Running rich?

[Quiggers]

Hi all,

I have a 93 D1 V8 fuel injected.

Chasing other dramas, I was reading here where, I think tombraider said, the Rover V8 was well known to soot spark plugs.

So my question is: I've occasionally thought my engine was running rich? How do I go about working out if the mixture is correct?

I'm about to put ina new set of plugs as they're sooty and I think two have given up completely, after about 20,000ks.

GQ

[Blknight.aus]

good luck...

you'll need to read the EGO sensor and know its vranges and you'll have to do it while the engines running while the sensors hooked up.. (not impossable tho)

some mech/dyno shops have exhaust gass analisers as part of their setup, run it over one of those.


the 3 common causes in an injected engine (genericly) crook ego sensor, crook maf or equivelent or a pressure regulator thats failed to a higher pressure position.

cheapish to fix when you know what to blame

[Quiggers]

Thanks Dave, you're as always, so helpful!


(Does that come with subtitles????lol)

This issue is obvioulsy not a quick fiddle with a few simple tools? ........

GQ

[shorty943]

No Quiggers, now put the hammer back down.

Shorty.

[Blknight.aus]

Thanks Dave, you're as always, so helpful!


(Does that come with subtitles????lol)

This issue is obvioulsy not a quick fiddle with a few simple tools? ........

GQ

umm yes no maybe...

Im tipping my definition of simple tools is different to yours....

your spark plugs will also give you an indication

[PhilipA]

What about the water temperature sensor.Or a crook themostat.
maybe the "choke" is on.
These to me would be no 1.
Regards Philip A

[Blknight.aus]

nope water temp sender not so much, the air temp sender (part of maf) maybe if the temp sender was shot your temp gauge would be out too...

no choke on EFI.

[Blknight.aus]

from memory (and on tonights preformace forgetting which state sydneys in (apart from wrecked) I wouldnt trust it much) the sensor and sendor for the gauge are one and the same... so a fault on that would also have the temp gauge going nanas....

(I really need to go back and do yr 10 english, grammer and proof reading again)

me thinks I should dig out my old service manual for the disco... but I know where it is and Its packed in the bottom of the bottom box cause I didnt think Id need it again....

[Quiggers]

I'll keep the hammer in the tool box, Dave!

maf = mass air flow meter, yes?

I replaced the plugs at 1600hrs today, very sooty - after about 10000ks on them.

Eight cylinders, all fine, but I reckon it runs rich.....

GQ

[Blknight.aus]

dead serious... had a heap of stuff happen in the begging of my quiet time (phone rang, computers beeped, mobile rang, alex cried someone at door you know the drill) anyway twas a bit much for the connection between the brain and reality and she slipped out of gear for a bit... (more lube should help slow that problem)

The evidence is here http://www.aulro.com/afvb/showthread.php't=34245

anyhow..

yeah MAF=Mass air Flow or for the purpose of this thread the stuff that does the same job as a MAF there being more than one way to skin a cat and all..

Sooty plugs are one of four main causes (assuming by soot you mean a light coating of carbon that is easily removed by wiping)

1. over fuelling (may also be from a blocked air filter)
2. wrong temp for the plug (too cold plug)
3. too long between services
4. prolonged cold idle/excessive idle times/something else causing hunting at idle

1. is hard to square up on an EFI donk without brainy tools
2. is easy (but not cool for prolonged use)on a v8 keep 2 old plugs in(clean them first), replace 2 with one step hotter and 2 with 2 steps hotter the last 2 put 2 of the same type in (use diagonally opposite sides of the engine to eliminate external temp influences) it may run a little funny but after about 500k you will have enough info to tell you what you need to change. whichever plugs came up cleanest are your bet.
3. just needs em changing more often, I used to check mine every service and get say 30-40k from a set of plugs depending on how good the fuel was and how I was driving.
4. is pretty much self explanitory, dont idle it more than you need to, and give it some nice long cruisey runs... Bug one was prone to fouling when SWMBO used it for just running the groceries and movies to and from the shops (70 second drive tops).

There is one adjustment you should be able to do with just a screwdriver and a spanner and thats to adjust the idle port air bleed but this will effect idle as well..

more on that later if changing the plugs doesnt help.

[justinc]

Ah, Lucas 14 CUX, this I know a bit about...


1) Temp WILL upset fuelling, BADLY on these non Lambda controllled versions in Oz.

2)Thermostat must be minimum of 88deg, and must be working quickly.

3)Back to the old throttle pot adjustment again, must read 300mV +/-20mV, as close to 320 as humanly possible at idle, or the ECU thinks the demand for more fuel is there, and increases fuelling via injector pulse width.

4)There must be no vacuum leaks.

5) The cam and valves must be in reasonably serviceable condition.(!)

6)The coolant temp sensor is not the same as the temp guage sender.

7)The fuel temp sender may at fault, but unlikely as its default setting will only make it harder to start in really hot weather, won't effect at any other point.

8)Tune select resistor, located taped to ECU loom with blue two pin plug, must not be open circuited.

9)The ignition timing is retarded? Try running it at 9 deg BTDC.

10) The AFM could indeed be at fault, only easy way is to substitute with a known working example and try it.

Just for interests sake,My money is on the thermostat, and/ or the ignition timing.

JC

[justinc]

Oh, and the worn out cam and valve seats leaking is a close second.

JC

[Pedro_The_Swift]

My D1 takes FOREVER to heat up,,
(compared to the D2)
When my MAF went it would only run properly at full throttle(:D)
and you can imagine how the fuel guage responded

Has it been replaced before Quiggers?

[justinc]

Fit a new thermostat asap Oh Swift one. It may pay for itself in 12 months...
I also found the genuine ones are best, and use a genuine tin /coated gasket. easier to fit.

JC

[Pedro_The_Swift]

Fit a new thermostat asap Oh Swift one. It may pay for itself in 12 months...
I also found the genuine ones are best, and use a genuine tin /coated gasket. easier to fit.

JC
'tis the reason I havent done it---
again.

Hey Scouse! do you do Paypal?:D:D

[PhilipA]

Quiggers,
The sensor which informs the ECU of the engine temp is located on the front drivers side of the manifold, facing upward and has an injection type plug.
Often it is just dirty contacts on the connector which increases the resistance.
The sensor which controls the gauge is located on the front of the manifold next to the thermostat and has one wire.
To check your MAF, you can put a volt meter on the signal wire and rev the engine. If you get a change in voltage it is working OK. The end wire is a reference which is trimmed by the pot on the MAF. It should stay constant. By the way, dirty contacts on the MAF can also affect economy.
I do not think its your MAF.
Ideally a dyno session would tell whether you are actually running rich.
The more technical diagnostic solution is to get a wide band oxy sensor and controller, and see what the mixtures are doing. But they cost $600.
I am currently setting up a narrow band sensor $15 off Ebay, and a jaycar reader about $19.this will tell me if I ever get around 14.7 or over 14:1, as the sensor reads about 1 volt at 14:1 and nil at 15:1, and 0.55 at 14.7:1.
You can also read the oxy sensor just with a multimeter.
The most expensive part will be to get an exhaust place to fit a boss for the sensor.
I do not know what I do then!!! LOL
I have a Unichip , so theoretically it should be possible to tune the ECU to 14.7 on cruise, but who knows. I strongly suspect that when they dyno your car they trim full throttle only and the part throttle settings are left to fall out.
This is my 2007 project, to cheaply improve fuel economy.
Regards Philip A

[Quiggers]

Wow! This all sounds fascinating, think I'm going to print off some of your wonderful notes and go fishing (under the bonnet).

I actually think this motor is in good condition overall (despite the recent oil sludge problem which has now hopefully been sorted).

If I put the foot right into it, I get a cloud of smoke from the exhaust. It is NOT oil smoke (as in worn rings etc) as the smoke is not that colour -

The smoke is a medium flat grey colour and very slightly brown.

However, this Disco does idle for probably far too long - having read what I have above - and it does do lots of short hops - less than 3 kms.

So maybe there are a few reasons already.

Just done a 30 k run and it ran just fine. A nice donk.

The new plugs (put in yesterday) are hotter than the old ones.

Thanks guys!

Cheers, GQ