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1997 GMC K1500 5.7l will not start


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todpal1
New User

Jan 11, 2013, 8:18 PM

Post #1 of 7 (3457 views)
1997 GMC K1500 5.7l will not start Sign In

Here is what happened. My son told me that (Scrubbing Bubbles) does a great job on cleaning and engine. So, I decided to go for it. I did not spray anywhere near the computer. After rinsing with a very minimal spray rinsing, I started the engine and let it warm up to let it dry off. The next day, my wife drove the truck 97 GMC K1500 5.7) to the store and called me to tell me it was running terrible. So after a few moments of looking it over, I decided to remove the cap and rotor to see if moisture had got in. It did. I cleaned it up and the truck started. Well after a few days of sitting, I went to drive it again and it was running rough again. there was a lag in throttle response. I drove the vehicle to the parts house and the scanner said is was the EGR. Changed it and no change. After a few attempts to crank, it would start and as soon as I would give it the gas it would stall, did this over and over. Called a mechanic and he told me this modle vehicle has an issue with the coolant sensor shorting out. Changed it and had to remove the plugs to dry the block out with all the gas and finally started. drove it to work it, it ran great. That afternoon, when I went to start it again, it was running rough again. it stalled on me one time. After i got it to start again i got on it hard and and i heard a metalic knock and the truck ran great again. Got it home and it has not run since. I have changed the TPS and the connector wire to the coolant sensor. So I decided to eliminate the engine by doing a compression check. Cylinders 1,3,5,7,2,8 are 200 PSI, 4-191psi., 6 is 196psi. Thats pretty good for an engine with 213000 miles on it. Before starting the compression check i removed the fuel pump relay to avoid the pump running. I also removed the coil wire from the coil.xaWhile i was testing the compression, the coil stopped firing on the second to last test. Bought a new coil no luck. Plugged the fuel pump relay back in and now i have no fuel pressure. Im missing something here.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 12, 2013, 3:17 AM

Post #2 of 7 (3409 views)
Re: 1997 GMC K1500 5.7l will not start Sign In

Well! Hope you are happy with your clean engine. NEVER WASH AN ENGINE! You managed to get it soaked enough to get water in distributor so no telling without extensive work to see what got wrecked. Do you wash a computer? Same idea - there are so many sensitive electrical parts and items connections purposely greased to save them this could be a real nightmare.

No fuel pressure now. IDK - swap relays that are identical like for A/C but if that "fuse center" got soaked too who knows now?

This may take painstaking checking everything electrical and connections and suggest a pro with some very high end skills and equipment to do so,

T


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jan 12, 2013, 4:19 AM

Post #3 of 7 (3400 views)
Re: 1997 GMC K1500 5.7l will not start Sign In


Quote
Before starting the compression check i removed the fuel pump relay to avoid the pump running.


I'm afraid that doesn't work on this truck. This engine will run without a fuel pump relay even being in the truck. The fuel pump is alsoo powered through the oil pressure switch.

You need to put everything back together and start from scratch.


All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.



Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.


2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.


3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.

4) If all of these things check good, then you would need to do a complete compression test.

Once you have determined which of these functions has dropped out,
you will know which system is having the problem.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



todpal1
New User

Jan 12, 2013, 9:17 AM

Post #4 of 7 (3385 views)
Re: 1997 GMC K1500 5.7l will not start Sign In

You obviously did not read my post to well. I ran the vehicle after it was rinsed off. That means I did not push any water into the distributor. After i stopped the truck and let it sit over nite the steam from the engine obviously went inside the distributor. If you are driving down the road in a rainy situation and you hit a puddle of water wrong your going to get the distributor wet or this is like saying do not drive in the rain because your your engine will get wet and will not start. Or dont go to a website that has a raining back ground, the pc will get get a virus. Im looking for suggestions to fix a problem, not critiize what i do with my toys. Engines are made to wash. and keep clean. I personally do not like to work on a dirty engine. If this is all you have to offer then thank you for your time. no need to respond back. Anyway it seems to be the charastic of a CRANK Sensor.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Jan 12, 2013, 9:26 AM

Post #5 of 7 (3381 views)
Re: 1997 GMC K1500 5.7l will not start Sign In


Quote
Engines are made to wash. and keep clean.


What, are you nuts? Modern cars have over 50 electronic control units in them and they are not designed to get wet. Driving in the rain is nothing like washing an engine. You keep that up and you'll find yourself spending thousands to fix what you destroyed.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



todpal1
New User

Jan 12, 2013, 9:31 AM

Post #6 of 7 (3377 views)
Re: 1997 GMC K1500 5.7l will not start Sign In

Thank you for your advice hammer. I have completed all the sugestions your asking. Did not realize that power is still GOING TO PUMP. I have a few sensors left to change. Crank, Mass, Map, then the pc. Just going to replace them all. Thanks


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Jan 12, 2013, 10:23 AM

Post #7 of 7 (3363 views)
Re: 1997 GMC K1500 5.7l will not start Sign In

Just curious, but have you considered troubleshooting this? MAF and PCMs aren't really that cheap.





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Jan 12, 2013, 10:32 AM)






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