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Re: no data from ecm
If no comunication with the escanner ,
1 of the problem can be a bad ECM.
I have replaced lots of them for this problem.
2 can be a bad MAP sensor. or TPS sensor.
You can try to get manual codes fro this truck. Is possible OK.
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Check the throttle plate for varnish or carbon build up , clean with throttle plate cleaner . Have engine sensors scanned with a scan tool ,mass air flow sensor may be dirty . I'd tell you to check fuel trims with scan tool but you are probably not familiar with these . They show how much fuel the engine computer is adding or subtracting . Great diagnostic tool for trouble shooting engine running problems . Also a scan tool is great to check O2 sensor switching rich to lean an back to rich signal . The engine runs in open loop when cold which means the PCM doesn't look at O2 sensor data till warmed up . PCM/ECM adds more fuel till warmed . Then it will go into closed loop fuel control , the PCM/ECM watches O2 sensors . May have a vacuum leak ,check with can spray carburetor cleaner ,spray around the intake manifold an listen for the engine RPM to pick up or may even stall the engine. Understanding Short Term and Long Term Fuel Trim
You need a better code reader, ie "Mechanic". The ECM should control "Running rich or lean". Is engine light? Quote, Service SOON or Service NOW. SOON is usually minor, but needs to be found in the codes. "NOW" need to be checked immediately.
I guess my first question would be, is the check engine light on ? If the fuel system is too rich the O2 sensors should be reporting that to the computer. There could be a trouble code that would point you in the direction of the problem. Otherwise, it could be a weak injector, or a wiring problem that is keeping one or more injectors grounded. Are all of the spark plugs fuel fouled ? No problems with the air filter and intake ?
CHECK AC COMPRESSOR CLUTCH COIL WIRE CONNECTOR HOOK UP.IF AC COMPRESSOR CLUTCH COIL WIRE CONNECTOR HOOK UP WRONG OR WIRE HAS A SHORT IT WILL BLOW THE ECM FUSE AND AC COMPRESSOR FUSE.CHECK FUSES AND AC COMPRESSOR WIRES.
DTC P1133 O2 BANK 1 SENSOR 1 TOO FEW TRANSITIONS Circuit Description The powertrain control module (PCM)/engine control module (ECM) constantly monitors the oxygen sensor (O2S 1) activity for 100 seconds . During the monitor period, the PCM/ECM counts the number of times that the O2S 1 switches from rich to lean and from lean to rich. With this information, a total for all switches can be determined. If the number of switches is too low, DTC P1133 will set. The lean-to-rich and the rich-to-lean are greater than 18 switches.
The PCM/ECM will turn the MIL off on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present.
A history DTC P1134 will clear after 80 consecutive warm-up cycles have occurred without a fault.
DTC P1133 can be cleared by using the scan tool CLEAR INFO function or by disconnecting the PCM/ECM battery feed.
Diagnostic Aids DTC P1133 is most likely caused by one of the following items:
Fuel Pressure - The system will go rich if the fuel pressure is too high. The PCM/ECM can compensate for some increase. However, if it gets too high, a DTC P1133 may set. Refer to "Fuel System Diagnosis".
Leaking injector - A leaking or malfunctioning injector can cause the system to go rich.
Manifold Absolute Pressure (MAP) sensor - An output that causes the PCM/ECM to sense a higher than normal manifold pressure (low vacuum) can cause the system to go rich. Disconnecting the MAP sensor will allow the PCM/ECM to set a fixed value for the MAP sensor. Substitute a different MAP sensor if the rich condition is gone while the sensor is disconnected.
Pressure regulator - Check for a leaking fuel pressure regulator diaphragm by checking for the presence of liquid fuel in the vacuum line to the pressure regulator.
Throttle Position (TP) sensor - An intermittent TP sensor output can cause the system to go rich due to a false indication of the engine accelerating.
O2S 1 contamination - Inspect O2S 1 for silicone contamination from fuel or improper use of RTV sealant. The sensor may have a white powdery coating and result in a high but false voltage signal (rich exhaust indication). The PCM/ECM will then reduce the amount of fuel delivered to the engine causing a severe surge or driveability problem.
if the exhaust clogs it just dies. your cat ( converter) probably clogged due to a very rich condition, which was detected by the computer, hence the light. my bet is a clogged fuel injector or a sensor (either oxygen or air flow) failed. this made it run rich and the cat probably melted.
Your Jimmy is running rich, air fuel ratio is not correct. Start with cleaning your MAF sensor, a dirty MAF sensor will cause your engine to run rich or lean, other causes would be a faulty fuel pressure regulator. Start with the simple and to common and try cleaning your MAF sensor, you can pick up a can of MAF sensor cleaner at most auto parts store like Auto Zone or Part Source.
Also make sure your engine is running at the proper operation temperature 190", cold running engine will cause the ECM to run your engine rich. Causing the back soot and fouling up your spark plugs and intake ports with carbon.
The ECM was programed to recognize the 4.3 vortec to run at 190" and anything cooler will cause it to run rich and poor on economy.
Thank you for using fixya and good luck.