No more Bosch fuel pumps produced. What is the next best?

Did you replace just the fuel pump or the entire assembly including the fuel pressure regulator? The fuel pressure regulator has a check valve too but is associated with rapid pressure loss rather than the slower pressure loss of the check valve inside the fuel pump module.
 
In the 2000 TJ, I replaced the fuel pump with an OEM Bosch when installing the GenRight tank. Old pump worked fine, so it's a spare. New pump was a little balky, so I began switching to ON and waiting for the CEL to extinguish before cranking. Time for seat belt, sunglasses, etc. Worked so well, I also do it on the 2002 Tundra and the 2007 Frontier. I like that it saves cranking time, always get a right-now start.
 
  • Like
Reactions: Jerry Bransford
toximus said:
An easy way to test if it's a problem is by starting the cold engine by turning the key on once. And then compare by priming the fuel by turning the key on multiple times before cranking the engine.
Click to expand...
If I don't prime two times it takes like 15 20 seconds to start.
 
Jerry Bransford said:
Did you replace just the fuel pump or the entire assembly including the fuel pressure regulator? The fuel pressure regulator has a check valve too but is associated with rapid pressure loss rather than the slower pressure loss of the check valve inside the fuel pump module.
Click to expand...
Entire assembly.
 
Mark K said:
In the 2000 TJ, I replaced the fuel pump with an OEM Bosch when installing the GenRight tank. Old pump worked fine, so it's a spare. New pump was a little balky, so I began switching to ON and waiting for the CEL to extinguish before cranking. Time for seat belt, sunglasses, etc. Worked so well, I also do it on the 2002 Tundra and the 2007 Frontier. I like that it saves cranking time, always get a right-now start.
Click to expand...
That's what I been doing in the last couple days, but some times I forget and is a little embarrassing.
 
toximus said:
Yup. You've got a problem.
Click to expand...
What could it be?
This morning I didn't prime, (Jeep in the garage) I crank it and stop at 20 seconds, second try started right up, ran it for like 3 minutes, pull it out from garage and turn it off, went back In the house, came back and didn't start at first try, second try started right up. I got to work parking lot turn it off, crank it and started right away.
I am so intrigued. No problems when the jeep is running.
I got no Check engine light on.
Though I have ODB connected and emission readines shows Catalyst and O2 sensor heater on red (meaning not ready for emission test)
By the way, I am not a mechanic, I just like the challenge to work in my vehicles.
Any help will be apreciated!

Screenshot_20210128-073624_Torque.jpg
 
gonzvj said:
What could it be?
This morning I didn't prime, (Jeep in the garage) I crank it and stop at 20 seconds, second try started right up, ran it for like 3 minutes, pull it out from garage and turn it off, went back In the house, came back and didn't start at first try, second try started right up. I got to work parking lot turn it off, crank it and started right away.
I am so intrigued. No problems when the jeep is running.
I got no Check engine light on.
Though I have ODB connected and emission readines shows Catalyst and O2 sensor heater on red (meaning not ready for emission test)
By the way, I am not a mechanic, I just like the challenge to work in my vehicles.
Any help will be apreciated!

View attachment 221620
Click to expand...
Most likely the fuel pump isn't holding pressure. I'd start there.

Edit: Oops. I see you already tried that. Did the issue change at all when you changed the pump?
 
gonzvj said:
I replace the whole assembly twice with no luck. Should I change just the fuel pump with the Bosh 69316 from Amazon?

View attachment 221633
Click to expand...
I've been following since I have a similar issue but I'll chime in. I replaced my fuel pump with this one and still have a long start/fuel pressure leakdown. Just the pump, not the whole module.
 
toximus said:
Most likely the fuel pump isn't holding pressure. I'd start there.

Edit: Oops. I see you already tried that. Did the issue change at all when you changed the pump?
Click to expand...
The fist pump I replaced, pressure was 44 psi while running and went down to 10 psi 3 hours after shout it off. Second one was 55 psi while running and hold the pressure longer, but neither solved the problem.
 
gonzvj said:
The fist pump I replaced, pressure was 44 psi while running and went down to 10 psi 3 hours after shout it off. Second one was 55 psi while running and hold the pressure longer, but neither solved the problem.
Click to expand...
Since you said there's no fuel leaks, the issue is either going to be on the fuel pump end or on the injector end.

My gut feeling is that the pump assembly is still the issue, but the chances you have a 2nd bad one is unlikely. The regulator would be the part you want to replace with OEM or Bosch. If you aren't chomping at the bit to drop the tank again you can rig up a cap for the end of the fuel line up by the engine and then test if you lose as much pressure overnight. That would rule out leaky injectors. Sending an oil sample to Blackstone for analysis could also show if the injectors are leaking.
 
  • Like
Reactions: Tob
toximus said:
Since you said there's no fuel leaks, the issue is either going to be on the fuel pump end or on the injector end.

My gut feeling is that the pump assembly is still the issue, but the chances you have a 2nd bad one is unlikely. The regulator would be the part you want to replace with OEM or Bosch. If you aren't chomping at the bit to drop the tank again you can rig up a cap for the end of the fuel line up by the engine and then test if you lose as much pressure overnight. That would rule out leaky injectors. Sending an oil sample to Blackstone for analysis could also show if the injectors are leaking.
Click to expand...
That's what I am doing today after work.
I'll set up the gauge before the fuel rail. To separate both ends.
And about dropping the tank, I am getting use to it. The last time it took me an hour to drop it, replaced pump and re installed it. Everything was already clean from the first time.😂
 
gonzvj said:
That's what I am doing today after work.
I'll set up the gauge before the fuel rail. To separate both ends.
And about dropping the tank, I am getting use to it. The last time it took me an hour to drop it, replaced pump and re installed it. Everything was already clean from the first time.😂
Click to expand...
Update!
Yesterday I isolated the fuel rail and injectors, pressurized them with 60 psi. While pressurized tested for exterior leaks with soapy water, didn't see any bubbles anywhere.
In 3 hours the pressure dropped to 53 psi.
Then I pressurized the other end going to the tank with 55 psi and the pressure dropped to 35 in 3 hours.
In the morning before going to work it was at 30 psi. (Garage is warm)
Right now the jeep is sitting at work parking lot (temp around 40 degrees) and the pressure dropped to zero from 7:00am to now. The leak seems to be worse in cold weather.
I don't know if is the pump or just the FPR.
I am ordering Mopar fuel pressure regulator and Bosh fuel pump from Amazon. We'll see when I get them what happens.

Thank you all for your replies!!
 
  • Like
Reactions: Tob
Well, I am giving up on this. Replaced fuel pump with Bosh, Mopar FPR, Fuel injectors, and the issue continued,
I have replaced the Crankshaft sensor, distributor pick up, distributor cap and rotor, ignition coil, spark plugs, also the battery was week so i replaced too, but, the issue persist.
Attached is a video of the no start with good fuel pressure at 35 Degrees temp. i can crank it all day and it will not start at first try, but second try usually works. today we are in the mid 20's and it took a little longer to start. The picture is all the parts I have replaced ( I get good discount at Napa). Good thing is, I have a lot of good spare parts.:)
What else is there to look at?
PLEASE HELP!!!!

20210210_184734.jpg
 

Attachments

  • 20210209_180626.mp4
    6.5 MB
gonzvj said:
Well, I am giving up on this. Replaced fuel pump with Bosh, Mopar FPR, Fuel injectors, and the issue continued,
I have replaced the Crankshaft sensor, distributor pick up, distributor cap and rotor, ignition coil, spark plugs, also the battery was week so i replaced too, but, the issue persist.
Attached is a video of the no start with good fuel pressure at 35 Degrees temp. i can crank it all day and it will not start at first try, but second try usually works. today we are in the mid 20's and it took a little longer to start. The picture is all the parts I have replaced ( I get good discount at Napa). Good thing is, I have a lot of good spare parts.:)
What else is there to look at?
PLEASE HELP!!!!

View attachment 225639
Click to expand...
When it finally starts is there a plume of black smoke? Leaky injectors would create a very rich start.
 
Top Bottom
Back