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Eric
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Discussion Starter #1 (Edited)
Okay, so , I've had this problem since I first brought the BKO home back in October. It has a hard time firing after it's been sitting for more than ~5 hours. At first, I suspected the fuel system. I thought the pressure was being let out of the fuel rail while the truck sat. All the components tested fine, though. I have replaced a few since then for various reasons, too.

However, the other day, I cranked the truck and the injectors, actually seemed to flood the cylinders because it would not light off. At least, that's exactly how the motor acted. Like it got flooded. Usually, I have to crank for, about, 4 seconds, stop, and then crank again. At this point, it, usually, fires after a few rotations. Not this time.

Battery's new, new Motorcraft coil, new wires, new plugs, new cap and rotor. I haven't, really, gotten around to thoroughly testing the TFI module, though, for lack of understanding, exactly, how it works. I ran through the first two module tests in the Haynes manual, however, and it passed (didn't have a "helper" to complete the rest of the testing procedures). I, also, have the base timing advanced to ~13* with plugs gapped at .055".

1.) Could the PIP be sending a faulty signal during cold starts for some reason (if that's even possible)? If the truck sits for less than 5 hours (still warm), it fires right up like it should.

2.) Could it be a faulty temp sensor sending wrong signals to the EEC for cold-start timing? Wouldn't a faulty temp sensor affect drive-ability, though?

3.) Is there, just, something I'm missing with the fuel system? Doesn't the in-line pump prime the pressure in the rail as soon as you turn to KOEO, anyways?


Truck runs fantastic, otherwise. Just looking for some input on a direction to head in. It's no secret that electrical is my weak point. This issue has been tolerable, in light of more pressing ones, but, flooding the cylinders was the last straw.

Thanks guys,
Eric
 

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Try a new dizzy.
 

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Eric
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Discussion Starter #3
A whole new one? Isn't the module the source of most problems? Just wondering. When I pulled the dizzy a while back, the gear, shaft, seal, etc. all seemed fine.

Also, am I correct in believing that the in-line pump primes the fuel rail when you hear the "whine" when the ignition is turned to KOEO? Even if the rail lost pressure after sitting over-night, the pump priming on start-up would be enough to load it back up, correct? Just making sure I'm not over-looking something in the fuel system. All parts tested fine, operationally.

Thanks,
Eric
 

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...

Also, am I correct in believing that the in-line pump primes the fuel rail when you hear the "whine" when the ignition is turned to KOEO? Even if the rail lost pressure after sitting over-night, the pump priming on start-up would be enough to load it back up, correct? Just making sure I'm not over-looking something in the fuel system. All parts tested fine, operationally.

Thanks,
Eric
I think that's right (I'm still learning). My issue I'm working on sounds very similar to yours. I suspect the pressure is leaking down (maybe through a check valve in the in-line pump?) and the pump isn't re-pressurizing right away. Today, it took three or four cycles of key on till the pump turned off, then key off. After that it started right up. I have a new in-line pump ready, but I want to test some more before I install it.

Can you actually hear both pumps whine when you turn the key on, or is it just the in-tank pump?

I'm sure someone will be along to correct us if we're wrong. ;)
 

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Eric
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Discussion Starter #5
You can hear both pumps. There is test in the Haynes manual you can perform to make sure the in-tank pump is working. I, also, replaced my in-line pump about 2 months ago after an undesirable test result. Didn't solve the issue, though. Also, my fuel pressure regulator was replaced. Again; nothing changed.

As mentioned, all fuel system components test within spec, now. :shrug

Eric
 

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That sounds an awful lot like the classic TFI issue.

Fortunately, it's very simple to convert to EDIS8.
 

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Is it easier to start with the timing set to stock setting? When it won't start, have you checked spark? Have you pulled codes yet? A "new" distributor is usually filled with old parts, you would be better served by rebuilding your own if it is indeed bad. Most auto parts stores can test your TFI. If it tests bad replace with a Motorcraft grey TFI.
 

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Both my Broncos and my 5.8 F150 have done the exact same thing. Swapping the dizzy fixed it. It's the PIP.
 

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Eric
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Discussion Starter #10
What the hell??!!! I replied yesterday. I guess I didn't hit the "Submit Reply" button. Damn. Let's try this again:

That sounds an awful lot like the classic TFI issue.

Fortunately, it's very simple to convert to EDIS8.
I don't know what EDIS8 is. Different/newer-style dizzy?

Is it easier to start with the timing set to stock setting? When it won't start, have you checked spark? Have you pulled codes yet? A "new" distributor is usually filled with old parts, you would be better served by rebuilding your own if it is indeed bad. Most auto parts stores can test your TFI. If it tests bad replace with a Motorcraft grey TFI.
No codes being thrown. Although, on a couple occasions, the tester has shown "6" instead of "8" when you do the KOER test and it checks for cylinder count. This is leading me to believe I have a crossfire issue between the 7 and 8 cylinder (fairly common).

Both my Broncos and my 5.8 F150 have done the exact same thing. Swapping the dizzy fixed it. It's the PIP.
"Swapping the dizzy" just made the list today. It almost died on me on the way to work, missing badly. Thought I was gonna have to pull over.

Silver70, have you made any progress on your no-start?
Yes. I popped the hood when I got home today. Double-checked my fuel pressure to make, absolutely, sure I wasn't starving for fuel. Pressure gauge read 30 PSI while running. Good-to-go there.

Checked the routing of the 7 and 8 plug wires to make sure they weren't touching anywhere along the run. When I touched the 7 wire, at the dizzy end, I got zapped bad. When I'm a better conductor than the wires, I believe it's time for new wires.

Also, I'm picking up a brand new dizzy from O'Reilly tomorrow. A manufacturer I've never seen before. Claims to use 100% new parts. Got a lot of other stuff going on, right now, so I can't swing a Motorcraft unit ($$$). Check this one out: distributor I'm picking up.

Eric
 

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Let us know about the quality of the new distributor. Keep your old one just in case. Here's a step by step from Steve83 on replacing the PIP on your existing distributor (that's how I fixed mine).

http://www.supermotors.net/registry/media/1031122
 

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Eric
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Discussion Starter #12
Thanks forbye.

Well, I dropped in the new dizzy today, at work, and I have to admit: I'm pretty impressed. The ad is true. Every part is brand new. Nothing re-manned. It's made in Taiwan, but, a Navy buddy of mine has toured some manufacturing plants, over there, and told me their standards are much higher than, typically, found in China and are on par with Japan. Materials were comparable with my stock dizzy and it doesn't look like any corners were cut. Lifetime warranty (pretty good for a new part).

The new distributor dropped right in with zero issues. Also, some new 8mm plug wires were added. I found the elastomer compound on the harmonic balancer had come apart, too, when I got home. Replaced that. Set base timing with SPOUT disconnected at 12*. Truck idles better than it ever has. Smooth as glass, pegged at 750 RPM. I might bump timing up to 14*, depending on how it drives tomorrow.

The real test will come tomorrow morning after the truck has sat over-night. I'll see if I have the same cranking issue. Gonna be pissed if there's, still, a problem. Not, really, sure where to look next if there is. Injectors are the only thing left.

Eric
 

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Eric
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Discussion Starter #13
UPDATE:

Same cranking issue today. Truck idles and drives fantastic, though. I don't know what the deal is. I mean, it'll fire the first time if I crank, continuously, without stopping, for 5-6 seconds. Most newer cars fire after just a couple rotations the first time. Am I, just, asking too much of an older truck?

I know the Bronco is SD and set up for bank-fire operation, in which the injectors are pulsed, 4 at a time, into the intake ports. The fuel, then sits there until it is drawn into the cylinder on the intake stroke. Works much like a very advanced carburetor in the respect that has a certain amount of fuel "waiting" outside in the runner.

Newer vehicles are multi-port injected, where each cylinder gets it's very own injector timed in accordance with that cylinder and nothing "waiting" in the intake runner to be drawn in.

Could my injectors not be "loading" enough fuel in the port to create a suitable amount for combustion on start-up? Maybe they're clogged/dirty filter screens?

Eric
 

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I have to admit I know very little about the injectors as I'm still learning as I go, but if it was clogged/dirty screens wouldn't that also cause issues at idle and/or while running? I've seen threads about cleaning the injectors, maybe you can try that. I sure hate to see you throwing any more parts at it till you know what the problem is.
 

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5-6 seconds is a long crank. I have an 89 f150 5.0 and it takes 1 second of cranking to fire, max. I'm not bragging, just establishing a baseline. Ok now the fun part... losing pressure in the fuel system over 5 hours is to be expected but loss of volume is not. what i mean is the fuel rail is higher up than the fuel tank and fuel can bleed back into the tank leaving nothing but air in the lines. If this occurs it can take multiple cranks or second to pump fuel all the way from the tank up to the rail and injectors. I know you said you had 30 psi of pressure but was that after it was already running. If so I would leave the gauge on the truck while you are at work or overnight. after sitting, when you first turn the key to "on" position (not start) does the fuel pressure rise back up to KOEO Fuel Press Spec. Pardon my lengthy response, I tend to ramble.
 

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I'm shocked to hear the new dizzy didn't fix it. What happens if on the first crank of the day you just spin it over for a second then let off and crank it again? Will it fire right up?
 

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Eric
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Discussion Starter #17
5-6 seconds is a long crank. I have an 89 f150 5.0 and it takes 1 second of cranking to fire, max. I'm not bragging, just establishing a baseline. Ok now the fun part... losing pressure in the fuel system over 5 hours is to be expected but loss of volume is not. what i mean is the fuel rail is higher up than the fuel tank and fuel can bleed back into the tank leaving nothing but air in the lines. If this occurs it can take multiple cranks or second to pump fuel all the way from the tank up to the rail and injectors. I know you said you had 30 psi of pressure but was that after it was already running. If so I would leave the gauge on the truck while you are at work or overnight. after sitting, when you first turn the key to "on" position (not start) does the fuel pressure rise back up to KOEO Fuel Press Spec. Pardon my lengthy response, I tend to ramble.
No worries. A lot of info is much more preferable and desirable than not enough. I appreciate you relating the cranking duration of your truck. That lets me know that there is, genuinely, an issue and that my situation is not "typical".

Also, I know there is a one-way check valve in the single-function fuel reservoir that is located on the frame rail. However, I don't know if this part is even serviceable. I know you can get a new O-ring for the housing, but, I don't know about the, actual, check-valve itself. If this is the issue, aside from picking up one from the JY, I need to find out what my options are for replacement/repair.

I will check my "primed" KOEO pressure at the rail tomorrow morning and post back what it reads. I have done this test after the truck has been running, and it passed, but, I have not done it after it has sat over-night.

I'm shocked to hear the new dizzy didn't fix it. What happens if on the first crank of the day you just spin it over for a second then let off and crank it again? Will it fire right up?
That's okay. A new dizzy was on the "to-buy" list for a long time, anyways. I have to say, it smoothed out my idle tremendously. It is not a purchase I regret. Even my buddy was over, yesterday, and mentioned, "Damn... that thing sounds good. What'd you do?"

Also, if I crank, briefly, turn off, and crank again, it will not fire. It's like I need to crank for quite a while to get it to fire. Like, I can crank 4 seconds, let it sit, then it fires after another 2 seconds of cranking. Or, I can crank for a total of 6 seconds and it fires the first time. Or, I can crank for 3 and 3. It seems to need to crank for, about, 6 seconds total, no matter how I split it up, to fire.

I will do the KOEO pressure test, first thing tomorrow, and post back with the results.

Thanks guys,
Eric
 

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The check valve is what i was getting at. I am curious, if you were to prime the fuel system like 3 times in a row (seeing as the fuel pump normally runs for about 2 seconds when turning the key to on) would it fire up. Seen a number of bad check valves in other vehicles in the past.
 

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Eric
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Discussion Starter #19
Okay, just tested the truck. I left the pressure gauge on all night and came out to 0 psi this morning. Funny thing is, I turned the key and it primed to 34 psi. Cranked and it fired right up. First time that's ever happened. It was, kinda, warm today so I'm wondering if, maybe, that helped the seal out that might be leaking. I dunno. :shrug

I think I'll order a new reservoir this week and see if that helps. Again, I don't know if the check valve can be serviced, or not, and have not read anything about it. Whatever... I'm planning on keeping the truck, so, I'll just chalk this up to "restoration" costs.

Eric
 

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Instead of letting it crank for an extended time, next time you go out for a cold start cycle the ignition key to run listen for the fuel pump to finish priming, cycle key off, then back to run, basically prime the pump 2-3 times without ever turning the engine over. After that try to fire it, my '88 BKO did this all the time, I never tried to get to the bottom of it, but obviously if it fires right up after doing this, then fuel is leaking down to somewhere, either out the injectors and into the intake and down the cylinder and into your oil, or it's leaking back into the tank. I'm thinking most likely is back to the tank.

Good Luck,
Jason
 
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