Hello everyone, I am having an odd issue with my car. The other day I was getting ready to go to work and car would not start. Cranked over fine just wouldn't fire up. Luckily I have another car so I went to work for a couple of hours came home for lunch and tried to start the car and it fired right up with no issues. Had no issues for 3 days then this morning was going to go out for breakfast and again that same issue, cranking over fine but just would not start. So today I had some time to take a look if I am getting fuel and spark and all are fine lots of fuel getting to the rail and spark is fine. I even replaced the cap and rotor sine they were original but still would not fire up.

So after checking everything and not getting anywhere I left the alone and went to pick up my wife at work. Got home an hour or so later and figured I try one more time to start it and the car fired right up with no issues.

The car runs fine when started and its only happened to me these 2 times since I got the car 4 months ago

Any help would be appreciated

 

dwiniarz,

I could be wrong but how old is your battery? try a new one and see if it solves your non (cold) start issue...

 

battery is not even a year old

 

I once had an intermittent non-start (though, would crank) that ended up being a fuel pump relay on it's way out. When it next won't start, why not pop in a borrowed relay and see what happens.
Scott

 

So it's 12:30pm and just tried to start the car and again cranks fine but won't fire.

Midwestjag can you tell me where the relay is located. I am pretty new to this car

 

Also what relay should I borrow?

 

The location changed over the years of this car's production, but I believe your '90 is like my '91: the relay stands alone on the left side of the car (the "driver's side" in LHD cars), in the engine bay, towards the back of the engine. It should be rather near the accumulator sphere for the brakes. You can temporarily borrow one from the horn or windscreen washer. Unless they've been removed, all these relays used to come with shields indicating their use on the top.
Scott

 

So i ended up finding where the relays are - under the glove box in the car (Yellow socket) Yellow relay - there were two yellow sockets so tried both. Still no luck car is still not firing up.

Anyone else have a suggestion?

 

Hmmm... I looked once again at the Haynes manual, and while the 88-89 cars do place the fuel pump relay under the glove box (which, I suppose, is possible for your 1990 to carry over, especially if it is an early VIN for the year), it puts it on a brown base, not a yellow one. On the other hand, it says the 90-92 cars are supposed located the FP relay in the engine compartment on a yellow base. Just want to be sure you're looking at the proper relay!

For another idea, you should research in the archives and elsewhere the effect of a Throttle Position Sensor and a non-start.

Scott

 

The only relays I got in my engine bay are right by the headlights and they are all labeled so I am sure that they are not for the fuel.

I moved the brown socket relay around in side and still no fire.

Today no fire at all

I am thinking cant be a fuel issue I get plenty of fuel coming to the rail.

 

Hello...

Don't know if you got your non-start fixed, I hope so..

But I was going to post a similar problem with my '90 XJ40. Started this morning, but went back about 4 hours later to take it out for a drive and it kicked a few times then refused to start. Had to jumper it over to another vehicle for the battery was getting low.

Tried again with nothing. Checked Spark and good and strong. Used a little start fluid spray, not even a burp.

Backing up a few days, while on a local drive the oil pressure dropped to '0', I nursed it back home ( 1 mile ) and parked it and took my other car. This morning then I started it and oil pressure camne back to 45 lbs within a second of starting. Oil level at the fill mark. That is when four hours later I attempted to start it.

Will go out now and check the fuel pump relay.

The car has 175k miles on it.

 

Mountain:
I wouldn't worry about the oil pressure so long as the level is good. The pressure sending unit is a common failure on these cars. My '91 does the exact same thing and there's nothing wrong with it. Most of us live with it; others replace the switch with one that gives a "static" pressure reading rather than one that is constantly moving.

Your non-start could be relay, but it could also be a lot of other things. Start with the basic stuff as reported above and report back. The Crankshaft Position Sensor is a most common cause of non-starts - but that's a bit pricier to replace without knowing if it's actually bad.

Scott

 

Hello Part 2

Swapped relays, no start, relay will come on for about 2 seconds when key is turned on - Like it should.

Disconnected fuel line to fuel rail, no pressure what so ever. just a few drops of fuel came out. No flow when key is turned on.

Getting good spark...

Started raining and getting dark so tomorrow will check power to pump and pump operation.

Will post results tomorrow...

 

I still haven't figured out my no start issue but its been good for the last week or so, starting with no issues, just waiting for it to come back so I can do some more testing. I will report back when I find the issue.

 

Pilot I think your issues is with fuel pump, cause when my key is turned I get lots of fuel

 

I am sure that is the problem also.

This weekend has been busy for me and it will be a few days before additional testing will be done.. Will report as to my findings.

 

Started from scratch today.

Here is what I found on my '90 with 4.0 engine

- Fuel pump works well ( I think ) jumpered the relay so the pump gets full time power. "cracked" open fuel line and it has fuel and pressure, can hear bypass valve letting fuel go through.

- It has spark from the coil

- No error codes

- It will kick a little when trying to start...

So I blocked the fuel return line to make sure bypass is not allowing proper pressure. And it started. It would run rough above 1600 RPM and not go over 2,000 RPM. I removed the clamp on the return line and it stayed running. Also then the power returned to "normal" and RPM would smoothly run up. Let it run for a few minutes, turned the engine off, and it restarted as normal.

Ah.. those English!

It may have just been programmed this way to get back at us because of a little squabble in 1776...

 

Update...

After driving it for a few days it still had a rough idle, had to warm up for about 5 minutes before it had "normal acceleration". Not smooth at 65 mph, so I knew something else was a problem.

Removed and cleaned the Mass Air Flow sensor. The MAF sensor was quite dirty. It drove a little better after that but not like a Jaguar should. Records showed that plugs and wires were changed about 10K miles ago. Thought I would check them anyway.

Removed totally warn out Proper number standard Champion plugs, no way they were 10K mi plugs and it had a set pf aftermarket auto parts store plug wires installed. ( By a receipt in the car's records these were installed by a Colorado Jaguar Dealership! )
I then installed a set of Autolight Platinum Plugs. Since my purchase that 4.0 never idled so nice, took it out on the road and it ran like it was a V8 ( well a lot better for sure )

Found a lot of moisture induced rust and crud of unknown origin, down in the holes and on the base of the plug. No carbon buildup on plugs, good and clean but very worn tips.

Cap and rotor are in VG condition but will replace plug wires.

At 70 mph indicated it is now indicating 28 mpg where as before the best was 25 mpg.

Now I have my Jaguar back to like it should be....