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

[cwong]

After he towed it in I began to pick it apart. I looked at the pump relay and even jumpered the wire but it never came on. Looked at the PK2 light on the dash and it behave normally. So, I dropped the tank because I metered the gray wire at the pump relay but it didn't show any ground. Took out the pump and inspected. It was obviously new. I rigged the pump with my 12v drill battery and it worked. Checked the connector on the pump and it metered fine. Looked at the plug/harness that goes from the relay to the pump. The gray wire was fine but noticed the black ground wire was pushed back. Replaced the pin and wire, all is fine now.[/quote]

ponchonutty:
Where is this black groud wire?
Is it by the relay panel or by the fuel pump?

Thanx...

[ponchonutty]

Originally Posted by cwong

After he towed it in I began to pick it apart. I looked at the pump relay and even jumpered the wire but it never came on. Looked at the PK2 light on the dash and it behave normally. So, I dropped the tank because I metered the gray wire at the pump relay but it didn't show any ground. Took out the pump and inspected. It was obviously new. I rigged the pump with my 12v drill battery and it worked. Checked the connector on the pump and it metered fine. Looked at the plug/harness that goes from the relay to the pump. The gray wire was fine but noticed the black ground wire was pushed back. Replaced the pin and wire, all is fine now.

ponchonutty:
Where is this black groud wire?
Is it by the relay panel or by the fuel pump?

Thanx...[/quote]
Unfortunately, it is the plug on top of the fuelpump. If you have skinny arms, you can reach on top and get it unplugged and pull it out. But, you gotta know what you are trying to unplug since you can not see it.

[kerspse]

Your Fuel Pump is going bad. Replace it now or get stranded.

[ponchonutty]

Originally Posted by kerspse

Your Fuel Pump is going bad. Replace it now or get stranded.

Who are you replying to? You can't assume anything. Just like this last Tahoe I looked at. Who knows how many pumps the guy would have installed on his own!!!

[listo]

Im Having The Same Problem Would Someone Post Step By Step Trouble Shooting guides . What Do I Chech First And So On. Also Provide Location Of Parts To Be Checked. Thank You

[txgearhead]

Turning Over/No start - Interesting thing I came across a few weeks ago. The fuel pump has a sensor that checks for unwanted air (pump gets dry). If the pump thinks it is dry, it cuts off to protect itself. Afterwards, it will act just like you ran out of fuel. It'll Turn over, but won't start until you get some more fuel. I was low on fuel, 2nd to the last red line and was headed up hill and punched to get around some traffic. The effect of both going uphill and harder than normal accelleration forced the fuel away from the pump and next thing I'm doing is muscling this rig around a curve! I parked facing downhill and it would not start. I put 2 gals of gas and it fired right up as if nothing was ever wrong. Not the fix for your prob., but something to keep in mind.

My experiences w\ the Passlock engaging has always centered around trying to turn the key too fast to start or to turn off then trying to start again. I purposely sit and wait for all the dash lights to go off before I start and pause for just a second in park before I turn off the ignition. It seems I wasn't letting the Passlock recognize the key, so it shut off. I haven't had a problem since

Food for thought, Good luck!

[timaah]

I've been having the same problems with my '99 C1500 for the past few years. Only mine is a bit different. If it rains or it is very humid my truck will not start. I have replaced the coil, ICM, Dist. cap, rotor, sensor under the rotor, plug wires, plugs, crank shaft position sensor, fuel pump, fuel pump connector plug, knock sensor. I'm about to change out the fuel pressure regulator next. Tonight I had the truck running, then I shut it off. I then got the garden hose and watered down the distributor. I then tried to start the truck. It turned over and fired a little bit, but it would not start. It's looking like I have a distributor problem. Any one else out there have this problem?
Tim

[baskentball]

I've been having the same problems with my '99 C1500 for the past few years. Only mine is a bit different. If it rains or it is very humid my truck will not start. I have replaced the coil, ICM, Dist. cap, rotor, sensor under the rotor, plug wires, plugs, crank shaft position sensor, fuel pump, fuel pump connector plug, knock sensor. I'm about to change out the fuel pressure regulator next. Tonight I had the truck running, then I shut it off. I then got the garden hose and watered down the distributor. I then tried to start the truck. It turned over and fired a little bit, but it would not start. It's looking like I have a distributor problem. Any one else out there have this problem?

Timaah,

Did you ever solve your problem? I believe my 97 Tahoe developed the same problem last week. I tried starting it last night, turns over a couple times then drags really hard. It acts like it wants to run (kind of rumbles then dies) but won't start. It was extremely humid and raining last night which is why it makes me think I have the same problem as you.

Thanks,
baskentball

[EisMCA2]

I've been having the same problems with my '99 C1500 for the past few years. Only mine is a bit different. If it rains or it is very humid my truck will not start. I have replaced the coil, ICM, Dist. cap, rotor, sensor under the rotor, plug wires, plugs, crank shaft position sensor, fuel pump, fuel pump connector plug, knock sensor. I'm about to change out the fuel pressure regulator next. Tonight I had the truck running, then I shut it off. I then got the garden hose and watered down the distributor. I then tried to start the truck. It turned over and fired a little bit, but it would not start. It's looking like I have a distributor problem. Any one else out there have this problem?

baskentball or timaah,

My 97 Tahoe has been doing this for about 6 months now almost every time it rains or is extremely humid. Cranks over but will not start. It will sputter a few times and then kicks in like there never was a problem. Temperature doesn't seem to affect it. Once it does start, it runs great. Today it has completely given up and will not start. Has anyone figured this out? This seems to be a common problem. I'm going to finally try the fuel pressure regulator.

[baskentball]

EisMCA2,

My problem ended up being my crankshaft position sensor. I stumbled upon the service bulletin (pasted below) while I was searching for Vortec timing problems.

Timaah was kind enough to email me after I posted. His problem ended up being the distributor cap.

Hope this helps,

baskentball

--------------------------------------------------------------------------

Engine - No/Hard/Slow Start/Backfire/Kickback

File In Section: 06 - Engine/Propulsion System

Bulletin No.: 00-06-04-014

Date: April, 2000

TECHNICAL

Subject:
No, Hard, or Slow Start, Backfire or "Kickback" During
Crank/Start, "Grinding" or Unusual Noises During Crank, DTC P0338
(Replace Crankshaft Position Sensor)

Models:
1999-2000 Cadillac Escalade
1995-2000 Chevrolet and GMC SIT Models
1996-2000 Chevrolet and GMC C/K, M/L, G, P Models
1996-2000 Oldsmobile Bravada
with 4.3 L, 5.0 L, 5.7 L or 7.4 L Engine
(VINs W, X, M, R, J RPOs L35, LF6, L30, L31, L29)

Condition:
Some customers may comment on one or more of the following conditions:

^ Backfire during crank/start
^ "Kickback" during crank/start
^ "No" start
^ "Slow" or "hard" start/crank
^ "Grinding" or unusual noises during crank/start
^ Cracked or broken engine block at the starter boss
^ Broken starter drive housing
^ Broken starter ring gear on flywheel
^ Any combination of the above

Cause:
A condition may exist that allows the crankshaft position sensor to command up to 50 extra degrees of spark advance during engine cranking only. This in turn exposes the engine to higher than normal cylinder pressures which may result in an inoperative condition to the starter drive housing, the engine flywheel starter ring gear, or the engine block at the outside edge of the starter boss.

Correction:
Inspect for a stored powertrain DTC code P0338. This DTC will NOT illuminate the "Service Engine Soon" light. If this code is stored, the Crankshaft Position Sensor, P/N 10456607, MUST be replaced and the remaining components inspected for damage (engine block at the starter boss, the starter drive housing, and the engine flywheel starter ring gear).

Notice : When DTC code P0338 is set, failure to replace the Crankshaft Position Sensor could result in repeated inoperative conditions of the starter or flywheel.

Important : Some flywheel wear is normal; broken or missing teeth and/or cracks, are not normal

[baskentball]

I wasn't for sure if you would get notified of my other reply. It's posted below.

Thanks

[EisMCA2]

Thanks baskentball,

Got it going now. It apparently is the crankshaft position sensor. I did replace the cap and rotor and it's running.

Anyway, I've noticed a lot of people with this same problem so maybe this will help other bone-heads like me. I'm not a mechanic so this may not be exact terms.

I've been messing with this for about a year. Usually it would start after several really rough cranks and then it would run just fine. Today it just wouldn't start. Even after recharging the battery for another go around. The fact that it happened every time it rained kept throwing me. Made me think it was a pressure problem which made sense that it could affect a fuel pressure regulator if it was failing. But the fact that temperature never seemed to affect it made me wonder. The humidity thing led me to think I should look at the distributor again. When trying to start it, it seemed like it was advanced too much and was fighting against itself. I unplugged the coil wire so it couldn't fire and it turned smoothly when cranking. Turned the engine to top dead center on 1. I figured out later that the notch on dampener lines up with notch on the block. I replaced the cap and rotor since they were a bit worn. I marked the direction the rotor was facing and when I put the cap on, I adjusted the distributor so that the #1 terminal was dead on with the rotor (follow the raised area on the cap from the #1 plug wire and this will let you see where the #1 terminal lines up). By this time the battery was recharged (ran it down while trying to start it all day). It started up just fine and is running great. It now gives me a check engine light (never did before). The code is for the crankshaft position sensor. So, my next move is to hope it doesn't crap out when it rains before I can get the crankshaft position sensor replaced. Seems like the new cap and rotor along with adjusting the distributor fixed it but I am going to do the crankshaft position sensor as well. Tired of getting caught in the rain. This may or may not help but I would have liked to have read this a year ago. Thanks.

[outlaw24]

EisMCA2,
Did the Crankcase Position Sensor work for you too ? Has anyone heard. I have the same basic problem except I am getting a random misfire to multiple cylinders on the days that it runs. 95 % of the time its running you do not feel the misfires. Like everyone else almost everything has been replaced. - Outlaw24

[EisMCA2]

Did the Crankcase Position Sensor work for you too?

Outlaw24,

When I was having the problem, it would run great once it started. Never felt any misfires. All I ended up doing was adjusting the distributor and changing the cap & rotor. I still have an engine light and the code says it is the crankcase position sensor but I just need to wipe that out. It has been starting like it did when it was new. From what I understand for this setup is that the computer adjusts the timing, not the distributor but if the distributor gets any farther than 10-12 degrees off, it can't accommodate. My problem seems like it was caused by the distributor being farther off than 10-12 degrees. All I did was mark where the rotor was pointing when #1 cylinder was at top dead center. Then when I put the cap back on I adjusted the distributor to line up #1 terminal with the mark I made for the rotor position. I still haven't figured out why it only did this when it was really humid or raining but it is running great now and I spent less than $50. I hope this helps.

EisMCA2

[rr7774]

check ur ignition switch , when you turn the key three wire attached to plug when turn the key could have canm e off in the colum....security alarm system coul be messing with it.