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On your '89, there is a fuel pressure check valve in the fuel line on the output side of the fuel pump.
Have you checked the VCM for stored fault codes?
I'm also wondering whether the "coolant sensor" you replaced was the single-terminal sender for the temperature gauge on the instrument cluster, or the two-terminal sensor that provides the signal to the ECM?
Also, if your coolant thermostat is stuck open, the engine may not be reaching full operating temperature, which causes the ECM to continue to apply cold-start fuel enrichment even after the engine has warmed up, so it will run rich. If the thermostat and coolant temperature sensor (CTS) are both inoperative, this can lead to excessively rich running.
Have you done a compression test on all six cylinders?
Cheers,
Don
Okey I'm gonna have a look at that check valve, thanks!
Have got a fault code some times but no code.
Yes the coolant sensor was the one for the instrument but I have measured the other one both cold and warm at it gives the right output.
Did a compression test also and nothing abnormal there either.
Which one? Didn't know there was a separate one? I have the fuelpump under the car and thought there was one built in the pump or am I wrong? Actually heard a slurping sound last from the tank so maybe it's broken, but shouldn't this just affect the car when it's turned off by loosing pressure then? While driving the pump should keep the pressure up and the check valve wouldn't make a difference?
I really don't know, it's just that you've changed just about everything else and I recall owners with external pump models having issues with a check valve.near the pump.
Seems to me though if the valve is there to prevent backflow and if it fails, logical that pressure would drop in the rail. I'm pretty sure I saw an illustration of an external pump assembly (posted by Don) that showed the valve,
It was small and inline near the pump IIRC.
My 94 car has an in-tank pump so different system,
Coolant sensor is very inexpensive, false economy not to replace it, it can cause all sorts of problems with fuelling/starting/running
Here's the diagram Larry mentioned. The check valve is part #2. Some of us have added an additional inline check valve. See my photo albums.
I like Jim's idea of testing for excessive current draw or sagging voltage to the fuel pump. You can check the fuel pump wiring by following the schematics, which you can download at this link:
I really don't know, it's just that you've changed just about everything else and I recall owners with external pump models having issues with a check valve.near the pump.
Seems to me though if the valve is there to prevent backflow and if it fails, logical that pressure would drop in the rail. I'm pretty sure I saw an illustration of an external pump assembly (posted by Don) that showed the valve,
It was small and inline near the pump IIRC.
My 94 car has an in-tank pump so different system,
Coolant sensor is very inexpensive, false economy not to replace it, it can cause all sorts of problems with fuelling/starting/running
Larry
Originally Posted by Don B
Simon,
Here's the diagram Larry mentioned. The check valve is part #2. Some of us have added an additional inline check valve. See my photo albums.
I like Jim's idea of testing for excessive current draw or sagging voltage to the fuel pump. You can check the fuel pump wiring by following the schematics, which you can download at this link:
What do you think of putting an check valve between pump and filter? Worth a try ain't it? Or just good incase the other one goes bad. I checked the voltage on the pump when the pressure was low and it was giving 14volts and sounding good?
I think I may have found the problem but I'm not sure. I think it's the fueltank. Inside the tank where the return line comes through, there goes by a hose into the fuel cell inside the tank, I guess it's so that the car always have gas in the fuelcell..? The thing is that I removed this hose thinking it was the feeding line so the fuel came directly to the feedline and skipping the fuel cell.
When the hose was removed it seems like the fuelcell ran low or something and that leading to the fuel pressure getting low and a lot of powerloss? But when it was removed the fuelpump is quiet.
But then I connected the hose again and the fuel pressure remained good and there was a big difference in power. BUT now the fuelpump is noisy and buzzing loud like ot has done before, and the car is staling and having hiccups.
Was a big difference with the hose connected and not connected even though both ways it doesn't run good. But doesn't this mean the problem must be something in my fuel tank? And how then? Cleaned it and it seemed to flow fine but maybe not good enough still?
But why would the pump start buzzing when the return hose into the cash tank in the tank?
Last edited by Simon Johansson; 03-16-2020 at 02:20 PM.
I think what you are calling a fuel cell is what Jaguar calls the swirl chamber. Here's a diagram of the fuel system:
This diagram is from the manual at the link below, which is for the 4.0L cars, but it contains a lot of information that is also relevant to the 3.6L cars:
I think what you are calling a fuel cell is what Jaguar calls the swirl chamber. Here's a diagram of the fuel system:
This diagram is from the manual at the link below, which is for the 4.0L cars, but it contains a lot of information that is also relevant to the 3.6L cars:
Yes exactly, thanks for the diagram! But what do I go from here, could it really be the tank? Why does the fuel pump only buzz when the return goes inte the swirl camber? The car runs much better with the hose connected but if I give the car some throttle it starts jumping and thrusting and I can hear the pump even while driving.
It's like the return line is a little loggedc in the swirl camber so the pump needs to push extra hard to get it through and therefore it gets loud? Just speculating becauu I'm running out of ideas and it's getting frustrating haha.. can add that my idle is almost not enough to keep the car alive when I just started the car, but when driving and stopping it's no problem, just at the start of the car. And i have set the idle by the book and it's good after the start, just takes a while before it settles.
It seems possible that despite all of your new parts there is dirt in your fuel tank clogging flow into that "swirl chamber." Unfortunately that is a complex thing to fix. You have my sympathies. Good luck!
It seems possible that despite all of your new parts there is dirt in your fuel tank clogging flow into that "swirl chamber." Unfortunately that is a complex thing to fix. You have my sympathies. Good luck!
Yeah I could have thought it is a bit complex, will need to cut the tank open in order to to that somehow. A new tank for this modell with the separate fuelpump I can't seem to find anywhere. Would I just be able to drill up the connections in the bottom of the tank with a drill so that the fuel flows directly from the connections at the bottom of the tank and skips the swirl tank? In know it's not such a good idea because it gets easier for dirt and such to flow through but was thinking of a last way fix..? A new tank will be hard to fint and won't be a easy job to get it clean either so was thinking of drilling then go like that for as long as possible?
Here is a video of the pressure gauge and the pump noise. You can hear when I pull the vacuum hose to the FPR and then de pressure goes up and the down when I connect it again. But it's swaying so much so it feels like the pump is drawing air and not a steady flow and therefore sounding like that and the gauge acting like that because it did not sway like that before?
The swirl chamber is designed to help ensure that the fuel pump remains primed and pumping fuel even under low fuel conditions and while cornering or ascending/descending hills, so I don't see how it could be your problem.
Is it possible that one of your fuel pipes has become kinked or obstructed, or the new fuel filter is obstructed?
The swirl chamber is designed to help ensure that the fuel pump remains primed and pumping fuel even under low fuel conditions and while cornering or ascending/descending hills, so I don't see how it could be your problem.
Is it possible that one of your fuel pipes has become kinked or obstructed, or the new fuel filter is obstructed?
Cheers,
Don
Maybe the line to the swirl tank is partly clogged and therefore the pump don't get as much fuel as needed? Don't seem impossible? The car has been out of trafik for 14 years untill 2018 but the owner had took som spin around the neighborhood from time to time but other than that it's been sitting in a garage. Therefore maybe rust in the tank has loosened and clogged the lines to the the swirl tank? Don't know how it's designed but just speculating because the problem has occurred newly.
Have changed the filter twice so no problem with that, checked the fuel lines and they are looking really good.
It must have been the swirl tank or something partly clogged in the tank, I drilled into the connections so that the fuel was drawn from the bottom of the tank and so skipping the swirl tank, then put a filter with metal strainer and that your able to screw apart and wash before the fuelpump so that dirt from the tank don't get into the pump!
So happy that I finally located the fault, and now I have ha fully serviced car after all the new parts and fault searching haha!
but no More staling and hiccups, perfect fuel pressure and so on.
only one problem left and it is that the idle is poor when ju start the car, impossible to get I stable when the car is cold, need to put my foot on the gas pedal. When driving and after that the idle is perfect it's just when I start the car, worst when cold but not great at all when warm either but it doesn't die. Any ideas about that?
03-16-2020, 10:31 AM
