Yea it holds at 45 to 50 when the engine is at operating temp.(sometimes)

I've never had it hold there on a "cold" setting. FSM didn't mention doing the test hot vs cold so i don't know what the variation means. I have read that it's "normal" for the pressure to rise when it's hot but I don't know if that applies to a renix.

 

I might look for sit in the fpr. "HOT" means the pump has just been pushing stuff. Cold, the junk might not be pressed in to where it causes trouble. I've seen that in other things, the blockege/crud can back away until flow brings it back. Just a thought! If you find something in there I want a gold star!

 

Btw, solid info Spaz. (in my opinion). Clean your Iat like randall did! (and welcome to the forum!)

 

I moved the IAT to my air box today. Also put a new coolant temp sensor on.
Out side temp today got up to about 80*.

When I'm done I drive 5 miles, turn her off & wait exactly 5 minutes.

HNS continues. I raised the hood to let the heat out & she stumbled to a start about 20 minutes later.
So now I suppose I'm down to maybe 3 or 4 things. Bad (new) FPR, bad check valve, leaking injector, & Lord knows what else.

This is getting old(er)

 

Leaving the fuel pressure tester on there?

 

Yep. Cold I have 39 & 31. Shut down cold she drops 20 plus quick & in less than 7 minutes she's on zero. Hot I have 39 & 31. Shut down hot she climbs to 40 plus & holds & as she cools down the psi falls.

If I shut down while Hot (MOST) of the time she will hold 40 plus for 8 to 10 minutes then between 20 & 30 minutes she's on zero.
The warmer the ambient the longer it takes. Opening the hood speeds the process up.
Driving the pressure is spot on 31. If I goose it it will drop about 5 psi then jump to 35 or so then level out @ 31.

 

How old is the fuel pump?

 

No idea. I bought her last June from a retired mechanical engineer down at Tyndall AFB just outside of Panama City. He was real picky with this Cherokee. Told me she had never been off of a paved road & his wife was the primary driver. Dang thing is super clean & looks brand new. He had it undercoated cause of the location & there isn't a spec of rust anywhere, inside, under or outside. Drives like a dream & is as strong as new rope. Lots of new parts from him plus all the stuff I have done.
Most of the things I did was just because of her age.
He gave me all the service receipts but there isn't one for the fuel pump. The tank is pretty new(still shiny) but the pump is one of those Airtex.
It's been getting louder & louder even with the new ballast resistor.

He is no longer at Tyndall & I have no idea how to contact him.

 

The coil and CPS are two that might fail hot, but you have the same symptom after changing both. 40# fuel pressure isn't too high.

If you have spark at no start and it doesn't fire with starting fluid, it's flooded. The idea enough injectors are leaking to do that rubs me wrong, but you are loosing the pressure somewhere! You tried floorboarding it?

Cruiser, should he check his coolant temp and Iat sensor resistance? (and wires)

 

Ditch the airtex and throw a Bosch in there and then see what happens.

 

Their resistance drops as it warms up. Cold with less resistance is when they would "call in " for more fuel. A short in the wiring to ground might be sending an "I'm cold, send more fuel" signal, which may flood it, if it's hot.

 

Yep.

 

Yep pressing the pedal is the ONLY way she will start when it's HNS. Even then you have to be patient & just keep trying. In other words it's not as if "well I have HNS so I'll clear the flood & be on my way". It still takes time. Just not as long as it would if you didn't press the foot feed.
I ohm'ed the old CTS & it was at 500. I put in a new one today just because. Made no difference.
I haven't checked the IAT. I just moved it to the air box after a good cleaning.

 

I'm leaning that way

 

I'm not seeing how even an Airtex could flood it. The regulator should let off extra pressure. Now with the pressure #'s about right I just don't get that. That said...since your pump will fail in the rain on a Saturday night....having that as a spare under the seat might be sort of nice.

Renix will cut the fuel to the injectors with the throttle ON THE FLOOR. I'd think if you have spark, your plugs are wet, and THAT doesn't work, ether your injectors are leaking, or maybe an issue with the ECU. (very unlikely, I gather).

I'm wondering if checking continuity to ground on both the Iat and engine temp sensor wires might make sense. I'd need to look again the see which is which, but one member, CPTslackass, found his wires grounding/shorting there, which gave him all sorts of grief. Also I myself had some that come off the injector gang, that go down to my lower sensors really mess with me.

I'm not sure I saw that you have a crisp, blue spare during "HNS"