Jaguar Repair: IT runs but dies on the road, bosch platinum, jumper wire


Question
QUESTION: I have 1984 jag xj6,VDP series lll
MY DAD JUMP MY FUEL PUMP BY A SMALL CONNECTOR BYPASSING THE FUEL
SOLENOLD. AND THE CAR FIRED UP. BUT LOST POWER AFTER PARKING.

I THEN LATER CHARED THE BATTERY WHILE HOOKED UP TO THE CAR.
AT THAT POINT I WONDER DID I MESS UP THE WIREING AND THE RELAYS

CURRENTLY I PURCHASE A NEW BATTERY WITH A CRANKING 700 COLD AND
A 875 CRANKING AMP DURALAST .
IT NEVERED TURN OVER,

THEN PURCHASE NEW BOSCH  PLATINUM +4 PLUGS.
AND NEW 12V COIL.

AND STILL DOEST TURN OVER.  I SEE THE INSIDE LIGHT JUST NOW VOLT
POWER ON THE DASH. AND THE CAR BARLY CLICK. ITS ALMOST LIKE A MOVIE
WHERE THE CAR DONT WORK.





ANSWER: Hi Brandon,
You are going to have to slow down and clarify what you mean as I can't make out what you are saying.

You can't bypass the fuel solenoid because when it is powered, the right tank is used and when there is no power, the left tank is used. It has nothing to do with the fuel pump.

While it is a bad idea to charge a battery while it is connected to the car, it can't harm the wiring or relays but could harm the ECU but even then I have seen ser III cars charged many times and no harm was done. UNLESS YOU CONNECTED IT UP BACKWARDS!!!!

The ser III Jag does require a high amp hr battery. But if you put in a new battery and the engine does not turn over, it is no use buying plugs and a coil because they have nothing to do with the starter turning the engine over.

When you try to start the engine and you only hear a "Click" you need to do two things. First confirm that the battery is fully charged. Then with the hood up put your finger on the metal relay on the fire wall just behind the intake manifold and have someone try to start the engine. If you feel the relay "Click" then remove the large White w/Red tracer wire from the relay and confirm the car is in "Park" and connect a jumper wire to the (+) post of the battery and touch the jumper wire to the White w/Red tracer wire end. If the starter just "Clicks" then you need to clean and tighten ALL battery connections (+) and (-) connections including the engine to frame ground strap.
Howard

---------- FOLLOW-UP ----------

QUESTION: CURRENTLY I PURCHASE A NEW BATTERY WITH A CRANKING 700 COLD AND
A 875 CRANKING AMP DURALAST  AND I GET FIRE NOW. BUT SOMETHING IS DRANING MY BATTERY DOWN.
ONCE I TAKE THE CARE DOWN FOR A DRIVE, IT SUDDENLY LOOSE POWERE COMPRESSION AND DIES

Answer
Brandon, it is no use buying parts until you know what is wrong. Chances are that you will run out of money before you run out of parts to buy.
You MUST TEST to find out what is failing first. All engines only require 3 items to run, compression, fire and fuel. There are conditions on each but when you have a engine fail, one or more of the three is missing.

Compression will not usually come and go, so you need to look at fire and fuel first.

Fire is easily tested by just putting a timing light on a plug wire (when the car is in a failed mode) and have someone spin the engine over and watch the flash of the light.

Fuel can be tested by spraying starter fluid into the intake while someone spins the engine. (when the car is in a failed mode)

You MUST establish which is missing (while the engine is in a failed mode), once you do that, then you can run further tests in that system to narrow the problem down further. This is the only sure method to find problems.

If the car only dies at times but will restart, you still need a method to SEE which of the three failed at the time it died. First you need to read my "Tech Tip" on how to start an engine. Then we can proceed to each test of each system. Some tools are required but not many, probably less costly than the parts you have already put into it.
Howard