too rich! (unlike me)

[masterb]

Help required please,
My newly acquired 1987(D) 3.6 manual, is running a bit rough, and i suspect a bit if not a lot rich.
I have ran the car without an air filter, and this seems to make the engine run a bit more Happilly.
But this is of course just for test reasons,as i dont want to run around without a filter permenantly.
recent new plugs, distributor and rotor are like new, and recent new oil and filter, plus air filter is new, but not a K&m which i am toying with fitting although not happy with the cost of those.
Have been told and suspect myself that the vacuum advance on the side of the distributor could be the culprit/cause?
Main symptoms are a crap start up and idle from cold, and a bit of stuttering and pinking at low revs. When revs are higher the engine is happy and certainly goes.
But at low revs for gear, the car runs poorly.
any other tune ups or tips would be appreciated.
Thanks in advance,
Paul B.

[poprivet]

http://www.jagweb.com/aj6eng/richness.php
Pop

[masterb]

Thanks for the quick reply Pop.
However , I had already read this on the AJ6 site.
The problem being, is that I am a beginner with Jags and also only a learner Spanner jockey.
So possibly yourself or someone can clear these point up for me , taken off the AJ6 site.

(at the rear of the manifold plenum)???? Come again?

The idle speed and mixture will now need to be readjusted . Ok can prob handle that but How and where?

Haven,t received my workshop manuals yet so that doesn't help.
I have the Kirby Palm stuff but this seems to be mostly for the V12's?
Thanks again.
PaulB.

[poprivet]

First step I suppose is to eliminate the distributor/vacuum advance as causing the problem but there seems to be little information on these early 3.6's and parts may prove difficult as well.
Even Jaguar gave up on that particular system going to the microfuelling in Feb '87 which solved many of the ignition problems.

Once everything is found to be mechanically correct, an enhanced ECU should transform the car and give an easier way to make any adjustments needed.
Pop

[masterb]

Thanks for tips again.
Tried a few things yesterday,
Checked the vacuum advance on dissy, diaphram seems ok , checked air line/pipe to and from dissy to throtle body.
This proved be ok, bot the small metal push on part at throttle body was ,loose +not sealed so sorted that.
Checked and adjusted butterfly,positioning/ rest point and did a slightly naughty mod/adjustment by bending the throttle stop, so that the butterfly opens fully.
Checked the (full throttle??) vacuum micro switch? dont know the proper name for this, but the one i meen sits on top off the manifold is white in colour and has 2 wires coming out of it from a micro switch.
This seems ok too, going from either a short or too open circuit , depending on whether a vacuum is applied.
Not sure again what the correct term for this part is, but it appears to be some type of choke, but for air?? at the front of the manifold(possibly seated on the M.A.F) found this was sticking , which was causing to high idle speeds, and hopefully the reason for my poor cold starts.
Not had chance to fire her up from cold yet this morning, so dont know if that is cured.
Still runs like a asthmatic on a marathon though, appears to be that when you give the accelerator a bit more push/go the engine splutters.
New theory is that the car is not getting enough fuel when, you try to accelerate.
So going to try a new fuel filter today, and failing that possibly a new fuel pump?
P.s exactly how much vacuum/pull is generated from manifold or throttle body? and if diaphram on dissy is ok? how much advance should i see if i apply a vacuum?
Ta again for Help.

[masterb]

Bit worrying that , it now appears?
That rather than running to rich, my car is not running rich enough!!! ???
I dont expect good fuel economy or i would have bought a fiat panda, but the thought of even less MPG is some what traumatic.

[masterb]

Nope,after further examination, i still say mixture is wrong, and is to rich.
Almost like the choke is permenantly on?
My friend with a 3.6 suggested he thought it was'nt getting enough fuel, due to maybe filter or pump.
Fitted a new filter no difference, pump does not look or sound faulty, and does not make sense that it will idle happily, although sometimes a bit high 1000.
Or if you have the car up to about 80 and put your foot down it goes fine.
That to me suggests that the pump is able to send enough fuel.
How do i adjust the mixture and make it leaner.
Or if the Choke is stuck on permenantly , where is it and what can i do with it?
Thanks in advance 4 any posts.
MrB.

[almcl]

Just in passing, is the fuel return operating correctly?

If the return line is blocked or restricted then the system will over fuel (except under high demand situations.)

[masterb]

Thanks almcl,
re:if the return line is blocked or restricted
could you clue me up on where this is?
in regards to the engine compartment or to where ever it goes?
Presumably back to the boot??\but why and what does it do? how does it work.
Cheers.

[almcl]

re:if the return line is blocked or restricted
could you clue me up on where this is?


Not for certain, unfortunately.

But if your 3.6 is laid out in similar fashion to my 4.0 then there should be two fuel lines running underneath the left side of the car. The one that doesn't go into the fuel filter is the return. There are rubber sections (to the rear) and metal ones. These last are susceptible to misplaced jacks when the tyre bay gorillas get a bit enthusiastic as well as stone damage etc.

If you can get underneath safely have a look for any sort of restriction.

[jthorne]

Have you checked your throttle return springs?

[masterb]

Tanks very much for that Almcl.
Will have a look when i get a chance.
Just for an update, some one suggested to me that the cold start injector, also may double as a extra injector under full throttle?
any way took the offending injector off tonight,(the one directly behind throttle body, checked and tested ok, and blew out with compressed air.
Also Can anyone else with a 3.6 tell me what way up there fuel pump is?
Mine was i think upside sown when i purchased it, and by that I mean the electrical connections were on the bottom????
well reversed that to, along with the new fuel filter.
Still Runs like a asthmatic, when you give it some boot, if you run it gently or at high revs she is fine.
This is really annoying me now!
Is there any truth in or possibility this is a sensor on or near the MAF? that sense's weather its cold? and should make the car run richer?
If this is knackered is that why my car is ok , untill you add some load/acceleration.
In other words it is not being enriched when needed, but on normal running/ low load is fine?
Ta 4 any input
MrB.

[Mark_B]

How about enlisting help from one of those mobile 'car tune up' people that advertise in local paper? One with generic diagnosis gear and experience. Try to find an experienced person. Compression checks, ignition spark voltage, exhaust co level.

The trouble with 'trying things out' in diy-mode is that it can often put on extra faults in the process, without you realising it (like fitting wrong parts supplied in error, or adjusting something in vain to partly compensate for a hidden fault somewhere else).

Here's my suggestion for the hat: ignition ht flashing over (i.e. within distributor) before getting to plugs, can happen when under load?

[almcl]

Just looking at some of your previous posts.

There isn't a choke on a fuel injection system. The ECU adjusts the injector open time to give more or less fuel depending on, among others:

water temperature
engine load (air flow)
rpm
air temp

If it idles high, then too much air is getting in. The ECU will fuel accordingly.

If it's running rich then either the ECU is being fooled by one of the sensors (water temp is a favourite for going high resistance and thus telling the ECU the engine is cold and needs more fuel) OR one or more of the injectors is delivering too much fuel. Several possible causes for this.

Can you get it to do its running rich trick and then immediately remove the plugs and examine them? If they are all sooty, then the ECU is possibly being fooled by one or more faulty sensors, or the regulated fuel pressure is wrong. If just one or two are then maybe dirty injectors are the problem.

[dogbitedavie]

the fuel pump on my 1987 xjs-c has the electrical terminals facing down, so yours sounds as if its fitted ok.
have you tried the air flow meter and associated connecting hoses?
if there is an air leak it will make the car run weak especially when under load