I initially posted about my issues with the retainer clips on my 2002 S type fuel pump and sending unit.

https://www.jaguarforums.com/forum/s...-clips-197990/

I've since replaced the motor part of the fuel pump in the tank but it still won't start. Now I'm wanting see what the best way to check for spark is. Also when I printed out the VERY long list of where and what all the fuses, relays and diodes are I see about 8 places where it says "fuel" or 'fuel pump". That's confusing.

So.........how to verify I'm getting spark AND how to test for fuel. I know that one should be able to depress the needle on the shraeder valve under the hood on the fuel rail. I did but it didn't exactly squirt out. Just a little bit dribbled out. Sounds like I need to do some further fuel pump testing and/or fuses, relays and whatever an inertia switch is. I did check that little red button under the left side of the dash too.

Thank all of you for you help. We all know how frustrating these things can be. I just can NOT afford a Jag mechanic right now. Thanks again

 

Sorry if there's a double post on this. I'm new and learning how to navigate around here.
QUESTIONS: I was sure that a bad fuel pump was the reason it wouldn't start. A couple wanna be backyard mechanics agreed. We depressed the schrader valve on the fuel and and got nothing. They said it should shoot gas out. Fine. So I found this video on Youtube where you can replace just the main part of a fuel pump for $10. I ended up paying more like $22. So after all the nightmare of finding new fuel line retainer clips and putting it all back together, it still won't start. When I depress the schrader valve, I get just a little bit of gas, hardly any. So I printed out the long list of fuses, relays, diodes, etc and found about 8 that said fuel or fuel pump. Not sure how to test a relay. Any hints on what and how to test the next thing?
Now I'm wondering if I'm even getting spark. What is the best way to test for spark on this car? I'm working alone so I can't have someone crank it while I hold a spark plug to ground. thanks for any help

 

Steve,

I've copied this question to S-Type forum. It's different from your original issue with the broken fuel line clips so I've started a new thread for it.

Graham

 

Hmmm, you're still not getting fuel even after replacing this part.... your friends are correct, if it has proper pressure ( around 35 psi with ignition on ) it should be shooting out. I'd think you may still have a problem with the fuel pump, or possibly relay.


Before you move on to checking spark - I'd be trying to sort the fuel issue first.... You can try swapping relay R15 ( Fuel Pump ) with relay R7 ( Blower Motor ) see if this makes any difference. If not we'll need to move to checking why the fuel pump still isn't creating pressure ( you may need to replace entire fuel pump unit ).

 

Okay, printed out the chart and went out to the car. As far as I know there are only 3 places where there fuses and relays; in the trunk(boot) under the dash on the right (passenger USA side) and under the hood. I did not find one that looks like the one you sent me.
Second, under the hood is the only place I found relays with BOTH an R15 and an R7 in the same location AND they are two different sizes.
This is for a 2002 S Type. I do have a very long list printed out with all the numbers, sizes and colors of all the fuses and relays for what I believe is my car and yes, 15 is the fuel pump and 7 is the blower motor but there are two different sizes.
Also, why would I need a whole new unit when it seems like the only vital part in that device is the actual pump motor?
Oh what to ?????????

 

Charts are in the handbook - right? Or/and in the workshop manual & electrical guides (free downloads).

BTW you likely have spark. Don't be worrying about that at this stage.

 

Sorry - I forgot the fuel pump relay is the mini relay in the boot/trunk. There should be another mini relay there next to it, swap it with that one.

 

A couple quick questions: What handbook with charts? I don't have one. And where do you find the free downloads of workshop manuals and electrical guides?
Next, not sure where the 'signature line is in my CP.

 

Hi Steve,

To add your vehicle info to your signature line, click on the User CP link above and at the left margin. At the left side of the new window you will see the heading User Control Panel. Look down to Settings & Options and click Edit Signature. At the top of the new window is a preview of your current signature. Scroll down to the edit window and add your car's year, model, engine and mileage info. When you're happy with how the information looks, scroll a bit further down and click on Save Signature. All done.

Regarding some of the free downloads available, start with these links:

S-Type HOW TO Guides

Another great resource is jagrepair.com, hosted by our member Gus. There you will find helpful documents like this:

Jaguar S-Type Electrical Guide 2002

Jaguar S-Type Electrical Guide 2002.5

Cheers,

Don

 

+1 on that! One crisis at a time...

Got to thinking there have been a lot of fuel pump problems on the forum lately. What are the odds of that? I remembered recently posting some troubleshooting, with simple voltage checks and relays to be swapped. Found it in this thread, post #3:

https://www.jaguarforums.com/forum/s...y-fuse-197725/

Turns out not only does that guy have the identical problem, he's even posting under your user name! Oy vey, what a coincidence!

Note the happy emoji to show I'm having a little fun with you. I'm just trying to get across the importance of correcting one fault (no fuel pressure) before convincing yourself of another (no spark). Run those tests and get back to us. I'd suggest sticking with this thread, not the other, as this is where most of the best info has been posted.

 

Okay, now I know about the mini-relays in the boot. I switched those two. Nothing. Fully charged battery and nothing. Still no pressure at the schrader valve. I put a multi-meter on the elec. connection going into the fuel pump and I get 12 volts. GRRRR... now what? Are there other relays? Fuses? Diodes? And what and where is what they're calling an 'inertia switch'?
Been without a car for 2 weeks now. Not fun. But I'm determined to fix it. Thanks for all the help!

 

As you can see from the workshop manual & elec. guide the pump is driven by a module (via PWM - see my sig).

Best bet is probably trace through each of the wires - either study the elec guide or use the pinpoint tests.

 

Here's my latest on this nightmare: I took the day off work to roll up my sleeves and address this because, well, I had to, I don't have a car until I do.
So...........I wanted to make sure that I had 12 volts going to my fuel pump AND my sending unit. I unplugged the connections at the devices and sure enough, I had the voltage. Fully charged battery by the way. So then I printed out the pages from the online manual that showed which fuses, relays and diodes were involved with the fuel pump. Even though I had the correct voltage at the pump and sending unit I still discovered a burnt out fuse in the boot, #17, blue, 15 amps. I don't know how to test those other fuses with the clear plastic in those little 'boxes'. Number 23 in the boot is one of those and is a 30 amp fuse marked for fuel pumps, not pump, pumps, plural. Under the dash is fuse #4 marked for inertia switch. Same type of clear plastic box fuse. Not sure how to test it. Wait, Ohm meter.. ok.. duh. Under the hood is fuse # 5, 20 amps, yellow, marked for fuel injection. It was good.
So..........now what? do I just go buy some relays and cross my fingers? Is there a way to test them? What about diodes? Should I replace the one for the fuel? And what about modules? Should I get into that part of it? So frustrated. I spent hours on this and still no pressure at the fuel rod. GRRRRRRR
Thanks for letting me vent.

 

Have you checked the fuel filter to make sure it is not partially blocked? A filter mostly clogged with debris from bad gas would strain the pump and perhaps lead to an early demise...

Can you her the pump run at all? If you have adequate current at the pump, then either the new pump is bad or something is keeping the fuel from reaching the rail.

I could be all wet here, but that is what comes to mind...

 

Okay Steve,

First things first, from the Unsolicited Advice Department: Arrange the use of another car for a few days. This will help prevent the "I've got to fix this" panic mindset, which doesn't always work so well and sometimes gets very expensive.

We've got some specific things for you to check, and need you to respond in detail with what you've found. My mind-reading skills aren't what they used to be, so you will not insult me if you type slowly. That's just one of the drawbacks of long-distance troubleshooting. Don't assume I can see what you are seeing.

We also don't know your experience level, especially with electrical troubleshooting. Myself? My boss says he thinks I was born with a meter in my hand. In your replies, I'm seeing a lot of panicked squirrel-chasing. Not meant as an insult, but that tactic isn't going to help you.

Back to business, in post #10 above, I sent you off to another thread. Copied directly from that thread for convenience:

"Wiring diagrams here:

http://jagrepair.com/images/AutoRepa...x2032002en.pdf


See section 3.2 for the V8, or 3.4 for the V6.

You can do much of your troubleshooting from relay R7 at the rear power distribution box.

1) Unplug R7 and check for 12VDC at socket #3. This is unswitched battery power. If no voltage, check fuse F17 in the rear power distribution box.

2) Check for power at relay socket #1. With the ignition off, you should see nothing. Turn the key to ON and you should now see 12VDC. If not, check and reset the inertia switch. If still no voltage, check fuse F4 at the primary junction box. This is at the outboard side of the US passenger footwell.

3) If power checks good at both locations, try swapping that relay with a known-good relay from another location. I think the fog lamp relay (R7 at the front power distribution box) is the same. Try the fog lamps to confirm that relay is good, and then swap the two to see if the fault follows.

4) If still no joy, access the two wires between the rear electronics module and the pump. I'm not sure which connection is easiest to access, whether at the module, the pump itself, or that connector in the middle. Whichever you use, you can check continuity through the pump. If open, the pump is bad."


So far all I've seen is you've kinda done some of that stuff, and I have to break out my extrapolator to make sense of what you have and haven't checked. That ain't stuff I'm just making up. Do those steps in order and report back exactly what you've found. Be kind to my feeble old mind and even label your replies 1, 2, 3, and (wait for it...) 4.

Don't order any relays just yet. Don't go swapping diodes. Don't change the pump again. Don't go worrying about the 12V at the pump yet. The 12V you read there may be a misleading signal from the Rear Electronic Control Module, but without enough current commanded to actually run the pump.

You mentioned the confusing nomenclature at F23 at the rear power distribution box. I'm not seeing F23 as part of the fuel pump system. Are the locations printed on the cover? Maybe you've got it spun around?

You also mentioned rear fuse F17 was blown. See my question #1 (of 4) copied above. This is the power that actually runs the pump (via the Rear Electronic Control Module). You didn't specifically say you replaced F17, but I'm assuming you did. Did it blow again? If so, do NOT replace it a second time until you figure out why. It's generally okay to replace a fuse once, but after that, it's time to investigate why. We can walk you through that, but need to know more details.

Also, V6 or V8? And a little more history on the car, too. Have you owned it a while and this problem just started? Did you buy it as a project and it's never run for you? Help us help you.

 

Do you have spark though? Check that before any other time is invested. If not, check the Crank Position Sensor. If that is faulty the ECU will prime, but cut fuel if you try to start. If the CPS is not working it will most likely not have the pulse to let the ECUs generate spark too.
I have been through this, but a 35 usd sensor made my car fire up immediateley.

 

Not sure how to reply to a specific person in here. Anyway, thank-you kr98664, you're awesome! I will go down that list one step at a time this coming weekend. But in the meantime..
Here's what I've done so far:
From the very beginning I made the mistake of pulling out the sending unit thinking that was the fuel pump. Ooops. In the process I ended up breaking a couple of those screwy plastic fuel line connectors which sent me scrambling off trying to find some new ones. Even the local Jag shop didn't have any. What a nightmare.
Next I pulled the fuel pump itself out.
Okay, here goes, I'm going to confess something. I saw that Youtube video where the guy replaces the pump part of the fuel pump for $10. He was right! I ordered one from Amazon. It was just a little bit more. It came in a couple of days and I was able to do the swap. I put the fuel pump all back together. In the kit that they sent me with the pump were a couple of mesh filters but would absolutely NOT fit my setup. Just giving the old filters a visual and also being too lazy, in a hurry and burnt out on the process up to here, I left them in. Now I'm wondering if I mess up there and should have waited to get new ones. Yeah yeah, I know... bad move.
But I put the fuel pump back in with the new motor and the old filters. Shame on me.
Now back over to the other side where the sending unit is.
I still needed those stupid retainer rings so I spend and entire day driving around to different junk yards trying to find a Jag like mine that had them. I go ripped off by one junk yard that charged me a fortune for them but I bought them anyway.
So now both the fuel pump and sending unit are back in.
Next I printed out the charts and list of where all the fuses, relays and diodes are relating to fuel.
They all looked good. Well... my bad.. I passed up on one that was actually blown, the one in the boot. I got new fuses and put a new one in there.
I did that relay swap that someone in here suggested. Still nothing.
I don't hear a motor running when I turn on the key and there is no pressure coming out of the schrader valve.
Truth be told, I don't know how to test a relay.
I don't know how to test for spark either.
Next ????????????
What and where is the crank shaft sensor as Vortex suggests checking. And how do you check it?
What is the ECU? And what is a 35 USD sensor?
I want my 56 Chevy Nomad back....(just kidding, I love my Jag)

 

Here's a good tutorial on how to test a Ford-style relay:

Part 1 -Bench Testing a Ford Relay (A Step-by-Step Guide)


One thing that article doesn't really cover, though. If the relay contacts are pitted or otherwise damaged, they might still let a tiny trickle of current through for an ohmmeter to show as good. But under a heavy load (fuel pump, rear window defroster, etc.) not enough current will be able to flow. So don't let a seemingly good ohmmeter indication convince you a relay is good. The ohmmeter test is not conclusive. That's why I recommend swapping relays with one from another system that is proven to work properly.

Testing for a spark? That's a little tougher with the coil-on-plug design. But for the moment, since you are not getting any fuel pressure at the injector rail, I wouldn't worry about the spark. Chances are the ignition system is fine.

One other thought, and hopefully somebody more knowledgeable can chime in. Isn't there an anti-theft mode that shuts off the fuel pump but still allows the starter to engage? I think the logic was the thief would crank the starter until the battery died, but the engine would never start without fuel pressure. If this is true, could that have accidentally been triggered?

 

You wrote:
What and where is the crank shaft sensor as Vortex suggests checking. And how do you check it?
What is the ECU? And what is a 35 USD sensor?

I attached a pic for the V8, because I still do not know what engine is in your S. The cranksenor (no7) controles spark signals and pump function to the brain of the car, the Electronic Control Unit (ECU). That sensor is easy to replace and is cheap at $35 (US-dollars). I got it from a Jaguar dealer at that price.
It restored fuel pressure and spark, runs like a dream.

BTW, you can measure the resistance of the sensor first, but you need to have a good multimeter (which costs as much as the sensor)

 

One other thing I forgot to mention is that for about a month before my car finally refused to start it was getting harder or and least a bit longer to start. Instead of starting right up it would take more like 5 or 7 seconds of cranking leaving me worried that it wouldn't start, then it would start.
By the way, new coil overs and plugs were installed 2 months ago.
Thank you guys for all your help and suggestions. I'm taking the day off work AGAIN today to get back into working on this. The rain has kept me from it this past week.