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98 silverado cranks no start
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budbarner
New User
Nov 26, 2009, 9:06 PM
Post #1 of 11
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98 silverado cranks no start
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98 Silverado 1500 5.7 4x4 55,000 miles automatic. I started the truck yesterday, drove it 200ft, shut it off for 5 minutes, then it wouldn't start. It cranks but won't fire until I let go of the key, then it'll fire occasionally as if it's diesling for a few seconds. I sprayed starting fluid in the intake and directly in the throttle body but it does the same thing. Charged the battery for a few hours to make sure it's strong.
Hooked up a timing light to each spark plug wire, they're all getting spark when it's cranking. Pulled a spark plug and it's getting a strong spark. The code reader says NO CODE.
Cylinder compression is 170 lbs. Disconnected lots of connectors looking for corrosion but couldn't find any. checked all fuses with ohmeter, they're all good. Crank position sensor has power and reads 5vAC. Cam sensor has power but reading is erratic, switching between 4.5v-145vAC without staying on any reading for very long. Knock sensor tested ok. Spark plugs, air filter, and PCV replaced 200 miles ago. The truck doesn't get used much, but it ran well 2 days ago and started well before it quit with no performance problems.
Disconnected the battery for 2 hours then reconnected it but it still does the same thing, cranks strong, no sign of firing until the key is turned off, then it'll sputter just a bit. Since starting fluid doesn't affect it I suspect the problem is not fuel. Pushing the schraeder valve on the fuel line squirts fuel out.
The security system shuts off the fuel but, since starting fluid makes no difference, I doubt that's the problem.
Any ideas?
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 27, 2009, 3:41 AM
Post #2 of 11
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Re: 98 silverado cranks no start
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What is the fuel pressure?
Have you used an adjustable spark tester to determine just how strong the spark is?
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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.
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DanD
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Nov 27, 2009, 8:29 AM
Post #3 of 11
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Re: 98 silverado cranks no start
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Yes you’re going to need to know what the fuel pressure is. If this truck’s fuel delivery system hasn’t been up-graded to a SFI (Sequential Fuel Injection) and is still using the CSI (Central Sequential Fuel Injection); it asks for 60- 66 Lbs fuel pressure.
The CSI system uses mechanical pop-it nozzles to spray the fuel into the engine. Fuel pressure is what opens these nozzles; much like older style diesel fuel injector and when they say you need 60- 66psi, they mean it; at 58psi the pop-it valves will not open.
That could be why you’re getting a bit of firing as you release the ignition key. Battery voltage will jump up, just for a second, as the starter disengages. This momentary increase in voltage, may just spin the fuel pump a little faster; giving you the magical 60psi to fire the engine?
The SFI retrofit isn’t cheap but neither is a fuel pump for one of these; but if your pump can consistently produce 56-60psi the SFI system will run without a problem. A SFI system uses actual electric injectors and works more like a multi port system. You get them from the dealer and it’s a direct fit changeover.
Dan.
Canadian "EH"
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budbarner
New User
Nov 27, 2009, 8:58 AM
Post #4 of 11
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Re: 98 silverado cranks no start
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I'll check the fuel pressure, but if it's a fuel problem I think it should start with starting fluid. Ether doesn't make any difference.
I opened the hood last night and saw lots of arching around the spark plug wires. I replaced them today, no difference. I also forgot to mention that There's lots of pressure coming out of the exhaust when cranking, the exhaust doesn't seem to be clogged.
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DanD
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Nov 27, 2009, 9:52 AM
Post #5 of 11
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Re: 98 silverado cranks no start
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You would think it would fire with starting fluid but it is strange stuff and to tell you the truth I would stop using it. One cross fire from the ignition system and you light the starting fluid with an intake valve open and you’ll be picking the shrapnel from the valve covers out of your hood or your forehead.
Dan.
Canadian "EH"
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budbarner
New User
Nov 27, 2009, 10:00 AM
Post #6 of 11
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Re: 98 silverado cranks no start
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Fuel pressure is 64lbs, within limits
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Loren Champlain Sr
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Nov 27, 2009, 6:40 PM
Post #7 of 11
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Re: 98 silverado cranks no start
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Bud; If this is the horizontal type distributor cap, might be worth a try. A plug wire goes in 'here', but comes out 'over there'. I've had several that drove me nuts.
 If you look at the lower left picture, you'll see what I mean.
Loren
SW Washington
(This post was edited by Loren Champlain Sr on Nov 27, 2009, 6:43 PM)
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Sidom
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Nov 27, 2009, 7:27 PM
Post #8 of 11
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Re: 98 silverado cranks no start
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After reading your post I was kinda thinking the same thing that Loren posted. I've even had problems with new caps crossfiring. The problem with this design is it usually happens inside of the cap where you can't see it due to the electrode design. Also those are good for the rotor burning thru.......
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budbarner
New User
Nov 29, 2009, 12:37 PM
Post #9 of 11
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Re: 98 silverado cranks no start
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I'm not sure what Loren is indicating, maybe that the wires are mixed up? The pictures show a cap like mine. I'm surprised Chevy even had a cap and rotor in 1998. I know the wires aren't crossed. The cap has numbers on it and I changed only one ignition wire at a time. After I changed the wires there was no performance difference.
I turned the key this morning and the truck started right up. I spent 2 days working on it with no success, left it for a day, then it starts with the turn of the key. I drove it, restarted it, no problems. I'm going to assume the cap got wet on the inside due to humidity. I'll put a new cap and rotor on it. It's too bad these caps aren't vented.
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Hammer Time
Ultimate Carjunky
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Nov 29, 2009, 1:01 PM
Post #10 of 11
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Re: 98 silverado cranks no start
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What Loren is pointing out is the the tower on the outside does not align with the rotor contact inside. A wire coming in one side of the cap may actually have a contact point on the other side of the cap.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 29, 2009, 1:01 PM
Post #11 of 11
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Re: 98 silverado cranks no start
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What Loren is pointing out is the the tower on the outside does not align with the rotor contact inside. A wire coming in one side of the cap may actually have a contact point on the other side of the cap.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.
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