Hello all. I have a 1994 XJS Convt. 4.0. After running for a while and turning the engine off will let sit for a few minutes and try to re-restart it takes me approximately 3-4 try's before it will start the engine. Very strange as when it is cold she turns right over no problem.. Replaced fuel inj. Temp sensor without any changes. Wife won't drive until it starts again first try. Panics that she will get stuck.. Any thoughts??

 

Check all the cable connections and grounds but most of the time with symptoms you dscribe it's the starter motor or solenoid switch.

 

Huge different issues:


1. No crank.


2. Cranks, but does not fire.


Different diagnostic paths and fixes.!!!


Carl

 

Cranks, but does not fire. I have to try 3-4 times and then it kicks over. It seems to have a rough idle when it engages for a second or two..

 

starter is fine and cranks the engine fine just does not kick over...

 

That leaves two sub paths.


1. Weak or no spark. At the fail time, check ignition Ht. Nice fat blue or wimpy orange, or none!!!


2. Fuel. too much or not enough ? I'd start with too much. Flooded ?
Old tech to clear a flood. Throttle wide open and crank. Not as clear cut with FI as it was with carbs, but still indicative.


3. shot gun. go over all HT and LT wires and connectors for loose, corroded or frayed.


4. Quicky: At time of a no start, jump 12v battery to + post on coil nd crank. Ignition switch issue or wires from it!!!


A worn out ignition switch ion my XJ wuzza six caused a lot of issues.


Carl

 

Could it be an EGR valve

 

Sounds like a possible fuel pressure/evaporation problem. Try the following, as a diagnostic maybe? When it is in the hot and not starting condition, turn on the ignition and for a couple of seconds or so the fuel pump will run for a few seconds (presuming a similar system on the car as on the V12s from that point of view). Turn off and then immediately on again, repeat three or four times. On the last one, turn and engage the starter and see if the engine starts. If so, that would tend to confirm a fuel pressure drop or fuel rail evaporation when hot. Floor the throttle also when trying.


If the car starts in this way, could be the fuel pressure regulator is not holding pressure in the rail when the car is hot.
Greg

 

Will try this weekend.. Thanks