Hi I recently purchased a 77 xjs, the car had been in dry storage since 1999. I have recently got it running but it has a misfire. The car has new plugs leads and a distributor cap. I have done a compression check and it it's pushing 140 on all cylinders. I seems that cylinders 1, and 5 on the LH bank are not firing. Does anyone have any suggestions on where to look next? I have attached a photo of the LH spark plugs. Cheers

 

Get a 9-volt battery and some leads and see if the injectors click.

 

Good tip thanks. Yes the are clicking, is it possible for the injectors to be blocked?

 

Anything is possible but in my experience if they click it should be spraying something burnable. It may not be a perfect spray pattern but it should not be a hard miss either. Plumb in a pressure gauge, then bring up the fuel pressure with a jumper wire on the fuel pump momentarily. Observe...when activating the injectors briefly with the 9v battery, the pressure will drop much faster then with no injector activation.

After you know it's getting fuel and spark...let it run and get hot. It may clear up.

I just brought back a V12 to life... it was missing. It had spark, fuel and compression but still missed. Something was off but only when the engine was running. It did start to get get better after running hot for about 30 minutes. encouraged, I let it run for a few hours and it cleared it self up completely. It was probably a sticky valve that was not sticky during low RPM testing.

 

thanks ill I'll give that a shot. I have had it running on race fuel at 1500 rpm and it does seem to run smoother once its warm, but I have not run it for more than 20 minutes. I'll make sure there is fuel at all cylinders and give it a longer run. Cheers for the advice.