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eddie_tdi
13th February 2008, 08:15 PM
hi guys, im new to this forum, became a member a couple of hours ago, im looking to buy a December 1994 Landrover Discovery V8i, its cheap, unregistered, however it does come with log books.

There seems to be an idling issue.

it starts no problem, however, the idle is very erratic, and it has no "guts" - even at idle. Its almost as if it is running on 5-6 cylinders or something. I've done a compression test, all within 10kpa of eachother, there doesnt seem to be a vacuum leak, and the firing order is correct, and each spark plug and lead works fine. The engine isnt making any knocking noises, and when you do the (screwdriver against the rocker cover and against the ear trick) it all sounds normal. The oil isnt emulsified (its not grey/milky). The fuel pump does seem to work alright.

Would it be safe to say that perhaps the diaphram on the fuel reg has buggered out and thats why it is running erratically? My understanding is that the fuel pump delivers the pressure, so when i start it lets me, however because it cant buld up enough pressure, the injectors are starving or running lean.

Im new to Landrovers, and EFI's (my daily is a stock carby fed 1982 XE ESP)

Any possible advice will be greatly appreciated

Cheers
Eddie!~

justinc
13th February 2008, 08:53 PM
Eddie, Have you checked the quality of the fuel in the tank? If it is unreg, could it have sat around for ages?

JC

Jezzaol
13th February 2008, 09:03 PM
In most case you will just need to clean out the Throddle Body with carby clean, They seem to build up S#it and they idel very rough almost stalling at lights Etc. Just take off the hose between your Air flow meter and inlet, hold your throdle open with one hand and spray with the other, Put a rag under the pipe so that the Dirty fluid runs into it. You will be amazed at what comes out of there !

Then put it back togeather making sure you have no air leaks between you air box and inlet and start her up, will run rough for a few seconds and then shoudl run smooth once again !

It may be somthing else? but its worth a try, Somone may also be able to advise a better way to do the above ?

Cheers

Jeremy




hi guys, im new to this forum, became a member a couple of hours ago, im looking to buy a December 1994 Landrover Discovery V8i, its cheap, unregistered, however it does come with log books.

There seems to be an idling issue.

it starts no problem, however, the idle is very erratic, and it has no "guts" - even at idle. Its almost as if it is running on 5-6 cylinders or something. I've done a compression test, all within 10kpa of eachother, there doesnt seem to be a vacuum leak, and the firing order is correct, and each spark plug and lead works fine. The engine isnt making any knocking noises, and when you do the (screwdriver against the rocker cover and against the ear trick) it all sounds normal. The oil isnt emulsified (its not grey/milky). The fuel pump does seem to work alright.

Would it be safe to say that perhaps the diaphram on the fuel reg has buggered out and thats why it is running erratically? My understanding is that the fuel pump delivers the pressure, so when i start it lets me, however because it cant buld up enough pressure, the injectors are starving or running lean.

Im new to Landrovers, and EFI's (my daily is a stock carby fed 1982 XE ESP)

Any possible advice will be greatly appreciated

Cheers
Eddie!~

eddie_tdi
13th February 2008, 11:10 PM
well the rego only ran out a week before christmas, so its not too long for fuel to go 'stale' as such, if i take the afm off and spray 'carby cleaner' would that fix it? and if it does, could it wreck the O2 sensor?

matbor
14th February 2008, 08:16 AM
well the rego only ran out a week before christmas, so its not too long for fuel to go 'stale' as such, if i take the afm off and spray 'carby cleaner' would that fix it? and if it does, could it wreck the O2 sensor?

No O2 sensors in S1 Disco's, you can retrofit them though.

Can be MAF/Stepper motor/temp sensors, probably in that order !

Matt.

SPROVER
14th February 2008, 04:19 PM
I had a very similar problem a few weeks ago on my 93 Disco V8.My idle started to play up on petrol and gas.Checked and changed everything and it turned out to be the stepper motor.I took it off which took about 5 min and cleaned it out with WD-40.(its all i had) There was a lot of dirt and gunk which came out of it but after that my idle was perfect.Better then ever:D

eddie_tdi
14th February 2008, 06:47 PM
sorry but what is a stepper motor and where would i find it?

eddie_tdi
14th February 2008, 06:51 PM
its ok i found a pic of a stepper motor when i googled it:
http://www.goldfish.org/~mcooper/disco/mid_fuelreturnandsteppermotor.jpg

but im wondering, can this cause a rough idle and can it cause the engine to not want to even rev up? (ie past 1500-2000 rpm?)

matbor
14th February 2008, 09:02 PM
Trying doing a search in the forum, this topic has been covered alot.

Matt.

eddie_tdi
14th February 2008, 09:11 PM
i realise that this has been covered alot, however, each one i checked out, basically had the problem, but the original person who had the problem never came back and mentioned what the specific solution was, so i didnt have a choice but make this post

AussieLandRover
15th February 2008, 10:16 AM
I took my steeper motor off and sprayed WD40 in it as well as I have noticed my idle was slowly going up and down at lights and really going up and down when I start the engine when it's warm.

Any way sprayed the WD40 and it made the engine hesitate or jitter for awhile but made no improvement.

matbor
15th February 2008, 10:46 AM
I have found in the past that the stepper cleaning only works for so long, best to just replace it if you can afford it :eek:

The other thing that causes bad idle on mine is that the connector on the MAF meter works it's why lose sometimes, and i just have to bend the pins up a little and that seems to fix it for a while. Also make sure the hoses that come off the MAF are tight.

eddie_tdi
15th February 2008, 12:25 PM
would it make it sound like it is running on 6-7 cylinders if the stepper motor is dirty or u/s? and would it hesitate to rev at all?

matbor
15th February 2008, 12:33 PM
would it make it sound like it is running on 6-7 cylinders if the stepper motor is dirty or u/s? and would it hesitate to rev at all?


Not sure of that, sounds more like a sticky valve, but by no means a expert, someone else might time in shortly that knows.... does it disapear after 5-10 minutes ?

eddie_tdi
15th February 2008, 01:11 PM
nah it doesnt disapear at all, unfortunately i cant have a look at the car at the moment as it is at my gf's property in spencer and im back at home in sydney, when i was at spencer during the week, i called up alto landrover and had a chat with the mechanic, i started the car so he could listen to it over the phone, he initially thought it could of been a sticky valve, but sorta started thinking about the fuel system more.

When i turn the car to the "on" position, i can hear the fuel pump start for the 5 or so seconds, then it switches off. i think the fuel regulator is ok because the bleed valve on the fuel rail on the left bank of the injectors has plenty of pressure in it, (the tyre valve looking thing squirted fuel out when i depressed the valve)

i inspected the spark plugs, they didnt look overly fouled or on the other hand they didnt look like they were pitted or coroded etc..

i inspected the oil, i didnt find any emulsified water (grey milky colour)

i even thought that maybe the firing order was all **** about, but that was fine (firing order is in a clockwise direction right?)


when i started the car, i got my gf to look at the colour of the exaust, when it was about to stall, i tried to give it a few pumps to keep it running, and she told me that it looked like black smoke (unburnt fuel)

the condition of the exuast tip doesnt show any oil build up, just a clean looking black carbon.

hmm i dunno....

SPROVER
15th February 2008, 02:40 PM
When i had my problem i went through and changed everything one by one.First i did new leads and plugs,Another air flow meter(good to have a spare anyway),New dizzy cap and rotor,new thermostat,new coolant temp sensor.
I would start by cleaning the stepper motor and then putting on new leads and plugs.Its always good to do these if you dont know how long they have been on there.Then a new dizzy cap and rotor.Best to buy genuine LR ones when you get the dizzy cap and rotor.The cheap ones are crap.(Believe me i found out the hard way).
If the problem still persists it could be your fuel pump.Check the pressure it is getting from the fuel rail.Should be lots of info on here about it.Hope this helps.
Cheers!

AussieLandRover
15th February 2008, 03:14 PM
Just had my problem get worse going across down and then I found out why the spark plug lead was loose and now is all good for me but still when I start the engine warm the rev will go up and down 2 to 3 times and then normal.

SPROVER
15th February 2008, 05:37 PM
Your engine revving a little higher at start up is the stepper motor doing that.

AussieLandRover
15th February 2008, 06:22 PM
Your engine revving a little higher at start up is the stepper motor doing that.

But 2 or 3 times after warm start up ?

LoveMyV8County
16th February 2008, 02:05 AM
(firing order is in a clockwise direction right?)



Yep, clockwise.

AussieLandRover
16th February 2008, 03:42 PM
I rev problem is all gone now I brought a can of Carby & Throttle Body Cleaner removed the electrics of the throttle body removed the 2 large vacum tubes placed a thick large rag under the whole throttle body then gave it a good spray all over in there and let it sit for about 10mins then gave it another good spray in there. I cleaned in there with a clean rag soaked in the cleaner. I put everything back together. It took alittle to start the engine but she kicked over was rough a little but smoothed right out and I took her for a spin.

Now she idles smooth I no longer have the revs jumping up and down after a warm start or the idle slightly going up and down at light's.

:thumbsup:

eddie_tdi
16th February 2008, 04:27 PM
hmmm interesting, did it however want to rev before you put the cleaner before hand? mine doesnt want to rev past 1500-2500 rpm

AussieLandRover
16th February 2008, 07:09 PM
hmmm interesting, did it however want to rev before you put the cleaner before hand? mine doesnt want to rev past 1500-2500 rpm

If your engine doesn't want to rev or rev high enough or stall at lights etc it would be your throttle positioning sensor I had the same problem with my falcon.

eddie_tdi
16th February 2008, 07:45 PM
where is the throttle positioning sensor? would you mind taking a photo of it, and just letting me know what the correct setting is and how to adjust it please, thanks mate

AussieLandRover
16th February 2008, 07:54 PM
where is the throttle positioning sensor? would you mind taking a photo of it, and just letting me know what the correct setting is and how to adjust it please, thanks mate

It's non-adjustable if it's faulty you need to get a new or used one. You will find it very easy if you look at the opening of the throttle body it will be on the outer leftside held on by 2 srews and a wiring connector.

eddie_tdi
20th February 2008, 06:01 PM
hey there guys, i was just speaking with alto land rover on the phone again, they are fairly certain that it sounds like stickly valves.

is this easy to repair? i realise that i would have to take the heads off, and strip the valves and springs off to de coke all of the carbon off, but would that be all i need to do?

AussieLandRover
20th February 2008, 06:44 PM
I take it it's also smoking then.

eddie_tdi
20th February 2008, 08:54 PM
hmm nah its not actually..

eddie_tdi
14th March 2008, 05:12 PM
*bump*

i still have the same problem gentlemen, help please, im desperate :(

eddie_tdi
15th March 2008, 06:35 PM
spent the day working on the disco, my findings:

- the bypass air valve/stepper motor apears to be working fine and wasnt really caked up in carbon etc
- the throttle position sensor apears to be working fine too,

however it does only to be running eratic. (fud-fud-fud-fud-fud) There is a spark at every spark plug, only time it wants to rev is with an aid of carby cleaner sprayed into the maf as i start to accelerate.
I increased the timing a little and then started the car, it apeared to be running much better (still alittle eratic though), so i took it for a test drive. I didnt get it any more than 50 meters, then it started running eratic again



** Does this mean that the MAF sensor is shot? (because in theory this is telling me that the injectors arnt getting enough fuel) - right? ??

if it is the maf, how much would it cost for a second hand 5AM MAF, and would anyone here on this forum have a spare one

thanks
Eddie~!

eddie_tdi
15th March 2008, 06:39 PM
i forgot to mention, it is backfiring alot too, even before i adusted the timing

RonMcGr
15th March 2008, 06:51 PM
i forgot to mention, it is backfiring alot too, even before i adusted the timing

In that case I doubt it is fuel.
I guess you have not changed the spark plugs?

Those things can be totally useless and still look serviceable.

If it were mine, I'd change the plugs and have a really good look at the rest of the ignition system, as the coil could also be faulty.

I have struck this problem before in Ford V8's and two stroke motor bikes. :D

If it were mine, new plugs, new coil and if the problem is still there, run it at night with the bonnet up, put it under load and look for sparks from the plug leads.

RonMcGr
15th March 2008, 06:53 PM
hey there guys, i was just speaking with alto land rover on the phone again, they are fairly certain that it sounds like stickly valves.

is this easy to repair? i realise that i would have to take the heads off, and strip the valves and springs off to de coke all of the carbon off, but would that be all i need to do?

They would :D
If it were true you would hear a hell of a lot of "clacking" from the lifters.

eddie_tdi
15th March 2008, 06:54 PM
yeah, im yet to replace the leads and plugs, i do know however it (at one stage today was running perfect) there is plenty of spark

im just wondering if can a faulty maf cause an eratic behaviour (***AND when you hold the throttle at a patricular position the revs just drop away)

DiscoClax
15th March 2008, 09:04 PM
Have you tried unplugging the MAF while it's running badly to see if anything changes? Ditto for TPS. The engine will run (badly) on either without the other. If the problem changes when you unplug and then plug back in, then at least you know that component is doing something... If nothing changes it indicates that it may be cactus.

Also, try twisting the MAF pins SLIGHTLY and carefully, cleaning the connectors and plug the connector back in ensuring none of the pins back-out. Just doing this fixed similar symptoms in mine. Been faultless ever since :D

Also, if you want to clean the MAF with carby cleaner ensure that you spray into the little hole next to the offset venturi inside. It's that port that does the "sensing" and it need s a good blast to clean it out, preferably whilst giving it a rev. Just spraying generally into the MAF will do bugger all.

Good luck.

eddie_tdi
15th March 2008, 09:52 PM
yeah disconnecting it actually seems to make it run better, as strange as it sounds.. i didnt disconnect the tps, because it seemed to be running right, my mate is a wizz with electronics etc and efi cars, so he was saying that it was working fine. Unfortunately the car is at my gf's property 2 hours from my place so i'll have to wait till i head out that way again before i can investigate some more.

I just bought a brand new Air Mass Flow Meter (5AM MAF like mine) on ebay from the UK for $133.10 (postage is 1included in that price) so lets hope that after that, and a set of new leads and plugs etc, i can start to enjoy the disco rather than scratching my head as to why its running like a demented dog with three legs

lol

ps, is $133.10 a good price for a brand new 5AM MAF meter?

DiscoClax
15th March 2008, 10:10 PM
$133 sounds like a dead-set bargain to me. I'd expect closer to GBP133... or even more. Is it a genuine Lucas item? Where'd you get it from?

eddie_tdi
15th March 2008, 10:17 PM
it was actually GBP$46 (AU$99.62 approx) plus GBP$16 postage, total GPB$62

i think there is one left

ebay item 230232199983 i got it through "goldstar international" which i think has been renamed as GOLDSTAR.DBD34 an ebay store i found

RonMcGr
16th March 2008, 07:51 AM
yeah, im yet to replace the leads and plugs, i do know however it (at one stage today was running perfect) there is plenty of spark

im just wondering if can a faulty maf cause an eratic behaviour (***AND when you hold the throttle at a patricular position the revs just drop away)

Well, replace the plugs today.
If it fixes the problem, you have saved a lot of money.
If not, did deeper.

Generally, I start at the combustion chamber and work back.
Obviously others will disagree, but it is the cheapest and easiest way.

DaveS3
20th March 2008, 07:35 PM
I didn't read the whole thread but my car was idling very badly due to the breathers comming off the Intake manifold.

Insure that both breathers are connected.

Dave.

Bravefart
21st April 2008, 12:14 AM
Hi Eddie,
I'm new here too, although I'm not living in Aus I have an Aussie passport so feel I qualify as a mamber.
I recently had the same problem with my 1994, V8i disco, no low end power and running rough, I found it was a duff injector, changed that and the bottom end power improved dramatically. The advise the others are giving is also valid but sometimes it's the simple things.
Simon

F_U_Z
5th November 2009, 04:10 AM
Hi There,

I have a 1998 D1 that has sticky valves.

I bought the car for a bargain not realising this was the case. The test drive and the mechanic that checked the car didn't pick it up. I only noticed the day I picked it up and drove it down the freeway. It felt like it needed a wheel balance (I could feel the vibrations through the steering wheel!)

The next day I filled up with fuel (ultimate 98) and had the tires balanced. All sorted.

It wasn't till nearly a year later I did a 1400KM trip in it using regular unleaded (after only using U98) that the "problem" resurfaced. At around 80kph the issue would develop until i backed off the throttle or floored it and it would eventually smooth out.

I tried all the things listed in this thread to no avail. Finally I began to suspect sticky valves. I learnt how to drive around the problem by modulating the throttle but eventually decided to seek advice to fix it.

Here's what I found out. The Rover 3.9 doesn't like to be driven like a grandma - especially on regular fuels. You have got to give your engine a good rev under load. MOST IMPORTANTLY, using a fuel such as Ultimate 98 is a cleaner fuel and has a higher level of detergents in it to keep your engine cleaner. I ran Ultimate 98 in the car for a tank of fuel flooring it all the time and it actually to reduced the sticking valve severity. On-going Ultimate 98 usage saw the sticking valves become barely noticable.

I have also read that the synthetic oils possibly contribute more than mineral based oils to the valve carbon deposits. But I am not 100% confirmed on this yet. I use a Mobil Semi Synthetic 10W 40 and it seems to be working well.

So, I have sticky valves but are just waiting till I can be motivated to get the heads off and fix it properly, but have found a work around to get me by in the mean time.

One last thing I also tried which I think made a difference was running a fuel additive called "Valve Saver Fluid" by Flash Lube. It is a lead replacement Upper Cylinder Lubricant. http://www.flashlube.com/en/valvesaverfluid/index.html I used one bottle over several tanks of fuel and it definitely improved the reduction of the sticking valves.

Sorry about the essay, and please comment if I am making no sense :)

F U Z

MacMan
5th November 2009, 06:05 AM
F U Z, that sounds awfully like crossed wires to me.

To me the 80kph wobble would suggest worn steering swivel bearings with insufficient pre-load, not sticky valves.

Also, in general, synthetic oils are LESS likely to cause carbon build up and sludge than mineral oils. I'd be most interested to see what you are reading.

However, proof will be found when the heads come off.

roverv8
5th November 2009, 08:19 AM
I just bought a brand new Air Mass Flow Meter (5AM MAF like mine) on ebay from the UK for $133.10 (postage is 1included in that price) so lets hope that after that, and a set of new leads and plugs etc, i can start to enjoy the disco rather than scratching my head as to why its running like a demented dog with three legs

lol

ps, is $133.10 a good price for a brand new 5AM MAF meter?

I also have a 94 Disco V8 auto
Im very intrested what happens when u fit the new MAF.
I have duel fuel, runs great on LPG and generally ok on petrol.
However, occasionally if i start it on petrol, it doe's exactly as you describe, idle is higher than usual and when you try to rev it wont rev up properly, like you said only to around 1500-2000 rpm
But most of the time it's perfectly normal,
Ive been leaning toward the MAF playing up

F_U_Z
7th November 2009, 02:36 PM
F U Z, that sounds awfully like crossed wires to me.

To me the 80kph wobble would suggest worn steering swivel bearings with insufficient pre-load, not sticky valves.

Also, in general, synthetic oils are LESS likely to cause carbon build up and sludge than mineral oils. I'd be most interested to see what you are reading.

However, proof will be found when the heads come off.

Just to clarify, the engine running poorly with the exhaust valves not seating properly resulted in the engine shaking to the point you could feel it throught the car as a shake and could be mistaken for a poorly balanced front wheel. :)

I'll try track down the article for the oil...

roverspec
8th November 2009, 10:31 PM
Just a quick note to let you know BECARFUL of running Synthetic oil in the V8 motors in the fleet.

I have had a lot of people given the wrong oil up here and it has been fully synthetic.We are in the process of doing H/gaskets on a 04 disco and the heads are that sludge it's not funny and get this the has only done 72501kms. They had been running 0w30 oil not good for those motors but of course fine for the new ones.

The older v8 i found still like the mineral oil as long as you service it regularly and treat them right.

Just another thought on the subject

carla