What is "good" fuel pressure? 20-40-60-80-100 psi?

Simply knowing that pressure exists is a good first step, yes....and yes, no special tools required for that. If no pressure exists then that avenue must be explored.

If pressure DOES exist then you have to know how much. If you only have 15 -20 psi regulated pressure the engine won't run. If you have 60 or 70 it will flood right out and not run

Spec is 36 psi and you need to be in the ballpark....maybe 25-40 psi or so.

As it stands the "no injector click" situation needs to be solved as well....best to tackle that first anyway!

Somehow we got off on this cold start injector thing....which is a total red herring !



Cheers
DD

 

where is the IRP...........also if there is a fault between the start relay and diode.. is it just a matter of a new wire

 

RH innder fender, well forward, down low....roughly across from the p/steering pump. About the size of a pack of cigarettes, silver

Here's an alternative to checking for 12v at the IRP, if you want: check for 12v at the injectors with the key "on". If no voltage at the injectors you can go back to the IRP and/or the "main relay"



I'll double check my diagreams when I get home but, yes, I recall the wire is uninterrupted between the diode pack and the starter relay. No connectors, no intermediate compenents

Cheers
DD

 

ok i put a new connector on the "new wire" between the start relay and the diode with a new connector into the diode. there is power from the start relay at its post, but if i test the new wire and so on there is no power...................any ideas

 

more.. now the fuel pump does not make any noise

 

ok, take a break and retrace your steps. You said the car was running one day and not the next: What exactly happened?

BTW: by the time you get this car started, you will be an expert at diagnosing no-start problems.

here's what I saw on tv last night regarding an XJ-6 Series 3.

1) they couldn't get the engine started.

2) they went through all the science, they called rocket scientists from NASA, you name it, it would not start. Everybody scratching their heads, snorting their noses, etc.

3) then someone noticed the computer in the trunk has a Parallel Connector, like a Printer connector. well, sort of. "Oh look, this is just like a computer printer cable".

4) long story short: the connector was removed just for fun, and the pins were corroded, (green oxidation), So someone came up with the brilliant idea of using a brass "toothbrush" and cleaning all the pins shiny.

5) and the engine started.

Just a thought.

 

the part where the diode plugs in in green oxi.. on all terminals..ill try it thanks Jose

 

i didnt catch it at 1st,, but your saying to look for that conection in the trunk for the computer?

 

yes, the computer's plug in the trunk, worth checking, you have to remove the upholstery cover / panel, unscrew two black plastic screws and washers, that's where the computer ECU lives, passenger side, a silver box with a parallel plug connected to it. Before you remove the plug, wiggle it in first, then try to start the engine.

 

Worth checking/cleaning ECU pins on general principles.....AND as a possible cause of injectors that do not operate, if indeed it's been confirmed that they are not operating. I've lost track of where we are.

However, a fault at the ECU pins will have nothing to do with a fuel pump that doesn't run.

I suggest trying to fix ONE problem at a time.

Cheers
DD

 

By all means clean the terminals at the diode pack ! If the pump still doesn't operate. try this:

Fuel Pump Circuit Checklist



Cheers
DD

 

Doug the last thing i did was test and had power from the start relay but not at the diode.. i chaanged out the wire and connectors and still nothing but now the fuel pump wont power.. the injectors still do nothing but i am leaving that alone until i fix this other mess.
if the diode is bad i would asume it wouldnt show power at # 3 terminal .. is thaat correct.. if so where can i get one? cheap hopefully cant find one on ebay or net in general.. i guess only a jag dealer?

 

and Jose I will try the plug in the trunk also Thanks

 

The diode pack is DAC1861. Might be discontinued, I dunno. Try Everyday XJ for a good used one or Coventry West 800 331 2193 to see if a new one is available. Last I checked they were stupid expensive new.

If you're good with a soldering iron you can "rebuild" the diose pack with about $2.00 of small parts from Radio Shack



Yes, with the key turned to "start" you should have voltage at the #3 terminal of the diode pack. If you don't it doesn't prove that the diode is faulty. It just means that voltage from the starter relay is not reaching the diode pack.

Cheers
DD

 

ok if there power coming out of the start relay, with a new wire and connectors to the diode why wouldnt there be power at #3.. andthanks for the info again

 

Is there? Is your new wire connected to the "W2" relay terminal?







Stretching a bit, but what the heck....weird things happen

The "W2" connection at the relay has two terminals joined together. What if one of them....the one for the wire to the diode pack....was broken?

If you haven't done so, unbolt the starter realay from the fiewwall and hold it so you can take a good look at the terminals and the stamped markings.

Cheers
DD

 

went to terminal 3 from start relay to diode term 3..............whats or were is the w2 relay terminal.

 

The starter relay terminals are marked W1, W2, C1, C4, C2. Turn the relay upside down....you'll see the stampings.

Cheers
DD

 

Ok thought I would put this out there and see if by chance someone might see something missed. I bought the xj6 when the car would start. When I test drove it ,,,It would start after a few attempts. It would have to idle for about five minutes on its own then it ran OK……..If you tried to give it gas it would die and a restart would take a long time almost like it flooded.
My test drive was fine. It ran pretty good but not like it should. I got the car home and from that point on when I started to work on cleaning it I would start it just to keep up the battery. However that’s when it was hit or miss. One day it would start the next it was a no-go. Then it would not start for anything.
That’s when I started posting to get help from you all and it is greatly appreciated. In thinking back on all the old posts does anyone have any new ideas?

PS…A new diode is almost impossible to find. Other than Dougs contacts for parts does anyone have a source for this part.

 

ok, you can contact David Boger at Everyday XJ tell him you need a good used Red Diode Pack "relay", and a fuel pump, David does NOT sell junk, tell him to send it to you a.s.a.p. He'll take care of you. At this point substitution is the only way to test and or eliminate this diode pack and the fuel pump; All the testing in the world with voltmeters won't work as well as a good used substitute part.