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Technician Chris
Technician Chris, Technician
Category: Car
Satisfied Customers: 425
Experience:  I am a certified ASE Master Technician with L1 Advanced Diagnostic Specialist and over 15 years experience.
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cheverolet lumina: 1990 Chevy Lumina 3.1 L will crank but will

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1990 Chevy Lumina 3.1 L will crank but will not start, The car has 37,000 miles no check engine light replaced crank sensor no start, replaced ignition module no start replaced ECM started ran 40 minutes. Replaced fuel filter the following night car started shut down when it got warm wouldn't start. Put fuel in large vacuum port car will start then stop. How does one trouble shoot this problem. Our test equipment is for 1996 and newer.
So you have good fuel pressure, and when you force fed fuel into the vacuum port, it did start, but failed to stay running? Hmm, with such an old car, but only 37K miles on it, when in the last time the owner filled up w/ gas? I would replace the spark plugs and drain and refill the fuel tank to eliminate both those issues. If the gas is super old, the plugs may be fouled and the fuel contaminated. Worth a try!
Customer: replied 4 years ago.

The car has had new gas in the tank a number of times. The fuel seemed ok when the fuel filter was changed. When it quits it will start sometimes when it cools off then shut down when it come out of closed loop. What fires the fuel injectors and how do you test them on a 3.1? Also the owner was driving the car regularly the trouble started after adding fuel injector cleaner to the fuel.

You will need a :"noid light" to test each injector connector. This can be purchased off of any major tool truck: Snap On, Mac, Cornwell, etc. This will tell you if each injector is getting power. When you replaced the ECM, you stated it ran for 40 mins. How did it run? Was it running rough? Misfiring? running great? Let me know.
Customer: replied 4 years ago.

the car ran great


How do you use a noid light on a 3/1 4 of the injectors are under the intake.

It is just a small electrical tester. You unplug the connector at each injector (one at a time) and plug it into the noid light then start the car, the noid light is just a bulb that flashes every time the connector is powered indicating the fuel injector circuit is good.
Customer: replied 4 years ago.

sorry it took so long to respond I went to bed. The 3.1 injectors are under the intake manifold the engine can't run with the intake off. Is there another test that can be completed. There is one injector at each end of the intake will the noid show anything with just two injectors. I can purchase a light tomorrow if there is one on the truck.


Yes, you can just test the ones you have access to. The tool is very small and just plugs into the injector connector. I also found a TSB 09-06-03-004D that may apply.


Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant)

2011 and Prior GM Passenger Cars and Trucks

This repair can be applied to ANY electrical connection including, but not limited to: XXXXX XXXXX electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition.

This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 - Engine/Propulsion System).


Some customers may comment on any of the following conditions:


- An intermittent no crank/no start
- Intermittent malfunction indicator lamp (MIL) illumination
- Intermittent service lamp illumination
- Intermittent service message(s) being displayed


The technician may determine that he is unable to duplicate the intermittent condition.


This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions:


- Vibration
- Thermal cycling
- Poor connection/terminal retention
- Micro motion
- A connector, component or wiring harness not properly secured resulting in movement


On low current signal circuits this condition may cause high resistance, resulting in intermittent connections.

On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative.


Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass.


DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin.


3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s).
4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present.
Customer: replied 4 years ago.

I had a meeting tonight will work on car tomorrow to see what the injectors are doing.

Here is an easy 2 second check - the under side of ignition coils can develop a bubble that will cause an intermittent misfire - just remove the coils 1 by 1 and look at the under side of them - no bubbles? still good.

Customer: replied 4 years ago.

Just checked the fuel injectors they have no power. The plugs have spark. Should I try to find a shop manual so all connectors related to injectors can be check? Is there a test procedure for injectors not firing?


Thank you


If an injector is not getting any power at all, most likely there is an open in the electrical circuit. Please see the below wiring diagrams to help find the open. The problem may also at the PCM connector. Did you check the connector itself to see if any build up is in there causing an open at the connector? See the above TSB for details.





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