need help with 97 disco
 

hello,
I am looking for any advice from any experienced landrover owners and/or mechanics. my 97 discovery is showing a random misfire in the number 7 cylinder. when the mechanic hooked the computer up it sited "excessive emissions" as the cause. Unfortunately this is all anybody can tell me and three shops have turned me away saying they don't know exactly what is causing this misfire. THe misfire is getting so bad that it will occasionally stal out at stop signs. any advice would be extremely helpful. other than this small headache i love the car.
burton

RE: need help with 97 disco
 

i had a customer with a smiliar issue on a non-rover product. do you happen to know if your vehicle has a mass air flow sensor? it would be somewhere around the air intake box or air cleaner...with some wires going to it..the issue that he was having was that he had a crack in the intake tube between his mass air flow sensor and his throttle body, with means unmetered air was going into the engine, and it happened to be leaning only one cylinder out, and ruining spark plugs, causing a very similar condition.

RE: need help with 97 disco
 

Remove all the spark plug wires from the plugs. Look into the boots and if there is any signs of arcing or corrosion the lead needs to be renewed. Especially check #7.

If all OK then you may have A valve stick issue.

RE: need help with 97 disco
 

Thanks For the Help. I checked around the air intake manifold and found that a rubber hose acting as an oil manifold vent which lead to the air intake manifold was badly cracked and dried. Replaced that and thought to have fixed the problem. It definitly helped but on a 50 mile drive yesterday i still had the same problem. looked for other cracks but could not find any. Any other suggestions?
Thanks again Burton

RE: need help with 97 disco
 

Did you check the plug wires ? A cracked PCV hose will not cause A single cylinder misfire code.

RE: need help with 97 disco
 

bait,
I was looking at past post today and noticed others with my problem and you adviced and fixed one persons problem by suggesting replacing the road speed transducer. do you think this would fix my problem. I know before i said that the computer was reading that only #7 was misfiring but this is coming from a mechanic who supposedly fixed my car two times and may not be completely true. any help would be greatly appreciated.
burton

RE: need help with 97 disco
 

97's were notorious for exhaust valve stick,also check your reluctor wheel and bent or misaligned teeth can do this also.just did a valve job on mine today:)

RE: need help with 97 disco
 

The classic signs of A VSS going bad are odd cylinder misfire codes 1,3,5,7. One or any combination of them. The computer gets A false signal from the sensor at highway speeds saying the vehicle is going 200+ mph. Since GEMS has a speed limiter programed in, it shut off one bank of cylinders. GEMS is bank fire so it Shuts off 1,3,5,7. Another symptom is your speedo jumping around. I doubt A VSS would cause stalling at idle.

How about them their plug wires partner, check'm yet ?

Rovertech,

Did you ream out the ex guides or put in the new style valves and guides ?

RE: need help with 97 disco
 

hey,
The wires were replaced three weeks ago. and the speedo does jump around and has twice stopped working all together. The car didn't stall while idleling but while coming to a stop. If it isn't the vss, and a valve stick problem how intensive is that job. thanks again for all your so far.
burton

RE: need help with 97 disco
 

O.K. another trouble.
I replaced the road speed transducer today and now i can't start the car. It just wines like the starter is not engaging. I tried taping the starter and that didn't help at all. Does anything need to be reset when something like that is changed? any advice is greatly appriciated.
thanks again Burton