So after spending a fairly long down time fixing my cooling system and the piping to the atmospheric tank…I had to charge my battery to go on the test drive…I drove the car for about an hour…and all performed well. That was two days ago.
Tonight after a long day working in the heat…I decided on an after dinner drive. The car started fine. Made a couple short drives and stops…10 miles or so. I decided on a quick drive thru the local lake park…lots of steep hills and turns.
The drive into the park was uneventful …but coming out I went down the steep hill and around the curve and the engine died. Actually with the radio on…I had not heard the engine die…just the dash warning lights come on…i tried to restart but was unsuccessful. I coasted to a stop mid way up the next steep hill. I attempted to restart several more times…with only a couple sputters before the battery was flat.
I called the tow truck and patiently waited with the hood up. Thinking maybe letting things cool might help. The ignition amplifier seemed warm…but I never actually felt it after a drive before…so I can’t say it was abnormal.
I rolled back to the bottom of the hill on more level ground.
The tow truck arrived and as a last ditch I tried starting the car. It started and ran for a brief period before it died again.
Once home and rolled off the truck…I tried starting again…battery flat…I tried a quick boost…it sputtered but would not stay running. The battery went flat again.
I will dig into this new issue later this weekend…but my first thoughts are debris in the fuel system and a clogged fuel filter from a spirited drive up and down steep hills and tight curves…or potentially a battery charge issue…
Maybe I jinxed myself… a couple weeks ago I shared a picture with friends including a snarky comment about my XF on the side of the road…not broke down…but actually coming to rescue.
I would change the retched Ignition Amp regardless if I was you… it’s only 10$ and it’s a good insurance.
And don’t forget the thermal goop between the Amp and the casing.
Fuel pressure regulator, fuel filter and check if your fuel pump runs…
The F.I. system does require a full battery charge to work properly. However, if the car’s charging system is working OK there should be enough voltage supply to keep the engine running once it starts. So, anyway, fully charge the battery and see if she’ll stay running. If so, look for a battery and/or charging system issue
My gut feeling is a fuel system issue as well but, really, the ‘could be’ list is long. Shouldn’t be too hard to narrow things down if the engine remains in ‘no start’ mode. After checking for spark (always a good stepping-off point) a fuel pressure test might be in order. Or…pull the fuel filter and empty the contents into a clean jar. What you see (or don’t see) might dictate your next steps.
If you have spark, fuel flow, and fuel pressure then you might wanna verify that the injectors are actually operating. Or, in reality, you could do that first, if desired.
My preliminary checks after charging the battery…engine spins over without any attempt at starting. When I turn the ignition to the run position, I hear what I believe to be a relay activating…but I do not hear the fuel pump run for any period of time.
Time to dig the shop manual out…first I need to visualize the fuel pump location and check power to it.
Fuel pump (and filter) are in the trunk. Pull out the spare tire and the carpet that hangs down and covers the fuel tank and associated plumbing and all will be revealed. There might be a bolt on steel cover below the battery that partially obstructs the fuel pump and surge tank if memory serves
As an aside, when I turn the key to run on my 89 XJ-S V12 (and my previous 85), I can hear the pump running behind me clearly. Sometime the ABS pump is a bit louder, but your 85 won’t have that.
Yes, you should hear the pump running for 2 seconds or so…
First thing, check with a test light if the pump gets 12v when you turn the ignition on.
If no, by-pass the fuel pump relay to see if the pump works. (details in the Book). It could be bad connection, bad relay or even bad ECU…
If yes, you fuel pump could be stuck from a piece of debris that entered the pump, (it happened to me once).
Try reversing the polarity, give it a try and report back with you findings.
For troubleshooting, in cases like these, I have put LEDs on all the important relays, so with a glance I can see what is happening… very useful.
Best,
Aristides
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
10
Did you install those LED’s yourself? Are they across the coil to confirm it’s getting power, or are they connected to the contacts to confirm they are closed?
Yes, I installed them, very easy to do.
The LED (and a 800 ohm resistance) is in parallel with the coil, so I know if the relay gets a “signal” or not.
I could have put and a second on the secondary circuit but I was lazy…
And for the relays that have the reverse spike protection diode, there is no danger of spike currents going back to the ECU as the LED is also a diode.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
12
They have the wrong polarity to protect against spike currents, don’t they?
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
13
Cute idea, but I don’t think I would go that route just because I wouldn’t want to put a possible water leak in the top of the relay case. I’ve had enough trouble with relays that weren’t located right-side-up (there are sometimes vents in the bottom). I would have installed such LED’s in the base instead.
I don’t know if I understood you exactly Kirbert…
This is what I know:
The polarity of spike currents is reversed, created by the coil when it switches off and the magnetic field diminishes very fast creating a “back-flow” current. That current, being reversed, will not pass through the LED diode.
I have seen two ways of diodes incorporated in relays:
In series with the coil, working like a one-way valve, or
Reversed and in parallel with the coil, so any reverse spike current will be self consumed in the coil itself.
Yes I have thought of that.
The LED is a very tight fit in the hole and a drop of glue in the inside assures that it’s 100% waterproof.
On the sensitive metal case relays I’ve also put some silicone between the case and the base to be sure.
That would work too.
Best,
Aristides
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
15
The ones that have a diode in series with the coil – like the EFI relay in our Jags – prevent the relay from energizing if the battery is connected backwards. They do nothing for voltage spikes. The ones that are reversed polarity and in parallel with the coil absorb the voltage spikes, thereby protecting any transistorized controllers that may be controlling the relay.
I was the local auto parts store…figured I would see if they could get a fuel pump…they asked me what my vin code was? A 0 or an 8…I never had that asked before…not quite certain what they mean. Anybody got any ideas?
I’ve seen this many times over the years. I was wondering if it referred to with/without cats, high comp versus low comp, or something like that. But…I’ve never seen mention of this in any Jaguar tech literature or parts catalogs.
I think it’s simply an aberration that has never been edited-out of the various parts cataloging data bases…which are shared by many manufacturers and vendors.
Gary,
I have had good luck freeing up stuck fuel pumps by reversing the polarity of the power leads back and forth numerous times. This reverses the direction of the pump motor and sometimes the back and forth motion is enough to dislodge small debris.
The next question is why did the fuel pump get stuck. You need to check the surge tank for debris and for the presence of an intact fuel strainer. Some have added an aftermarket fuel filter between the surge tank and the fuel pump to protect the pump from in-tank debris. I tried to do that once but couldn’t get the additional hose and aftetmarket filter to fit without any sharp bends that would restrict fuel flow.
