In May I got off the freeway and at the stop light the engine was running really rough and the engine code light came on. It was running fine on the freeway. I went to Advance Autoparts to read the code. When I got there the passenger side exhaust seemed really hot and had some smoke coming up. Code read O2 sensor Bank 1 sensor 1. I bought a new sensor and drove home. When I got home the driver side catalytic converter input was cherry red. I don’t have tools at home so I planned to fix it at work the next day. In the morning the truck ran fine. I changed the O2 sensor and drove the truck around the parking lot and it ran fine. On the way home the truck just died on the freeway and engine code light came on. It didn’t make any strange noises or I didn’t hear anything break. I had it towed to a repair shop. They said the engine had no codes, good fuel pressure, and low compression in cylinders 1 and 3. Based on the age and mileage of the engine, they would not work on the engine. Therefore I had the truck towed to work where I have an indoor space to work on it.
I did compression check on all cylinders, 6 were low, one was normal and one was high. At this point I suspected blown head gaskets, in part because a couple years ago I began losing small amounts of coolant and seeing condensation in the oil fill cap. Oil was not milky, but this continued until I put a stop leak in, then is stopped. I pulled the heads off and had them rebuilt. The rebuilder said both heads were warped. I reassembled the engine and same condition, cranks but will not start.
Now the engine codes were Random/Multiple Misfire, O2 Sensor circuit voltage B1S1 low, and MAP/MAF – Throttle Position Correlation. I purchased new MAF and MAP sensors and changed them. Still not start. Now additional code, Throttle/Pedal Position Sensor/Switch A Circuit Low. I then changed the throttle body position sensor. Still not start.
I checked to see if I had spark by grounding a spark plug on the engine and cranking it. I did not see any spark, but I was far away because I was only one available to crank it. I changed crankshaft position sensor and camshaft position sensor, still not start. I purchased spark check light and noide lights. With these I saw I was getting spark, but bank 1 was more weak. I found one of the two ground wires on bank 1 ignition module wiring was not connected to ground and after adding a wire to ground the spark intensity was better. I then sprayed starting fluid into the manifold, still no start. Sometime during all of this I discovered that if I left the truck sit overnight and then put the throttle to the floor, after a cranking a while it would try to start but sounded “hollow”.
Now I purchased a new ECM and had it programmed to my vin. No change, engine cranks but will not start and no the ECM shows no codes.
At this point I really can’t figure it out. I’m wondering if the timing chain jumped a tooth, but that seems really unlikely. More likely it would break. Any ideas?
I did compression check on all cylinders, 6 were low, one was normal and one was high. At this point I suspected blown head gaskets, in part because a couple years ago I began losing small amounts of coolant and seeing condensation in the oil fill cap. Oil was not milky, but this continued until I put a stop leak in, then is stopped. I pulled the heads off and had them rebuilt. The rebuilder said both heads were warped. I reassembled the engine and same condition, cranks but will not start.
Now the engine codes were Random/Multiple Misfire, O2 Sensor circuit voltage B1S1 low, and MAP/MAF – Throttle Position Correlation. I purchased new MAF and MAP sensors and changed them. Still not start. Now additional code, Throttle/Pedal Position Sensor/Switch A Circuit Low. I then changed the throttle body position sensor. Still not start.
I checked to see if I had spark by grounding a spark plug on the engine and cranking it. I did not see any spark, but I was far away because I was only one available to crank it. I changed crankshaft position sensor and camshaft position sensor, still not start. I purchased spark check light and noide lights. With these I saw I was getting spark, but bank 1 was more weak. I found one of the two ground wires on bank 1 ignition module wiring was not connected to ground and after adding a wire to ground the spark intensity was better. I then sprayed starting fluid into the manifold, still no start. Sometime during all of this I discovered that if I left the truck sit overnight and then put the throttle to the floor, after a cranking a while it would try to start but sounded “hollow”.
Now I purchased a new ECM and had it programmed to my vin. No change, engine cranks but will not start and no the ECM shows no codes.
At this point I really can’t figure it out. I’m wondering if the timing chain jumped a tooth, but that seems really unlikely. More likely it would break. Any ideas?
Aug 19, 2025 at 7:47 AM
