I have a 2005 Jaguar S Type 3.0 L. When I drive the car it hesitate when under load.
I changed the spark plugs, 6 coils, and fuel filter but have the same problem.
I checked the fuel pressure while I am driving and found out it fluctuates between 18 -45 psi.
Looks like I need a new fuel pump. My fuel pump has a square connector with 6 wires. I am having problems finding a similar fuel pump. The ones Jaguar is selling me or the ones I find from salvage yard have a round 4 pin connector.
Has anyone come across this before? Is there a way to purchase an adapter to convert my 6 pin connector to a 4 pin connector?

 

The pressure is meant to fluctuate (it's a returnless system, too) so don't assume you have a bad pump.

Yours may still be bad, but you'd need to know more to be able to say.

Someone here may have a better idea than just throwing parts at the car, hoping to get lucky. I expect OBD would help but you'd need to know how to use it in a case like this.

If you get no better help I'd go looking for an expert (on your car model) jag tech.

 

I actually had a mechanic connect to the vehicles computer through the OBD connector. As we were driving he was telling me the fuel pressure and concluded it was the pump.

If not the pump what else could cause the car to hesitate. I have changed the coils, sparkplugs, and fuel filter.

I have had nothing but problems with this car. There are so many problems I dont know where to begin. With the money I have spent on purchasing it and repairs I need to keep it for a years to make any financial sense.

I purchased a salvaged 2005 S Type as a donar car so I could use it for parts. As luck would have it the pump is different from mine. It has a 4 pin connector not a 6 pin connector like mine.

Need to know if there is a way to make the 4 pin pump work in my car.

 

If you want to be convinced that the fuel pump produces varying pressure read the workshoip manual (JTIS will be good enough even for your car year, free if you look or $5-10 on ebay).

Surely that's not all he watched but also surely he'd have looked up how the pumped system works.

 

I changed the fuel pump and it looks like everything is working fine now.

 

Lucky you. I also have a 2005 s_type, replaced the pump 3 months, 3k miles ago after the car died on the highway doing 70mph. Had to be towed to a shop. The pump was replaced and now exactly the same problem, had it towed home this time. Fuse to the pump was blown, replaced the fuse but still does not start. I have no desire to spend money on another pump if that is really the problem. Still need to test the fuel rail and see if I'm getting gas up there.

 

Something is causing the pump to blow because that problem is very very rare on here.

Has the fuel filter been changed each time, for example? Or, could a line be kinked?

 

changed the filter when the pump was replaced. I'm getting no fuel to the engine. Pulled the electric connector from the pump and tested the leads. It is hot all the time, when I turn the switch on the current does not change using a volt meter. Also the ground level does not change. I have pulled every fuse and relay the manual says is related to the fuel pump and it still has power.

Just about out of ideas.

 

Er... the pump is PWM-driven from the module, isn't it? If so, it's not exactly "hot" or "not hot", although the module and PCM (which feeds the module via another PWM signal) will be very confused if you mess with the pump I expect. It looks to be a feedback system so I wonder what happens when you interrupt the way it works!! Did you read JTIS about it?

No fuel to engine might well be a blocked or kinked hose.

Obviously the fuel pressure sensor needs to be working or the PCM will do the wrong thing.

 

Don't have JTIS and can't find much for my 2005 on the net. All the JTIS manuals I find only cover up to 2004.
Really doubt a kink or blocked hose is the issue since the pump should still run if that were the case. I pulled the gas line off by the engine and it was bone dry, seemed odd for it to be that dry. I may disconnect the gas line at the pump and at the s valve by the fuel rail and shoot some air into it that will tell me of a blockage.

I didn't mess with any thing electrical other than read the voltage and ohms at the connection point of the pump.
Fuel pressure sensor is an interesing thought, I'll try and check that out.

I am going to swap out the pump relay and see if there is any change.

Thanks for the ideas, please keep them coming..

 

JTIS will be more than adequate for this.

 

Swapped relays, it clicks when the key is turned to on, pump doesn't run.

What is the plastic cylinder in the engine area, looks like and same size as a fuel filter, hose / fuel line connects to it. Might it be the fuel line presure sensor?

Man I am frustrated with this. I rebuilt many engines over the years (an old gear head..lol) this thing just seems to be the fuel pump. Maybe I got a bad one 3 months ago.
Pump has a warranty but it came from the shop who put it in when the car broke down. The shop is over 100 miles away so gettng them to help with a claim is going to be tough. It would be nice to have a way to test the pump itself. At least then I can be sure, and have a better case for the warranty claim.

 

I've pulled about all power and the pump connector still has 11 volts going to it. Even unplugged the rear ecm cables in the trunk, still have power. ha ha. That should not happen since the power is supplied via the ecm from what I have read.
If I disconnect the battery I do lose power to the pump. again. ha ha.

I have a 2004 electrical diagram for S-type, tried to understand the current flow. But the wire colors do not match with my car so there must have been a change. I know there was a change in fuel pumps during 2005, mine is the more expensive one.

Putting my meter across pins 1 and 3 of the pump connector shows the 11 volts, I also get 11 volts by using pin 1 and a frame ground.

 

I pulled the fuel pump and looking at the 4 wires the number 1 and 4 drive the pump while 2 and 3 go to the float. I don't know the starting point so the numbers are just in relation to each other, 1 being pink and black strip while 4 being all black. Now the question is why does number 4 have have full ground when from what I understand it varies based on the recm to control the pump. I also believe the number 1 is always "hot" so do I have a bad recm along with a bad pump? Did the recm make the pump go bad or did the pump short out and damage the recm? Since this pump is under 3 months old I would guess the recm is bad and damaged the pump..... BUT how to tell? These things aren't cheap.

 

The cars went from no CAN (1999-2002) to some CAN (2003-sometime) to more CAN (dunno exactly when), so it may be that. The newer diagrams are on jag's TOPIx.

Maybe appeal for a member with similar age car you could compare against or just buy a used RECM etc and swap.

Really you should check voltage waveforms using a 'scope for this......
Many shops wil have one or try an electronics student or the like.

The RECM is on the bus network and such as dealer OBD tools can talk to it.

 

interesting. I haven't scoped for many many years, could be interesting. Getting down to basics, the fuel pump is still just a pump and is a dump pump at that, no talking going on between it and ecm except a little rheostat feedback. So way the rem provides the ground when the car is turned off has me very puzzled.

I unplugged the recm and then lost the ground at the pump so I know it is not a bad wire. So there are two possibilities 1) the recm is bad or 2) I am stupid and don't know what is really going on in the system, the recm is fine and a new pump will solve everything.

I have looked for a used recm and found few, still want $300 plus used. Guess I can try that route and if mine turns out not to be bad I can just sell the newer one.

Thank for putting up with my ramblings.

 

The pump doesn't talk as such (the RECM does) but I suppose there will be the usual electric stuff (current, back EMF, y'know). The RECM could sense that stuff.

I'd use a scope as it's PWM so a meter is fairly useless.

 

I think your pump is bad. 2005 was an interesting year for them. There are two fuel tank designs and therefore two fuel pump set ups. I would recommend getting a genuine pump. You will need to find a good dealer to talk to cause the tanks are listed as original or hybrid or something else. The REM very very very very rarely goes bad, not to say its impossible but havent seen too many go bad. The REM provides the PWM ground to the pump depending on engine requirements. These pumps keep a constant pressure but vary volume. The feedback is only the REM talking to the ECM saying that it is doing as requested, not the actual pump saying its doing as told. There should be six wires as well. two pump wires and four level sensor wires. Hope this helps.

 

Thanks Black,
I have the 4 wire pump instead of the 6 wire, not sure which is the newer style. I spent last night reading up on pwm and fuel pumps, very clever stuff.

I'm trying to talk to a friend who is an electrical engineer (he is on vacation) so I can understand a little better. Hopefully he has a scope we can connect to the pump leads and see what is going on, as suggested by Jagv8, Jag has been very polite not telling me I'm an idiot.

The thing I just can't understand even considering pwm technology is why would an ohm meter show ground on the wire going to the pump when the key is off, I read the ground often controls the pump speed. Even if the positive were to be used as the pulse why would it have any current when the key is off. Seems one wire should break the circuit even with pwm when the key is off. When I understand that I might go duhhhh, now it makes sense. LOL

I assume if I were to place 12 volt current for a few seconds to the pump (which I removed from the car) it should run unless it is shorted out. The pwm design would not matter when the pump is stand alone??

From what I have read these pumps RARELY fail so it seems for my original pump to blow a fuse and die then the replacement (new from Jaguar) to blow a fuse and die exactly the same way (3 months later with no warning) would cause a person to wonder what is going on. That is why I am looking for a source for pump death.

Thanks again.

 

I didn't read the last few posts, but when the fues popped, (problem...) did you check the fuel safety cut off switch?