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Fuel pump issues by tnkgnr
Started on: 10-21-2020 11:18 PM
Replies: 17 (314 views)
Last post by: tnkgnr on 11-28-2020 02:29 PM
tnkgnr
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Report this Post10-21-2020 11:18 PM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hey there,

I have an 86 3.4pr and have been blowing fuel pump fuses somethin fierce. I got a new pump, new strainer, new fuel filter and swapped everything out no problem. The system charges to 40 odd psi as it should. The interior of the tank was pristine - no rust or particles.

Thing is, since I swapped the pump, it's had what I think is an unacceptable whine to it...as if it's struggling to do its job (but the whine doesn't increase with load on the engine). Seems like the car has diminished oomph at high RPMs. After about a week of doing perhaps five trips, tonight the fuse blew again for the first time since changing everything as I was taking off in first gear.

Any ideas what the problem could be? I reused the old pulsator when changing - that shouldn't be a problem right? When I had everything out, I made sure to check all the wire insulation from the sending unit to the firewall for any potential shorts, but didn't see any evidence that was a problem.

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Warlordsix
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Report this Post10-22-2020 08:11 AM Click Here to See the Profile for WarlordsixClick Here to Email WarlordsixSend a Private Message to WarlordsixEdit/Delete MessageReply w/QuoteDirect Link to This Post
You typically don't need the pulsator with most modern pumps. If you have a turbine-style pump, and you probably now do, it runs quieter than the older gerotor pumps, draws less current and doesn't produce the varying pulsations that required use of pulsators with the older, gerotor pumps.

Ernie

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tnkgnr
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Report this Post10-24-2020 02:23 PM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yea, but having a pulsator, even with the turbine-style fuel pump that is there now, shouldn't make you blow fuses right? There's no way to hook it (pulsator) up backwards, correct?
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Report this Post10-24-2020 03:16 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
Check the vent line on the tank.
If it's blocked, pump is creating a vacuum in the tank.

See Section 6C in Factory Service Manual.
Can be checked without dropping tank.

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[This message has been edited by fierosound (edited 10-24-2020).]

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tnkgnr
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Report this Post11-09-2020 04:23 PM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
Did the evap line test and it works properly (blew in lower hose - not able to push air, applied vacuum to upper hose and then was able to blow through lower hose). I also applied vacuum to steel fuel vent line, and then was able to release it by opening the gas cap, so there's no blockage.

Guess it's dropping the tank again for me...unless there are any other ideas out there.
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tnkgnr
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Report this Post11-09-2020 05:39 PM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
I jacked it up to look around and I think I may see a problem. Is it possible to pinch a line by tightening the straps too much? Notice the gap between the center brace and the gas tank in this pic.
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Patrick
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Report this Post11-09-2020 06:02 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by tnkgnr:

Is it possible to pinch a line by tightening the straps too much?


None of the rubber fuel lines are located under or on top of the tank.
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tnkgnr
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Report this Post11-09-2020 06:05 PM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
I was thinking the solid ones could also get crushed?
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Patrick
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Report this Post11-09-2020 07:34 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by tnkgnr:

I was thinking the solid ones could also get crushed?


Not if each one was located correctly in its "track".

In any case, the tank only goes up so far, and "over tightening" of the straps wouldn't move the tank up any higher.

 
quote
Originally posted by tnkgnr:

Any ideas what the problem could be? I reused the old pulsator when changing - that shouldn't be a problem right?


Well, there's a good chance that this pulsator is 34 years old. Perhaps it doesn't seal as effectively as it used to, and the fuel pump is spinning like crazy (because of less load) due to fuel leaking past the pulsator/pipe connections. How quickly does the fuel pressure drop when the engine is turned off? I wager it drops very quickly.

[This message has been edited by Patrick (edited 11-09-2020).]

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tnkgnr
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Report this Post11-09-2020 08:51 PM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yea, they were all in the tracks correctly.

It does drop off quickly. I've verified that it's not the injectors leaking. Guess I'll just drop this thing and replace the pulsator with some submersible fuel line.
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Patrick
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Report this Post11-09-2020 09:24 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by tnkgnr:

Guess I'll just drop this thing and replace the pulsator with some submersible fuel line.


Yes, make sure you get the right stuff... SAE 30R10 submersible fuel line (Gates 27093, NAPA H209)

Don't make the same mistake I made. Have a look Here.

[This message has been edited by Patrick (edited 11-09-2020).]

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tnkgnr
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Report this Post11-17-2020 01:15 PM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
All right, new pump/strainer installed and running. Will start driving it tomorrow and we'll see if the fuses keep popping. I ordered up a Bosch one this time...was pretty nervous since the polarity appears reversed from the original.

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tnkgnr
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Report this Post11-18-2020 11:05 AM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
Dang this thing is loud...almost obnoxious. https://youtu.be/8BFAb-VmLUA

Anyone else install one of these Bosch 69222 pumps and it sounds this way? https://www.rockauto.com/en...1&cc=1249107&jsn=865
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tnkgnr
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Report this Post11-19-2020 10:45 AM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
Popped another fuse on the short test drive. Again while taking off in first gear. I disconnected the supply line at the fuel rail and primed the pump - when I did so, the pump was nearly silent...so I'm thinking maybe some sort of obstruction might be in there?
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tnkgnr
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Report this Post11-19-2020 12:29 PM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
Oof...just did a fuel pressure test - nearly 80psi! Maybe the fuel pressure regulator?
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Patrick
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Report this Post11-19-2020 01:15 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post

Does the return line flow freely?
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tnkgnr
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Report this Post11-20-2020 10:04 AM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
With the return line disconnected, the pump still makes the loud noise and the pressure spikes to near 80psi. The fuel does come out of the return line, but more of a very quick dribble vice the flow from the supply line.

I guess this test confirms that the issue is somewhere in the fuel rail (I suspect the pressure regulator, which should be here tomorrow).
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tnkgnr
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Report this Post11-28-2020 02:29 PM Click Here to See the Profile for tnkgnrSend a Private Message to tnkgnrEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sigh...got the part and go to replace it and see this - looks like some sort of adjustable regulator, and the new valve doesn't fit that housing.

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