I have been working with a friend on his 92 RAM with a 5.9 TBI. He had replaced the oxygen sensor and IAC. The driveability problem that occurs is that when you are accelerating in a higher gear we get the jerking and loss of power. I right away thought it was fuel pressure related but a monitor of the fuel pressure when the truck is doing this shows the pressure is ok. I do have a question about the vacuum line that connects the TB to the fuel pressure regulator. I never see any vacuum on this line and don't know if that's correct. This is only in the driveway and vacuum would only lower the fuel pressure so haven't followed up on it. Back to the driving issue. When the hesitation occurs I have monitored the computer readings on my code reader. The pulse width gets limited to about 6 milliseconds when this hesitation occurs. So if the computer is limiting fuel then some sensor is controlling it but all the other readings look fine. Any idea what could limit the fuel output? I did a search on this form and two things I need to check are the connections to the MAP sensor and someone said the output of the injectors should be perfect cones. I would have thought I would have noticed that when I was inspecting them. I see the fuel hitting the butterflies but it looks like it is in one general spot under each injector. That's another issue, I can seem to find any information on the TBI. His manual (Haynes) doesn't cover it and searching the internet hasn't produced anything. Any help appreciated.
Mike O.

 

Just look down inside the throttle body while the engine is idling. There should be a fine cone of atomized fuel that reaches the sides of the throttle body with no gaps or streams. Low ambient light and a flashlight helps to show off the cones easier.

 

The injector spray cones look ok. The map sensor puts out about one volt and about 8 inches of mercury(I think that's the right units) at idle. I have a readout from 23 computer inputs and I don't know what is normal for some of them. Some are easy like coolant temp or RPM. Is there a list of values that the computer expects to see from all the sensors for a properly running 92 5.9 TBI manual trans engine? The O2 sensor is suppose to operate between 0 and 1 volt and mine puts out .6-.8 volts but is that normal, high or low? The O2 sensor has been replaced and it seems to check out by the Haynes manual but I have heard of people getting bad O2 sensors out of the box. Any idea what would explain this symptom;
Any ideas of what else to check?