Iffy ignition

inkybandit · 06-24-2010, 06:44 PM

Recently, upon turning the key the truck will start (or almost start), then get weak and stop. I'll turn the key again, and it starts no problem. This startup failure only happens the first time I try to start it in a day; the rest of the day it works like a charm. Is this an electrical problem or what? and how do I fix it?

Thanks

Wrench · 06-25-2010, 09:31 PM

I would do a fuel pressure test (KOEO) before first start. When was the last time you changed your fuel filter?

inkybandit · 06-27-2010, 11:09 AM

Replaced it last summer with an oil change

inkybandit · 06-30-2010, 08:55 PM

I did a fuel pressure check and it was pretty low (31 psi). After I shut off the engine, pressure dropped pretty rapidly back to practically zero. I'm under the impression that it should stay pressurized for a few minutes, correct?

So what are the likely candidates: pressure regulator, pump, filter?

MrShorty · 06-30-2010, 11:18 PM

Was it 31 psi with the pump running or was that after the pump shut off?

I forget exactly what the spec is (if you have a Chiltons, they have a nice fuel pressure diagnosis chart in there), but the system should not drop more than a few psi after 2-5 minutes. Usual culprit is the check valve in the pump.

06-24-2010, 06:44 PM	#1
inkybandit Wannabe Elite Explorer Nashville, TN '92 XLT Join Date: Dec 2004 Posts: 13 Vehicle Specs (Original Poster)	Iffy ignition Recently, upon turning the key the truck will start (or almost start), then get weak and stop. I'll turn the key again, and it starts no problem. This startup failure only happens the first time I try to start it in a day; the rest of the day it works like a charm. Is this an electrical problem or what? and how do I fix it? Thanks

06-30-2010, 11:18 PM	#5
MrShorty Wannabe Elite Explorer Spanish Fork, UT 92 XLT and '87 Bronco II Join Date: Dec 2001 Posts: 4,934 Vehicle Specs	Was it 31 psi with the pump running or was that after the pump shut off? I forget exactly what the spec is (if you have a Chiltons, they have a nice fuel pressure diagnosis chart in there), but the system should not drop more than a few psi after 2-5 minutes. Usual culprit is the check valve in the pump. __________________ Mr. Shorty 92 XLT 4x4 87 Bronco II XLT 4x4 '98 Chev K1500 Suburban SLT 4x4

06-25-2010, 09:31 PM	#2
Wrench Wannabe Elite Explorer Courtenay, BC 99 B4000 4.0L OHV Join Date: Dec 2005 Posts: 257 Vehicle Specs	I would do a fuel pressure test (KOEO) before first start. When was the last time you changed your fuel filter?

06-27-2010, 11:09 AM	#3
inkybandit Wannabe Elite Explorer Nashville, TN '92 XLT Join Date: Dec 2004 Posts: 13 Vehicle Specs (Original Poster)	Replaced it last summer with an oil change

06-30-2010, 08:55 PM	#4
inkybandit Wannabe Elite Explorer Nashville, TN '92 XLT Join Date: Dec 2004 Posts: 13 Vehicle Specs (Original Poster)	I did a fuel pressure check and it was pretty low (31 psi). After I shut off the engine, pressure dropped pretty rapidly back to practically zero. I'm under the impression that it should stay pressurized for a few minutes, correct? So what are the likely candidates: pressure regulator, pump, filter?