Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: Old Ray]
#3253941
08/26/24 07:36 PM
08/26/24 07:36 PM
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Joined: Jan 2003
Posts: 10,956 Freeport IL USA
poorboy
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Got to start someplace, so: The fuel pump has its own power and its own ground, and the gauge has its own power and its own ground. Then there is a low fuel light that attaches to the gauge. With all your wiring changes, I would want to be sure that you have not mixed the two grounds up, and that you don't have something connected to the low fuel light wire (which i believe is a simple ground for the dash light as well)
The gauge and the pump are separate things that simply use the fuel pump housing to hold the sending unit for the gauge, on the original fuel pump set up. one should work, even if the other doesn't. Since neither is working while in the tank, I suspect a wire problem at the pump wire connecting point.
That is where I would start. I would also suggest you remove however you hot wired the pump to stay running and put it back like it originally was.
Just another thought... about a month ago I ran into this problem: My experience is, these pumps don't like to be left sit very well. Removing and reinstalling them with times of sitting in between can't be good. The fuel pump in my coupe died (90 Dakota stuff) after a year of just starting it and moving the car just to mow around it. When I was ready to start driving it again, it would run for a few minutes, then die. If you left it sit anywhere between 15 minutes and a couple hours, it would work great for another few minutes before it just quit working again. Finally, after a few days of messing with it, it just quit all together until I rounded all the stuff up to replaced it. The day I was ready to start to install the new pump, the car fired right back up and I drove it into the garage. replacing the old pump with a brand new one solved the problem. I have ran 3 tanks full of fuel through it since the pump replacement.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: Old Ray]
#3254916
08/31/24 12:17 PM
08/31/24 12:17 PM
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Joined: Jan 2021
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Moparite
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super stock
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but if the engine does not start the engine controller via the crankshaft position sensor only lets the pump run for 3 seconds for the prime. As soon as you put the ignition to "on" the pcm will prime the pump. This is enough to get the engine to start(49 psi). After the pcm sees the engine is running it will turn on the fuel pump via the relay. Not sure if there is a ground wire in the harness going to the tank but i would make sure the sender has a good ground to the body/negative battery terminal. I would check to see if you are getting full fuel pressure at key on. Also make sure the battery has a good charge. The magnum pcm's don't like weak battery's.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: Moparite]
#3255034
09/01/24 04:49 AM
09/01/24 04:49 AM
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Joined: Dec 2014
Posts: 6,447 ohio
ruderunner
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Not exactly related but something to check while apart. Are the Jeep and Dakota tanks the same depth?
I've seen situations where the wrong pump was installed and wouldn't reach the bottom of the tank. For example a pump for a standard tank installed in a larger capacity tank. I think this was a common mix up on Wranglers.
Angry white pureblood male
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: Moparite]
#3255121
09/01/24 01:22 PM
09/01/24 01:22 PM
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Joined: Sep 2016
Posts: 257 British Columbia, Canada
Old Ray
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Thank you for your help, I do appreciate it. If the following sounds cranky it because I am very old and have to get thoughts down on paper before I forget them. As soon as you put the ignition to "on" the pcm will prime the pump. Yes, but only for 3 seconds, hard to tell if the pump is running. After the pcm sees the engine is running it will turn on the fuel pump via the relay.
But what if it is not running ?
Not sure if there is a ground wire in the harness going to the tank but i would make sure the sender has a good ground to the body/negative battery terminal.
Yes there are two grounds, one for the gauge and one for the pump but I think they become a common splice. I would check to see if you are getting full fuel pressure at key on. No pressure if the pump is not running. Also make sure the battery has a good charge. The magnum pcm's don't like weak battery's. The battery has a battery tender that is on all the time.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: Old Ray]
#3255205
09/01/24 07:42 PM
09/01/24 07:42 PM
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Joined: Jan 2003
Posts: 10,956 Freeport IL USA
poorboy
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I bought a replacement fuel pump for my 90 Dakota at Orilly's for around $75 (just the pump) about a month ago (the pump comes with out the strainer, pay the extra $15 and get a new one of those too, because the old strainer won't come off the old pump in one piece, like they told me they would). Can't say how long its going to last, but its working well for right now.
Depending on which EFI system you have, most have a port (with a cap on it) on the fuel rail on the motor with a Schneider (?) valve (looks like a stem for adding air to tires). If you remove the cap, and depress the valve, gas should squirt out if the pump works at all. Turn the key on for 5 seconds, then turn it off, pop the cap off and depress the valve to see if it squirts gas or not (be prepared, if it has gas, it comes out fast, its under pressure). If no gas squirts out, the pump didn't run. Its that simple. The pump pressurizes the fuel line so fuel is available when the injectors open to start the motor.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: poorboy]
#3255223
09/01/24 09:40 PM
09/01/24 09:40 PM
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Joined: Sep 2016
Posts: 257 British Columbia, Canada
Old Ray
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I was thinking of that ........ can I use a tire gauge and a rag and a fire extinguisher ?
Last edited by Old Ray; 09/01/24 09:42 PM.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: Old Ray]
#3255304
09/02/24 09:39 AM
09/02/24 09:39 AM
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Joined: Jan 2021
Posts: 1,182 rust belt
Moparite
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Yes, but only for 3 seconds, hard to tell if the pump is running No pressure if the pump is not running. The pump has a check valve so once the pump primes the system(for 3 seconds) it will hold the pressure. That is if the check valve is working! Pump does not need to stay running during crank only after the engine starts.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: Old Ray]
#3255405
09/02/24 05:03 PM
09/02/24 05:03 PM
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Joined: Jan 2003
Posts: 10,956 Freeport IL USA
poorboy
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I Live Here
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I was thinking of that ........ can I use a tire gauge and a rag and a fire extinguisher ? I would probably use a small flat blade screwdriver, the gas probably wouldn't be very good for the tire gauge... If nothing is hot, the fire extinguisher probably won't be needed, but something to wipe up the sprayed gas might not be a bad idea. if there is no gas there, you know the pump isn't working. Pretty easy test, though could be a bit messy.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: 6PakBee]
#3255523
09/03/24 08:54 AM
09/03/24 08:54 AM
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Joined: Sep 2016
Posts: 257 British Columbia, Canada
Old Ray
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Your wish is my command your Lord. (too many choices for a old guy before your recommendation, thanks) Amazon.ca Hello RAY, Thank you for shopping with us. We’ll send a confirmation once your item has shipped. Your order details are indicated below. If you would like to view the status of your order or make any changes to it, please visit Your Orders on Amazon.ca. Order Confirmation Your guaranteed delivery date is: Friday, September 6 Ship to: Ray Invermere, British Columbia Canada Your shipping speed: Two-Day Shipping
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: poorboy]
#3255861
09/04/24 07:37 PM
09/04/24 07:37 PM
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Joined: Jan 2003
Posts: 10,990 North Dakota
6PakBee
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Just another tool to sit on the work bench to probably never get used again. At almost 68, I'm not collecting tools anymore. If you never have to work on EFI vehicles, I agree, it's just a shop ornament. But if you do....another story. If you have a "no-start" condition with EFI, first thing I do is check the fuel rail pressure. I just had a friend with an intermittent no-start condition on a '96 S-10 with the 4.3. We were chasing our tails until we hooked up the test gauge and did multiple starts. It was obvious that the control relay was the problem. Replaced relay, all is good. BTW, I'm 72 and I'm still buying tools I don't have.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: 6PakBee]
#3255933
09/05/24 10:02 AM
09/05/24 10:02 AM
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Joined: Sep 2003
Posts: 20,567 north of coder
moparx
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"BTW, I'm 72 and I'm still buying tools I don't have. " how well i know the feeling ! i'm a tick older, and i do the same, even if it's just for a one time use, and i'm also fabricating tools for stupid or odd circumstances. these fabbed tools are usually "constructed" from a bucket of "junk" tools i keep around for just this purpose. the bridgeport and the lathe get workouts during tool fabrication as well. and then there is the problem of "tool storage"............... it just gets worse when you run out of storage or tool boxes to keep this "stuff in ! it never ends ! as i told member Crowbait, now that you are the executor of my estate, just look at all the "stuff" you will inherit or have to get rid of.........
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: 6PakBee]
#3256101
09/06/24 01:40 AM
09/06/24 01:40 AM
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Joined: Jan 2003
Posts: 10,956 Freeport IL USA
poorboy
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Everything I own is EFI, has been since 2011. I have had a pretty good run with EFI stuff and I have built several rides with EFI. I'm not afraid of it, and I understand how it works. I have not had a need for a fuel pressure gauge set up so far, in all these years. I don't have the space to store things I don't use, and I don't have the money to waste on tools I probably won't use a second time. I am not addicted to this stuff, and I'm not collecting it.
I have younger friends that are in the automotive business, if I have a need for something I don't have, or can't figure out, I will go to them. I don't mind paying my younger friends for their equipment or their knowledge. Its the circle of life.When I was young, older people paid me to do the things they didn't know how to. Now that I'm older, its time for me to pay the younger guys to do the things I don't know how to.
When I retired in 2018, I quit working on other peoples cars. I sure don't intend to start doing that again. Its just my 3 piles of junk I need to keep running. Two have mid 1990s EFI systems that I have very good knowledge of, and the other has an 04 EFI system. I don't really care to work on anything concerning the 04. If it quits running, its going into a shop anyway, I'm not fixing much of anything on it.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: poorboy]
#3256131
09/06/24 08:50 AM
09/06/24 08:50 AM
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Joined: Sep 2016
Posts: 257 British Columbia, Canada
Old Ray
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Gene, private message sent.
Not sure if it went, please let me know if you got it / Thanks (don't get old)
Last edited by Old Ray; 09/06/24 10:52 AM.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: Old Ray]
#3256152
09/06/24 10:44 AM
09/06/24 10:44 AM
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Joined: Sep 2003
Posts: 20,567 north of coder
moparx
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"Butt Crack Bob"
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i got my "college edjamacation" in EFI when my best friend and i installed a late model LT1 in his 55 chevy belair. to say that was a STEEP learning curve, would be an understatement for sure ! one thing that helped tremendously, was when i fished a complete cadillac FSM out of the dumpster at the local chevy dealership. that provided the wiring diagrams necessary to get the car running, as well as the many trouble shooting methods to find out where we screwed up. that car turned out to be a GREAT running [and driving] car, and a local fellow just HAD to have it, so after offering a STUPENDOUSLY ridiculous offer, the car was his. since then, we have built several other vehicles for local guys, but none has been EFI equipped.
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Re: Confessions of a confused (and humbled) really old Hot Rodd
[Re: Old Ray]
#3256235
09/06/24 02:32 PM
09/06/24 02:32 PM
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Joined: Jan 2003
Posts: 10,956 Freeport IL USA
poorboy
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Gene, private message sent.
Not sure if it went, please let me know if you got it / Thanks (don't get old) Ray, I have responded to your message. Hopefully it will help.
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