Idle/Backfire Problem

[deeb]

so i finally got the oil pressure situation straightened out...

couple more things to address:

1) the truck idles pretty high when in park/neutral (1500-2000 rpm). i have searched all around under the hood looking for any vac leaks, ive even tried spraying some carb cleaner looking for any leaks. i drilled the cap off and tried adjusting the idle control screw also, its tightened all the way- still idling high.

2) when in gear the idle goes down to around 1000 rpm which im happy with, but when the idle is down, i hear a misfire coming from around the passenger side ex manifold, maybe down to the cat.

3) the vehicle is generally sluggish- which im thinking/wondering is a result of the misfire stuff? maybe air/fuel ratio is off?

ive switched the plugs and inspected/sprayed down the wires for any arcing.

im stuck...anything else i should be looking into?

thanks
chad

 

[joey]

Ok, just for a recap, what has been done so far.

 

[deeb]

Ok, just for a recap, what has been done so far.

1) dropped the sump, cleaned lifter
2) changed oil, changed filter
3) ran 1/2 can seafoam through crankcase 1/2 through gas. 1 can through intake.
4) new plugs, sprayed down/tested plug wires
5) cleaned out oil cooler- oil pressure is up to *****!
6) drilled out that little cap/messed w idle screw

as of last night it was idling aroud 1500 when in out of gear...my buddy came over and ran his scanner for codes- it threw 1314 and 1314 (or something like that) both were some sort of misfire codes. cleared the codes and instantly the truck's idle went down to about 1100 and was a bit more responsive.

so its still idling a bit high and running kinda flat.

-also as far as the misfire type sound... im still baffled on that one, its definitely coming from the the passenger side of the engine somewhere in the area of the ex manifold or cat? and when it misfires, i can fell the push with my hand over the tailpipe.

my buddy who works at the local LR shop said it sounded like it could be the flexplate bouncing around? that sound probable to you?

also, is it possible to set the base idle on these guys without using a T4 or some equivalent?

thanks
chad

 

[joey]

First thing I would do is clean the IAC and the TPS as well as the throttle body. Others say not to do this next step, but I would also clean your MAF with a good MAF cleaner follow instructions on the can. Do not do this unless the engine is cold and you haven't turned the key on recently (you don't want the MAF to be hot). Check your air filter to make sure it isn't clogged.

Next to insure you don't have a dirty injector, if you know for sure it is on the passenger side, unplug each injector one at a time to see if the issue gets worse or no change... if worse obviously injector isn't bad, if no change you may have found the issue.

I would also consider a compression test to make sure you haven't got either a valve issue or a slipped liner.

 

[Disco Mike]

Chad, what year and how many miles on your truck?
Don't clean out your MAF if it is a D2, that will **** it.
Have you cleaned the t/body, how about the idle control?
Back fires are more common from timing and or burned exhaust valves.

 

[deeb]

thanks for your help guys...

first off, mike...its a disco I (98) with 107K and yes ive cleaned the throttle body.
i thought that Disco I didnt have an IAC or IACV???

joey...if there is an IAC where is it? how about the TPS? what should i clean them with?
maf cleaner? electronic parts cleaner?
also, for testing the injectors do i just unplug them at the wired/electronic plugs?

thanks
chad

 

[joey]

http://forums.landroverworld.org/showthread.php?t=16547 For location of IAC and TPS

I Would use contact cleaner or MAF cleaner.

Unplug the electrical plug from the injector.

 

[deeb]

dude- sorry if im an idiot, but i only see one part of interest in that link. the black electrical interface that has 2 (look like rivets/bolts) to the intake, its on the front side of the intake.

is that IAC or TPS?

then, the picture below shows the throttle linkage? is there anything i can do with that?

thanks

 

[joey]

The first pic with the red lines around it is the TPS IIRC, under the hose and is the IAC The sit right next to each other... I Could be backward on which is which, but I think I am correct.

 

[Disco Mike]

Deed,
You might want to seriously consider down loading a free copy of a Rave CD, shop manual, so you know what to look for and how to test different items.
Do you currently have any fault codes showing up, if so, what are the 4 digit fault codes. Ifr you have none, the your injectors and most of the other sensors are most likely with specs.