Smeddy2

Okay, well I'm tired of trying to read through threads so I'll just ask. What do you guys use for checking fuel pressure and where did you buy/how much? I have a crazy surging idle problem at all times and I'm running out of stuff to check so I'm moving on to fuel pressure. I have a mityvac hand pump for check vacuum pressure but I'm not sure if it can be used to check fuel pressure. I've heard of drilling in the fuel rail and tapping to use a fuel pressure sending unit to accompany a gauge but I have no taps, and no fuel pressure gauge. I have also heard of parts I can use from NAPA to make my own pressure tester but I don't know what parts I'm supposed to get.

-Brand new head gasket, water pump, oil pump, rv head, 261 cam, oversized SS valves, set valve lash etc about 1-2,000 miles ago
-I've checked coolant level and bled all air out.
-I've had AAV problems in the past but have cleaned out all the junk in that and this time the surging is different.
-Swapped out cap and rotor on the dizzy
-have new plugs, new wires and new coil
-adjusted TPS
-I checked AFM a long time ago but I haven't checked recently
-checked coolant temp sensor when it was cold and the ohms checked out good
-Checked injectors a few months back and they all had good resistance readings and they have new o-rings and I have ran seafoam through the system a couple times
-New fuel pump and fuel filter however my filter may be clogged due to microrust from the old tank (thats why I want to check fuel pressure)
-PCV checks ok
-New O2 sensor
-Checked timing
-Ordered new vacuum lines but haven't set up the gauge on any of them yet to check for pressure
-New thermostat
-I have NOT checked compression because I don't have a compression tester plus I figure I just rebuilt the top end and am not burning any oil or coolant.

Running out of stuff to check/replace!

Smeddy2

Bueller?

94toy22re

I rented one from autozone and then took off the cold start injector and hooked the tester up there.

Smeddy2

Cool, that sounds like a good idea, I didn't think to see if someone rented one. Does it just hook up to the banjo fitting that connects to the cold start injector?

94toy22re

I took the hardline off that goes to the cold start injector and hooked the tester up to the fuel rail

Smeddy2

Awesome, thanks. Looks like I'll be giving autozone a call. Then I will have a fun saturday morning sit down with the old FSM and just go through the troubleshooting list for "Rough Idle"

94toy22re

After I did the street rv head and 261 cam I had rough/surgering idle and was just a missplaced vacuum line

b4wheeler

iTrader: (1)

Got this off of another site, a few years old... ->

Locate the diagnostic check connector in the engine compartment, use a test light or digital meter, check for power at Fp terminal when cranking or if the engine is running. That will tell you if the fuel pump is getting power or not. If the pump is getting power, next crack the fuel fitting for the cold start injector at the plenum, if you get a good spray of fuel, you have fuel pressure. Next disconnect one of the injector connector and connect a test light across the two terminals, if the light blinks while you are cranking, you have injector pulse signal. If that is the case, you have to do a little more testing to determine what is going on.

Smeddy2

Thanks 94toy, I don't think I have a vacuum line misplaced because for the past month or two it has purred like a kitten, perfectly smooth at 750. I took it to NTB to get new tires put on and get an alignment and after I got the truck back I had the idle issue so I know I either developed a vacuum leak or some part of the EFI system is malfunctioning.

Thanks b4wheeler, that'll be helpful for checking my injectors and stuff. I am pretty sure I have fuel pressure because I jumped the fuel pump terminals and hear it turning on and if I pinch the return fuel line off the FPR I can feel the pressure build up and the FPR starts to hiss. I just need to make sure i am maintaining pressure and it isn't leaking out somewhere.

To make my day suck even more, I am stuck at work because now my clutch won't disengage....I just can't win.