my post in "strange occurrence" has been resolved sorta. With all the info that I was given in that heading. I narrowed it down to the vacuum advance. so I disconnected. I would like to see a drawing of that vacuum system if someone has it.
but now I need to get back to the issue iv'e had from the beginning.
here's a description
I disconnected the vacuum at distributor since it's shot.

So I'm going to work and it's running fine, just not 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.

I took a video but can't get it on here for some reason. but it is showing how when I pull over when there is the problem. Pulled over, floored the gas and it jumps to 3500 down to 1500 and just stays there until it starts backfiring thru the carb. turn key off for 10 seconds, restarts goes up to any rpm and stays, put in gear and go a few feet or a mile and all this crap starts again.

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".

 

so I might just be rambling now. This makes me second guess almost everything I've been doing.
This is what it was doing when I first got it. I thought it was fuel related.
I changed the pump, filter, plugs,cap,rotor,to get no results
then I tinkered with the afm and found out it was stuck and I got it freed up and ordered a new to me afm(used). it only acted like this when I was trying to get going from a stop. then it would clear up and go before I crossed the intersection.
This is happening after it gets warm now(hot). so I need to ask if there is some type of electrical device that changes something with fuel or spark when it gets hot? Yesterday I bypassed the coil stuff and went from battery to coil with a hot wire. no change at all.

 

Yes.

You have an AC Delco ignition module (Part # D1906) inside your ignition amplifier. They are well known for giving trouble when hot. Easy to replace but you'll need some tiny sockets to open up the amplifier. The module is about $50 if you stay with AC Delco....less if you go aftermarket

Also, the ignition coils are known to act up when hot. Any 12v coil with about 1.0 ohm resistance will work. I prefer the Lucas DLB170 if they still make it.

Cheers
DD

 

This very well might be the information I'm looking for. The coil is new also, so I'm off the check out the ignition module. I was thinking it was something that controls the spark. Fingers crossed.

 

Well I fried the starter so now I have a new starter. still not fixed. a new coil is sitting at the parts store, Ill get that in the morning. let you know then.

 

I got called to work yesterday so I didn't get to my jag. But I figured that I would start from the beginning and check everything I've done. The fuel was the first thing and could be this.
Question. Where is best to check fuel pressure for pump and for pressure regulator? I ordered all the parts I could need(I hope). and I want to start checking parts before I go pay for the wrong parts again. I read it somewhere in these forums, but I can't seam to find it now.

 

Most commonly the hose to the cold start injector is disconnected from the fuel rail and the pressure gauge attached to the now-vacant nipple.

Cheers
DD

 

Alright I hooked up the fuel gauge and it read like this. at the first start, watched the pressure raise to 35(+/- 3) and then it fired up. started driving around it dropped to 21 and stayed there. Trying to restart and it only got to 24 and then back to 21 when I started driving. didnt start the loosing speed for about 5 miles then it started the lack of power and a couple of back fires, but it still had the same 21 psi. I have a spark tester hooked up this whole time on two cylinders and they are good spark(slow at idle, fast as I drove).WTF?

 

BTW. I have the fuel gauge hooked to the back of the fuel rail. opposite side of the rail from the regulator.

 

That's OK. You obviously have a 'tee' arrangement.

Cheers
DD

 

Yes, that is how i have it set up.

 

21 psi is too low. It should stay close to 36 psi. Maybe more like 30-36 psi or so, depending on vacuum.

The only spec from Jaguar is 36.25 psi while cranking the engine

My guess at this point is that your pressure regulator is on the fritz...although the fuel might be weak as well. Have you checked the unregulated pressure?


Cheers
DD

 

How do I check the unregulated pressure?

 

that was a stupid question. I did that last week with my finger and someone helping. I disconected the filter and put my finger over the hole. had my mom cranking the ignition. the pressure built until I couldn't hold it. I didnt have a gauge that day but it was definately pumping great pressure if i couldn't hold it back.
So I'm guessing now that I should change the regulator?

 

I found another post titled "Series 3, 4.2 Fuel issues (I think)". this is all the same symptoms as I have minus the dirty fuel. he obviously said something wrong and noone responded back to him, so I cant find out what happened.

 

BTW. My a/c is not belted. I din't know why yet, but will it effect fuel system since it the return runs thru it? I just read that the fuel goes thru the A/C.

 

that wasn't it. filter was a slight bit dirty but not that bad, changed it anyway. no change. I guess all I have now is to return the pump for a new one. I think the only other thing is the injectors, but I really don't think that is it. But what do I know? After all this, I'm second guessing everything I've done.

 

IMHO, the only time lack of fuel cooling is likely to be a problem is under extreme conditions....like city traffic in Las Vegas in August. Lots of people have dead/disconnected air conditioners and report no running problems.

Cheers
DD

 

That's typical in all the cars I've worked on and owned. But you all are the only ones I know with jags. I don't know any one in person that owns a jag little lone know anything about them. So thank you for your input. It is very appreciated.
I will figure out why the a/c doesn't work once I get this problem fixed.
The guy I bought it from had just changed the pump and it didn't need it. So as with most people I'm sure he bought the cheapest he could. That is the worst idea to all of mankind when your dealing with a fuel pump. I should have thought of this first before I spent all this time and money on all these parts.
Cheap fuel pumps have screwed with me a dozen times before. I always get oem or the best I can.
Will I ever learn?

 

Btw, IMHO? Injector manifold heat oppression. Lol Abbreviations confuse me a lot.