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1. my 1983 B23 Kjet (usually) runs well when cold, but starts running very rough and has no power when warm.
2. cleaned IAC
3. KJET has supposedly been rebuilt, and I’m certain that there’s fuel coming from the pumps.
4. Have not checked the fuel pressure
5. when I unplug the fuel distributor connector as shown, nothing changes. Is this supposed to happen?
6. Does anyone have any idea what might be the case?
7. wondering if it might be temp sensor (??), the switch on the distributor or a relay that’s starting to default.
8. pictures attached for the wiring of vacuum hoses and fuel distributor.
1. That's because the fuel pressures are not correct, and/or the injectors are not spraying well at low flow times.
2. That's not an Idle air control valve. That air valve simply allows more air when cold, heats up electrically and closes off. On later cars the iac/idle motor/air control valve (whatever you want to call it) can vary the amount of air when needed. Your device simply closes after x time. It's purpose is to raise the idle when the engine is warming up.
3. What has been "rebuilt". Fuel distributor, control pressure regulator, injectors?
4. You are going to need to do that. If clearing the injectors does not fix it - line, control and rest pressure measurements will be needed to diagnose -
5. What's shown in your picture is the Control Pressure Regulator. What plugs into it is simply 12volts. That powers a heater to change the control pressure during the first couple of minutes after starting. The CPR and the air valve act as the choke - to give the engine more fuel and more air when cold.
6. Yes the injector are not spraying the correct amount of fuel.
7. The only temp sensors are for the gauge and for the cold start injector - neither of them are your problem.
Test the injectors - pop the injectors out (with hoses attached) and lay them on the valve cover. Wire the fuel pumps to run all the time with the key on. (jumper connections at the fuel pump relay, or fusebox)
Push the fuel metering plate up from the bottom with a tool (obviously take the hose loose from the air filter)
Observe the injector spray pattern - It should be 4 pretty cones - but it won't be. Barely push the plate up to simulate idle speed - are the injectors are firing pretty little cones (nope) dripping (maybe) some are doing something and others not so much (yep) Pushing the plate fully up can help clear the injectors - do that for 5 -10 seconds a couple of times and see if the spray pattern improves. If the pattern does not improve - either the injectors or the fuel distributor has a problem.
I trust you understand how the system works. Control pressure is the amount of pressure trying to hold the air metering plate down. (the resistance you feel when manually pushing the plate up with the fuel pumps running) When cold/first started the control pressure is lower - allowing the plate to move higher for a given amount of air - therefore more fuel when cold. If for instance the control pressure regulator is not changing the control pressure - someone can adjust the mixture to somewhat compensate for that - but the mixture will be so far off either when cold (then it won't start) or hot - where it won't run well.
1. That's because the fuel pressures are not correct, and/or the injectors are not spraying well at low flow times.
2. That's not an Idle air control valve. That air valve simply allows more air when cold, heats up electrically and closes off. On later cars the iac/idle motor/air control valve (whatever you want to call it) can vary the amount of air when needed. Your device simply closes after x time. It's purpose is to raise the idle when the engine is warming up.
3. What has been "rebuilt". Fuel distributor, control pressure regulator, injectors?
4. You are going to need to do that. If clearing the injectors does not fix it - line, control and rest pressure measurements will be needed to diagnose -
5. What's shown in your picture is the Control Pressure Regulator. What plugs into it is simply 12volts. That powers a heater to change the control pressure during the first couple of minutes after starting. The CPR and the air valve act as the choke - to give the engine more fuel and more air when cold.
6. Yes the injector are not spraying the correct amount of fuel.
7. The only temp sensors are for the gauge and for the cold start injector - neither of them are your problem.
Test the injectors - pop the injectors out (with hoses attached) and lay them on the valve cover. Wire the fuel pumps to run all the time with the key on. (jumper connections at the fuel pump relay, or fusebox)
Push the fuel metering plate up from the bottom with a tool (obviously take the hose loose from the air filter)
Observe the injector spray pattern - It should be 4 pretty cones - but it won't be. Barely push the plate up to simulate idle speed - are the injectors are firing pretty little cones (nope) dripping (maybe) some are doing something and others not so much (yep) Pushing the plate fully up can help clear the injectors - do that for 5 -10 seconds a couple of times and see if the spray pattern improves. If the pattern does not improve - either the injectors or the fuel distributor has a problem.
I trust you understand how the system works. Control pressure is the amount of pressure trying to hold the air metering plate down. (the resistance you feel when manually pushing the plate up with the fuel pumps running) When cold/first started the control pressure is lower - allowing the plate to move higher for a given amount of air - therefore more fuel when cold. If for instance the control pressure regulator is not changing the control pressure - someone can adjust the mixture to somewhat compensate for that - but the mixture will be so far off either when cold (then it won't start) or hot - where it won't run well.
I love this reply. Thanks! Will check it out and report back.
1983 b23 Kjet - Runs fine when cold, runs very rough when warm
