I am back to looking at why my Series 3 will start but not keep running...

I am going over everything again and in the manual it states that the internal resistance of the Auxiliary Air Valve needs to be 33ohms, i am getting just under 21ohms.

i have seen on other posts similar lower than normal results.

Without knowing exactly what this air vale does and how a low resistance would affect it i am running blind..

Can someone please interject some sanity for me. (Starting to clutch at straws)

thanks

Russell

 

The AAV increase idle speed on a cold engine by admitting more air....sorta like a controlled air leak.

As I recall .....it uses a bi-metallic spring to open the little shutter/gate which lets the extra air in. An internal heater heats the spring to close the valve. Heat transfer from the water rail keep it closed.

Anyhow......

if you remove the AAV you can see the little shutter...funny shape. Put it in the 'fridge and observe the amount that the shutter is open then plug it into the harness and start the car. You should see it gradually close. It never completely closes.

Could you be more specific in your description of the problem?

I ran a Series III 4.2 for a couple weeks in the dead of winter with the AAV removed from the car and the hoses blanked off....and had no problems at all except that I had to goose the throttle a bit for maybe a minute on cold starts to keep the engine from stalling. After a minute or so, no difficulties.

Cheers
DD

 

He,he. Goosing is a technical term for a bit of throttle pedal depression.


Carl

 

Greetings Russell, but BIG, BIG mistake asking us to help with your sanity. Crikey, sorting Jaguars is one thing, but mate, I gave up the quest for sanity years ago! If we were all sane, we would be driving draughty little butter boxes like Joe Normal, our neighbour! Hahaha.

I wonder if you might perhaps be chasing the wrong goose here. As Doug says, even a badly malfunctioning AAV should not produce the symptoms you describe - starting perfectly, but then dying. Forgive my hesitation at this point, but like Doug, I need more specific info. How long after starting, does it die? Have you checked fuel pump, filter etc? Must admit I don't have my references in front of me and I confess I get confused across our range of XJ6s and XJ40s. It sounds like it may be fuel related . . . but even if not sure, IMHO, it IS the the place to start logically checking.

Check consistency of fuel delivery - pump, filter and, if fitted, state of inertia switch and/or CPS derived signals to ECU, both designed to limit fuel pump run to 2-3 seconds under fail conditions. In checking fuel delivery both initially and beyond your "stall time" take care to do so safely in view of high injector pressures.

Best wishes,

Ken

 

Hi Russell,

When the engine stops, is it an abrupt 'cut out' stop or does it splutter a bit before whimpering to a stop?

Abrupt leans towards electrical, whimpering suggests fuel.

You need to isolate whether the problem is fuel or electrical.

Fuel - faulty fuel pump, dirty filters and or fuel lines, clogged injectors

Electrical -faulty coil, spark plugs & leads, dizzy, ignition amplifier, ignition diode, electrical wiring under bonnet (hood)

Auxiliary Air Valve only helps with initial cold engine start thereafter being bypassed by the system and even then, you can still start the engine with it not functioning if you have to by goosing (I love that word thanks Doug) the throttle.

Looks like you will be hunting more than Easter eggs this weekend!

Good luck & Cheers,

Nigel

 

Thank you for all the replies so far, as requested a little more information

Engine has just undergone a full mechanical re-build, i;m still trying to get it to start and run for the first time.

In terms of how the car starts i have to give it a little throttle and the car will come to life and rev to 200 rpm or thereabouts and i have to feather the throttle to keep the girl alive, when i say alive i will say the engine does not react well to the throttle input and it takes a lot to keep it going. When i left of the throttle the car will whimper and die, it does not just stop.

Things done so far:-

- All 6 injectors and cold start injector was sent off the the guru (name escapes me) on the east coast for a full rebuild. All injectors have good resistance readings.
- 1 fuel tank fully drained and 5 gallons of fresh fuel added in its place. I purged all of the fuel out of the rail up to the injectors and also in the delivery line itself, clean fresh fuel can be confirmed at the rail.
- Fuel pressure at the rail is a keen 36psi, once the engine is shut off the pressure holds and does not fall off.
- With the ignition on if i manually open the flap in the AFM the fuel pump turns on as expected.
- Checked resistance of the pick-up coil in the distributor and reading was well within spec
- i tried putting a jumper between the + terminal of the battery and the + side of the coil with no change.
- The resistance of the AFM is lower than specified in the manual, 20ohms vs 33ohms
- Have confirmed a .002" clearance in the butterfly of the throttle body
- Messed a little with the Anti-run on valve to the point of slackening off the spring rate just a touch and also opening the idle screw without any difference.
- Checked that the black wires at the rear of the intake manifold are solid and create a good connection.
- Ignition timing set to approx 18BTDC (Statically timed only), i also confirmed it is timed on the compression stroke of #1 cylinder which is at the back of the engine

When the engine was re-built i confirmed repeatability of the cam to crank timing, all marks lined up each and every time. The tappet clearances were adjusted to meet specification.

I feel it's a fuel issue, however I'm still open to an electrical issue, i know when something is placed under load with a bad connection it can create erratic symptoms.

I also am open to the fact that i might have made a mistake with all the checks previously performed, with that said this weekend i am going to start again, i have ever checked the voltage at the AFM, the throttle switch or on each of the Injectors so that's where i will start.

What have i missed?

Thanks

Russell

 

Hi Russell,

18 deg btdc is fairy advanced

I had mine set at 15 deg until I sourced a supposedly set for unleaded dizzy which was and is set at 10 deg btdc and I have not had any ignition problems in that department since.

What octane fuel are you running? With these engines, the higher the better.

Also affecting this are the vacuum hoses. Were they re installed correctly after your engine rebuild?

Cheers,

Nigel

 

Wow, you really covered the bases! You're gonna make us *work* to figure this one out, huh?

I'll be back after some mulling


Cheers
DD

 

A 'noid light' is an way to check for injector pulse $5-10 at the local auto parts store

OTC Tools Bosh Fuel Injection Coastal Tool Supply

Lacking that, do the injectors click when you crank the engine?

You should see 12v on both wires to each injector with key on, engine off

Also check the connector at the coolant temp sensor. If faulty, repair. If it's Ok, use a paper clip to jump the terminals inside the connector. Start engine. Any change?

No leaks in ducting between the AFM and the throttle body?

Cheers
DD

 

Russell, your added info really does tend to confirm a fuel related rather than electrical issue. Both your sequence of checks thus far, and your preparedness to go back and calmly repeat each, is backed by the good advice you have received since. However, to pick up on Doug's question about confirming each injector solenoid is clicking, add these to your "to do" list . . .

• beg or borrow a stethoscope (or make one) and really concentrate on confirming each injector is working;
• how much time has elapsed after engine/injector rebuild - these suckers hate being idle for long (pun is unavoidable);
• back off your static timing setting to 12-15 degrees BTDC - erring a tad on the retard size of optimum is always preferable to setting an initially aggressive advance;
• beg or borrow a "known to be working" full set of distributor rotor, distributor cap and associated full set of plug leads - after first checking each lead's correct cylinder marking - any nearby mate or fellow member with similar model/year car can help with this.

On the latter, HT breakdown issues on the 4.2L six are not the far more common weakness seen on V12s, but cracking and/or tracking across dizzy caps is not unknown. Hang in there Russell. I sense your solution is near at hand and will be just as character building as a "dead" capacitor was for me in an otherwise total engine rebuild that for many days, refused to even cough. Across 50 years since, I've learned patience and persistence.

Cheers and best wishes,

Ken

 

Very useful tool, about $7.00 at most auto parts stores

http://www.toolaid.com/sites/default...hoto%20300.JPG


Excellent point. I waited too long and have to have all *12* injectors redone !


Worth a try, but 18º is correct factory spec for the USA Series III 4.2 after 1984 or so

Cheers
DD

 

The engine itself was put together over the past few months, the injectors on the other had were rebuilt over a year ago.

When the engine is running/cranking i cannot hear a definite "click-click-click".

I will check the voltage at the connector over the weekend and will visit the local parts store for the tool mentioned in another post.

When it comes to the vacuum tubing there in lies a question. I have looked at the parts guide which shows where the pipes should go, however there are 2 stubs on the underside of the intake manifold, 1 right behind the intake tube to #1 cylinder and another that seems to be a drain right at the bottom, i am assuming the vacuum tube is placed on the stub behind #1 intake tube and the other is either left open or a blank tube is placed over it and only removed to drain anything in the intake plenum.

 

Right, one of those is a drain and should be capped off.

The other, as I recall, goes to the 3-port vacuum regulator for the vacuum advance system. Just cap it off as well, if you no longer have the vacuum regulator.

Cheers
DD

 

Thanks Doug, that's the way i have it set right now.

I have contacted the guy who cleaned the injectors last year and he echoed what has been said here, the recommendation is to re-install within 60 days of receipt, it's been 14 months.

Tomorrow i will check for voltage and a good firm "click" from all injectors, if voltage is present with no firm click then off the injectors come and will go back for "resurrection".

 

Well here's my pennyworth !

1. A group of earth (ground) leads are connected together towards the back of the inlet manifold.If these fail to make a good connection or are broken it will prevent the EFI from functioning.

2.The EFI system relies on a pulse from the ignition system. If this is missing the EFI will not function. On cold start the cold start injector that is not timed floods fuel into the engine, but the engine will soon stop if there is no fuel from the injectors.

3. There is an injector resistance pack that relies on good contacts being made. I think this pack is in the engine compartment somewhere.

 

Fraser

I have checked this group of ground wires and all seems to be good and solid, There is good continuity between these wires and the engine so they are grounding well.

Russell

 

2PR Power Resistor DAC1211 is located drivers side front wheel arch under the air filter.

It is solid state so rarely fails, but as Fraser points out, it too needs a clean connection and where it is located, road dirt can and does build up on it.

 

Now with the full relevant story, prompted by Doug and I (modesty, eh - LOL) it's probable that some, or your entire set of injectors, are stuck and/or not working correctly.

As per my earlier post - now confirmed by your re-furbisher - these things hate being idle. My intro to this was in the '80s with race prepared 6L Jaguar twin turbo V12s fitted to our unlimited hydro "Jagged". We laid in 4 sets (actually 50) for our 2 engines, only to find that all but the initially fitted sets had to be serviced before use in the following season . . . another reason to be nervous when cars are laid up unstarted for many months over your long winters.

My current pre-HE XJ-S project car had to have several injectors replaced, just to get a fast idle to get it on the transporter. Having then sat awhile here, I can tell that several more are sickly. My mate here, like you, bought in injectors, plugs, hoses etc for his XJ6 rebuild and, for a range of reasons that delayed re-fitment, found 4 injectors had to go for service because their "click" was not a-clacking! Hence my questions seeking the timing of your re-build.

Given enough years re-building these engines, we learn lessons. This forum helps spread the word but, just like a dead capacitor on the old points based dizzy, this injector issue should be writ large in the minds of all enthusiasts.

Cheers mate,

Ken

 

Thanks Ken,

A good friend in the UK had all sorts of problems with a Daimler Double Six a number of years ago with it running on all 12, he suspected an injector issue and i'm willing to bet this was the problem, he ultimately gave up on the car and sold it on, thankfully without a great deal of $$ invested, shame really if that were the cause of the problem and so easily fixed of course.

I will go and get a set of NOID test lights today and verify the ECU is sending the required signal to each injector, following a successful result i will move onto listening for the injectors to "click"

I am assuming i should be able to hear them click over the noise of a cranking engine correct?

 

I knownits highly unlikely, but is.everything plugged into the correct spot?
When i had the head off of mine i rebuilt the wiring harness, everything looked right but car would not run more than a few secs then shut off! I had two wire plugs in wrong spot, crossed the cold start injector with the thermotine, so csi was getting constant 12volts, overfueling like crazy! Easy to screw up with new harness as the two wires are about same length, and have same connection on end. Like i said, highly unlikely but possible,