1998 Chevy S-10 MISS FIRINGG

Tiny
I122H9
  • MEMBER
  • 1998 CHEVROLET S-10
  • 4 CYL
  • 2WD
  • MANUAL
  • 200,000 MILES
I HAVE A CODE WHICH IS NUMBER FOUR INJECTOR MISS FIRING. I HAVE NEW SPARK PLUG AND WIRES, FOUR NEW INJECTORS, I HAVE CHECKED THE WIRING AND FOUND OK. WHEN THE NUMBER FOUR INJECTOR IS UNPLUGGED IT MAKE LITTLE TO NO DIFFERINCE IN THE ENGINE LIKE THE OTHER ONE DO YOU CAN DEFFENTLY TELL WHEN THE OTHERS ARE UNPLUGGED.
Friday, May 1st, 2009 AT 3:01 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Have you checked if the injector is getting power with a noid light? Also, if you are sure it is working, have you checked compression in that cylender? Finally, if you pull that plug after the car has run for awhile, is it wet with gas or dry?

Joe
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Saturday, May 2nd, 2009 AT 1:40 PM
Tiny
I122H9
  • MEMBER
  • 4 POSTS
When the plug is pulled after it has ran for a while it is dry and no I have not check for power with a noid light just with a multimeter.
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Monday, May 4th, 2009 AT 8:35 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Were you getting power? If you are getting fuel and spark, you need to check compression.
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Tuesday, May 5th, 2009 AT 10:59 AM
Tiny
I122H9
  • MEMBER
  • 4 POSTS
I checked power at the injector and I am getting 14.5 volts just like the rest of them. And as soon as I get homw from work I will check compresion at the cylinder. Should there be constant power at the injector at all times. I have also checked the ground to make sure it was getting a good ground and found that it was getting the proper ground.
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Tuesday, May 5th, 2009 AT 11:27 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
The injector should pulse power not be consistant. Check to make sure nothing has shorted out causing it to get constant power.
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Tuesday, May 5th, 2009 AT 7:47 PM
Tiny
I122H9
  • MEMBER
  • 4 POSTS
OKAY I RENTED A NOID TESTER AND FOUND THAT THE ELECTRICAL AT THE INJECTOR IS WORKING PROPERLY. I DID A COMPRESSION TEST A DRY ONE AND ONLY HAD 60PSI IN NUMBER FOUR WHEN I WENT TO DO A COMPRESSION CHECK ON THE NUMBER THREE TO COMPARE I BLEW THE HOSE OFF THE FITTING. IT WAS A CHEAP TESTER I RENTED FROM AUTO ZONE BUT THAT JUST GOES TO TELL ME IT HAS TO HAVE AT LEAST 125PSI BUT TO MAKE SURE I AM GETTING THE ONE FROM MY DADS SHOP AND IT IS A GOOD ONE. ALSO I AM GOING TO DO A WET TEST TO SEE IF IT IS MY RINGS OR IF I HAVE A CHIPPED OR BURNT VALVE. DOES THIS SEEM LIKE I AM HEADING IN THE RIGHT DIRECTION?
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Friday, May 8th, 2009 AT 8:01 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Yes you are going in the right direction. 60 PSI is the cause of the miss. The wet test, like you said, will help you determine if it is a valve or rings.

Let me know what you find.
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Friday, May 8th, 2009 AT 8:09 AM

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