#7 is first on the passenger side - the fuel line feeds to the back of the head, next to the downpipe.

I have the FRx, a complete Hutch/Harpoon mod, a recently-replaced OEM fuel pump, and a fuel pressure gauge.

 

Not in your class of fixit, but: if the fuel was getting different on #2,&7 because of heat, trims should change or cyl contribution @ idle will be lower noticeably and repeatable. cover/plug the front with a tarp & hood closed (for a very short while{think about it}) on a cool day to duplicate hot days.

All that being said, heat soak in the full sun ought to replicate failing electrics.

maybe tugly is just feeling lonely, and wants the usual attention?

 

What brand of oil are you using? - the CJ-4 specifications can allow up to 20% aeration IIRC, but many oils have much lower test results.

What fuel system mods have you done? Have you seen any change in the fuel pressure gauge when the symptoms occur? If your going to check the fuel line on the passenger side you might consider replacing or gutting the restrictive fuel fittings into the head and gutting Fuel Filter Check Valve Assembly.......just a couple of thoughts while drinking coffee this morning on the deck.

 

Rich one of pet peeves is keeping heat in where it belongs and out of where it doesn't belong. Mind you I have up & down pipes wrapped. Some guys are like don't bother it doesn't matter well it does to me. Does it help ??? Well this is the stuff I'm going to use on my trans lines by the down pipe and do the fuel lines too. I have had very good luck with Thermo Tec products in the past. It's good stuff!
Thermo-Tec : Thermo-Shield

 

I'm guessing you meant to say Stinky. I have a whole list of things I'd much rather do than troubleshoot this long-term intermittent problem - like set my head on fire and put it out with a mallet.

I use Mobile 1 with a Mobile oil filter - 2000 miles on the oil. ICP, IPR, and FIPW never stray from normal.

Fuel pressure reads about 60-65, unless my right foot itches... then it can dip down to 45 PSI for just a sec and pick up to 50 PSI.

I have never pulled the fuel line to look at those. IIRC, they're on the head end of the tube, right?

 

What? Did I miss the change order?

 

Rich is that the fitting going into the head? Where is the fitting you are showing? Because this sounds like a modd I would like to do. I have already modded banjo bolts due to their restrictive nature. Now when doing this modd since you are getting rid of the restriction does it affect fuel pressure? I would think it cause a lower pressure??

 

That's good info. I'll be shopping for something like this today.

 

The fuel line feeds directly into the rear of the passenger-side head, so #7 gets first dibs on whatever feeds the fuel rail.

 

First but still disrupted with the check valve. The straight fitting that Clay sells will fix that. I don't know if that your problem but its on both cylinders closest to the connections.

 

Yes.

before I forget, check the passenger side fuel line bracket (@ 3/4 the way down the head). When I put regulated returns on both my 7.3L's the metal bracket that holds the fuel line in place on the passenger side had worn a groove in the fuel line. Last month when we pulled the engine it just about broke through - it only took @ 2lbs of pressure to snap the fuel line in 1/2.

Yes, the fittings at the end of the fuel line going into the head. As posted above, one at the rear passenger side of the head and the other at the front drivers side.

With Strictly Diesel's/Driven Diesel Regulated return I have no drop in pressure - 65 psi - unless I have it in the higher HP tune then it will drop to 50 initially then slowly recover back up. Similar to Tugly's experience.

 

I took that fuel line bracket off the passenger side two years ago, and the fuel line looked OK at that time.

I ordered all things fuel fittings from Clay - including the Viton seals. I needed a fresh air filter (for inventory) anyway. It looks like Stinky's spider and CAC boots are going to get a cleaning.

 

Gotcha.....but the cylinder closest to the radiator on the PS is #1. Mongo got confused for a second.

 

But you didn't remove the check valves. That is an increase in fuel flow. I read about banjo bolts but really don't know much about them. Plus what direction do the bolts have to be in? Anyway, I still think your problem is electrical Tugly.

 

I haven't ruled anything out yet, I'm just going to blanket the suspects. With the IDM and PCM swap, electronics are getting ruled out. I've already inspected all my cabling and insulated the high-abrasion points, plus I replaced the UVCH and VC gasket a couple of years ago. The 42-pin reads good, but I'll do the IDM connector readings when my other IDM gets back from Swamps.

My gut tells me this is fluid related.