Edd575 Posted November 8 Posted November 8 (edited) I have an 87 302 that does not start, OBD1 shows code 95 secondary fuel circuit. I have zero pressure at the schrader valve on the fuel rail. The fuel relay is good as is the inertia switch. I can hear the high pressure pump run with the key turned on. I have pressure from the tank, thought the HP pump nd the fuel filter so I went for the pressure regulator andter I pulled the plenum. I not have a spry from an injector, fuel on top of the engine so I have made headway. Still no pressure on the gauge but I must have messed up an injector O-ring. Set on order. I have a threaded hole near the center of the intake and have no idea what is supposed to be there? Sensor of some kind? I don't find any wires in the area that don't have a home. Edited November 11 by Edd575 engine correction
mat in tn Posted November 9 Posted November 9 there is supposed to be an "intake air temp "sensor that screws in there and there is a plug laying there with two wires waiting to get plugged in. this being missing is a MAJOR vacuum leak and the afr will not be correct.
Edd575 Posted November 11 Author Posted November 11 thank you that was the first reply made sense, it looked like a sensor hole. I'll have to find the wires, I have had the upper intake off and both fuel rails but did not see any strays, I'm going have to look again. Any idea where in the harness they would emerge from?
mat in tn Posted November 11 Posted November 11 sorry I may have jumped the gun. I went back and looked closer. the iat and plug are in place forward about 5". so, I'm studying the picture as best as I can and now, I have another observation/question. you say it's a 351w but the bit of the upper intake that I can see looks to be eight rectangular runners like the 5.0. the 5.8 had oval runners. as to what the center 3/8"npt threaded opening is I'm drawing a blank on. I just went out to the garage to look, and I have a complete 96 5.0, 93 5.0 and another intake lower on the shelf and all have the boss yet none of mine nor any I can remember have had that port drilled and threaded. so, I am at a loss. at least put a 3/8npt plug in place till a need is figured out. as far as the ecu giving a code, if you have a vacuum leak this big it will not recognize proper fuel / afr and may very well give a seemingly erroneous dtc. as to measuring fuel pressure. be certain that the adapter is opening the rail Schrader valve. it is recessed a bit and often it's hard to get it just right.
Edd575 Posted November 11 Author Posted November 11 I also misspoke in the original post. I checked the VIN and it is the 5.0 302 not a 351 like I was told when I bought it. I forgot to change the engine info if that makes any difference. I have found many issues from no fuel to the spark plug wires run for a 351 and I know that is different.
ArdWrknTrk Posted November 11 Posted November 11 Are you sure this isn't the knock sensor? (E3AZ-12A699-A). Seems about the right location. I think the EVTM shows all those sensor locations, though I don't often look too closely at the EFI diagrams
mat in tn Posted November 11 Posted November 11 jim the knock sensor is in back of the intake screwed into the block about where the oil pressure sender is on a 460. as for the firing order. what year is it again? ford used one firing order for the 302 and that carried on through 1990 yet they also used the same firing order as the 351 on any h.o. 5.0 engines and eventually all 5.0 with sequential efi and mass air systems.
mat in tn Posted November 11 Posted November 11 one point that crossed my mind. the location. it is central in the lower intake. that's where the exhaust crossover is. not an intake runner. so, it should not be a vacuum leak. this makes me think it could be relevant to egr temp, is this possibly a California emission vehicle. just looking for a clue.
Edd575 Posted November 28 Author Posted November 28 I have plugged that hole and have the engine started. The prior owner said it ran one day and wouldn't start the next. He replaced almost all the fuel system tank to the pressure regulator. He tried a new distributor and another ECM, yep, threw parts at it plus it is not a 351W as he said but a 302. Wrong firing order, distributor off a couple teeth, and the biggest issue was melted wires under the upper in take. Fixed those issues and it runs. More work as the rr has brake fluid running out ot the drum.
ArdWrknTrk Posted November 28 Posted November 28 Melted wires? Was there a fire or EGR leaking? Glad to hear you've got it running Happy Thanksgiving. 🦃
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