97 TAHOE 5.7L VORTEC WON'T START...GM Merlin ideas?

[rhandwor]

Originally Posted by j cAT

this is my last response to you . what is the fuel pressure ?

You can hook up a pressure gauge at the fuel filter connector. Then blow through the filter and make sure it isn't plugged.

[bigbluefan]

I will have to check it again and post the answer

[rhandwor]

http://www.bergerweb.net/PasslockFix/index.shtml
http;//www.ebay.com/ Search Innova scanners for obd 2 They have 3 used ones for $69.00 plus shipping.
Weather you have a problem in this area or not a scan tool with codes and freeze frame will save you time and money. Just the loss of a vehicle for a week and a rental car is costly.
The color codes are different but the procedure is the same. My other links have colors for this truck. My BCM is between the steering and glove box if I remember correctly.

[rhandwor]

http://www.youtube.com/watch?v=4ox_IhgGLYU
This shows a lock smith repairing a a lock cylinder and reprogramming so the vehicle will start.

[rhandwor]

Originally Posted by bigbluefan

rhandwor, ok checked the fuel pump relay its working properly. I'm running out of things to check ? any ideas of what it could be

My fuel pressure regulator is adjustable you may have to get a loaner gauge at Auto Zone and hook up to fuel rail to adjust. I just noticed you had a 2000 not a 1998.

[bigbluefan]

Fuel pressure was 38. checked for power and ground, jumped from point number 30 and 87 fuel pump ran and stayed on. tried to start it but it still won't start. took battery to be recharged.

[j cAT]

Originally Posted by bigbluefan

Fuel pressure was 38. checked for power and ground, jumped from point number 30 and 87 fuel pump ran and stayed on. tried to start it but it still won't start. took battery to be recharged.

fuel pressure need be key on engine off 60-65 psi. .

37 psi would not start an LT 1 engine which the spec is 40 psi...

if you installed an airtex pump this is quite common ...

use delphi or ac delco.

good luck .

[rhandwor]

Originally Posted by bigbluefan

Fuel pressure was 38. checked for power and ground, jumped from point number 30 and 87 fuel pump ran and stayed on. tried to start it but it still won't start. took battery to be recharged.

If you used Auto Zone they will give you a free pump.
You would be better with a Delphi pump.

[bigbluefan]

Thank you everyone for all the good advice. My truck is finally working.

[rhandwor]

Originally Posted by bigbluefan

Thank you everyone for all the good advice. My truck is finally working.

Good work I'm glad you got it running.

[ajworcester]

i have a 1997 chevy tahoe LS 4dr. 4wd. i have had a check engine light on for a long time. random misfire and cam/crank correlation error. i changed my plugs and wires and timed it and the check engine light is gone. however before i fixed this issue i was having trouble where it will start and run perfect but randomly not start. it will crank and crank but no start and then when it decides (minutes to hours later) it will start and run fine. no problems at all. i checked the fuel pressure and was getting avg. 50psi. i changed the pump and filter and still have this issue. what else could it be? i have 198,000 miles on it. when it sits in the garage overnight it seems to start fine but if it sits out in the sun all day it wont start. i dont know if it has any thing to do with it or just a coincidence. new alternator, water pump, plugs, wires, fuel pump, fuel filter, battery, all fluids are good.

[j cAT]

Originally Posted by ajworcester

i have a 1997 chevy tahoe LS 4dr. 4wd. i have had a check engine light on for a long time. random misfire and cam/crank correlation error. i changed my plugs and wires and timed it and the check engine light is gone. however before i fixed this issue i was having trouble where it will start and run perfect but randomly not start. it will crank and crank but no start and then when it decides (minutes to hours later) it will start and run fine. no problems at all. i checked the fuel pressure and was getting avg. 50psi. i changed the pump and filter and still have this issue. what else could it be? i have 198,000 miles on it. when it sits in the garage overnight it seems to start fine but if it sits out in the sun all day it wont start. i dont know if it has any thing to do with it or just a coincidence. new alternator, water pump, plugs, wires, fuel pump, fuel filter, battery, all fluids are good.

5.7L requires 60 psi key on eng off.

[ajworcester]

with a new pump and filter what would cause the pressure to remain at 50 vs. 60?

[j cAT]

Originally Posted by ajworcester

with a new pump and filter what would cause the pressure to remain at 50 vs. 60?

the fuel regulator ... if the regulator returns too much fuel back to the tank the pressure will be too low.

when at idle the engine is at max vacuum the regulator is calibrated to reduce the fuel pressure. with the engine off you have NO vacuum therefore the regulator should be calibrated to provide 60-65 psi......

the other reason would be poor pump flow.....or power ... to check this you momentarily restrict the return fuel line to see the pressure surge up to 75psi plus...

when the engine is turn off the pressure should hold for 15 min if it drops to zero you must find out why.. leaks/pump check valve ,leaky injectors ,fuel lines..

[skijeck]

I read all of the solutions, but didn't see this one. So, you may think, what does this have to do with not starting? The answer is this: I have a 1999 suburban with 327,000 miles on it that I was using to drive 30 miles a day. Still runs good. I took into have the water pump replaced and when I got it back, I have trouble getting it started. I have two pistons with low compression's. This didn't just happen, it's old. Anyway, they called me up and said it's hard to start, I told them it always started on the first key turn without using the gas pedal. Because it was so hard to start, I change plugs, wires everything, check fuel pressure, good...but would flood as soon as I tried to start it without using the gas pedal. 3 months went by sitting. I decided, one more attempt. Talked with this mechanic and he told me the Temperature Sensor on the intake manifold was the problem. He explained, because it's bad, it thinks the engine is very hot and tells the computer to send maximum fuel which it did. $14 later for a new one, a bit hard to start due to sitting, but once it started, all is good. 5 days after and starting it daily, it's back to turning the key and it starts right up. That's the cheapest fix I ever had. Sorry for the long winded answer, but I though you all should know.