Trucks giving me a headache!!!
Oct 22, 2019 | 04:01 PM
#21
Lets take it from the top again.
#1, hard start when warm.
This is typically one of two things, either the cold start system or the fuel pressure up system.
If it's repeatable it will be easy to diagnose! If it's random it could be a wiring glitch.
You start by bringing the system up to operating temperature. Next disconnect the electrical plug from the cold start injector (located on the upper intake near the middle), and try to start it. If it fires right up with a reasonable amount of crankshaft revolutions, you have a cold start system issue. Some likely causes are, #1 30+ years of scale build up on the cold start timer sensor which is mounted in the front of the of the lower intake (this build up acts as insulation in your house) it gives the sensor a lower reading of the coolant temperature, #2 poor grounding of the sensor (this ones alot less common). You want to make sure to clean the sensor body and the intake where it screws in, this insures it has a good thermal and electrical connection. (While you have the CSI timer out, clean the engine coolant temp sensor next to it in the same way!)
You could have a leaking cold start injector, which causes an over rich start up, you check for this by unmounting the cold start injector (CSI) from the intake and powering up the fuel pump at the diagnostics box (you need to jumper B+ to FP, and turn the key to the run position). Now check for any leakage at the CSI (there is a specification for this but let's just go with any drips vs no drips for now.)
Next up is the fuel pressure up system (FPU system), this is controlled (mostly) by the sensor mounted I to the thermostat housing (engine side of the upper radiator hose) this sensor tells the computer to open or close a vacuum switch valve (VSV) in-between the fuel pressure regulator and the intake. This system replaces the cold start injector system when performing a warm start of the engine and relies on the temperature switch on the thermostat housing (as mentioned).
Locate the file pressure regulator of the rear side of the fuel rail, follow its vacuum line back to the vsv and mark the hose on the fuel pressure regulator side with a bit of tape (you'll be disconnecting this later from the VSV). Follow the other vacuum line from the VSV to the intake and mark it also (you will again disconnect this line, but this one needs capped off on the intake). Now start the engine as before and bring it up to operating temperature. Disconnect the regulator's vacuum line (don't plug it, we want it to see no vacuum), disconnect the VSV line and plug the intake pipe you pulled it from. Now you want to attempt to start the engine.
As before we are expecting it to start in a resonable amount of crankshaft revolutions.
#2 I've done forgot, but iirc it was idle speed fluctuates?
You need to start with verification or setting of the base idle speed. Get the engine up to operating temperature (somewhere in the 170-190° range). Jumper the diagnostics port TE1, (you're gonna have to look this up or ask I'm lazy and disinterested after that first bit =P ). Now with an semi accurate tachometer (the dash one is good enough), adjust the idle air bypass screw in the throttlebody to spec (750rpm).
#3, AC compressor..
This is a whole different kettle of fish. We can start with a simple explanation. You AC compressor if in good health, with proper refrigerants and lube, will run non-stop indefinitely. (It doesn't cycle on and off for protection, it cycles on and off to regulate the temperature!)
Diagnosing why it doesn't self activate we can tackle later. It's depending on several inputs, an important one is the engine speed so fix that first!
This is typically one of two things, either the cold start system or the fuel pressure up system.
If it's repeatable it will be easy to diagnose! If it's random it could be a wiring glitch.
You start by bringing the system up to operating temperature. Next disconnect the electrical plug from the cold start injector (located on the upper intake near the middle), and try to start it. If it fires right up with a reasonable amount of crankshaft revolutions, you have a cold start system issue. Some likely causes are, #1 30+ years of scale build up on the cold start timer sensor which is mounted in the front of the of the lower intake (this build up acts as insulation in your house) it gives the sensor a lower reading of the coolant temperature, #2 poor grounding of the sensor (this ones alot less common). You want to make sure to clean the sensor body and the intake where it screws in, this insures it has a good thermal and electrical connection. (While you have the CSI timer out, clean the engine coolant temp sensor next to it in the same way!)
You could have a leaking cold start injector, which causes an over rich start up, you check for this by unmounting the cold start injector (CSI) from the intake and powering up the fuel pump at the diagnostics box (you need to jumper B+ to FP, and turn the key to the run position). Now check for any leakage at the CSI (there is a specification for this but let's just go with any drips vs no drips for now.)
Next up is the fuel pressure up system (FPU system), this is controlled (mostly) by the sensor mounted I to the thermostat housing (engine side of the upper radiator hose) this sensor tells the computer to open or close a vacuum switch valve (VSV) in-between the fuel pressure regulator and the intake. This system replaces the cold start injector system when performing a warm start of the engine and relies on the temperature switch on the thermostat housing (as mentioned).
Locate the file pressure regulator of the rear side of the fuel rail, follow its vacuum line back to the vsv and mark the hose on the fuel pressure regulator side with a bit of tape (you'll be disconnecting this later from the VSV). Follow the other vacuum line from the VSV to the intake and mark it also (you will again disconnect this line, but this one needs capped off on the intake). Now start the engine as before and bring it up to operating temperature. Disconnect the regulator's vacuum line (don't plug it, we want it to see no vacuum), disconnect the VSV line and plug the intake pipe you pulled it from. Now you want to attempt to start the engine.
As before we are expecting it to start in a resonable amount of crankshaft revolutions.
#2 I've done forgot, but iirc it was idle speed fluctuates?
You need to start with verification or setting of the base idle speed. Get the engine up to operating temperature (somewhere in the 170-190° range). Jumper the diagnostics port TE1, (you're gonna have to look this up or ask I'm lazy and disinterested after that first bit =P ). Now with an semi accurate tachometer (the dash one is good enough), adjust the idle air bypass screw in the throttlebody to spec (750rpm).
#3, AC compressor..
This is a whole different kettle of fish. We can start with a simple explanation. You AC compressor if in good health, with proper refrigerants and lube, will run non-stop indefinitely. (It doesn't cycle on and off for protection, it cycles on and off to regulate the temperature!)
Diagnosing why it doesn't self activate we can tackle later. It's depending on several inputs, an important one is the engine speed so fix that first!
Oct 22, 2019 | 04:10 PM
#22
Registered User
Joined: Apr 2016
Posts: 1,583
Likes: 291
From: Alaska
Akwheeler, this generation of engine (actually none of the 22re, and I am pretty sure 3vze) use a stepper controlled idle air valve. These use a bimetallic valve that opens an closes with coolant temp (the first generation 22re uses an auxiliary heater signal from the ECU also).
They indicated above that the idle air screw was the one used not the throttle plate stop screw. There are two idle air bypass screws, one in the VAFM (has a factory plug over it, dont touch this unless youre an old grey beard with ooddles of engineering degrees and fancy kit!) that bypasses the vane and another molded into the throttle body that bypasses the throttle plate.
You can adjust the throttle body bypass but you need to insure the engine coolant temperature is upto a minimum spec (from memory its 170°) and that the diagnostics jumper is in place, this proceedure sets your base idle speed.
Yeah this! If you don't give clear and detailed results of the tests and adjustments recommended you are leaving us in the dark. This is frustrating for everyone involved.
They indicated above that the idle air screw was the one used not the throttle plate stop screw. There are two idle air bypass screws, one in the VAFM (has a factory plug over it, dont touch this unless youre an old grey beard with ooddles of engineering degrees and fancy kit!) that bypasses the vane and another molded into the throttle body that bypasses the throttle plate.
You can adjust the throttle body bypass but you need to insure the engine coolant temperature is upto a minimum spec (from memory its 170°) and that the diagnostics jumper is in place, this proceedure sets your base idle speed.
Yeah this! If you don't give clear and detailed results of the tests and adjustments recommended you are leaving us in the dark. This is frustrating for everyone involved.
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