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.
the car ran great
How do you use a noid light on a 3/1 4 of the injectors are under the intake.
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)
Models: 2011 and Prior GM Passenger Cars and Trucks
Attention: 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.
Supercede: 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:
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:
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.
Note 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.
Important 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.
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.
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?
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.