Topic: I am stumped; please help!

[jfrabat]

OK, so here's the deal: I decided to change a bunch of stuff on my Jeep to try to get it to run decently once again, as it was shutting off when coming to a stop and doing other odd things like not wanting to start after it shut the engine off (either by decision or error).  Nd since I had abused it a bit, I also wanted to do some general maintenance and fixes.

So, I changed the following:

Spark plug wires
Distributor cap
rotor
coil
new plug on the coil
Charcoal canister
fuel filter
fuel hoses before and after the fuel filter
Fuel injectors
TPS
IAC motor

In any case, I replaced everything but and the Jeep was running very smoothly.  Fuel pressure was stable (36 with vacuum, 42 or 43 without, IIRC).  Engine RPM was fine, the engine did not bog down with the AC compressor as it was doing, and the engine would fire right up after shutting it down.  As a result, I figured either the leak on the hoe before the fuel filter, the charcoal canister (which sounded s if it was full of sand), or the ignition (the cap posts showed a lot of corrosion was the culprit).

Then I replaced the windshield washer water reservoir, and again turned the engine on, and the engine started acting up (kind of sounded like a vroom, vroom, vroom).  I decided to check the fuel pressure again (it also started acting up when I tried to fire the Jeep after shutting down), and I noticed the fuel pressure was all over the place (the needle going from 30 PSI to 45 or so VERY quickly).  I took a video that I will post later on...

Now, I should point out that I still need to drop the tank to change the sending unit (pump included), so the fuel is VERY low (below the E on the gauge); could the low fuel be the cause?  Anyway, any help is greatly appreciated!

[sharpxmen]

it can do that if the fuel is low, but i don't know how low actually was. the other thing that can do it is if the power to the pump goes on and off. I suggest adding some fuel (enough so it's not a question if it catches air) and see if its still the case.

[jfrabat]

I will have to try aftwrbI drop the tank...  No use in putting fuel in now if I have to drop the tank.  But any other ideas just in case its not that?

[sharpxmen]

if you have a kinked hose on the return but the upper pressure would be much higher i think you'd get like 60, 40, 60, 40) - go up till the kink straightens, release, and so on.

[jfrabat]

Here' the video...

<a href="https://www.youtube.com/v/f9ctljIzeLY" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">https://www.youtube.com/v/f9ctljIzeLY</a>

[grumpygy]

Private Video

[neale_rs]

Sounds like it is out of gas.  In JP Magazine they told how you can disconnect one of the fuel lines and use the Jeep's own fuel pump to pump out the gas.

[sharpxmen]

i get the same "This video is Private"

[jfrabat]

i get the same "This video is Private"

Sorry, should be fixed now...

[sharpxmen]

hmm, i don't think that's lack of gas or kinked return since it won't do it without the vac line. do you have a break bleeder kit with a vacuum pump? if yes hook that up to the FPR and slowly increase vac but no lower than 20inHg (16 to 18 i think it's idle) and see if it still does it, if it doesn't then it's most likely the vac line (maybe it's collapsing, i don't know) or maybe it's the FPR, might not hold vacuum - can't remember if yours had the o-ring or just teflon tape around the thread under the locking nut - might want to test if it holds vac and if not try to put some teflon tape there.

[jfrabat]

hmm, i don't think that's lack of gas or kinked return since it won't do it without the vac line. do you have a break bleeder kit with a vacuum pump? if yes hook that up to the FPR and slowly increase vac but no lower than 20inHg (16 to 18 i think it's idle) and see if it still does it, if it doesn't then it's most likely the vac line (maybe it's collapsing, i don't know) or maybe it's the FPR, might not hold vacuum - can't remember if yours had the o-ring or just teflon tape around the thread under the locking nut - might want to test if it holds vac and if not try to put some teflon tape there.

I have another FPR (stocker); I could simply replace it...  Not that much work anyway...  And at least I could test it.

[sharpxmen]

it acts like the vacuum varies, try the stock one. i bet it's the line and/or elbow to the fitting, after you put it back was between 35 and 40, before that was 30 to 42 or so, are the lines hard plastic or soft?

EDIT: but before you do any more work add 3 or 4 liters of fuel, won't prevent you from taking the tank off but at least would give you an idea if the tank almost empty could add to this (with the vac disconnected was varying about 2 psi which is not normal).

[jfrabat]

it acts like the vacuum varies, try the stock one. i bet it's the line and/or elbow to the fitting, after you put it back was between 35 and 40, before that was 30 to 42 or so, are the lines hard plastic or soft?

They are silicone.  I can measure vacuum at the elbow; that can tell us if that is the issue.

[sharpxmen]

how's the fit of the elbow on the fitting, did you try pressing and holding it against the fitting by hand? Add some fuel too, 5 liter tops will be enough.

[jfrabat]

how's the fit of the elbow on the fitting, did you try pressing and holding it against the fitting by hand? Add some fuel too, 5 liter tops will be enough.

I could feel the vacuum with my finger, so it looked fine at first glance, but I did not pay too much attention to it...  I'll try the fuel trick, and see if this clears it out anyway.