Truck stalled, won't start....Fuel Pressure is only 18 psi
Thread Starter
Joined: May 2008
Posts: 8
From:
Truck stalled, won't start....Fuel Pressure is only 18 psi
Ok, I know this sounds likea bad fuel pump. I would just like more opinions before having the parts shipped to me in Italy. I've only had the truck for two months and the fuel gage has always been erratic below half a tank, which I know is a common Blazer problem. Now, here is the rest of the scenario....
Friday afternoon -ran the tank nearly empty before putting 30 more liters in (possibly bad gas)
Friday evening - changed the idler pulley because it was squeaking (possibly bumped something in the engine bay in the process)
Saturday morning - drove 10 miles to the store....about 2 miles into the trip, heard a thunk under the truck like I ran over something, but saw nothing in the rearview mirror (possibly knocked something loose the night before). Continued onto the store, shopped, went about 3 miles to the grocery store...still no problems. Left grocery store, made it about 2 miles down the road and the truck stalled pulling up to a red light. I didn't even realize it until the light turned green and I tried to give it gas. Truck wouldn't start...sounded like it wasn't getting fuel...just cranks and cranks and there is no gas smell.Towed it to the garage.
Saturday night - read forums for ideas andread about intermittent starting issues where other trucks would sit for awhile and then start fine.
Monday - tried to start. Just cranks
Today - checked fuel pressure at schraeder valve and only had 18-20psi. Dropped the tank enough the check the connector and thump on the pump. Still 18psi(holds steady with the ignition off). Removed the fuel filter to try to blow out any obstructions. Connected pressure gage at the fuel filter inlet and had the same 18psi...even tried thumping the pump while it was pumping. Blew out the filter with compressed air and reinstalled it. Concerned that the gage was faulty, I cupped the inlet with my hand and blew compressed air into it and got the gage to read over 60psi easily...so I'm pretty sure it is working correctly. I can hear the fuel pump run every time I turn the key on or off, but it doesn't seem as loud as before....could just be my imagination though.
Now, I've searched the forums and google for hours and I know the fuel pumps are a common problem. What about the fuel pressure regulator? I'm still unclear as to when it actually regulates the pressure. Is there just one in the engine bay, under the intake plenum? Or is there one in the fuel tank, too?
What are your opinions? Thanks.
- Travis
Friday afternoon -ran the tank nearly empty before putting 30 more liters in (possibly bad gas)
Friday evening - changed the idler pulley because it was squeaking (possibly bumped something in the engine bay in the process)
Saturday morning - drove 10 miles to the store....about 2 miles into the trip, heard a thunk under the truck like I ran over something, but saw nothing in the rearview mirror (possibly knocked something loose the night before). Continued onto the store, shopped, went about 3 miles to the grocery store...still no problems. Left grocery store, made it about 2 miles down the road and the truck stalled pulling up to a red light. I didn't even realize it until the light turned green and I tried to give it gas. Truck wouldn't start...sounded like it wasn't getting fuel...just cranks and cranks and there is no gas smell.Towed it to the garage.
Saturday night - read forums for ideas andread about intermittent starting issues where other trucks would sit for awhile and then start fine.
Monday - tried to start. Just cranks
Today - checked fuel pressure at schraeder valve and only had 18-20psi. Dropped the tank enough the check the connector and thump on the pump. Still 18psi(holds steady with the ignition off). Removed the fuel filter to try to blow out any obstructions. Connected pressure gage at the fuel filter inlet and had the same 18psi...even tried thumping the pump while it was pumping. Blew out the filter with compressed air and reinstalled it. Concerned that the gage was faulty, I cupped the inlet with my hand and blew compressed air into it and got the gage to read over 60psi easily...so I'm pretty sure it is working correctly. I can hear the fuel pump run every time I turn the key on or off, but it doesn't seem as loud as before....could just be my imagination though.
Now, I've searched the forums and google for hours and I know the fuel pumps are a common problem. What about the fuel pressure regulator? I'm still unclear as to when it actually regulates the pressure. Is there just one in the engine bay, under the intake plenum? Or is there one in the fuel tank, too?
What are your opinions? Thanks.
- Travis
BF Guru
Joined: Dec 2006
Posts: 6,594
From: Fort Worth,Texas
RE: Truck stalled, won't start....Fuel Pressure is only 18 psi
[sm=welcomesign.gif]to the Forum. Looks like you are on the right path with your diagnosis of a bad fuel pump. Let's just review the procedureof checking the pressure:
With the pressure gauge hooked to the schraeder valve and the key turned to the 'on' position, the pressure should be ~53-65psi. Turn the key off and the pressure should not drop more than ~2-3psi and stay there for several minutes.
If this was the method you used, and with the test you did at the filter inlet, I'd say the pump is bad. Do yourself a big favor when you buy a new pump assembly and get a genuine AC/Delco unit. The aftermarket brands just don't have a good track record.
With the pressure gauge hooked to the schraeder valve and the key turned to the 'on' position, the pressure should be ~53-65psi. Turn the key off and the pressure should not drop more than ~2-3psi and stay there for several minutes.
If this was the method you used, and with the test you did at the filter inlet, I'd say the pump is bad. Do yourself a big favor when you buy a new pump assembly and get a genuine AC/Delco unit. The aftermarket brands just don't have a good track record.
RE: Truck stalled, won't start....Fuel Pressure is only 18 psi
DirtyT -- it definitely sounds like your fuel pump. I'm glad someone else is posting this topic again, because I had the same problem yesterday. Since my Blazer's 12 years old with 167,000+ miles on it, I've beenexpecting my fuel pump to die soon. Here's the scenario:
Yesterday during my lunch break,I pulled up to a stop light, and it stalled out. Since the fuel gauge hadn't moved in a few days (seemed stuck on half a tank), my first thought was that the gauge died and the tankwas empty. So I called AAA to have them deliver me some gas. It started back up, but it took several attempts to get it to start. I drove it straight to a gas station and added more gas. Then it didn't want to start again. After the third attempt, it started right up and got me back to work, about 2 miles away. After work, it got me home, which was about another 10 miles, but then it died just as I pulled up in front of my house.
Then this morning, it started right up and got me all the way to work, with zero problems. Since I've recently already done a whole bunch of troubleshooting when I had a previous startup problem (turned out to be the starter, which I replaced, along with the fuel filter), I know it's not the fuel filter, starter,or ignition switch. I checked the fuel pump relay, and it's not that either.
However,I did smell fuel coming through the vent both times it stalled out.At first I thought it could be the fuel pressure regulator -- but since the smell went away after driving a little, I think it's just because I flooded the intake while starting it. I have a fuel pressure gauge,but since I think the pump is dyingbut not yet dead, the test may actually be useless. Ifeel the age of the truck warrants replacing the pumpanyway for preventive purposes.
If anybody thinks there's something else I should check before doing the fuel pump replacement, please let me know.
Another interesting piece of information: My local stealership gave me a $960 estimate for a fuel pump and tank. I compared it to RockAuto.com, whose total came out to only $499, including shipping and additional hardware. WTF?!?
Yesterday during my lunch break,I pulled up to a stop light, and it stalled out. Since the fuel gauge hadn't moved in a few days (seemed stuck on half a tank), my first thought was that the gauge died and the tankwas empty. So I called AAA to have them deliver me some gas. It started back up, but it took several attempts to get it to start. I drove it straight to a gas station and added more gas. Then it didn't want to start again. After the third attempt, it started right up and got me back to work, about 2 miles away. After work, it got me home, which was about another 10 miles, but then it died just as I pulled up in front of my house.
Then this morning, it started right up and got me all the way to work, with zero problems. Since I've recently already done a whole bunch of troubleshooting when I had a previous startup problem (turned out to be the starter, which I replaced, along with the fuel filter), I know it's not the fuel filter, starter,or ignition switch. I checked the fuel pump relay, and it's not that either.
However,I did smell fuel coming through the vent both times it stalled out.At first I thought it could be the fuel pressure regulator -- but since the smell went away after driving a little, I think it's just because I flooded the intake while starting it. I have a fuel pressure gauge,but since I think the pump is dyingbut not yet dead, the test may actually be useless. Ifeel the age of the truck warrants replacing the pumpanyway for preventive purposes.
If anybody thinks there's something else I should check before doing the fuel pump replacement, please let me know.
Another interesting piece of information: My local stealership gave me a $960 estimate for a fuel pump and tank. I compared it to RockAuto.com, whose total came out to only $499, including shipping and additional hardware. WTF?!?
BF Guru
Joined: Dec 2006
Posts: 6,594
From: Fort Worth,Texas
RE: Truck stalled, won't start....Fuel Pressure is only 18 psi
ORIGINAL: Psychropod
...I have a fuel pressure gauge,but since I think the pump is dyingbut not yet dead, the test may actually be useless. Ifeel the age of the truck warrants replacing the pumpanyway for preventive purposes....
...I have a fuel pressure gauge,but since I think the pump is dyingbut not yet dead, the test may actually be useless. Ifeel the age of the truck warrants replacing the pumpanyway for preventive purposes....
Thread Starter
Joined: May 2008
Posts: 8
From:
RE: Truck stalled, won't start....Fuel Pressure is only 18 psi
ORIGINAL: rriddle3
[sm=welcomesign.gif]to the Forum. Looks like you are on the right path with your diagnosis of a bad fuel pump. Let's just review the procedureof checking the pressure:
With the pressure gauge hooked to the schraeder valve and the key turned to the 'on' position, the pressure should be ~53-65psi. Turn the key off and the pressure should not drop more than ~2-3psi and stay there for several minutes.
If this was the method you used, and with the test you did at the filter inlet, I'd say the pump is bad. Do yourself a big favor when you buy a new pump assembly and get a genuine AC/Delco unit. The aftermarket brands just don't have a good track record.
[sm=welcomesign.gif]to the Forum. Looks like you are on the right path with your diagnosis of a bad fuel pump. Let's just review the procedureof checking the pressure:
With the pressure gauge hooked to the schraeder valve and the key turned to the 'on' position, the pressure should be ~53-65psi. Turn the key off and the pressure should not drop more than ~2-3psi and stay there for several minutes.
If this was the method you used, and with the test you did at the filter inlet, I'd say the pump is bad. Do yourself a big favor when you buy a new pump assembly and get a genuine AC/Delco unit. The aftermarket brands just don't have a good track record.
Thread Starter
Joined: May 2008
Posts: 8
From:
RE: Truck stalled, won't start....Fuel Pressure is only 18 psi
So what is the list of parts I need to change the fuel pump? Looking on rockauto.com was just confusing, there are so many different parts. I was planning to buy the fuel pump and fuel filter. What else? What will fix the fuel indication?
BF Guru
Joined: Dec 2006
Posts: 6,594
From: Fort Worth,Texas
RE: Truck stalled, won't start....Fuel Pressure is only 18 psi
I'll repeat the advice to stay with AC/Delco for the pump. The part number can get confusing, so I recommend calling rockauto.com and asking them. Be sure they know that you have a 4dr because the pump is different for the 4dr and 2dr versions. You will want the complete assembly, sending unit and all.
Thread Starter
Joined: May 2008
Posts: 8
From:
RE: Truck stalled, won't start....Fuel Pressure is only 18 psi
Well, I just bought an off brand on ebay for $94. I hope it comes complete and fixes the problem. Guess I'll find out in a week or so. I went back to the truck today and swapped out the fuel pump relay and it still didn't start. I didn't bother hooking up a pressure gage today...just wanted to swap relays real quick. I noticed that the pump doesn't make a steady humming sound...more of a warbling sound. Should it be a steady-tone humm?