93 chevy conversion van hesitates when starting out
93 chevy van hesitates when starting out or backing up. Also runs very rich. This problem has been going on for years, been to two repair shops and no one has an answer. Bad gas mileage too. Now, it is getting worse and even dies occasionally.
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lol everything but the actual cause of the problem. The big clue here is your gauges. What sensor going bad will cause the gauges to jump? Ask your mechanic that wasted all your money replacing good sensors. Then you may want to find a good mechanic.
The problem is a wiring problem. Probably the main hotline running from the ignition to the fuse block. Somewhere in that area. If you have the spark circuit on a scope you would find it flat line when it hesitates.
I dont think it is a short because if it was you would have blown fuses or smoke and or electrical smell. So it has to be an open circuit that would be nearly impossible to find.
If I was going to just start replacing things, I would start with the ignition switch and then the fuse block and then any hot wires to and from both elements.
if your having cold engine start hesitation,you need to check the engine temp switch,it tells the computer how cold it is,so the engine can adjust to a rich start and not a lean one.if the switch is faulty and the computer is being told it is 80degrees,you will not get a rich mixture like no choke at all
The injector assembly also contains the pressure regulator. Since the truck has been sitting, you may have some corrosion in the regulator and the injectors. Try a fuel cleaner and the work on the regulator.
The cylinder 7 misfire is likely a symptom of the problem, not the problem itself.
Typically, the catalytic converter has an oxygen sensor in front and behind it. When the vehicle is warm and running in closed loop mode, the upstream oxygen sensor waveform reading should fluctuate. The downstream 02 sensor reading should be fairly steady. Typically the P0420 code triggers the check engine light if the readings of the two sensors are similar. This is indicative of (among other things - such as faulty sensors in the "emissions loop") a converter that is not working as efficiently as it should be.
I do not believe that it is a problem with a valve/head gasket or cam.