Hi Guys, this is my first post and thanks for all the Welcomes.

My 87 XJ40 is very reluctant to start when cold. It turns over OK and tries to start on a couple cylinders but wont run. It will eventually start after more cranking and then will run fine. So far I have replaced the fuel pressure regulator, the fuel pump, coolant temperature sensor, crankshaft position sensor, had the injectors cleaned and fitted a new set of spark plugs. I'm about to fit new a distributor cap and rotor arm. Can anyone suggest what else could be the cause. The car has covered 227000 Kms so replacing all the above seemed worthwhile.

Cheers, Nick

 

Hi Nick, and welcome to the forum. As you said, with that many miles, probably a good time for a tune up anyway! But as to the slow starting... My '94 has a similar problem right now, and I'm all but certain it has to do with a tired non-return/check valve - which on your '87 I think is attached to the external fuel pump. Short story long, fuel pressure is lost as the car sits. A proper fuel pressure test would verify if you've got the tools, or take it to someone who does. Alternatively, could could be losing fuel pressure past one (or more!) of the injectors. After so many years, things are bound to relax a bit...

Meanwhile, try the key-cycling trick when the engine is cold. Cycle the key through position II on the ignition - WITHOUT cranking - 3 or 4 times. This provides the same number of priming bursts from the pump, thus re-pressurizing the fuel line. Report back if that works.

Cheers!
Scott

 

Thanks Scott. I've tried the key-cycling method to no avail and also the fuel pump complete with non-return valve has been replaced with a Bosch unit so there should be no problems there. The injectors have been cleaned and tested by a fuel injection mechanic so this is why I'm stumped. I'll get the fuel pressure checked - I don't have the equipment to do that. I still think its a fuel problem as the spark is good and I've just pulled the spark plugs out and they are dry and clean. Seems funny it drives OK once started - really frustrating!

Nick

 

I had a similar problem with my '91 Sovereign after I had had the fuel pump replaced. A pub mate, who had done his apprenticeship on Jags, suggested that I turn the key all the way to start and release it before the engine fired three times. He said this should prime the pump, but that if the car wouldn't start quickly after the third "prime" then the problem would lie elsewhere. Mine started as soon as I turned the key to start the second time and I have not again experienced the problem. Maybe this technique would be worth a try.

 

Just a thought worth mentioning...how old is your battery? You need alot of cranking amps to get these cats fired up. Also have you cleaned/checked your ignition amplifier and coil?

 

Thanks for the responses guys - I have tried bypassing the pump relay so that the pump runs continously and then trying to start it - made no difference. I have cleaned the ignition amplifier contact and the coil wiring and connections and there is excellent spark from the coil HT lead and the spark plugs during cranking. Ah the battery. it is a few years old and probably needs replacing - I'll put that on my list. At the moment I'm checking to see if the distrubutor is fitted correctly as I checked manifold vacuum two days ago and the gauge shows 15 inches of mercury which indicates a retarded ignition (could also be worn engine). So I'll see where this goes and also check on the battery.

Thanks for the input and I'll keep you posted.

Cheers.....Nick

 

Nick:
If I'm following, we are still not sure about fuel pressure at the rail during cranking. To my knowledge, that is pretty much the only way to confirm that the system is providing, and holding, the required 40 psi to start the engine after the priming burst.

I have heard anecdotally that a weak battery will make for difficult starting.

Years ago when I replaced my distributor cap my car failed to start. The mechanic at that time said that I hadn't reinstalled the cap properly, although I thought I had. So, I'd check the alignment of that too.

Scott