3.6 hard to start

XJ40
1

hopefully this is a minor problem. My 89 3.6 can be a little hard to start. I have to push the accelerator whilst cranking , and it will misfire at idle for 15 - 20 seconds before it starts to run well.

I have new leads, plugs, distributor cap, rotor button, air and fuel filter’s.

Any advice would be very much appreciated!

Ryan

2

Ryan,

Sounds as if it is flooding. After cranking for a few seconds before it starts, switch off and remove a spark plug to check if it is dripping wet with petrol.

A possible cause of such a problem as you describe is a punctured vacuum diaphragm in the fuel pressure regulator (FPR). That allows neat fuel to be sucked in to the manifold to flood the engine.

Pull off the vacuum line from the FPR to the manifold to check for signs of fuel. It should be completely dry.

3

thanks bryan.

I checked the line , it is completely dry, no signs of fuel.

any other ideas?

ryan

4

Ryan,

Did you check a spark plug as I suggested to determine if the problem is flooding?

5

yep i pulled 2 spark plugs and they are fine, no signs on fuel on them

6

Ryan,

OK then - perhaps it is lack of fuel on start up?

Try the ‘key cycling trick’ in case fuel is draining back to the tank from the fuel rail via a defective FPR or a failed check valve in the fuel pump outlet so that it takes a lot of cranking to build up fuel pressure before the engine will fire.

Switch the ignition ON-OFF-ON six or more times before engaging the starter to take advantage of the priming burst from the pump each and every time you turn on the ignition. After the final ‘ON’ then engage the starter. If the engine fires immediately and runs OK, then the initial problem is lack of fuel pressure.

7

hey mate, that didnt seem to help either.

However, i think i may have solved the problem.

I removed the IAC Valve and pushed it up (open position) and re-installed it. The car started immediately. I then tested the valve by plugging it in whilst removed, and i could see it opening and closing.
I believe it was not screwed in tight enough - i undid it by hand! After re-installing it tighter, the car seems to start fine. Perhaps a small vaccum leak!

Ryan

8

Ryan,

That’s a new one! We live and learn - pleased you fixed it. :wink: