hello all, I am in need of some legit subject matter expert advise. My trailblazer has been to 3 shops after I toyed with it for 2 years, after 3 years at a local racing shop they said they could not diagnose the issue. If anyone has some time and they are willing to talk with me to try and point me in the right direction it would be very appreciated.
NEED HELP Troubleshooting Assistance Needed
- Thread starter t1000sk8
- Start date
Blckshdw
Moderator
I moved your post to its own thread, let's start by getting more information from you. Can you give us the details on what's going on? That way the people who have the most experience in those areas can respond?
Yes... Lots more info needed..
Make, Model, Year, Engine firstly
Whats going on?
Whats been tried?
What type of scanner, if any, do you have?
Make, Model, Year, Engine firstly
Whats going on?
Whats been tried?
What type of scanner, if any, do you have?
Mooseman
Moderator
And as an FYI, we don't do "one on one". It's all through the forum to get the maximum number of eyes from the community on your issue. We can't do that without details though.
Ok. So here goes. I got an 07 tb ls. It cranks, starts, runs for about 3-5 seconds then starts to sputter out. So far I have changed out the following;
Fuel pump
Crankshaft pos sens
Camshaft pos sens
Throttle body
Pedal sens
Pcm
Ignition
Vvt
Sai and pump
All fuses and relays
—-that’s all I can think of atm. Also now the windshield wipers stay on when the car is one and can’t turn them off. Also it constantly drains the battery regardless of what is on/hooked up. I have disco’d all electronics and lights on it to find the phantom draw, but it’s still present.
Fuel pump
Crankshaft pos sens
Camshaft pos sens
Throttle body
Pedal sens
Pcm
Ignition
Vvt
Sai and pump
All fuses and relays
—-that’s all I can think of atm. Also now the windshield wipers stay on when the car is one and can’t turn them off. Also it constantly drains the battery regardless of what is on/hooked up. I have disco’d all electronics and lights on it to find the phantom draw, but it’s still present.
Sputtering out makes me think no fuel. Put a voltmeter or small lamp in parallel with the fuel pump and see when it gets power and if it loses power. I’m wondering if the pump runs as you crank but then stops.
If this is the case maybe ignition switch bad, or security system disabling fuel pump.
If this is the case maybe ignition switch bad, or security system disabling fuel pump.
Mooseman
Moderator
I would check fuel pressure. I know you put in a new pump but that doesn't mean it's good. Been seeing bad new parts lately.
Also check fuel trims while it does run to see what it does before it stalls. Any codes?
Also check fuel trims while it does run to see what it does before it stalls. Any codes?
Mooseman
Moderator
I'm wondering if your BCM is working properly. Do you have the capability to scan more than just P codes? An elm327 and Scan Guage Pro on Android would be able to do that.
Blckshdw
Moderator
Body Control Module, it's a small computer located in the fuse block under the driver's side back seat.
To eliminate a whole raft of Electrical Issues and to help identify if you have a Problematic Fuel Pump, try these Simple Diagnostic Procedures:
(1) Use a Lighted Pin Probe to Check ALL of the Fuses in the Under Hood Fuse Box AND at the Fuse Box under the Left Rear Passenger Seat at the Fuse Box - BCM Unit. Make a Note of any that happen to be Burned Out and advise us back HERE.
(2) Pull the Fuel Pump RELAY #41 (NOT THE FUEL PUMP FUSE) and Start (or Try to Start) the Engine and allow the residual Fuel Pressure in the Lines to subside.
(3) Obtain a Can of GUMOUT Spray Starting Fluid:
(4) Undo the S/S Clamp holding the Air Plenum onto the Throttle Body just enough to have an opening to the Butterfly Plate.
(5) Have an Assistant turn the Ignition Key to the Start-Run Position and as the Engine Turns over... Spray a SMALL AMOUNT of the Starter Fluid into the narrow opening... DO NOT OVERDO THIS ACTION.
Keep an ABC Fire Extinguisher on hand and Do NOT perform this action inside of a Closed Up Garage.
(7) If the Engine Starts and Runs Briefly... THIS will eliminate the possibility of having problems with Engine Compression - The PCM - The Ignition System Coils & Plugs - The Engine Wiring Harnessing being Damaged by Rodents - or - The Ignition Switch.
(6) If this IS what occurs... as @Mooseman previously suggested... Focus on a Problem with Low Fuel Pressure ...or having a FAILED FUEL PUMP.
(7) If this is NOT what occurs during this effort, the Next Test is to confirm Ignition Spark from the Coil Over Plugs and a Relative Compression Test along with performing In Cylinder Dry - Wet Compression Testing. If ANY Coil Over Plug is DEAD SHORTED...It alone can prevent the Engine from Starting.
How to Use A Test Probe on Fuses:
At your earliest convenience... Let us know what happens... And Remember... You Only Need THREE Things to make an Engine RUN:
(1) AIR
(2) FUEL
(3) SPARK (with Compression)
(1) Use a Lighted Pin Probe to Check ALL of the Fuses in the Under Hood Fuse Box AND at the Fuse Box under the Left Rear Passenger Seat at the Fuse Box - BCM Unit. Make a Note of any that happen to be Burned Out and advise us back HERE.
(2) Pull the Fuel Pump RELAY #41 (NOT THE FUEL PUMP FUSE) and Start (or Try to Start) the Engine and allow the residual Fuel Pressure in the Lines to subside.
(3) Obtain a Can of GUMOUT Spray Starting Fluid:
(4) Undo the S/S Clamp holding the Air Plenum onto the Throttle Body just enough to have an opening to the Butterfly Plate.
(5) Have an Assistant turn the Ignition Key to the Start-Run Position and as the Engine Turns over... Spray a SMALL AMOUNT of the Starter Fluid into the narrow opening... DO NOT OVERDO THIS ACTION.
Keep an ABC Fire Extinguisher on hand and Do NOT perform this action inside of a Closed Up Garage.
(7) If the Engine Starts and Runs Briefly... THIS will eliminate the possibility of having problems with Engine Compression - The PCM - The Ignition System Coils & Plugs - The Engine Wiring Harnessing being Damaged by Rodents - or - The Ignition Switch.
(6) If this IS what occurs... as @Mooseman previously suggested... Focus on a Problem with Low Fuel Pressure ...or having a FAILED FUEL PUMP.
(7) If this is NOT what occurs during this effort, the Next Test is to confirm Ignition Spark from the Coil Over Plugs and a Relative Compression Test along with performing In Cylinder Dry - Wet Compression Testing. If ANY Coil Over Plug is DEAD SHORTED...It alone can prevent the Engine from Starting.
How to Use A Test Probe on Fuses:
At your earliest convenience... Let us know what happens... And Remember... You Only Need THREE Things to make an Engine RUN:
(1) AIR
(2) FUEL
(3) SPARK (with Compression)
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You have done a lot of things but not sure whether those wre done with your "troubleshooting eyes wide open" or as a "parts shotgun" approach.
One thing that you might try is find out why your wiper is on with key on. There appears to be some form of battery / ground "leak" somewhere so tracing thru the "simple circuitry" may allow you to find some area of interest for the rest of your "troubles". NOTE that tests that mrrsm lists as they will provide a check list of powerings at the fuse box.... which should be carefully checked.... that may include "splitting the layers" to look underneath for track problems in the lower connect layer.
One thing that you might try is find out why your wiper is on with key on. There appears to be some form of battery / ground "leak" somewhere so tracing thru the "simple circuitry" may allow you to find some area of interest for the rest of your "troubles". NOTE that tests that mrrsm lists as they will provide a check list of powerings at the fuse box.... which should be carefully checked.... that may include "splitting the layers" to look underneath for track problems in the lower connect layer.
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