Howdy yall. the vehuicle in question is a 1990 fleetwood motorhome with a 460ci, motor. its having an issue where the injectors aren't firing. its getting plenty of fuel (pressure at the rail), and with some starting fluid it starts then dies. the computer was changed, and still nothing. also new relays, and still nothing. wanted to know if anyone has a diagram of the connector. on my last ford someone posted up this pic:




would be awsome if someone had a diagram for it. the pic above was for my 1988 f-150 with a 5.0 . i'm guessing they are going to be different tho, lol. thanks

-Mike

 

The injectors are fed 12 volts power from the same terminals of the computer #37 & 57.
The same terminals are the grounds you should confirm are good , terminals #40 & 60.
If you don't have 12 volts (veh pwr) available at the injectors with the key on , that circuit shares that 12 volts with the items shown in the diagram that are tied in with terminal 37.
If you disconnect each one and the voltage comes up to 12 volts ,one of those items may be shorted to ground pulling the voltage down and preventing the injectors from firing. In checking the diagrams they are the same as far as the injector circuits are concerned. Let us know what you find.

 

I tested the grounds to the computer (4 of them), and they were all grounding fine. also the main power wire (pin #1) was geting 12.6 volts. the injectors are getting power as well. i had the origional computer, a reman one, and a known working one out of my 88 f150 (which has a 5.0, so not sure if it would have worked anyway), and nothing, it will start and continue runnning if i keep spraying starting fluid, but the second i stop, the motor dies. and its getting good fuel pressure to the rail. if i take a screwdriver to the test port, it sprays gas out, and will flood the top of the motor with gas in a few seconds, so there's plenty of fuel. its basically the exact same issue i had with my f150 (where the fuel pumps weren't comming on), cept the issue with that truck was the grounds, which were good in my case. i even snipped the wires off, and ran new grounds, just in case, still no good.

i did all this at the guy's place i was buying it at, lol. he dropped the price $500 since it wouldn't run. so i had the beast towed to my house, which was free (gotta love AAA ). So I hope to do some more testing now that its in my driveway. after some reasearch i'm seriously considering either going to a carb, or possibly mass air flow, tho i'm sure there's a lot involved with those methods as well, lol. thanks for the info so far, i really appreciate it

 

Can you try this, with the key on take the test lite and see if you have 12 volts to any injector itself. Then crank the engine and see if the other terminal of the injector plug is getting the ground it needs to operate. You do this with the plug off the injector. If so , the injectors should be working. You may have a different problem.

 

Is this something I can test with a noid light? Would those type of injectors be called ford TBI or bosch injectors? I ask because I just bought a noid light kit and want to make sure the correct one is in there before I open it, cause I can't return it if I open it, lol

 

well on a hunch i googled the numbers on the computer, and it turns out its from a 1995 ford explorer with a 4.0, lol. so i'm guessing thats my problem. does anyone have a list of computers, or knows what conmputer i need? thanks

 

This is how I see it.
You are probably going to take this motor home out on the road one of these days.
Personally I would try to get the right computer from a Ford dealer. There's no harm in checking with more than one dealer parts dept on the correct part # and price.
That way if you have any problem on the road you start with the correct part #.
There had to be some reason why the computer was changed in the first place.
It is not a nice feeling to install a replacement computer only to ruin that one too.
The dealer may be able to give you some info on what to check before installing the replacement computer. A shorted wire,solenoid, or part could be a present problem and it would be a good idea to run a few checks first.

 

the tank had been removed because the PO thought the issue was the fuel pump. and was installed like half way, so i pulled it back out, and found a bunch of wires that some squirels got to. none of them were cut, just the shielding exposed. may have been shorting out. so i fixed the wires, replaced all the lines, new clamps, clips, and all that fun stuff. just gotta get some of that blue turbo hose for the filler neck (PO cut the old one in half), and vent line. so i'll get the tank back in 2morrow, and start testing wires. and when i get a chance, i'll call ford and see what they can do. thanks
-mike

 

Got the tank and lines all changed out. also got the correct computer installed (i have another 1990 motorhome with the same engine/ trans that runs, but its destroyed, lol. had a huge brainfart with that, didn't click in my mind that they are both the same ). the junk one runs perfectly (just doesn't have any walls at the moment).

so i pulled the puter out of the junker, and still nothing. tried the noids (its a bosch injector btw) and nothing lit up. used the volt meter, and there's 12.6 volts to the injectors. tested the wires again, and the computer is grounding and getting power. i'm so lost . i put the "new" computer back in the junk RV, and it starts right up, so it didn't fry the comuter. and so far i've been disconnecting various sensors and checkign the connections on the computer plug, and everything has checked out so far. I've got about half of them checked (i have to put one end of the volt meter in the computer plug from the outside, then walk to the door, climb in and walk to the engine cover inside and touch the appropiate contact, and listen for the beep. this thing is 38 feet long, so its a long tedious process to check every single wire, lol. hopefully i'lll find something.

 

i've checked just about every wire i could see on the schematic. all seem fine. i'm getting good ground at pins 20 40 and 60, but wasn't getting 12 volts at 37 and 57 (i was but randomly). after some more testing, i found that none of the relays were working. i put new ones, and then the EEC relay clicked on, and got steady 12 volts at the injectors and computer. but the fuel pump relay still won't click on. the fuel pump works if i jump the relay, but the computer isn't activating the relay. and the injectors still aren't firing (noids still won't light up, and i verified that the noid light works on my other ford).

according to the diagram pin # 30 (the very first one they show in the diagram) goes to the "neutral drive switch" which goes to the "starter relay". would any of this cause the computer to not work?