Asked by May 02, 2018 at 11:02 PM about the 1986 Ford F-150

Question type: General

My 86 f150 turn on for a few seconds and can't get
it to start again or stay on it have a new fuel pump
any one have this problem before

5 Answers


that's because your fuel pump doesn't control the fuel system. The reason why you have fuses and relays is because you cannot really just start the car and expect the battery to communicate or feed juice to the fuel pump. This is why we have a MAS which communicates with the computer about how much fuel to feed up the line. Because the air / gas ratio of 13:7:1 must be met to operate ( properly ) at engineer specs. The last thing I would do is replace the pump and spend $350 to $500 on a pump replacement work. Troubleshoot the issue from battery to fuse box to tank select switch (if dual tank) and then go from there. start small and cheapest and check out your fuse box. ECU is near and 2nd black box relay is the fuel relay ( replace it) and the yellow fuse in front of it is your fuse for that circuit ( yellow 20 A , and is also the same fuse for the series- if applicable.). Replace those VERY cheap parts and go from there. If it was me, i'd take out my horn relay ( 3rd box in from near) and put in my 2 spot for my fuel relay. There really is no way to test your relay to see if it is good or not ( what I do is just go to junk yard and take relay off of other in that make model tenure. for my 96, I can take relay off of ranger, Crown Vic, or even AeroStar and know I have the same schematic in their relay and I'll be OK with it.) I replaced my fuel pressure regulator off an Aero Star, because I knew it was the same regulator during the mid 90's . PLUS, when you think about it, the van is front wheel drive and that motor is turned sideways. It's an easy grab to take the FPR. good luck

The reason I replaced the fuel pump was because a was not showing my gas tank gage level now that its working I checked all my fuses but I need to try the relays tanks


o k, so if you have the dual tank system as I do, pull out the tank selector switch and you will have 6 lines coming out. there is a video on you tube that explains which lines go to which ( there is actually only 5 because the ground wire doesn't count. Orange goes to sending unit blue/ white goes to pump. HOWEVER, it sounds like you only have 1 tank, and therefore do not have to deal with the select switch. Check your fuse panel for the right circuit to get your gas gauge to work right. ALSO, I would definitely change my gas tanks at some point and fuel lines. I am doing that to my 96. because metal will eventually rust and go into your lines. There is a way to clean out a tank too. It's costly either way you look at it. good luck)

I am back still having trouble turning my 86 f150 I check all the fuses and relays all are good but I check the voltage on the external fuel pump and only get 3.8 I'm not sure how many volts do I need to get on it


what does your owners manual tell you? for my 96, it don't say much at all ( because Ford wants you in the shop). SO at this point, I would change my gas filter and also my starter solenoid connections. Keep them clean and no rust. And underneath, check your starter as well.. no loose connections.

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