Subtopic	Posts		Updated
	Major hesitation 95 disco	2		07/26 11:29pm

By cagiva on Saturday, July 21, 2001 - 06:42 am: Edit

We just purchased our first Land Rover (96 Discovery SE7) a month ago and on our first trip it misfired (hesitated) a few times. So I took it to a Rover mechanic to have the engine light reset and have the codes read. He said cyclinder 5 and 7 had misfired. I'm hoping there's an easy fix, but the mechanic said its probably the valves. I guess Land Rover knows of this problem and has redesigned new valves. Well thats great for me... I get to spend an entire weekend tearing down the engine, purchasing new valves$$$, paying for a complete valve job, and then spending another weekend putting it all back together. Have been a long time Landcruiser owner, if it is a bad valve design, I would not be impressed. I could have bought a Dodge... Well enough complaining. Does anyone have any suggestions maybe fuel system, ignition, etc... It has always been my thoughts that sticky valves happen more at lower RPM not at freeway speeds and when they do stick you could hear a noticable ticking. Please Help Other than this recent problem, the truck is pretty cool!!!

By Stephen on Saturday, July 21, 2001 - 06:49 am: Edit

Check if your wires on your spark plugs are seated properly?
Using high octane gas?

By cagiva on Saturday, July 21, 2001 - 06:56 am: Edit

When I purchased the vehicle I installed Bosch Platnuims, is that a no-no with Rover engines. I always thought Bosch was better than Champions.

By Joe on Wednesday, July 25, 2001 - 08:21 am: Edit

Land rover published a technical bulletin regarding carbon buildup on valves and they established a program with dealers to replace the heads on vehicles experiencing the problem. In my case, I was too late and my cylinder sleeve on cylinder #5 slipped down into the block. Needless to say I had to replace the short block and just my luck- I was 1 month out of warranty. My dealer good willed me half of the cost of parts. After all that, I still experienced a problem with the misfire and check engin light - I think we finally got the problem resolved - It was the reluctor ring - It was not reassembled exactly in the right setting causing misfire and check engine light to come on.

By jason mack on Wednesday, July 25, 2001 - 04:23 pm: Edit

Get yourself a vacuum gauge. I use the mityvac hand pump with the gauge built in (30 bucks). Unplug the pcv hose at the intake plenum and hook up the gauge. You should get a steady reading of 15 psi. A sticking valve will cause the vacuum to drop from 15 psi rapidly and repeatedly. As in everytime the cylinder with the sticking valve is on the intake stroke air will be drawn in from the exhaust as well the intake and cause a drop in vacuum at the intake plenum.

By dave on Thursday, July 26, 2001 - 02:49 pm: Edit

The problem most likely is sticking valves and to be sure get a vacuum gauge with a few feet of hose and attach it to the vacuum hose at intake where the fuel pressure regulator vacuum hose goes. Tape the vacuum gauge to windsheild and road test car where you can dublicate fault. If vacuun gauge needle fluctuates its valve

Dave

By pjkbrit on Friday, July 27, 2001 - 06:42 am: Edit

MAYBE valves...may not be...the vacuum test should be with the car under load...most of the older v8s including my 94 with an erratic idle tend to show an erratic vacuum at idle...but under load my motor pulls like a train. (I have a permanent vacuum guage set to the left of the binnacle to help me drive more economically).
For sure you should get a compression test...that will reveal the state of your valves more reliably. Erratic vacuum can be caused by a worn camshaft, erratic ignition timing and/ or timing chain stretch which is also VERY common. I replaced and upgraded to a duplex chain which holds the ig. and valve timing rock steady. Timing chain replacement is a lot cheaper than the valve job and if you are up for it fairly easy DIY.
Pete