# 1996 Mercury 150 efi fuel pump issue



## BadMeat (Jul 8, 2010)

Hello, looking for someone who might be familiar with the above mentioned motor. Here is the issue: 

The motor won't start and I have determined it is an issue with the electric fuel pump. The motor will start and run when you can hear the fuel pump kick in. However, it will randomly not kick on and the motor will not start obviously. Then by some stroke of luck it will kick in and work. 

We have been able to hotwire the pump straight to the battery and it will power on and the motor will run fine, but for some reason it will not kick on with the key consistently. We have replaced the ignition and checked fuses. It almost sounds like there could be a short somewhere, but not sure. Are there any relays on the motor for the fuel pump?

Thank you in advance for your responses!

Outdoor Hub mobile, the outdoor information engine


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## UFM82 (Apr 6, 2004)

Different but the same...

Here is a link for the Merc manuals. Find yours with the serial number and go to the fuel injection section. This is THE factory manual and is exactly what you need. 

http://1manual.com/Mercury manuals/Service_Manual_Index.html

That being said, the fuel pump is powered by the ECM. If you are having intermittant issues you may have a bad ECM, but in my experience electronic parts tend to die complete deaths, not bit by bit. That is, I'm wondering about an open someone- loose connector, etc. However, when it is acting up THAT is the time to perform the tests outlined in the manual. Do you have power? Is there power to the pump? Out of the ECM? Blah, blah, blah. You can fix this- just read and follow instructions carefully. 

UFM82


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## duxsrus (Mar 3, 2011)

UFM82 said:


> Different but the same...
> 
> Here is a link for the Merc manuals. Find yours with the serial number and go to the fuel injection section. This is THE factory manual and is exactly what you need.
> 
> ...


What's the trick to viewing them? They all seem to be only 3-5 pages.


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## Workdog (Jan 10, 2007)

duxsrus said:


> What's the trick to viewing them? They all seem to be only 3-5 pages.


Click on "Service Manual Outline," then select any of the sections outlined in red. It's all there.


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## duxsrus (Mar 3, 2011)

Good deal. Thanks. I bought the Merc book for mine years ago but having it on the computer too will be nice.


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## sherman51 (Apr 12, 2011)

sounds like your fuel pump is just going bad. i have a mercury grand marquis. it started out just not starting. then i could turn the key off and back on a couple of times and it would start. then i started listening for the fuel pump to kick on when i turned the key on. if i heard it the car started if i didnt it wouldnt start. it didnt matter if it was warm or cold. so then i would just keep turning the key on untill i heard the pump. then it started.

i had just had the motor replaced so i thought it was just a plug not making a good conection. i drove it like this for about a month, then one morning i went out to go to the store and it wouldnt start. but it always ran good once i got it to start, thats why i didnt think it was the pump. so after it wouldnt start i checked to see if i had fire going to my pump, and it did have. so i took it to the shop and had them put a new pump on it. and that fixed the problem.

test the hot wire going to your pump and see if it is hot with the key on when it wont start. if it does its your pump. please let us know how this turns out.
sherman


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## BadMeat (Jul 8, 2010)

Thanks for all the responses. I am pretty certain, after doing some more research, that the ECU is bad. A lot of people have this problem. The red wire (positive) has a constant 12v applied to it rather the key is on or not. When you turn the key the ECU grounds the pump and kicks it on then. 

One way to test this was to test the connections at the pump but put the ground lead on a different ground. Sure enough it was reading 12v. I then made a jumper wire from the negative connection on the fuel pump to another ground on the block and the pump kicked on. Looks like I might need a new ECU  They're super expensive. What a bad week on the water, got to the river, trolling motor bracket broke and trolling motor almost fell into the water, then the motor wouldn't start, finally my Dad lost his balance in the boat and fell from the back deck and into the drivers console. Luckily I threw the rod down and tried to catch him, but he still hit his shoulder and we think he might have a broke collar bone. 

He's pissed because it's his "casting arm"! Hope it isn't serious!


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## UFM82 (Apr 6, 2004)

You've had enough bad luck for a long time- hope your Dad is OK. And OMG! I just looked online for ECUs. Good luck! I hope mine never goes out- it could end my boating days...

UFM82


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## sherman51 (Apr 12, 2011)

BadMeat said:


> Thanks for all the responses. I am pretty certain, after doing some more research, that the ECU is bad. A lot of people have this problem. The red wire (positive) has a constant 12v applied to it rather the key is on or not. When you turn the key the ECU grounds the pump and kicks it on then.
> 
> One way to test this was to test the connections at the pump but put the ground lead on a different ground. Sure enough it was reading 12v. I then made a jumper wire from the negative connection on the fuel pump to another ground on the block and the pump kicked on. Looks like I might need a new ECU  They're super expensive. What a bad week on the water, got to the river, trolling motor bracket broke and trolling motor almost fell into the water, then the motor wouldn't start, finally my Dad lost his balance in the boat and fell from the back deck and into the drivers console. Luckily I threw the rod down and tried to catch him, but he still hit his shoulder and we think he might have a broke collar bone.
> 
> He's pissed because it's his "casting arm"! Hope it isn't serious!


thats really bad news. i broke my collar bone when i was a kid. i really had a hard time. i couldnt even lay down, so i set in a chair to sleep. sure hope he gets better soon.
sherman


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## bountyhunter (Apr 28, 2004)

might search some outboard junk yards and find one. or google it.


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