SPONSORED LINKS

Fuel, spark, good injectors. Wont start (runs with carb cleaner)

Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
Its on the passenger side and has relays in it?If so there is your cooling fan relays primary and then the secondary boxes and then the ac comoressor relays they have nothing to do with the injectors. What would cause the injector wire to be 12 volts then drop down like that could be high resistance like corroded terminals etc. Its all the same problem you just have to find the reason for the voltage drop. Let me know what you find.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Sunday, August 5th, 2012 AT 9:03 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
Now I feel stupid. After unwrapping the wiring harnesses and chasing pink/black wires around, I found I did not have a good ground with my test meter. So. I have 12v at the fuse (constantly), AND, 12v at each injector (the pink/black side). So back to square one.
Was this
answer
helpful?
Yes
No
Sunday, August 5th, 2012 AT 9:38 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
Dont feel bad everyone has there bad days. Sonwhat problem are you having?
Was this
answer
helpful?
Yes
No
Sunday, August 5th, 2012 AT 9:40 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
Was running fine. After shut off 30 min later cranks but wont start. Has good spark. Has good fuel pressure, HAS 12v at each injector wire key on. Did run with carb cleaner sprayed into air intake. Pulled plenum ohm'd all injectors are between 1.5-2 ohms.
Was this
answer
helpful?
Yes
No
Sunday, August 5th, 2012 AT 10:12 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
All the injectors arent going to fail at the same time I would have checked for unjector pluse first. Which you said you have checked for that and its not there. Do you have a led computer safe test light?
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Monday, August 6th, 2012 AT 9:27 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
If you mean a Noid light I can borrow one from Auto Zone. When I did that before dismantling I had no light at key on and no light at cranking. But now that I've found 12v at the wire at key on the previous light test response doesnt make sense. I have also been told by a couple people that the GM 3.1 and 3.8 in that year have a problem where if one injector grounds out, they all ground out due to the way they are wired. Would you agree? If so, how can you test that as the plenum has to pulled to get to them all?
Was this
answer
helpful?
Yes
No
Monday, August 6th, 2012 AT 10:34 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
There is two sides to your circuit a constant power and a plusing ground. You know we have power now we need to check for a plusing ground from the computer. If the wires were grounded out the noid light would stay on solid when turning the key on. You need a computer safe test light to check the ground side of the circuit while cranking for a plusing ground.
Was this
answer
helpful?
Yes
No
Monday, August 6th, 2012 AT 11:54 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
Ok. Assuming you are not talking about the noid light, how do I connect the test light?
Was this
answer
helpful?
Yes
No
Tuesday, August 7th, 2012 AT 12:31 AM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
The aligator clip to the positive battery post then the test light point to the non power feed to the injector connector. Then crank the light should flash check all the connectors. The noid lights tests the circuit as a hole working. This will just test the ground pluse side of the circuit.
Was this
answer
helpful?
Yes
No
Tuesday, August 7th, 2012 AT 12:41 AM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
Finally got a test light. Connected as you say and no light when cranking. Also checked ohms, neg side of connector to engine block, and got full continuity reading.
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 4:29 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
You shouldnt have a constant ground to the non power wire if you did the injectors would stay open and flood the engine with gas. Also when you checked it with the noid light it would have had the noid light on constantly with the key in the run position. Which you said it didnt.
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 9:30 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
Correct on the noid light. So you are expecting no continuity to the no power side? I am so confused - the manager at the auto store that loaned me the light suggested checking continuity and that it should be present. Maybe he was thinking the power side. FYI all injectors are still disconnected.
SPONSORED LINKS
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 9:48 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
Yeah the computer controls the ground and pluses it shouldnt have a constant ground. That noid light should be on if there is power and ground.
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 10:00 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
So am I chasing a wiring problem or is this pointing to the computer?
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 10:14 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
Thank you for all your attention to this!
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 10:15 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
If it was the computer, would it still run with carb cleaner?
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 10:17 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
Your welcome thats what were here for measure the voltage across the injector harness with the key in the run position. Let me know what you find.
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 10:32 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
3v across hot lead and the no power lead. Same reading at all 6 connectors.
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 10:50 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,870 POSTS
So just the power feed side to negative side of the battery reads battery voltage?
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 10:54 PM
Tiny
BUS933S
  • MEMBER
  • 43 POSTS
Yes. 12v
Was this
answer
helpful?
Yes
No
Sunday, August 12th, 2012 AT 10:56 PM

Please login or register to post a reply.

Related Engine Not Running Content

How to fix an engine that wont start
VIDEO
How to fix an engine that wont start
Instructional repair video
Engine Not Starting - Top 3 Easy Steps
GUIDE
Engine Not Starting - Top 3 Easy Steps
Over the past 20 years on 2CarPros we have identified the top three problems that are easily fixed. This can save you a trip to the repair garage or calling a tow truck and...
VIEW MORE

Sponsored links