so I finnaly got my air flow meter changed out. almost completely fixed my starting problem and get going slowness. after close inspection of my old one. I found that the flapper inside has a semi-worn bearing causing it to drag on the casing. I could have easily fixed it if I knew. So I'm on a road trip this past weekend in a stormy area(1 1/2" hail) and as I was driving through the carnage I started having problems when I accelerate. couldnt go over 55 mph. real frustrating!!! anyhow, I made it home without a tow truck.
got to looking hard and the vacuum hose had fallen of the distributor(must have got knocked off by the water and hail splashing up from passenger tire. so I put it back on, and now it doesn't want to start untill I pump the heck out of it. I don't like pumping the gas and I shouldn't have to.
What chain effect could have happened? I thought well maybe I sucked water in the vacuum line, but I've driven it(still runs freakin great)and it still doesn't start very easy.
Any ideas would be helpful.
Thank you all for all your input and help.

 

A couple of ideas:


1. Save your leg muscles. FI cars have no accelerator pump like older domestic carb'd cars did. And, in those, over pumping merely created a tough start harder. flooded!!


2. Is cranking speed good. A dragging starter merely siphons off volts needed to fire the plugs and injectors.


3. There are some dainty wires and connectors in the ignition circuit. That storm may have messed them up a bit. Distributor to amplifier. Amplifier to coil. Coil to ignition switch. Oh, one more . A ballast resistor at the coil Some cars dropped 12v to 6v to protect something??? Jump 12v from battery to the + post on the coil. Crank. It may just fire up just dandy.


4. Go over that AAV carefully. Any airleak and the engine is seriously lean. toght to start an engine starving for fuel or getting to much air. same issue, lean mixture.


5. Fuel pressure at the regulator. Weak pump?


6. Logical diagnostic course. 1st. Make sure the spark plugs are getting a nice fat blue spark. All of them, each and every time.
2nd, if so, go to fueling issues.

7. If you need an working AAV, let me know, PM. I have a left over in a parts bin. .
Carl

 

Well vacuum checks out fine. Spark is good. Fuel is good. Idle doesn't change at all when vacuum disconnected,revving and idling. Seems to me the advance is not working and gets worse as it gets hotter. Heat sink somewhere? Getting confused and frustrated.

 

Amaezing:


Well, the vacuum advance clue is a good one. Odd timing or a but diaphragm. Related, oh yeah.


1. Remove the distributor cap. Twist the rotor. It should twist a few degrees and spring back when released. That determines if the mechanical advance is functional.


2. Use a Mitty Vac or even just your mouth to draw vacuum in to the advance diaphragm. Any limit, there should be. If not the diaphragm is leaking. And whoile doing that, watch the lever that comes from it. Is it moving ghe plated in the distributor. If not, it doesn't work.


3. Use a strobe timing light. Find the marks on the dampener. Mark with chalk or wite out for visibility. Run the engine at idle. Vacumn hose plugged. Should be at about 14 degrees BTDC. Initial advance only. Little if any mechanical. No vacuum. Rev it just a tad. More degrees BTDC? if so mechanical is functioning. Add the vacuum. rev a bit, even more degrees BTDC? All ina t about 35 degrees or so?


If no, fix.


Carl

 

That's it JagCad, I think you nailed it! The diaphragm is leaking. so now I need to find out if I can get the vacuum diaphragm replaced or if I have to replace the distributor.
What do your abbreviations AAV stand for? I really suck at trying to figure out what they mean.

 

so I do know that it does no good to really pump a fuel injected car,I merely meant pushing it down a couple times out of habit when it doesn't start right up.
It cranks over like a charm, no drag or anything.

I ran a jumper wire from battery to coil..no difference.
I don't know what you mean by AAV, but the vacuum is good, I can't find any leaks and it idles pretty good.
I need to check for consistent spark, but I haven't made a test light yet.I truly think the advance diaphragm is shot, I tried disconecting it while it was running and there wasnt any change also in adition to the suck/blow leak test(failed that also)
I just replaced the fuel pump a few months back and I tested it out just fine.

 

AAV means Auxiliary Air Valve, but I think Carl was referring to the AFM, Air Flow Meter.

before you dismantle the distributor and get into deeper water, check the Ignition Amplifier, a square box with two wires that sort of hangs near the distributor.

 

I'n not sure which part is the AAV, but I did jusst go thru all the BS with the AFM and it's not that.

I see the ignition amplifier. How do I check it? didn't I by pass it when I ran a wire from the battery to the coil?

 

to test the ignition amp, see this link:

Jaguar Repair: 1986 XJ6 4.2 constant energy, sng barratt, ballast resistor

 

thank you. I will get on it all 2moro morning(weather pending)

 

alright, it the advance module on the distributor.
Does anyone know the part number for this unit?
parts store show no listing so interchange numbers would be a great help.

 

Well I'm a bit confused more now. So I disconnected the vacuum at distributor since it's shot.
So I go to work and it's running fine just no trying to advance even though the tranny downshifted. Slowly inclines in speed like it should with no vacuum advance. Then after about 15 miles on the highway I notice the all of a sudden sluggish. Hit the gas and the rpms jump 3500 then drop to about 15 and I start loosing speed as if I was touching the brake. Let of the gas and it looses the sluggishness but has no get up and go. If I hold the gas down I loose more and more speed. If I let off and hold the rpms at the spot they need to be for the speed and gear I'm in it holds whatever speed you were going when you starting all this confusion. But if I start going up hill it slows down until I'm doing about 20 mph and back firing.
This is when I pull over, turn it off count to 30 and restart it. Doesn't really want to start. Cranks and cranks until finally starts. And then it basically goes for a mile or so then it starts all over again.
If I let it cool down for an hour or so I can make it that 15 miles again before it starts this crap.
Like I've said before I love this car and I won't give up but right now I'm pretty frustrated and I hope I can find a solution. Although I don't understand some of these detail about jags. Why does my distributors vacuum advance make vacuum? Does someone have a vacuum diagram drawing to explain this? Or is that unexplainable?
I really hope I put enough detail in this description that one of you can say "I know what that is".
I took a few videos to show you what I mean about the rpms but I can't figure out how to load them on my phone as I'm sitting here waiting for that hour or so, so that I can make it home without calling the tow truck.

 

No. The diaphragm on the distributor does not make vacuum. it reacts to vacuum. the engine is the vacuum source. A really good one, by the way.


You should not have to replace the entire distributor to fix a bust diaphragm. I don't recall the access. So, it might be necessary to remove the distributor to do the job on the bench.


As to getting one. David Boger at everydayxj for a good used unit or possibly NOS.


Electronic ignition on these cars mimics old style point and condenser, electronically.
The distributor creates the signal. The amplifier amplifies it and the coil reacts to make and break, just like the point distributor did


Heat and puny wires are the Achilles heel of the installation here. Each fixable.


Carl

 

PS


Call SNG Barratt, a forum advertiser!!


Carl

 

Thank you Carl. I just changed the ignition module. Now battery is dead. Waiting for a jump start to get here. But the way it was acting I don't think that was the fix for my starting over post. Or this one. It should have started before I killed the battery. Does a weak battery cause these problems in 1985?. I know it effects the newer ones.