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  #1  
Old December 11th, 2013, 04:48
Demonoid369 Demonoid369 is offline
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Unique telltale signs of fuel pump dying?

97'
4.0l
I know the common signs of a fuel pump going out is similar to many other things(CPS, dist. Etc....) but is there a specific tell tale sign that only comes from fuel pump? I plan to go rent a fuel pressure gauge after work but I was just wondering before I do, I have notice when I engine stalls, if I push the gas more, it fires right back up.
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Old December 11th, 2013, 05:02
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Re: Unique telltale signs of fuel pump dying?

Sounds more like a TPS to me.
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Old December 11th, 2013, 06:35
NW-ZJ-SCOTT NW-ZJ-SCOTT is offline
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Re: Unique telltale signs of fuel pump dying?

the only "Tall tale sign" I have for a fuel pump, Is when going up a hill and it starts to bog out.. I've had to replace two of them in a honda this way.. (second one had a Pressure gauge)
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Old December 11th, 2013, 07:20
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Re: Unique telltale signs of fuel pump dying?

When the fuel pump starts to fail you often notice when the engine uses the most fuel, high RPM, high speed, WOT. Sometimes when the rubber hoses rot, it will suck air, sometimes in a corner or when the fuel tank is low, is when you first notice.

If the engine craps out when you release the gas pedal, it is often the IAC is stuck shit. It may be from built up gunk or possible a voltage issue someplace in the charging/battery system. In effect when the IAC sticks closed and you release the pedal and throttle plat closes, the engine is starved for air.

TPS can get a flat spot (for lack of better name) one spot where the motor kind of falls on it's face. When mine went it was around 1/3 throttle.

The CPS can miss a beat or two randoml÷y when it is in the initial stages of failing, you may hardly notice at higher RPM's it becomes much more a factor at lower RPM's.
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Old December 11th, 2013, 08:44
Demonoid369 Demonoid369 is offline
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Unique telltale signs of fuel pump dying?

Ya the whole dist. Coil pack, ign. Coil, CPS, was replaced about a month ago, the tps was about 5 months ago as well as the iac.
If it sounds more like the tps or iac ill start checking those out then.
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Old December 12th, 2013, 04:58
Demonoid369 Demonoid369 is offline
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Unique telltale signs of fuel pump dying?

Well update, didnt get a chance to try and test the fuel pressure since I worked a double shift yesterday but my jeep does seen to be getting worse....
It now stalls/dies even when I have my foot on the gas, not just at idle or when I let off the gas. If I'm correct that eliminates the iac right?
Also when I'm on the gas, it seems to be bucking/lurching/shuddering??? Even when my CPS died, it never did that so is that safe to rule that out?
So if my guessing is correct, the only things I can think of to make this thing stall/die would either be the tps or fuel pump. I should be getting only a half day Friday so ill try and test both but I would greatly appreciate any ideas as to what is causing this
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Old December 12th, 2013, 05:02
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birchlakeXJ birchlakeXJ is offline
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Re: Unique telltale signs of fuel pump dying?

Be sure not to ignore a marginal battery. And yes, you can have a battery strong enough to start the engine but marginal enough to give the engine management system fits.

Any parts store will "load test" your battery for free. Not saying that is your problem, just don't want to be chasing your tail if your engine management system can't operate properly because of low available juice......
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Old December 12th, 2013, 05:21
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Re: Unique telltale signs of fuel pump dying?

I second checking the battery before spending any money.

You can test the TPS rather than just replace it.
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Old December 12th, 2013, 05:31
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Re: Unique telltale signs of fuel pump dying?

Quote:
Originally Posted by 8Mud View Post
If the engine craps out when you release the gas pedal, it is often the IAC is stuck shit.
constipated IAC??
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Old December 13th, 2013, 11:25
Demonoid369 Demonoid369 is offline
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Unique telltale signs of fuel pump dying?

Battery is good, the weird part was no code was thrown at first but now that I scanned it again I got P0351 ignition coil?!? I replaced that 2 months ago with all the other electronic parts that I did. But no check engine light showed??
I know that a ignition coil can cause stalling but I didn't expect mine to start failing 2 months.
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Old December 14th, 2013, 06:05
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Re: Unique telltale signs of fuel pump dying?

Quote:
Originally Posted by Demonoid369 View Post
Battery is good, the weird part was no code was thrown at first but now that I scanned it again I got P0351 ignition coil?!? I replaced that 2 months ago with all the other electronic parts that I did. But no check engine light showed??
I know that a ignition coil can cause stalling but I didn't expect mine to start failing 2 months.
We're getting some real crap replacement parts these days.
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Old December 14th, 2013, 08:40
O-Gauge Steamer O-Gauge Steamer is offline
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Re: Unique telltale signs of fuel pump dying?

What I can say about fuel pump failure is only based upon the failure I experienced in my '97...

It would just stop running. Always on the highway and after about 40 minutes or so. Was more pronounced when the tank was under half full.

The PCM does not monitor fuel pressure so it would stop running without throwing any codes. The issue was tracked down to the pump, the pump replaced and the issue went away with to old pump.

This is when I discovered that changing the pump is much easier on a pre-97...
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Old December 14th, 2013, 14:41
Demonoid369 Demonoid369 is offline
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Unique telltale signs of fuel pump dying?

Well I swapped the ignition coil, hope that helps but I tested the fuel pressure and well... Not what I was expecting.
Key turned to on: 45 psi
Idle running: at first it was fast and wildly fluctuating from 40psi to 50psi but after about 40 seconds it was fluctuating between 45psi and 50psi with same fast intensity.
Idle to wot: went wildly fluctuating between 40-50psi and as the throttle went higher the fluctuating decreases till I was 1/2-3/4 open throttle and the gauge stopped moving right at 49.2psi
Ill have video to post in a bit but from that, I'm going to assume my fuel pump is getting near to dying right? Or is the fluctuating normal?


If I do need to buy a fuel pump, which of these is the right one? I know from reading, stay away from airtex. But the descriptions on these confuse me as to which one i need

Would a economy one work or should I get a standard?

Last edited by Demonoid369; December 14th, 2013 at 14:46.
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Old December 14th, 2013, 14:50
NW-ZJ-SCOTT NW-ZJ-SCOTT is offline
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Re: Unique telltale signs of fuel pump dying?

I personally would buy the Bosch
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Old December 14th, 2013, 15:15
Demonoid369 Demonoid369 is offline
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Unique telltale signs of fuel pump dying?

http://youtu.be/qtkI2KJ3qr8

http://youtu.be/Ei5V3ByKm7w
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