89 F-150 Will not start
01-11-2018, 08:53 PM
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89 F-150 Will not start
I was driving on the interstate this week doing 70 and my truck just shutoff. I did not receive any warning lights or any prior major indication that anything was happening. When i finally coasted to a stop, I tried to start it and it would crank and run for about 2-3 seconds shake really bad and shut off. I have the 4.9l engine. My first thought was and still is that its not getting enough fuel. I have started trouble shooting the problem by changing the Relay and by putting on a new filter. I removed the lines from the filter and switched it on. I did get some fuel flow, but not what I would thing a high pressure pump should produce. I have two tanks, one of which has a leak that is part of a missed 1995 recall. I put some fuel in that tank just to check the internal pumps and there was no change. One thing that I have noticed is that I can normally hear the high pressure pump humming when the truck is first switched on, however now I don't hear anything. As I am not a mechanic at all, is there enough pressure from the internal pumps to produce the flow that was coming out of the high pressure pump if it is indeed my problem and not functioning? I'm not sure if any of this even makes sense, lol. I've done so much research that my brain is jumbled with overwhelming information. Thanks in advance for your help.
01-12-2018, 12:29 PM
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This isn't a maintenance question, so don't be surprised if the staff moves it to the '87-96 forum.
There are several known problems with '87-91 F-series gas engines. Any of them could be the root cause of your current symptom. I highly recommend you buy a Haynes manual, read it, and then follow the diagnostic steps before Ch.1. Click this & read the caption before buying the book:
(phone app link)
I also recommend you STOP buying or replacing parts blindly. You can create new problems by unnecessarily disturbing a 30-year-old antique truck, which will make diagnosing this problem exponentially harder. Buy, borrow, or rent a fuel pressure gauge (call your local parts stores, and shop Sears) to find out if it's a fuel-delivery problem. You may have to install a jumper wire as shown here to take the reading:
(phone app link)
(phone app link)
If only 1 tank works anyway, you might choose to semipermanently bypass the DFR since it's one of those known problems. The captions in this album explain what it is, why it fails, how to rebuild it, and how to bypass it:
(phone app link)
But before diving in too deep, install that jumper wire, turn the key to RUN, & measure voltage across the terminals on the frame (hi-pressure) pump motor. They're under soft rubber boots on the side of the motor (possibly behind a heat shield) inside the frame rail under the driver's seat. The terminals there are known to get loose, so if the wires come off when you slide the boots off, gently crimp the terminals closed so they're harder to slide back on. If the motor has ~12V, and it's not humming, it's dead.
You can check the tank pumps similarly. This diagram is CLOSE to how your truck is wired:
(phone app link)
For the actual wiring, try this site (you don't have to use a real e-mail):
http://www.bbbind.com/free_tsb.html
After getting access, click the red WIRING DIAGRAMS button. You might also want to browse the many TSBs that apply to your truck. Some of them could contribute to this symptom.
There are several known problems with '87-91 F-series gas engines. Any of them could be the root cause of your current symptom. I highly recommend you buy a Haynes manual, read it, and then follow the diagnostic steps before Ch.1. Click this & read the caption before buying the book:
(phone app link)
I also recommend you STOP buying or replacing parts blindly. You can create new problems by unnecessarily disturbing a 30-year-old antique truck, which will make diagnosing this problem exponentially harder. Buy, borrow, or rent a fuel pressure gauge (call your local parts stores, and shop Sears) to find out if it's a fuel-delivery problem. You may have to install a jumper wire as shown here to take the reading:
(phone app link)
(phone app link)
If only 1 tank works anyway, you might choose to semipermanently bypass the DFR since it's one of those known problems. The captions in this album explain what it is, why it fails, how to rebuild it, and how to bypass it:
(phone app link)
But before diving in too deep, install that jumper wire, turn the key to RUN, & measure voltage across the terminals on the frame (hi-pressure) pump motor. They're under soft rubber boots on the side of the motor (possibly behind a heat shield) inside the frame rail under the driver's seat. The terminals there are known to get loose, so if the wires come off when you slide the boots off, gently crimp the terminals closed so they're harder to slide back on. If the motor has ~12V, and it's not humming, it's dead.
You can check the tank pumps similarly. This diagram is CLOSE to how your truck is wired:
(phone app link)
For the actual wiring, try this site (you don't have to use a real e-mail):
http://www.bbbind.com/free_tsb.html
After getting access, click the red WIRING DIAGRAMS button. You might also want to browse the many TSBs that apply to your truck. Some of them could contribute to this symptom.