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1997 GMC Suburban won't start.
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c_robinson
New User
Oct 2, 2009, 9:34 AM
Post #1 of 4
(9686 views)
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1997 GMC Suburban won't start.
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1997
GMC
Suburban
5.7 l vortec
181000.
Noticed the service engine light come on on the way home from work. Stopped in at a part house and had the code pulled and it came back as a manual cylinder failure( i don't have a printout or what the exact code number was) after they looked it up on their computer they said that i just needed a tune up and possibly a coil. The next morning the car just wont start. Replaced the coil, wires and spark plugs and it still wouldn't turn over. The spark was very weak and the cylinders were loading up with gas. So I removed the plugs and let it dry out and replaced them with a new set and also replaced the distributor cap,and rotor button. Still wouldn't start but would backfire at point. Had the ignition module tested and it tested good once and bad once so I replaced it as well but still no start. All the hard starting had drained my battery so i replaced it as well but still no start. At this point I'm at my wits ends. When I go to start it it will hit for just a brief second then die out again or just backfire alot. I've had the time checked and the cylinder compression to make sure it didn't jump time and they checked out. Once again any and all help is greatly appreciated.
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Hammer Time
Ultimate Carjunky
/ Moderator
Oct 2, 2009, 11:38 AM
Post #2 of 4
(9673 views)
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Re: 1997 GMC Suburban won't start.
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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.
This may be difficult on the Vortec so look at the plugs and see if they are getting fuel fouled.
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.
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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.
(This post was edited by Hammer Time on Oct 2, 2009, 11:39 AM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Oct 2, 2009, 1:45 PM
Post #3 of 4
(9664 views)
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Re: 1997 GMC Suburban won't start.
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Exactly as Hammer said and to add that these "R(?)" code Vortecs really want fuel pressure within specs and it seems somewhat common. You may find as high as 54 PSI and they (some) won't start but might run if it can hold at least that much. I've just gone thru one that of course always tested fine and finally caught it. Would start when primed but wasn't as normal and stayed hovering 53/54 PSI that test so a fuel pump in that case was the fix.
They like (don't have exact spec in front of me now) 60-66 or so to run and start their best. If you find this to be the problem I strongly suggest using OE parts. More: Check the plug at the fuel pump as they can be the issue also - perhaps more common in our lovely rust belt!
Good luck finding the fix,
T
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Lee09isfine
New User
Oct 5, 2009, 5:29 PM
Post #4 of 4
(9653 views)
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Re: 1997 GMC Suburban won't start.
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These "R" code engines are notorious for the first design "spider" assembly under the plastic upper plenum to leak massive amounts of fuel from a ruptured regulator, causing your symptoms. Just take the air cleaner off of the throttle body. Take a flashlight and shine it down the throttle bore whilst holding the throttle wide open. You will likely see raw wet fuel on the bottom surface there.... this also causes the pressure to run low. GM has redesigned the spider with new pop off valve designs and a new regulator design. This fuel distributor is sold as an assembly.... I replace them in my shop often for these exact symptoms.... but DO see bad pumps, too.... but I use an oscilloscope to diagnose that. OEM is not all that mandatory. I use Airtex with great results.
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