Starting Issues TBI 350

[Jake292]

High voltage is usually a vac leak, or looowwwww.
Check the reference voltage supply at pin C of the MAP sensor (gray wire typically). Measure voltage between pin A (ground) and Pin C (+5 V ref) with a DVM. It should be right around 5 Vdc. With Key on engine off the MAP voltage (Pin B, light green wire typically) should read around 4.8 to 4.9 volts. If it reads the same as pin C the sensor is probably is history. Also check ground reference pin A. With everything off, measure resistance between Pin A and electrical ground (stud next thermostat). It should be fractional ohms.

Another functional check – with engine idling MAP output voltage (depending on idle vacuum) should be in the neighborhood of 1.2 to 2.0 volts. If it is stuck at 5 volts, check grounds and most likely MAP sensor is history.

everything checks out except the ground it shows around 50 ohms form the pin to the negative terminal on the battery. the MAP sensor in new as of December so it should still be good.

 

[Jims86]

everything checks out except the ground it shows around 50 ohms form the pin to the negative terminal on the battery. the MAP sensor in new as of December so it should still be good.

Check it from the MAP ground, to the terminal on the water neck.

 

[Jake292]

it shows 46.8 ohms

 

[Jake292]

I ran the following test on the iac valve:I started the truck and unplugged the iac valve, the engine speed remained the same.

this would signify that the iac valve is bad right?

 

[Jims86]

I ran the following test on the iac valve:I started the truck and unplugged the iac valve, the engine speed remained the same.

this would signify that the iac valve is bad right?

You must jump A and B and turn the key on for 30 seconds to close the IAC. take jumper out, start engine.
Should idle around 500.

 

[Jake292]

You must jump A and B and turn the key on for 30 seconds to close the IAC. take jumper out, start engine.
Should idle around 500.

ran this test and the idle stays the same. I replaced the IAC and it will start no problem.

I still have the issue that it will die when idling for a long time. it will slowly lower rpm and then sputter and die. Could it be something to do with the oil pressure fuel shut off?(idles to low and too low oil pressure shuts off fuel)

 

[Jims86]

ran this test and the idle stays the same. I replaced the IAC and it will start no problem.

I still have the issue that it will die when idling for a long time. it will slowly lower rpm and then sputter and die. Could it be something to do with the oil pressure fuel shut off?(idles to low and too low oil pressure shuts off fuel)

Is the plug for the idle screw still there or knocked out?

 

[jt1200r]

how old is your fuel filter

 

[Jake292]

Is the plug for the idle screw still there or knocked out?

it's still there.

 

[Jims86]

it's still there.

Ok, thats a good thing.
Any exhaust leaks on the drivers side?
the only other thing at this point in my thoughts, is a clogged cat....might have a hairball

 

[Jake292]

Ok, thats a good thing.
Any exhaust leaks on the drivers side?
the only other thing at this point in my thoughts, is a clogged cat....might have a hairball

I don't see any leaks. would there be a way to clean the cat or do I need to replace it.