Ok , I'm stumped on this one now.I have been having problems with my fuel pump cutting out at ant time it wants for no apparent reason.I redid all the wiring to the pump and the tank , and it still does it.I checked my grounds and they are fine.One thing I do notice once it kicks out though , and I'm not sure whats causing it.When I crank it over to restart the truck , there is a clicking under the steering column area , and the green light on the dash for the day time running lights flickers on and off.When it does start again the light is a steady green and it starts.

Does anyone have any idea what is under the steering column area that would affect the pump and the daytime running light on the dash while making a clicking sound?The clicking would probably be some kind of relay , but why would it affect the pump , and the running light indicator?I don't know where to looknow to fix this intermitent problem.It seems to run fine , then all the sudden it just dies , and won't start , I leave the key off for a minute or 2 , and after a few cranks it fires up again.I haven't even had it out for a drive since I got the transfer case repaired , and just replaced the master cylinder as that was leaking.But , in its current state its not really drivable untill I figure out why it just up and stalls.It was running fine before untill the pump quit a few times on me.The pump is good , it runs when its supposed to , other than the kicking out which I am guessing is a relay somewhere , or something else is shorting a couple things.

When you say "redid the wiring" is that from the fuel relay back or just
at the pump? On my '89 p'up the wires actually corroded in the insulating jacket of the wire. Dependending on which way I twisted the wire it would make or break the circuit.

It reads like you have current bleeding across wires in the harness. Check the connecting blocks where the interior harness meets the receptor for the engine compartment harness at the fire wall. You might have corrosion that's crossing circuits and bleeding enough voltage to make the pump relay drop out. I had the same sort of problem with my headlights. Unplugged the connecting block and gave both sides a good shot of electrical contact cleaner and I haven't had a problem since.

Ok , I'll give that a try.I've just been banging my head against the wall trying to figure this one.Of course its intermittent, so that makes it nearly impossible to track down easily.

And when I say I redid the wiring , its all brand new wire from where the stock harness was for the fuel tank sending unit , guage and pump.I didn't actualy put new wire all through the entire harness <img src="/forums/images/graemlins/scared.gif" alt="" />

Ok , I did a few things today to try and fix the problem.I had it suggested that it might be the module on the distributor , as even a rebuilt one , they don't always check those , so I swapped that out.It seems to run a little better , and is not stalling as often , but it still cuts out.I then put one of those perma-cool fuel filters on with the water peticock to drain water out of the fuel.This adapter has 4 ports on it , so I am using 2 for fuel in and out , then under the hood I put a 1 1/2" fuel pressure guage.The other one is blocked off for now , I need another 1/2 NPT to -6 fitting , then I am installing a pressure guage in the cab.I got one of those autometer kits with a 2 5/8 guage , and the pressure kit so you can install it safely in the cab.Anyway , I ran the truck again after putting in the under the hood guage , and I think that might be my problem.I am getting between 9 and 10 PSI at about 1200 RPM , and when it drops to 700-800 RPM it drops below 9 PSI.Once it hits 8 1/2 PSI the truck cuts out.I think I read in one of the manuals that it cuts out at 9 PSI as a safety feature.

Now , I have the Holley black external fuel pump , which is good to 14 PSI , which should run the truck no problem , and which it did for a while , but now the PSI has gone to crap.Heres is the specs on the Holley.
These Black electric fuel pumps from Holley feature an improved design for street and strip applications, a new lower housing casting for enhanced fuel flow, and a tumble-polished billet look with the distinctive black logo. These pumps have a 140 gph flow rate, only draw 4 amps, and have a maximum pressure of 14 psi with an externally accessible pressure relief valve. They weigh only 3 lbs., and include a mounting bracket. These pumps are compatible with alcohol or methanol fuels.

I'm wondering what the actual pressure should be on the 2.8 or 3.4 engines , and also if this sounds like a pressure regulator problem.Also , if it is a regulator problem , with a pump with a max of 14 PSI , do I really need the regulator?It seems with the 9 PSI it is barely putting enough pressure to run the truck , and once it idles and goes alittle lower , it cuts out , then I have to let it sit for aminute , and maybe it takes that time to build the pressure up again?

Any ideas on this would be appreciated so I can get it street ready again without worrying about staling in intersections.

According to the Haynes manual, the spec for the 2.8 is 9-13 PSI.

Ok , for some reason I thought it was 13-15 PSI , maybe I was thiniking of something else.Anyway , it should be constant pressure even at idle , and for some reason thats where the pressure dropped noticeably to the point it cut out.This was at idle in park also , once you shift to drive or reverse the idle drops even lower.I just flipped through the manual , and it lists 2 things to look at for this , clogged filter ,which its brand new and I had it off when I installed the bigger one right in the engine compartment and it was good.The other thing they list is to restrict the line between the regulator and the TBI and check the pressure , and if its below 9 or above 13 , then its the regulator.The one thing they don't say in here is where the regulator is.I did see something about some kind of regulator in the TBI itself , but I can't see that being the same one if they say to restrict the line before the TBI.

Anyway , I guess I'll try a few more things later today and see if it is my regulator thats causing the problem.Also , on the 4.3 TBI , was there an idle adjustment screw?My idle warm is ok in park , hanging around 700 , but once in drive it drops to about 600 or so , so I was thinking og bringing up the park idle to 800 so drive would be 700.

I'm a Ca Smog Tech. To me it sounds like your still not sure if its a power issue or you have a component breaking down under stress. Because you stated you had replaced a ignition part and it runs better and doesnt shut down as much I would suspect that maybe you have a coil or a relay issue. A relay can get hot and loose contact. A coil can miss intermittantly or just shut down. A bad ground could cause this. Or lack of tuneups could of stressed it to the point that its shuts down. This applys to an ignition module also. Now if your sure its a fuel issue maybe when it wont start spay some brake cleaner in the throttle to see if it tries to start or even starts on brake cleaner. If it shuts down when the cleaner is removed you now knw the problem. If it doesnt start then you know its a spark issue. Not knowing your vechicle its possible your computer ECM PCM has quads for the fuel injectors. These can go out also. Anyways just giving you directions to go.
Good Luck

Well , did a few more things today , I can drive it without it shutting down at higher RPM , but still seems to stall at low RPM once its hot.I have to leave it untill I hear a relay click from under the hood , then it fires right up again.If I don't hear the relay click , it will crank but not start.

I changed the coil and the fuel relay , neither made a difference.I watched the fuel pressure again , today it was going between 3 and 5 PSI at idle.It stayed in that range even when I took it up to 2500 RPM.No idea if the guage is faulty or whats going on.I actualy drove the truck for a bit , but once I got it home , it started doing the stall at idle the odd time , then when you hit the gas , the RPM would go up slowly where if I pushed that far on the gas pedal at other times , instant high RPM.

So , I'm still puzzled over what is going on.I did spray cleaner on all my wiring harness connections , so they are clean , and that didn't make any difference either.I'm at a loss here at what could be the problem.At least it is running now , and not as many stalls.

Well , figured out what the problem was <img src="/forums/images/graemlins/lol.gif" alt="" /> It seems the pump I had is not recommended for EFI engines.It started running the truck fine when I first got it , but then it can't keep up with the pressure for some reason.I picked up the proper pump for it (another Holley) and it purrs like a kitten.I even get the proper PSI with this one , its at an even 11 PSI at idle.The big test will be shortly , I am taking her out for a cruise and see if it stalls on me , hopefully not. <img src="/forums/images/graemlins/scared.gif" alt="" />

Was the stock fuel pump not up to the task of supplying the 3.4?

Just curious because I'm trying to get all my ducks in a roll before trying the swap my self.

Jim