting any cheap/easy fixes that could possibly cure the misfires, as we are remodeling our house and I really can't focus on the rover until after this summer. I have two questions in this post:

1. Is the MAF sensor supposed to look like this? It seems like one of the crucial wires is bent, but I'm not sure what they're supposed to look like.




2. What does this bundle of wires go to?? I have pulled them to the side a bit but when I got the car, they were resting on the exhaust manifold and got melted a bit. The rubber all along one side is gone and I think the copper inside is even a bit toasted.







Any help is appreciated, I have been soaking up tons of knowledge on this forum and can't wait to be able to dive into this rover project. My long term goal is to have it running smooth and do a very light build so I can do plenty of fire road exploration.

 

First, STOP DRIVING WITH A MISFIRE. Misfires are horrible for your truck and will cost you a lot of money in the future when you melt and have to replace your catalytic converters.

Lots of sensors run through that bundle. I would unwrap the bundle and separate the wires one by one. Whichever ones have melted insulation I would black tape over generously and tightly as possible. Then just re-wrap them. Do that with the battery unplugged and leave it unplugged for a day to reset the adaptive values.

Now to the misfire. After you've fixed the bundle of wires (because it's a fire hazard) and reset your adaptive values, try running the truck with the MAF unplugged. If the misfire goes away, MAF is your issue. I don't believe the wire is supposed to be bent like that. If you have to replace it, replace with genuine Bosch. Aftermarket MAFs don't work very well or for very long.

If misfire persists, unplug your O2s. You said there are O2 issues, what are they? Do you have codes you can share? O2 issues can cause misfires, MAF issues can cause misfires, a combination of the two is almost definite to. Again, genuine Bosch O2s. Aftermarket cheapos don't work at all. Trust me, I've tried. Amazon has the best price. If you're in a pinch you can just replace the fronts, the rears don't change hoe the engine runs. They only check to see if the cats are working correctly.

Also be sure to pull your spark plugs and check to see if they're fowled. New spark plugs, wires, and coils are always a good plan. I can conclusively tell you that cheap plugs, wires, and coils will work in a pinch. That said, 8mm Magnecor, STI, or Kingsbourne wires do make a difference. Kingsbourne are cheapest of the bunch. Ebay has the best price on coils, plugs can come from your local parts store. This is not a small job, but not hugely complicated. Just time consuming because you have to remove the upper intake manifold. You can reuse the gasket.

Since you're new, definitely be sure to do the 60k service. These aren't the most reliable vehicles, but as long as you are METICULOUS with your preventative maintenance she will almost definitely never leave you stranded. Unless your crank position sensor goes out, but that's about it. Be sure to use Rotella oil or some other diesel oil because the old school engine needs the extra zddp content.

 

Thanks for the help. I know it's a bad idea to run with a misfire, but I really can't throw a series of $100 parts at it right now. If I kill the cats, I may just have pipe welded in place of the cats (SC has no emissions test). Since I got the truck, I have:

-Replaced plugs and wires (wires are whatever came from Advance, unfortunately I hadn't read through the forums at that point)
-Run Seafoam through almost empty tank of gas
-Run two Seafoam induction cleanings
-Seafoam in crankcase prior to oil change
-Oil change with Rotella 15w-40 and MASSIVE oil filter recommended somewhere on the forums
-Replaced CPS when truck wouldn't start after changing plugs (turned out to be the inertia switch. Hopefully I will at least avoid that problem in the future)
-Swapped upstream o2's. I was getting bank 2 sensor 1 code, now I believe I'm getting both upstream o2 codes, leading me to believe the original bank 2 sensor is bad, and the bank 2 wiring is bad
-Cleaned MAFS and plug and various other plugs including o2's, added dielectric grease
-Got my left headlight working (small victories are needed)

I will wrap up the wires individually and let the system reset, as I haven't done that yet. What is supposed to hold those bundles away from the manifold? They seem awkwardly routed to me.

I'll try unplugging the MAF and driving it. I thought it was more of a 'if it doesn't get worse it's probably the problem'. The truck running better without it would be a nice guaranteed indicator if that was the case.

Codes.... I need to check them again but when I last checked, I had:

-P0300
-P0304, 0306, 0308
-P0130
-P0140
-P0141 (pending)
-P0150
-P0155 (pending)
-P1300

Again, this is after swapping upstream o2's. Prior to swap I was only getting bank 2 as far as upstream o2's go.

On my list for cheap / free fixes right now:
-Double check wire routing is good (I just replaced the wires where they were, they could have been wrong when I bought it)
-Unplug MAF
-Vacuum leak test (cigar test? Need to research)

Truck sometimes shaky in cabin at idle though idle stays steady. SES light flashes from 1K-2,500 RPMs and has extremely low power, but stops flashing and gains what feels like correct power above that range. I'm trying unsuccessfully to put this project on hold as the entire purpose of buying the rover was to get stuff done on the house.

 

Forthe wires, there should be a black tube/bar bolted to the side if the block next to them. They are usually zip tied to that.

The wires you used will be fine, just as long as they're new.

I understand the lack of funds. That's pretty much my perpetual state. You can cut put the cats and put pipe in their place. I'm in VA also without testing and I run without any. You'll just want to get the M18 thread long angled rear O2 spacers so the rear O2s think that the cats are in place and working.

What brand front O2s did you use? I've only ever had that problem when not using Bosch O2s.

 

Also, coils are unlikely to be your problem since the misfires are on cylinders 4, 6, and 8. Those are on different coils. You could reach back and just double check that the plug wires are on the coils tight. I've had that problem before.

Also, important to note that unplugging the MAF is a band aid, not a fix. It will run rich and you will get a definite decrease in gas mileage. Not as compared to driving with misfires, its better than that, but you will notice a drop comparative to the truck running correctly.

 

The plug wires were new, and putting them in was a great intro to life as a rover owner. Thanks for the O2 spacer tip. I knew I needed something but wasn't sure exactly what.

Sorry, my post was confusing. I swapped existing O2's with each other side to side, as I was only getting a code on bank 2. Now I'm getting both O2 bank codes, so I think the bank 2 sensor AND wiring is bad. Not sure where to trace the wiring.

I unplugged the MAF and it seemed like it might have more pickup, but I have been known to feel the placebo effect. SES still flashes.

That was my impression with the coils also. Definitely happy to not replace those.

Is it normal to only have bogging / misfires in that RPM range? Seems like it being ok at idle and higher RPMs rules out fuel flow issues and clogged cats at the very least. Does that point toward or away from MAF or vacuum related issues?

 

Yeah a flashing "check engine" light means pull over, turn the engine off, and stop driving it. You are just running the thing into the dirt man. Wow, that's not cool! There are a half dozen threads just within the last few weeks that are dedicated to misfire issues. About another 500 in the archives of you find the time to do a search. There are just way too many variables to try and give advice but Alex will steer you in the right direction. Please stop driving the truck until you fix it. You don't have to spend a lot of money to sort out a misfire. Check craigslist and Google for your local auto recycler and vehicles being parted-out. I found one 5 miles from my house through Craig's and was able to get whatever parts that I needed for cheap; like under $30 cheap. You just have to shop around for the places that are willing to sell LR parts the same as any domestic auto. They are out there. HMU if you figure out which parts that you need and I will help you out.

Also, FWIW, when buying parts new the old rule applies in that you get what you pay for. LR D2 does not respond well to cheap, slightly incompatible parts. They like quality, OEM/factory, Bosch, higher-end and so forth which is why you may be better off getting old factory parts that may work just long enough until you have the extra cash for a new OEM replacement. There are even a certain few spark plugs and wires that always work well, whereas most will not. So if you were to keep putting cheap, aftermarket parts on it, you would never find the source of the misfire issue. Not saying that's what you are doing but something to keep in mind going forward. Ask questions about brands and so forth if you are unsure.

 

Update to my MAF issues:

I picked up a junkyard MAF (Bosch) this week, and swapped it in two days ago. As stated before, when I unplugged my old MAF and drove around, there was no noticeable change in performance, leading me to believe the old MAF was non-functioning. After I swapped the 'new' MAF in, the truck started driving drastically differently. Sometimes it would have much better power/response at low RPMs (the range it had been bogging previously) but would have zero power at higher RPMs (feels like it 'hits a wall'). Other times it has no power through any RPM range, and others it has great power straight through the range until it shifts and then immediately hits a wall and has no power again.

My hope is that the 'new' MAF is a functioning part and that the decreased performance is due to my adaptive values being whack from having a non-functioning MAF up to this point. Is there any validity to this line of reasoning? How long / many drive cycles does it take for adaptive values to adjust? I can't find much along these lines on the forums. I tried the battery cables taped together overnight trick and it didn't seem to change anything.

 

I like this thread. Congrats on your purchase and project. The MAF sounds like a main culprit but it may have co culprits.

That wire bundle, if loose, gets on or very close to the exhaust manifold. Mine came loose and, after a few seconds melting plastic, grounded to the exhaust and shut me DOWN at 70 mph. Complete darkness (it was night unlit road, construction inches away), no power brakes or steering. I grabbed some zip ties for a roadside fix. There should be a bolt holding the metal heater lines to a position on the alternator bracket right behind the tensioner pulley. If that is in place, zip ties to the heater lines will (as long as the missing plastic insulation is covered up) fix you forever.