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'86 5.0 EFI Manual No-Start Issue

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Gary Lewis

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

The easiest thing to do is to check for spark. If you have spark and if you have some pressure at that valve I'd see if there's power to the injectors. If power to the injectors then see if you can detect the injectors opening, and to do that you could put a trouble light across an injector. If the injector is firing you should be able to see the light glow dimly. Or put your DVM across there and you should see the voltage go bonkers.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

fords4life

Re: '86 5.0 EFI Manual No-Start Issue

So.... I picked up an inline spark tester light and cheapo distributor cap on the way home. Plugged in the tester, turned the key and she fired right up.... So frustrating. I almost wish she hadn't so I could start working on discussing the issue. The cap definitely had some rough spots on some of the terminals so I'm going to replace it, but I'm no further along in diagnosing than I was.

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

Gary Lewis

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

Intermittent problems are the worst. Technically you don't ever know for sure that you fixed them, although usually you can tell in a few drives that you have. But until then you worry about it.

Anyway, keep us posted.....

Gary, AKA "Gary fellow": Profile

fords4life

Re: '86 5.0 EFI Manual No-Start Issue

So after some rain yesterday and last night, the problem is back..... I had a few minutes before I had to leave for work so i got a couple things checked. Confirmed I have spark via inline test light on cylinder #1. Also looked at the throttle VREF which is second on the list for the EEC IV No Start Pinpoint Tests. I just wasn't sure which wires I needed to confirm voltage on. There are 3 in the connector. I have 3.8v between Orange/Green, and 5.0v between Black/Orange. If someone can confirm which wires are correct, it will at least tell me which way to go in the testing next.

I'll have to see how far I can get going through the Pin point test without a breakout box.

Thanks for all the help and guidance.

Nathan

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

Gary Lewis

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

Are you checking the voltage to ground? I'll see if I can find the correct procedure.

Gary, AKA "Gary fellow": Profile

85lebaront2

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

Voltage is checked to the Signal Return wire for the sensors. 1985.5-1986, check the EFI system ground near the battery, it is an open style with 2 1/4" wide flat pins and is attached to the negative batter post clamp with the bolt. If it has high resistance the whole system goes FUBAR on you.

TPS wiring, 5.0V VREF circuit 351, O/W; Signal return SIG. RTN, circuit 359, BR/W; TPS signal, TPS, circuit 355 DG/LG. I have a voltage chart, Gary has it also for the testing. Sweep check should be done with a analog meter as digital doesn't update fast enough to accurately measure the response.

Bill AKA "LOBO" Profile

"Getting old is inevitable, growing up is optional" Darth Vader 1986 F350 460 converted to MAF/SEFI, E4OD 12X3 1/2 rear brakes, traction loc 3:55 gear, 160 amp 3G alternator Wife's 2011 Flex Limited Daily Driver 2009 Flex Limited with factory tow package Project car 1986 Chrysler LeBaron convertible 2.2L Turbo II, modified A413

fords4life

Re: '86 5.0 EFI Manual No-Start Issue

In reply to this post by Gary Lewis

Gary Lewis wrote

Are you checking the voltage to ground? I'll see if I can find the correct procedure.

No, checking between pins on the plug.

85lebaront2 wrote

Voltage is checked to the Signal Return wire for the sensors. 1985.5-1986, check the EFI system ground near the battery, it is an open style with 2 1/4" wide flat pins and is attached to the negative batter post clamp with the bolt. If it has high resistance the whole system goes FUBAR on you.

TPS wiring, 5.0V VREF circuit 351, O/W; Signal return SIG. RTN, circuit 359, BR/W; TPS signal, TPS, circuit 355 DG/LG. I have a voltage chart, Gary has it also for the testing. Sweep check should be done with a analog meter as digital doesn't update fast enough to accurately measure the response.

I will have to see if I have an old analog meter, I might, but will have to dig.

Just to confirm, Circuit 359 should be BK/W, not BR/W? That's what my diagram shows and the wire color in the truck is BK/W.

If I put my meter on the pins for C351 and C359, I get 5.0v(with the digi meter) which is in spec per A2 on the pinpoint test. Next is A3 which is spark and I confirmed that this morning. That leads to A13 which is the Spout Signal verification. This is where it gets tricky because I don't have a breakout box. Can I pierce the wire for C324 that attaches to Pin 36 on the connector and verify voltage to ground that way? If I can do that, what about the timing switch portion at the bottom?

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

85lebaront2

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

Where are you located? I have an EEC-IV breakout box (was real handy when my Taurus started acting wonky). Chris Tubutis has my EEC monitor and recorder. Either way something could probably be arranged. My son drove his 1986 F150 5.0L for several months with the breakout box on the floor hump and a little pair of LEDs to show injector pulses plugged into it.

Bill AKA "LOBO" Profile

fords4life

Re: '86 5.0 EFI Manual No-Start Issue

I'm in Greeley, CO.

Any thoughts on piercing a wire to check the voltage? I have the power probe with the probes that clamp on to the wire.

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

85lebaront2

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

Piercing the wire will lead to moisture intrusion and eventually corrosion. If you slide a paperclip alongside the lead you wish to check at the EEC connector plug (easiest way on yours, pull the EEC out of it's mount so you can reach it better). The pins you want SPOUT 36, PIP 56, these are the ignition distributor to EEC and return. If you need more let me know.

Bill AKA "LOBO" Profile

fords4life

Re: '86 5.0 EFI Manual No-Start Issue

Thank you. Found someone local who might have a breakout box. I should know this weekend.

BTW... Got home tonight and she fired right up....

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

85lebaront2

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

Naturally, what else did you expect?

Bill AKA "LOBO" Profile

fords4life

Re: '86 5.0 EFI Manual No-Start Issue

So it rained last night....yup...you guessed it....truck didn't start. I was able to get my DVOM onto pin 36 on the back side of the connector and check voltage to ground while cranking. Voltage was 4.8v to 5.0v. The only thing I'm not sure of is how to simulate the breakout box being in the "computed" position for timing. Can I pull the spout connector by the distributor?

I am going to try and pick up a manual fuel pressure gauge and adapter for the fuel rail so I can verify that I'm getting enough fuel pressure.

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

Gary Lewis

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

I would think that dampness would cause low-level, meaning low voltage or low current, electrical problems rather than high current ones. And the fuel pump should be a high current device. In other words, if it is running then I don't think fuel pressure is the problem. If you have fuel pressure then I'd bet that you can ignore the fuel pump part of the problem solving.

But I'll defer to Bill on that as well as the rest of the questions.

Gary, AKA "Gary fellow": Profile

fords4life

Re: '86 5.0 EFI Manual No-Start Issue

Gary Lewis wrote

I would think that dampness would cause low-level, meaning low voltage or low current, electrical problems rather than high current ones. And the fuel pump should be a high current device. In other words, if it is running then I don't think fuel pressure is the problem. If you have fuel pressure then I'd bet that you can ignore the fuel pump part of the problem solving.

But I'll defer to Bill on that as well as the rest of the questions.

I would agree, but at this point, figured knowing what the pressure is would at least 100% eliminate that. Like I mentioned previously, fuel is definitely flowing, you can hear it, and if I depress the schrader valve, fuel comes out with the Key On. I just can't confirm if I have adequate pressure.

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

1986F150Six

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

In reply to this post by Gary Lewis

Electronics is not my strong point, but I am reminded of an issue I had years ago. My 1986 has been converted to Duraspark and the used replacement distributor had wires been cut, so there was no 3 wire connector [green, violet and black wires]. The distributor wires and the wiring harness were connected using blade connections, which worked. Later, I replaced the distributor [new], which had the female connector, but the wiring harness still had the blade connectors which were attached to the distributor connector.

Damp conditions created no start intermittently. Keep in mind that on a 6 cylinder, this electrical connection is down low, where road spray is abundant.

The connections were cleaned and liberal use of dielectric grease solved the problem.

85lebaront2

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

In reply to this post by fords4life

You should be able to hear at least two pumps running, one in the tank(s) and one on the frame. If the frame pump runs but not the in-tank, you will get pressure but not adequate volume, in tank only not enough pressure or volume as it would have to pass the frame pump with it stationary. On your diagnostic connector on the right front (near the solenoid valves) if you ground the T/LG wire, this will turn on the fuel pump relay and run the pumps. From under the truck you should at a minimum be able to feel the vibration on the in-tank pump and maybe even hear it. The frame pump should be reasonably easy to hear particularly if it has been replaced (the original Bosch pump was pretty quiet). If they are all running, try the old "wiggle" test, shake the relay plug wiring and the frame pump wiring and the plug near the frame pump, you are dealing with 32+ year old wiring and not super well weatherproofed at that.

Once again, I can not stress enough, check that ground connector, the pumps ground through the rear harness plug under the hood to G701 inside the cab near the EEC. The remainder of the system grounds at the battery through that double blade connector.

Bill AKA "LOBO" Profile

fords4life

Re: '86 5.0 EFI Manual No-Start Issue

Just a little more info. I've tried doing some of the diagnostics without the breakout box and I'm not real confident in the results.

I did confirm that I'm building 40psi of fuel pressure. So I have fuel and I have spark so the only thing left is the injectors. I'll look at those tomorrow as long as the truck still isn't running.... Also confirm inertia switch and clutch safety switch are good.

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

85lebaront2

Re: '86 5.0 EFI Manual No-Start Issue

Administrator

Inertia switch will kill the fuel pumps, that's what it is for, to shut off the fuel supply in an accident. The injectors are grouped 1458 and 2367 so #5 is on inj 1 (EEC pin 58) and #6 is on inj 2 (EEC pin 59).

Circuit #361 (red) provides the power from the EEC power relay (next to the EEC) to the EEC and all the controlled components (solenoid valves, IAC and injectors) there is a connector, C160, in the engine feed section, the EVTM does not give it's location, but it is probably near the firewall grommet where the EFI harness comes through from the inside.

Hope this helps.

Bill AKA "LOBO" Profile

fords4life

Re: '86 5.0 EFI Manual No-Start Issue

In reply to this post by fords4life

Well a solid resolution continues to evade me. I keep running into tests that I really need a breakout box for so I ordered one. Well 2 actually. Found a pair on Ebay for less than $100 bucks shipped. I'll be posting up the second one for sale when it gets here if anyone is interested.

I could replace the ECM and TFI and see what happens, but I hate throwing money at parts only to find it's in the wiring....

1986 F-150 SC 2wd 4spd 302EFI Base Model all OEM motor/trans/emissions equipment.

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