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Kjet fuel groaning

A

adamdrives

Active member
Joined
Aug 9, 2010
Location
San Jose
My 78 has had what I thought was a noisy main pump since I?ve had it. Recently it started having a noticeable drop in power, so I figured it was time to do pumps. (The car came to me 2 years ago half put together with 2 el cheapo pumps) I figured the in tank died and was killing/killed my main. Well, I was half right, the in trunk fuse had popped, but the pump was still alive. I had them so I replaced them anyway with a fresh sending unit. Started up, and she sounds the same. Confirmed power at both pumps. The noise is louder towards the bulkhead than rear floor, but too noisy with the hood open to isolate. It I put my hand on the filter and lines, I can feel the vibration more strongly then on the main pump. Does the accumulator act as a dampener? I?m not sure where to look next.

https://youtu.be/G7NuxPY2FF4

https://youtu.be/mkKcbDzOGwE

Thanks
 
The fuel accumulator is a spring diaphragm that just holds back fuel to build pressure and smooth out the flow. Fuel filter might be clogged causing a restriction?
 
Volvo used to sell an inline vibration damper to quiet down some of the louder pump setups. Some of those intank pumps are just noisy pumps. Might be better to also use the hose that volvo sells with the ridges in it to absorb vibration inside the tank. It's the short connector hose from the pump to the fuel pipe.
 
dl242gt said:
Volvo used to sell an inline vibration damper to quiet down some of the louder pump setups. Some of those intank pumps are just noisy pumps. Might be better to also use the hose that volvo sells with the ridges in it to absorb vibration inside the tank. It's the short connector hose from the pump to the fuel pipe.
Click to expand...

iPD still carries it but I have some thicker hose in there and even with an aftermarket pump it barely causes vibrations or noise especially with the thick rubber gasket between the sending unit and tank
 
dl242gt said:
Volvo used to sell an inline vibration damper to quiet down some of the louder pump setups. Some of those intank pumps are just noisy pumps. Might be better to also use the hose that volvo sells with the ridges in it to absorb vibration inside the tank. It's the short connector hose from the pump to the fuel pipe.
Click to expand...

Interesting. Wouldn't happen to have a PN would ya? Nothing visible in vida.

I don't think the problem is the in tank, it was making the same noise while the inline fuse was popped. I'm interested in the in line damper.
 
I had similar issues with my 82 turbo. I was convinced that replacing the in-tank pump would resolve the issue. It did not. Replaced main pump (Bosch) still same issue. Caused me issues for months, had it looked it, pumps tested, all working. Installed the IPD UPGRADED (assume more flow) in-tank pump - issue resolved.
 
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adamdrives said:
Interesting. Wouldn't happen to have a PN would ya? Nothing visible in vida.

I don't think the problem is the in tank, it was making the same noise while the inline fuse was popped. I'm interested in the in line damper.
Click to expand...

https://www.ipdusa.com/products/211...00-700-900-for-Volvo-MTC-VR406-3514360-246716

I believe this is the one he's talking about, doesn't change the fact the pump is still mounted rigidly to the return pipe

Try and get your hands on an automotive stethoscope lol. isolate the noise easier with everything running
 
The reason I don't think its the in tank pump is it still made the same noise with the in tank getting no power. I'd like to try a damper and see if that helps. Any particular location after the main pump that's ideal?
 
adamdrives said:
The reason I don't think its the in tank pump is it still made the same noise with the in tank getting no power. I'd like to try a damper and see if that helps. Any particular location after the main pump that's ideal?
Click to expand...

Are you sure that the intank pump is providing enough fuel flow to the main pump? My car was making exactly the same noises until i installed the upgraded pump. Other symptoms I had were loss of power and stumbling after ~30 minutes of driving (at lower revs).

Pump: https://www.ipdusa.com/products/5799/In-Tank-Fuel-Pump-Upgrade-Kit-for-Volvo-IPD-111016
 
It's a new pump, I haven't done a volume test. I had the same low power but oddly it was most noticeable in 1st gear. I'll consider the upgraded pump, I put one in my turbo wagon but that didn't have any issues like this one.
 
My kjet main pump will groan on shut off or priming when it builds a little too much pressure for a second and I have the upgraded intank pump but once running it won’t groan or anything, the entire kjet systems runs off pressure so if you’re losing power I’d imagine you’re losing fuel pressure. My kjet greenbook says 75-79 pump should run 100l/h with a draw of 9.5 amps on main pump and 1-2 amps in tank. E/F should be 65-77psi and Turbo 75-84psi with the gauge connected to WUR and fuel distributor(WUR unplugged), with the WUR regulator plugged in you should see 50-54 psi once it’s warmed up.
 
I've had intermittent main pressure pumps on kjet cause poor power. You are barely able to drive or accelerate and go 50mph. The engine would run fine for about 20 minutes then the pressure would drop and the ca was down on power. It was dropping to about 45psi and swinging wildly. Ran great after main pump replacement. It was an 81 B21F kjet with bosch ignition. Car was M46 with a 3.31 so it was still very slow...
 
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