Hey there everyone, after three days of scratching my head and cursing my truck i decided to get a code scanner. Since my truck wont start i can only do the KOEO or the (Key On Engine Off) test. So heres the scoop...A few days ago while driving the truck just up and quit running, after having towed to my house i went thru EVERYTHING!! And even replaced basically my whole ignition system and still wont start. The weird part is that i have spark, fuel pressure, all fuel pumps work fine, but the fuel injectors are not shooting into the combustion chamber. So anyways, i hooked up the scanner and ran the KOEO test. The first code group gave me 11 which means it passed, the second code group gave me 18 which the book says " Loss of TACH signal to Electronic Control Assembly (ECA). what exactly does that mean? Do i have to locate the TACH wire and test it? Or does that just mean the computer is bad? Please help me

 

I have the same code on my truck. My truck is the same as yours but it is an 85. Also, mine runs. The code 18 bothers me that it is on there. Other people on here have it but they haven't figured it out either. Anyone?

-Matt

P.S. Welcome to FTE! Make sure you read the Guidlines . See ya on the boards!

 

Does anyone know how to test the fuel pressure regulator on a 1986 F150 5.0 v8 EFI w/auto trans?

 

hey spitfire check the valve on the fuel rail, that looks like a tire valve. Take the cap off and press the needle in. This will tell you that ur fuel is at least up to ur rail and if you have a lot of pressure, you will know that ur FPR is working. Hope all goes well

 

I've done that and i do have pressure there but from what i understand, if the fuel pressure regulator is no good then it would just return the fuel back on down the fuel return line and back to the tank. If i'm wrong please let me know. I'm positive i have fuel and pressure in the rail, and im positive that im not getting fuel into the combustion chamber, which leads me to believe that the injectors arent opening up which means that either the computer is messed up or the FPR is bad, or something else that im unaware of.

 

ummm ur right bout the fuel returning to the line, but if ur gettin fuel out of rail then that means ur gettin fuel to the injectors at least

 

hey do u no where the computer is

 

spitfire, will it try to start on either? if it will then its definatly a fuel problem. if you dont have enough pressure at the rail then you may get fuel to the injector but almost no fuel will get through the injector orfice. you need to test the pressure at the rail. if you have low pressure id go for the pressure regulator as it has to be letting fuel back into the tank. if you have pressure there, then you could take a multimeter to the power on the injector and see if you get any voltage when cranking. have you pulled a plug to make sure its not getting fuel? what color is the spark that your gettin? is it a strong spark or weak? where did you check it at, the coil or a plug? you may also want to make sure your spark is firing at the right time, ie. a jumped timing chain.

 

fordfinatic- the computer is under the dash, just look to see where the wire harness comes thru the firewall and it'll lead you right to it. It has a bolt that holds the connector into the comp. and a bunch of wire going into it, you cant miss it.

 

ether, carb cleaner, or gas shot into the throttle body wont do anything. The fuel pressure is fine and the plugs are dry as a bone, even after cranking on it with the gas pedal to the floor. The spark isn't blue but its enough to start it if there was fuel getting to them. I'm pretty sure the timing is good too but since you mentioned it i will double check. Thanks for the info.

 

hey thanks a lot spitfire

 

is it the beige box with all the fuses, just wanna make sure

 

I had a code 18 it went away for a little while after replacing the TFI module, but came back and truck would not start, after replacing the stator it was fine. Try clearing that memory code and see if it comes back after cranking, if it does then you definitely have a problem with either the TFI module or stator, or wiring to it. Oh and disregard the other post lol didn't see you made a second one. Also one other thing check to make sure the pump below the drivers side door is running when you turn the key on and it primes, I went offroading one time and I got all the way home and it just died, the spade terminal on the high pressure fuel pump had come off.

 

Hey 79Spitfire, they sell a fuel injector tester. It's refered to by my mechanic buddy as a "noid light". You disconnect the injector lead and hook the noid light up to it and it flashes when the injector is signaled to fire.

You can get a fuel pressure tester and connect it to the service port on the drivers side of the rail. Try AutoZone if you have one locally. I know they rent tools. Pressure should be 35-42 psi with the vacuum line off the regulator. Sometimes the diaphram brakes and fuel runs up the vacuum line and into the engine causing a rich condition.

No start can be, low fuel pressure, low spark, or internal engine damage. Check that the rotor in the distributer is turning when you crank the engine to make sure you havn't broken a timing chain. Also verify the timing that at TDC on the compression stoke of Cyl 1 the rotor is pointing to #1 terminal. Timing chains can jump.

Check fuel pressure, injector firing, spark KV at the plug, Timing chain, then run a compression check. Also while I havn't seen it on an early EFI Ford truck, I've see low battery's cause no starts on GM cars as well as newer Fords with the returnless fuel system. The computer controls the output of the fuel pump and with a low battery you get spark but no fuel... GM's are fuel, no spark and fouled plugs...

Good luck.

David

 

Hey Fordfinatic, the computer is under the passenger side kick pannel. It has one big connector that has a screw in the center of it.

David