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Discussion Starter · #1 ·
My dad got it new in 88. He passed away 12 years ago and it set for 12 years. Had it transported to florida where I've been working on it and replacing parts. Got one thing left that's driving me nuts. I need help.
When starting it, it will turn over 14 to 18 times before starting. When it does start it runs like a new truck. No problems at all. If you drive it for say 30 minutes and turn it off for a little while it will start right up. If you don't start it for a hour or so it's right back to 14 to 18 turn overs before it starts.
Help please amphidromus
 

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You have a pressure leak in the fuel system. This is causing it to lose prime, so you have to crank it long enough for the fuel pump to get fuel back to the injectors.

This may be a leaky injector, a bad pressure regulator, or a bad fuel pump. Or a leaky hose that seeps gas out; I really hope not this, but due to age, you MAY want to replace all the rubber portions of the gas lines.

You'll have to test to find out.

Injectors - don't start the motor, but pull the ASD and jump the connections to what would be the 30 and the 87 pins (if you look at this picture



jump the 30 to the 87 with a pair of 1/4" FastOn / Quick Connect males on a 14ga wire, that will run the fuel pump.

Look down into the throttle body, and see if any fluid is collecting.

If it is, you have leaking injectors.

They can be resealed (the most likely cause!) with a O-ring set, such as this one at RockAuto .

If that's not it, next pull the fuel regulator off the side of the throttle body, and see if it smells like gas at the vacuum tap. Or just replace it; but the Delphi is expensive at $101+ at RockAuto. If that doesn't smell like gas, reinstall it, then I'd add a check valve right at the fuel filter (you HAVE replaced it, right?) coming out of it ... IIRC, it's 5/16" rubber hose, and I find these at Amazon.

If that fixes it, then you'll be looking at a fuel pump rebuild since the top hat assembly is NLA. I used a Bosch pump both times (second time I discovered that the sending unit being broken, and the timing being off due to the distributor slipping on my 1988, caused the fuel pump to be out of the gas in the tank on my sloping driveway ... they don't run good when there's no fuel TO pump!) and I'd highly recommend that, plus new submersible hoses for the top hat assembly.

But that's how I'd trouble shoot it. Injector seals first (and if the seals don't fix it, it's the injector itself ... I bought two from Five O Motor Sports and am happy with mine.)

Oh, if you do anything with the injectors - use a gentle touch fastening the hold down screw with the torx head, and use some vasoline or something similar to grease the O-rings with to help them slip in without cutting themselves.

In the meantime, try turning it on (but not starting it!), counting to 10 slowly, turn it off, count to 10 slowly, lather rinse repeat about 4 times and on the fifth time try to start it. I bet it starts right up.

RwP
 

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Discussion Starter · #3 ·
You have a pressure leak in the fuel system. This is causing it to lose prime, so you have to crank it long enough for the fuel pump to get fuel back to the injectors.

This may be a leaky injector, a bad pressure regulator, or a bad fuel pump. Or a leaky hose that seeps gas out; I really hope not this, but due to age, you MAY want to replace all the rubber portions of the gas lines.

You'll have to test to find out.

Injectors - don't start the motor, but pull the ASD and jump the connections to what would be the 30 and the 87 pins (if you look at this picture



jump the 30 to the 87 with a pair of 1/4" FastOn / Quick Connect males on a 14ga wire, that will run the fuel pump.

Look down into the throttle body, and see if any fluid is collecting.

If it is, you have leaking injectors.

They can be resealed (the most likely cause!) with a O-ring set, such as this one at RockAuto .

If that's not it, next pull the fuel regulator off the side of the throttle body, and see if it smells like gas at the vacuum tap. Or just replace it; but the Delphi is expensive at $101+ at RockAuto. If that doesn't smell like gas, reinstall it, then I'd add a check valve right at the fuel filter (you HAVE replaced it, right?) coming out of it ... IIRC, it's 5/16" rubber hose, and I find these at Amazon.

If that fixes it, then you'll be looking at a fuel pump rebuild since the top hat assembly is NLA. I used a Bosch pump both times (second time I discovered that the sending unit being broken, and the timing being off due to the distributor slipping on my 1988, caused the fuel pump to be out of the gas in the tank on my sloping driveway ... they don't run good when there's no fuel TO pump!) and I'd highly recommend that, plus new submersible hoses for the top hat assembly.

But that's how I'd trouble shoot it. Injector seals first (and if the seals don't fix it, it's the injector itself ... I bought two from Five O Motor Sports and am happy with mine.)

Oh, if you do anything with the injectors - use a gentle touch fastening the hold down screw with the torx head, and use some vasoline or something similar to grease the O-rings with to help them slip in without cutting themselves.

In the meantime, try turning it on (but not starting it!), counting to 10 slowly, turn it off, count to 10 slowly, lather rinse repeat about 4 times and on the fifth time try to start it. I bet it starts right up.

RwP
Thanks- Fuel pump,filter,gas line,fuel injectors and more all new. I'll check the fuel regulator out. When I first got truck to florida it started just fine.
 

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Could still be a bad fuel pump; if stuff never broke or was never DOA, we'd not have to have warranties.

But now knowing that, I'd definately look first at the injectors for leakage and the regulator.

If the injectors are new, the mechanic may not have known about the Vasoline trick on the O-rings.

RwP
 

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Discussion Starter · #7 ·
Could still be a bad fuel pump; if stuff never broke or was never DOA, we'd not have to have warranties.

But now knowing that, I'd definately look first at the injectors for leakage and the regulator.

If the injectors are new, the mechanic may not have known about the Vasoline trick on the O-rings.

RwP
OK the check valve's will be here Monday. Put new gas lines going into bottom of throttle body that was cracked and dry rotted. I'm trying the check valve first before spending $100 for a pressure valve. Now if you look at the picture, at bottom back of throttle body is that the pressure regulator to change if I need too? One more question- where do I put the check valve?
 

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dry First off, it's not a carburator, it's a throttle body injector.

The bronzish thing at the top rear is the pressure sensor.

Make it easy; pull the vacuum hose, and see if it smells like gasoline. If it does, the pressure regulator is leaking.

The check valve goes into a fuel line to the TBI unit; I'd put it at the fuel filter under the truck, driver's side, right about where your left butt check points when you're sitting in the driver's seat. Inside frame.

Does doing 4 or 5 prime cycles fix the long-start?

RwP
 

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Discussion Starter · #9 ·
dry First off, it's not a carburator, it's a throttle body injector.

The bronzish thing at the top rear is the pressure sensor.

Make it easy; pull the vacuum hose, and see if it smells like gasoline. If it does, the pressure regulator is leaking.

The check valve goes into a fuel line to the TBI unit; I'd put it at the fuel filter under the truck, driver's side, right about where your left butt check points when you're sitting in the driver's seat. Inside frame.

Does doing 4 or 5 prime cycles fix the long-start?

RwP
I just put the name carb on the picture so I could find it on the computer.
After I start the truck( long start) and drive it for sometime 30/45 minutes and turn it off it will start back like a new one.
Now if I let it set for 20/30 minutes it's right back to the long start. Hope I answered your question. How it starts is determined by how long you let it set after turning it off. Off for 5/10 maybe 15 minutes it starts right up. Off longer than that - long start. Just went and pulled the vacuum hose off pressure regulator. Both ends of the hose had a hint of gas smell. Not alot but some.
 

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I just put the name carb on the picture so I could find it on the computer.
After I start the truck( long start) and drive it for sometime 30/45 minutes and turn it off it will start back like a new one.
Now if I let it set for 20/30 minutes it's right back to the long start. Hope I answered your question. How it starts is determined by how long you let it set after turning it off. Off for 5/10 maybe 15 minutes it starts right up. Off longer than that - long start. Just went and pulled the vacuum hose off pressure regulator. Both ends of the hose had a hint of gas smell. Not alot but some.
That's a pure vacuum line; the only way it can get gas in it is for it to be sucked through the regulators.

I'd move THAT way up in your list now.

I meant to reprime - turn it on but don't try to start, count to 10 slowly, turn it off, count to 10 slowly. Repeat 4 more times. Then start it.

RwP
 

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Discussion Starter · #11 ·
That's a pure vacuum line; the only way it can get gas in it is for it to be sucked through the regulators.

I'd move THAT way up in your list now.

I meant to reprime - turn it on but don't try to start, count to 10 slowly, turn it off, count to 10 slowly. Repeat 4 more times. Then start it.

RwP
Before I forget again, I want to thank you for the time your spending helping me with my truck problem. Not a lot of help around these days.
OK this morning I did what you said above. Re-primed 4 times. Truck turned over 1 1/2 times and started. Not the normal long start of 14 or more times. I also pulled the vacuum hose off the pressure regulator again and this time strong gas smell.
 

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Before I forget again, I want to thank you for the time your spending helping me with my truck problem. Not a lot of help around these days.
OK this morning I did what you said above. Re-primed 4 times. Truck turned over 1 1/2 times and started. Not the normal long start of 14 or more times. I also pulled the vacuum hose off the pressure regulator again and this time strong gas smell.
Yep, it's bleeding down the prime.

And it's through the regulator.

Sucky, but that's an easy enough fix if your wallet is plump enough :devilish:

You can take that RockAuto listing and Google for other suppliers; you can also check local auto parts stores.

If it was strong, I'd replace soonest; it's pulling unmetered fuel into the intake, which makes the truck run rich, which makes the fuel not completely burn, which means it'll wash the cylinder walls, which means the ring seat will be damaged due to friction and it'll start burning oil worse. It's a domino effect.

Oh, and it bleeds your wallet due to bad fuel economy. (That's ALWAYS a consideration to me!)

BTW - I have a 1988 with over 436,000 miles on it (!!!) and only one engine rebuild.

RwP
 

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Discussion Starter · #13 ·
Yep, it's bleeding down the prime.

And it's through the regulator.

Sucky, but that's an easy enough fix if your wallet is plump enough :devilish:

You can take that RockAuto listing and Google for other suppliers; you can also check local auto parts stores.

If it was strong, I'd replace soonest; it's pulling unmetered fuel into the intake, which makes the truck run rich, which makes the fuel not completely burn, which means it'll wash the cylinder walls, which means the ring seat will be damaged due to friction and it'll start burning oil worse. It's a domino effect.

Oh, and it bleeds your wallet due to bad fuel economy. (That's ALWAYS a consideration to me!)

BTW - I have a 1988 with over 436,000 miles on it (!!!) and only one engine rebuild.

RwP
I got a regulator on the way from O'Reilly's. They give me a military discount so it isn't to bad. Would you still put the check valve on?
 

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Not now; the check valve was if there was no gas smell at the vacuum line of the regulator, to keep the pump from draining back.

Won't HURT, but not necessary.

RwP
 

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Discussion Starter · #15 ·
Not now; the check valve was if there was no gas smell at the vacuum line of the regulator, to keep the pump from draining back.

Won't HURT, but not necessary.

RwP
Got my new pressure regulator. Do I just take out the 3 screws and it pulls out?
 

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Discussion Starter · #17 ·
That, and swap the vacuum line.

Do lube the rubber O-ring before you install it, though; I use petroleum jelly myself.

RwP
Update - Changed the fuel pressure regulator($41.00) around 30 minutes. Put a check valve in($8.00) hour.
Hadn't replaced the injectors.
Truck looses no pressure now and starts like a new one no matter how long it sets.
Wish I had found this forum $900.00 ago. Live and learn.
Thanks Ralph
 

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ACTUALLY - that all comes from the factory service manual, or at least for my 1988. They can be had used on eBay for wildly varying prices in paper, or usually orderable from Bishko Books in paper (which is expen$ive, too expen$ive for my ta$te$) or on disc new.

Well, the check valve doesn't ... it's just a work around, but not a bad idea anyway.

RwP
 
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