Chevy hot fuel pump module

[Anthony Nolley Crosson Sr.]

Where is the hot fuel module on 1992 c1500 at?

[riverbanks]

Behind glovebox,you probably don't have one,limited in production,but internet seems to point you that way,what's the issue?

[Anthony Nolley Crosson Sr.]

I have power to oil pressure switch,fuel pump relay out to fuel pump itself,although it is only pushing 10lbs. Instead of 15 lbs. But this fuel pump is new 8 months in service,connections cleaned and die electrified. Have spark,new timing chain since old one had alot of slack/stretch. But I see on wiring diagram of this hot fuel module and can't find it,let alone know what it even looks like other then online pictures at parts links. So I am to understand this module turns on fuel pump for 20 seconds after cranking before ECU control and oil psi switch join that party? If so where in the giver is this said module?...lol thankyou for the assist. Oh the reason I am working on it is rats and mice nesting and eaten in wiring.so the ECM,some sensors,ESC,MAF_MAP, and anything else chewed through,shorted,grounded out. Ohm'ed out of range on alot. But now it just bothers me that I can't find this doggone module since it is the only thing I missed out of checking on. Before I rule out a bad new dump pump pushing 10 lbs. uphill into a new filter. Poops and common practice I thought I saw fine metal shaving when pouring out old fuel filter also. Checked grounds just don't wanna be dropping a fuel tank in my cold city street...again....lol. 20°- 40° is bad day for bongo. So if there is a bad hot fuel module/fuel pump module...(so many names everyone calls it it is confusing to say the least. The old ecm had a burned card on it. You could see a burned patch on it,so had to get another one. That will be a good mother  topic later.

[Anthony Nolley Crosson Sr.]

Addendum: I washed ,scrapped,probed,ohm'ed,voltage checked back probe connectors, sensors, and the new ECM for systems power,grounding, and signal, reference lines. Except this hot fuel/fuel pump module.92 c1500 4.3L non vortec ,V-6 262.

[Anthony Nolley Crosson Sr.]

I have ecm out,but the only module box I see is alittle white one.I will get a picture of the area.

[riverbanks]

White one,vss buffer,10lbs is in range?9 to 14

[Anthony Nolley Crosson Sr.]

So I still have a fuel delivery problem,I checked injector pulses with noid light and they blink.the one thing I notice is no fuel coming out inje tors. Can that be a bad regulator? Stuck open because when doing fuel psi test the gauge bleeds down when I stop cranking it. 

[riverbanks]

Strange,at 10psi you should be spraying fuel,has a fuel line been replaced? from rust,I think your clogged,what about deadheading pump at filter with gauge,see if it can get up to 25 or so,shut it off and watch gauge

[Anthony Nolley Crosson Sr.]

I think so to since I haven't ever flushed lines since I've gotten it. I looked @ diagram and gave are 8500lbs. And above for this fuel module so I am wondering if this light duty 1500 doesn't have a hot fuel module installed. There is continuity from tan wire @ pump relay to tank connector @ fuel pump /tank. So I am going to surmise that there isn't one. I could be wrong,but electrical diagrams aren't specific on the matter. Not to mention location or what it looks like. So I figured back to square A and start over....again..again. With then metal particulate in old filter,being both new on install,the pump was pushing 10 lbs. That pump failed,on its install I gotten 13lbs. back in july 2019. But my one dumb question is the bleed back when you stop cranking normal on the inlet side of TBI? The manual said something about the 4.3L having an automatic bleed down in the pressure relief section other then cracking open fuel cap. Are the inlet pressure controlled by the fuel pressure regulator going in or after the injectors going out. I was looking for a diagram on the 220 function but found nada on its breakdown. If the regulator's stuck open how do you know? With the return line shut off the pressure would increase, and the fuel pump is the culprit. due to a bad check valve in fuel pump. I blew into the pump and it stopped air flow even if not 10 -15 lbs. I know but no backflow and pulled on suction. So pressure should hold on inlet side of TBI, after fuel pressure regulator /injectors should be where bleed off occurs at return line. Or did I have a cortex inversion again? I didn't see no fuel @ injectors they were still dry so I am so confused right now. Is there an open popping pressure for fuel regulator not being reached or the regulator is stuck closed not letting fuel into injectors feeds to spray? I had fuel running all over me after changing fuel filter from both ends of filter lines pouring out contents of fuel,flow rate was good...like one arm and shoulders worth,freezing to...lol.  So now I am going to have to make a fuel shut off valve now (home (dumbo)depot)to build a tool next. But now how to test injectors for function of opening they had ranged in readings for ohms,can both injectors be stuck closed also?I know I am reaching here, I never had in depth trouble systematically in a row... although the truck did sit awhile without running 6 months while wiring harness repair after rats chewed harnesses, had alot of cross current shorts which blew computer and components. The truck is old and deserves a 2°chance now that I have the time I couldn't commit due to work. But darn it shimmy change! I love my CHEVY,my kids grew up in that truck,not to mention she saved my ash on plenty of occasions. Besides being retired (forced) I get bored easy,rather this then trouble anyday. To old and I am to slow now...lol 

[riverbanks]

Notice in diagram,it's a 5prong relay,you got 5?

[riverbanks]

1.3 ohms minimum for injector resistance

IMG_20200314_193003436

[Anthony Nolley Crosson Sr.]

The only thing viable is this lil box? With 2 part numbers on it...lol I am going to flush lines after the rain. Drop tank again. I wanna make a shut off valve for return line to check regulator while down there.

[riverbanks]

How about cutting return line,remove 6",put good rubber hose in it's place,then visegrips will do,after that,if no spray,I think your injectors got ruined

[Anthony Nolley Crosson Sr.]

I was going to use feral collars with a brass shut off ball valve with crush collars like diesel line fitting,have  to measure O.D. of return line tomorrow. Then going shopping at plumbing shops. It's a shame big auto parts stores lack the old way of craftsmanship. Everything is online...or we can order it to get back in 2-3 days B.S. I LIKE your idea too simpler but to the point,get it in gritty and plucky...lol did you know that my big time auto parts store "s distributor can't get the complete rebuild kit for the tbi unit anymore,but can get me a half rebuilt kit for more money without the other important stuff like injector screen filtrs,regulator diaphragm, or even a new spring!? Who the heck is in charge of flying that ship....?

[Anthony Nolley Crosson Sr.]

I just remembered I forgot to price new injectors while a autozone. If I don't write it down while brain storming, I walk in somewhere and control/alt-delete all the time. Thanks for reminding me...lol getting older sucks..body checks do that.