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Hot Lift Pump?

Bigburban

Bigburban

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I changed out my lift pump with a higher psi one I found. I had to find another place to mount it because it was longer so I used the bolt under the cab coming through that holds the drivers seat down to mount Lp on. (didn't want to cut any of the fuel lines till I got the bugs worked out) Took it for a long drive and noticed a big difference but when I got home and checked it the LP was hot to the touch? Do they get that hot? I have never noticed and that bothered me that it was hot. The new pump looks the same as the stock lift pump just delivers more psi 10-14 instead of 6-10. Long story but wanted to explain it in case where I mounted it is a bad location and could be causing it to be hot.
 
I will admit I have never went and touched the LP after a drive. The fuel is pretty darn hot after a while if the heater is working and still quite warm if not. The fuel is likely nearly 100F after a good drive where a good amount has circulated in the return lines. Its hotter in the IP.

What brand LP is it? Is it possible to wire it reversed polarity? One clearly positive and one clearly negative wire? Otherwise it may be restricted too much and having to pull a vacuum. Maybe the fuel tank cap isnt venting vacuum and there is too much holding the fuel in the tank. Or tank sock issue, unless thats one of the new things in the truck.
 
buddy said:
I will admit I have never went and touched the LP after a drive. The fuel is pretty darn hot after a while if the heater is working and still quite warm if not. The fuel is likely nearly 100F after a good drive where a good amount has circulated in the return lines. Its hotter in the IP.

What brand LP is it? Is it possible to wire it reversed polarity? One clearly positive and one clearly negative wire? Otherwise it may be restricted too much and having to pull a vacuum. Maybe the fuel tank cap isnt venting vacuum and there is too much holding the fuel in the tank. Or tank sock issue, unless thats one of the new things in the truck.
Click to expand...

Thats what I was wondering figured the fuel would be hot after a long drive. I put a stock LP Airtex E3309 on but after alot of searching I took it off and put an Airtex E8153 (diesel application) more constant PSI. I just had never seen how hot one was either until today, I was just checking for leaks when I noticed. Wire was color coded for stock wiring. I got my fuel cap from the Chevy dealer as to make sure I ordered the right one. No sock issues lots of good pressure. This pump did make a big difference. I could still hold my hand on it but it was hot........maybe I am just too paranoid!
 
Never had a LP get hot on me. I drove to the auto parts store on 2 occasions(once with each truck) and changed the LP in the parking lot, and it wasn't warm either time.
 
You can touch it - it isn't that hot... When the fuel lines melt then you need to worry. This will be in excess of scalding 140 degrees that the FFM heater runs at.
Check grounds and check the voltage to the pump. A low voltage condition will cause the pump to get hot. I would backprobe the connector with a couple of sewing needles and read the voltage while the pump is running.
 
higher pressure from the same little stock like pump, maybe thats because it draws more current so it gets a little hotter. Interesting kit for decent price, but if it lasts as long as others like it then the Walbro for twice the price might still be a better buy. Its lower flow capability that the Walbro, but a little higher pressure spec than the FRB5, a little lower than the FRC10.

summitracing/parts/ATX-E8153/ hot link to non site vendor disabled
 
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buddy said:
higher pressure from the same little stock like pump, maybe thats because it draws more current so it gets a little hotter. Interesting kit for decent price, but if it lasts as long as others like it then the Walbro for twice the price might still be a better buy. Its lower flow capability that the Walbro, but a little higher pressure spec than the FRB5, a little lower than the FRC10.

summitracing/parts/ATX-E8153
Click to expand...


Here's the stock 93 pump number. Airtex E-3158

summitracing/parts/ATX-E3158 live hot link disabled to non site vendor site
interesting that the numbers are all the same but in a different order.

The E-3158's i have on both trucks put out 10-12 psi at their highest(engine off) and slowly decline from there. I've been able to get the blazer's fuel pressure to drop to 4-5 psi just revving it in neutral in the driveway, and that's not getting crazy with the RPM either(2,500 tops). That's before the filter too, so i'm sure the pressure is a little lower after it. While driving and i stomp it I'm sure it's getting close to 0 psi. I've exchanged many on the 1 year warranty. They just don't last.

I"ll be installing a Holley Blue fuel pump on my blazer and perhaps a walbro frb-5 on the pickup before i purchase another stock LP regardless of year or manufacturer. Free exchange under warranty however, is different.
 
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OK moved it back over on the frame rail, still gets warm but I think it was a little to close to the tranny/tranfercase and getting heat from it. This little pump seems to be doing alot better than stock. We will see how long it last for 53 bucks! It also comes in a 24 volt app. as well.
 
Well this is my problem. I have a ssdiesel lift pump that was installed by a they guy i bough the truck from. I live in orange county new york and this winter this truck gave me a hard time startin! I though it was gelled fuel. so i added 5 gallon of kero. and some diesel 911. it started so i ran that tank down and then filled at a local truckstop with some know winter blend. thought my prob was solved till the truck sat for 2 days and would not start again. It would turn over. start to light up and then it would stall after about 5 seconds. With the ignition still on the lift pump would rattle as if it had no fuel, for about 1 min then stop. after cranking again. some thing stall and lift pump keeps on rattling for about a min. now that the weather is warmer i no longer have this problem. to answer your question about pressure it is now around 10- 15 psi
 
no its not i am going to install one. I installed a tranny temp, boost and exhaust gas gauge. thats the next project
 
you need to read up about the lift pump operation in the tech library. the last of it covers OBD1 and the quirks they have with the ops. also put a piece of clear tubing on the return line coming out of the IP so you can check for air. the LPs have a check valve that can fail also.
 
jihly said:
no its not i am going to install one. I installed a tranny temp, boost and exhaust gas gauge. thats the next project
Click to expand...

Where did you measure the pump pressure?

The LP keeps running when truck stalls when the oil is cold and it takes a while for the pressure to bleed out of the OPS that sends power the LP. The OPS only needs about 6psi to actuate its contacts.

You can try activating the LP each time before starting to see if starting is easier. I suggest modifying the LP power circuit to run the LP during the Glow/WTS time. There is a wire diagram in a file I posted near the end of that LP/OPS thread.

your hard start may be GP or starter/battery crank speed related.
 
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