97 Suburban hard to start

tresguey · 11-27-2008, 10:24 PM

1997 Suburban 7.4 4X4. This is my fiancee's truck and we are having problems starting it. Especially in the morning. I think it has something to do with oil pressure. Because when i crank it over in the morning it takes a good 6-10 seconds for it to start. And I have noticed that there is not pressure for the first 5 seconds I crank it. And it fires up when the pressure hits about 30 psi. After it starts i have good pressure about 90 at first the drops to about 60 when its warm and it runs normal. I can turn it off and restarts normal. I can even drive it to work and have it sit for about 8 hours and it fires right up normal. But if I let it sit for more than 12 hours it takes 6 - 10 seconds to fire up.

One thing that I did notice is she has a non-4X4 radiator in it and whoever instaled it bypassed the oil cooler in the radiator bacause of a wrong size fitting. I am planning on installing a stand alone oil cooler soon. just haven't had the time yet. I was thinking that maybe the oil was draining back in the pan from the cooler lines being looped and tied off in a high place.

Any help would be great.

gmctrucks · 11-28-2008, 01:57 AM

I don't think that the oil pressure would be it but I may be wrong. If I were you I would get up early when it's dark out and have someone try to start it and see if you see any aching/sparks anywhere in the hood area im thinking that moister is getting into you spark plug wires or something and that's what causing it to do that.
Good luck! GMC

leolkfrm · 11-28-2008, 04:59 AM

How's the starter and battery, how fast it turns over when cold will affect starting time

purplehavoc · 11-28-2008, 06:27 AM

Have you checked fuel pressure?
Sounds like fuel may be bleeding off when it sits and takes a few
seconds of cranking to pick it back up.
Your oil cooler lines won't have anything to do with your starting.
Is your ign. system in good shape as well?

tresguey · 11-28-2008, 02:04 PM

I will check fuel pressure and ignition. I thought there may be some sort of low oil pressure sensor that kills the engine that I was unaware of. Because for some reason it seems to start after i crank it over enough to hit 30 psi of oil pressure. As for the battery and starter, I just put a new starter in about two months ago. And it cranks fine. this problem has been going on for about 6 months now. And I have finally have time to really look into it. from what little info i get from my fiancee about the truck. She bought it from an old friend that had the engine rebuilt for her. Looking at it I can see that whoever did it really didn't care or didn't know much about vehicle care. Not saying I'm an expert. I will post what I find on the ignition system and fuel pressure.

stumpuller454 · 11-28-2008, 03:24 PM

fuel pressure should be 55-60psi and volume around 1 pint per minute......

87c10slammer · 11-29-2008, 12:21 PM

try priming it first before you start it.. turn the key to the on position for about 20 seconds before you start it.. it lets the fuel pressure build up so you wont kill your starter.. i had the same problem with my 4.3.. it was the fuel pressure regulator.. after i changed that it was no problem

tresguey · 11-30-2008, 12:35 PM

I went to check out fuel pressure, I turned the key over to the run position and the pump was not on. shouldn't it be on at this point?

bigz · 11-30-2008, 01:16 PM

yeah should be

gmctrucks · 11-30-2008, 04:06 PM

Quote:

Originally Posted by tresguey

I went to check out fuel pressure, I turned the key over to the run position and the pump was not on. shouldn't it be on at this point?

I don't know about that could it be primed already that it won't kick in meaning the fuel pump guys???????????

11-27-2008, 10:24 PM	#1
tresguey Junior Member Join Date: Nov 2008 Posts: 8	97 Suburban hard to start 1997 Suburban 7.4 4X4. This is my fiancee's truck and we are having problems starting it. Especially in the morning. I think it has something to do with oil pressure. Because when i crank it over in the morning it takes a good 6-10 seconds for it to start. And I have noticed that there is not pressure for the first 5 seconds I crank it. And it fires up when the pressure hits about 30 psi. After it starts i have good pressure about 90 at first the drops to about 60 when its warm and it runs normal. I can turn it off and restarts normal. I can even drive it to work and have it sit for about 8 hours and it fires right up normal. But if I let it sit for more than 12 hours it takes 6 - 10 seconds to fire up. One thing that I did notice is she has a non-4X4 radiator in it and whoever instaled it bypassed the oil cooler in the radiator bacause of a wrong size fitting. I am planning on installing a stand alone oil cooler soon. just haven't had the time yet. I was thinking that maybe the oil was draining back in the pan from the cooler lines being looped and tied off in a high place. Any help would be great.

11-28-2008, 04:59 AM	#3
leolkfrm Senior Member Join Date: Mar 2008 Location: N.Y. Posts: 4,300	How's the starter and battery, how fast it turns over when cold will affect starting time __________________ 4 wheels move the body 2 wheels move the soul B.W.A.I

11-28-2008, 03:24 PM	#6
stumpuller454 Senior Member Join Date: Dec 2007 Location: Grande Prairie, AB Posts: 2,043	fuel pressure should be 55-60psi and volume around 1 pint per minute...... __________________ SUPERCHARGED 454 K2500 GMC! 450hp and 600ft/lbs http://www.youtube.com/watch?v=WJ27RJHfJKE "sailing with Captain Morgan often!"

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11-28-2008, 01:57 AM	#2
gmctrucks Senior Member Join Date: Nov 2006 Location: Houston,Texas Posts: 4,035	I don't think that the oil pressure would be it but I may be wrong. If I were you I would get up early when it's dark out and have someone try to start it and see if you see any aching/sparks anywhere in the hood area im thinking that moister is getting into you spark plug wires or something and that's what causing it to do that. Good luck! GMC

11-28-2008, 06:27 AM	#4
purplehavoc Full Member Join Date: Sep 2008 Posts: 16	Have you checked fuel pressure? Sounds like fuel may be bleeding off when it sits and takes a few seconds of cranking to pick it back up. Your oil cooler lines won't have anything to do with your starting. Is your ign. system in good shape as well?

11-28-2008, 02:04 PM	#5
tresguey Junior Member Join Date: Nov 2008 Posts: 8	I will check fuel pressure and ignition. I thought there may be some sort of low oil pressure sensor that kills the engine that I was unaware of. Because for some reason it seems to start after i crank it over enough to hit 30 psi of oil pressure. As for the battery and starter, I just put a new starter in about two months ago. And it cranks fine. this problem has been going on for about 6 months now. And I have finally have time to really look into it. from what little info i get from my fiancee about the truck. She bought it from an old friend that had the engine rebuilt for her. Looking at it I can see that whoever did it really didn't care or didn't know much about vehicle care. Not saying I'm an expert. I will post what I find on the ignition system and fuel pressure.

11-29-2008, 12:21 PM	#7
87c10slammer Banned Join Date: Mar 2008 Location: levittown pa Posts: 2,197	try priming it first before you start it.. turn the key to the on position for about 20 seconds before you start it.. it lets the fuel pressure build up so you wont kill your starter.. i had the same problem with my 4.3.. it was the fuel pressure regulator.. after i changed that it was no problem

11-30-2008, 12:35 PM	#8
tresguey Junior Member Join Date: Nov 2008 Posts: 8	I went to check out fuel pressure, I turned the key over to the run position and the pump was not on. shouldn't it be on at this point?

11-30-2008, 01:16 PM	#9
bigz Banned Join Date: Oct 2008 Posts: 462	yeah should be