Question-------------------------
Followup To
Question -
John
I am quite impressed with the responses you give on the questions asked, and figured I would have seen the one that seems to bug allot of people (unless it is there and I overlooked it).
Check engine light - misfire on the cylinders.
What can one do to get over this problem?! I bought an OBD II scanner to reset it, but I may as well keep it hooked up! I have purchased: plug wires, top of the line Bosch plugs, have run premuim fuel through it - and still, the code comes off (well, light comes on) rather often, like four times a week often twice a day.
Is there an over ride, or where is this switch located?
PLEASE HELP!
Answer -
Hi Dan!
Thank you for the compliment about my responses. I'm glad when some of my suggestions help other Disco owners avoid paying extremely high service charges.
The Check Engine light (a fearful light indeed) is one that I am most familiar with on my '95 Disco. Resetting the light (disconnect of neg. cable on battery) often confirms if a problem was temporary (?) or serious. In your case, I can imagine that if you have serious misfiring problems, that light must be driving you nuts!
What codes are you trapping with the OBDII reader?
I need to know if your engine is misfiring at idle or thru the entire time it is running. How many miles/kilometers are on your Disco, engine size and is it diesel or petrol?
Simple misfires can be associated with incorrect plug gaps, faulty leads, vacuum leaks, injector problems, valve problems on diesel engines, low compressions, problems with fuel delivery (filter and/or pump) and failing ignition coil.
Get back to me soon and we'll see what we can do. Meanwhile, I'll look around for some data and prepare myself for your detailed response.
Regards,
JohnMc
John -
1997 Disco, SE7, 4.0, gas, 72,000 miles
I have really never felt a misfire or a back fire, that is part of what is throwing me for a loop on what it could be.
OBDII code - P0302 and on up (covers all cylinders misfire) for the 8 cylinders.
AnswerHi Dan,
P0302 : misfire on cyl. 2. hmmm. You say it happens on ALL your cylinders? Here's what I think:
You are going to need to test the fuel pressure. Some owners have complained about misfires and noted fuel line pressures of around 32psi. Should be around 35 to 37 psi.
Its possible that the fuel pump is flaking out on you.
Then have the MAF sensor tested to determine the voltage reading.
Lastly, you may need to have the ECU tested by LR. They can either scope it out for any anomalies OR temporarily swap it out to see if there is a dramatic improvement. Depends on how 'customer oriented' your dealer is. Hopefully, they want to help solve the problem at minimum cost to you.
You might want to check your alternator and battery cables to make sure there is no wiring fault that could be interfering with the ignition. Sometimes a battery cable can affect the wires this way. (just a shot in case you did not think of that already!)
If you are really having misfires, you could run the risk of ruining your catalytic conv. ($1500+) If you can, check your plugs to see what state they are in. Too rich and that unburnt fuel can affect the catalyst and burn it out! At meltdown, it could foul up the exhaust and cause all sorts of nasty problems with the engine. Rare but its happened!
I hope this helps.
Best of luck,
JohnMc
