Ford Fuel System :: 1989 F150 - Hot 28 Psi Fuel Pressure Shuts Off?
Jan 13, 2013
for the past week we have been trying to figure out what is wrong with our truck. We recently bought it and it ran fine. Then got in a minor accident just a fender bender and it started acting up so I got towed to garage. First it would run when cold, but when hot fuel pressure would drop to 28 psi.
So I put new fuel pump, it started but still did the same thing hot 28 psi fuel pressure shuts off. So I put regulator on it, then had 0 fuel pressure won't even start. So got a another regulator thinking I got a bad one, still 0. Checked relay, there fine. I'm gonna check lines and see where fuel stops at but everything is new on it.
View 1 Replies
Advertisement
I am a newbie as far as fuel injection. The original issue the truck had was no fuel. I tracked down the issues to a blown fuel pump relay and a melted inertia switch. I jumped the inertia wires with a new fuel pump relay installed and the truck ran at an idle and up to 3500 RPM when stationary. If the truck is going up a grade or needs more throttle it will start to lose fuel pressure and end up stalling. I had the fuel pressure gauge connected to the schrader valve on the fuel rail and had 30-35 PSI when idling. It runs good under light load on the throttle.
Under heavy load it starts to drop quickly and if you back off the throttle it will stay running some times. I changed the fuel filter and also replaced the high pressure pump on the main frame and it still has the same problems.The original pump was pumping about 13 ounces of fuel in the 20 second test that the repair manual suggested. I have even placed a jumper wire direct to the new fuel pump to bypass original wiring and possible problems. When it stalls under load (No Fuel pressure) at the schrader valve you can hear the fuel pump running but there is no fuel pressure.
If I turn off the ignition for a few minutes and then turn the key back to the on position it will start to pressurize and then start and run at an idle. I even replace the ignition switch as it was a little temperamental. I have not changed or checked the fuel pressure regulator as it is a pain to get to at the back of the engine. I do not want to spend a fortune tracking down this problem since the truck may not even pass its smog inspection and may be a parts truck only.
67 F-250 4x4
73 Crew 4x2 (4x4 Soon)
89 F-250 Super Cab 4x4
View 11 Replies
I have a '99 E-350 6.8L. Where is the check valve that maintains fuel pressure on the system?
I have been experiencing a starting issue when the engine is hot. Cold starts are usually fine. I've replaced the in-tank fuel pump (pump only, not the assembly) to no avail. I was out of town and didn't have access to a fuel pressure gauge when the problem started so I couldn't say what I had prior to replacing the pump. But now, with a new pump, when I check pressure, I get about 40 psi when I first cycle the key on, but it drops right back to zero as soon as the pump shuts off. If I cycle the key on a few times, sometimes I can get it to hold pressure at about 32 psi, and it starts fine. When I shut if off, it goes back to zero psi, sometimes gradually, like a bleed down, and sometimes immediately.
My conclusion from this was that the check valve was bad. I was told it was part of the in tank fuel pump assembly. Since I didn't replace the entire assembly, this made sense. So I just dropped the tank back down, but I don't see anything as part of the pump assembly that serves as a check valve. There is a rubber nipple on the end of the return line, but I don't see how that can hold any significant pressure.
So, before I go out and spend another couple hundred bucks on the complete fuel pump assembly, which apparently can't be purchased without the actual pump, I thought I'd ask. Where is the check valve that holds the pressure in the fuel system?
BTW, I also have replaced the fuel rail pressure regulator, but it made no difference (I went there first since that was much easier than dropping the fuel tank a second time).
View 8 Replies
My vehicle:
1976 F150 2wd Extended cab
390 4bbl
c6 transmission
4BBL Edlebrock Carb
Dual fuel tanks, only rear main tank connected
My problem: For the first year I owned the truck, everything ran fine and it started up really quickly even after it sat for a few days or a few weeks. I have since, for about the last year or so, had to crank it for 30-45 seconds to get it to start. This all started around the time my fuel pump went out. I replaced it with an Airtex fuel pump from Autozone. I also installed a glass in line filter before the carb in front of the distributor.
I noticed that after about 4-6 hours, the fuel had drained out of the filter and that's when I would have to crank it forever to get it going. It also seems like there is no fuel in the carb as it doesn't even try to start when it first gets cranked. I thought this was a bad pump, so I bought a new one last week and tried it again. Sure enough after about 4-6 hours, everything is empty again and it takes forever to start it. So it's not a bad pump, or so I think.
The other day I backed it into my driveway and left it, something I never do. I checked about 4 days later and there was still fuel in the filter. This makes me think that gravity is making it drain back to the tank.
Is there something that would cause this? Also I have found a one way fuel check valve online that is supposed to remedy this type of problem. Do they work for this situation? Or is there something else I should be doing to fix this? It has taken a bit of a toll on my starting system having to crank so long all the time. I have so far had to replace my starter, starter solenoid, and all the battery cables, starter cable, terminals, etc. due to excessive wear.
The valve I found is here : [URL] .....
View 3 Replies
I've got a 01 f150 yesterday stopped running (like it ran out of gas). Has half a tank. Fuel pressure at rails good but truck will not turn over. Fuel pump and filter less than year old.
View 1 Replies
I've had a fuel leak near the pump of my 79 F150 with a 400 for some time. I didn't know exactly where it was coiming from, but fuel was being sprayed on to the oil filter from something near the pump. I assumed it was the steel line, and that it had rusted through or cracked, and was going to replace it when I had a chance. I was poking around today though, and realized that the fuel was not leaking from the line, but from a hole in the side of the mechanical pump.
For someone who knows what these pumps look like, there is a horizontal cylindrical bump out near the top of the pump, on the side of the pump that is away from the engine. The fuel is spraying in a mist out of one side of that. To me, it always seemed to be a screw channel, but I didn't think the pump was 2 halves put together? Need to know more about my pump, what that bumped out section is, or why/how fuel could be spraying out of it.
View 4 Replies
1993 F150 302. What does the fuel canister purge solenoid/vac play in the furl/emissions arena?
View 5 Replies
cant figur this out have no signal to injectors and no power at fuel pump 88 f150 5-0
View 2 Replies
Why the frame mounted fuel pump might run after the key is turned off? Then when you turn the key on it may or not run. If it does run it keeps running. shouldn't this shut off after pressurizing the line? is their a pressure switch in the pump that's failing? This has the 3 pump system...
View 4 Replies
I have an 87 F150 4x4 4.9L EFI with a single tank. Fuel pumps keep running even when the key is off. I tried swapping relays but the problem still exists. The engine will start and run OK for about 15 secs. then die. I installed a new low pressure pump, high pressure pump seems to be OK. I also installed new fuel filters. I dont want to just throw parts at this truck, where do I go from here?
View 4 Replies
1994 150 300 6. parked truck after lunch finished work and it wont start no fuel comes out of the valve. Can't get the pump to work even when jumping the 6 pin. heard the relay click still nothing. Checked the inertia switch it wasn't popped. Took the pump out jumped it straight from the battery pump works . I know there has to be something i am missing...
View 7 Replies
I'm looking at replacing the fuel lines in my 94 F150 and the big question is what to do with hooking up to the fuel lines coming out of the fuel pump hat and the fuel rails? Ford uses a specialized pressure fitting on it's custom fuel lines. I think there may be some third party fittings that would replace these, but I'm not sure. I could use a standard hose and cable clamps, but I just don't trust that kind of connection for a fuel line.
View 5 Replies
I have a 1986 F150 6 cyl, dual tanks, no AC, manual fuel pump. Just recently, I have been having issues with the tanks. At first it seemed like the back tank was siphoning from the front tank. Now I have fuel coming out of my front tank filler neck. When I open the back tank gas cap, there is enough pressure to spray me with gasoline. I am not familiar with the fuel delivery system of my truck ...
View 2 Replies
Working on a 88 Ranger 2.9L 5-speed ext cab. The fuel pressure drops off fairly fast when turned off and I'm pretty sure that the check valve is bad. My question is, which pump has the check valve? It is a single mid tank set-up and has a pump in the tank and on the frame.
Pressure is fine while running. about 30psi @ idle and 40psi with no vacuum on the regulator. The pressure drops off within a couple of minutes which causes it to have to crank over for a bit to rebuild pressure and start.
It looks like the frame pump is readily available while the in take pump is special order. I just need to know which one has a check valve. I'm thinking the in tank pump, but I hate to waste money for the wrong pump.
Pressure drop rate
30 psi @ shut off
25 psi @ 1:05 min
20PSI @ 2:30 min
15psi @ 4:45 min
still dropping
View 7 Replies
I have a 1988 Ford F-250 Lariat, 7.5L 460, four-wheel drive. I have two fuel tanks on it, and I've been having a really annoying, obnoxious problem with it lately. After running it for a while, I noticed that I keep losing fuel pressure, and the truck stalls. When I try to start it, it does nothing but roll over. It just won't start. I've changed the fuel filter, I know both fuel pumps are working (I turn over the key, I can hear front, back, and high pressure pump attached to the left side frame rail kick in.) It's Fuel Injected, not EFI, hence that third pump. The problem happens a lot, and it's random. I could drive for 100 miles, stop to get something to eat, come out, and it won't start.
I thought maybe it was the fuel pressure regulator, but I don't think that's the case because it still runs. I would assume that if the regulator was bad, it wouldn't run at all. I also thought that maybe it was the relay, but according to some mechanics I spoke too, if I can hear the pumps kick in when I turn the key over, then the relay is fine. The only thing I could think of is that it might be the fuel selector switch. Maybe it's going bad, shorting out or something. When I flip the switch though, it switches between fuel tanks, and the gauge reads how much fuel is in it from the sending unit.
There's a schrader-type valve up by the fuel injectors. When I push it in, it barely squirts any fuel out, if at all, so I know the pressure is low. When I push it in on a good day, it sprays out like a water fountain. Just tried starting it again - no good. Pushed on the valve, it spurted out some fuel pretty well, but still won't start. Occasionally tries to, but ultimately won't. I know the spark is good, checked the plugs/distributor cap. Can't get the sucker to start.
View 14 Replies
I have a 89 F150 4x4 lariat with the 302 8cyl and dual gas tanks. I was driving to work and the truck died. I have spark and enough juice to turn it over so I must be getting no fuel. When I turn the key to the on position I do not hear the fuel pump whine as it primes, it's dead silent. I'm assuming the fuel pump is dead.
Are there any fuses to check? I did check the switch that goes off when in an impact and it was not tripped off so it's not the problem.
My hayes manual (which i find is wrong ALOT) says that 87-89 f150's have a single fuel pump that is external to the tanks and found along the left frame rail? Can anyone confirm? Someone told me they thought it might have 2 pumps but I switched tanks and the truck still didn't start (or make a fuel pump sound) so unless the planets aligned and BOTH pumps blew simultaneously I would assume there's only 1 pump.
View 14 Replies
I just purchased a 1989 F250 with a 5.8 motor. Great truck for its age. Ive owned other Ford trucks in the past and my Dad had them as a kid. Love them.
When I bought the truck from the 2nd owner it had a problem so I bought this truck with the problem figuring with my past knowledge I could fix it. Not the case. When I got the truck it would start fine and run really great but when it got warm it seems it would die and I would have to wait till it was cooled down to start back up and again it would run fine. Well the problem got worse and worse and now it wont run at all.
It will run on starter fluid so that leads me immediately to the fuel pumps. I say that plural because none of them will run it seems. I did a fuel pressure test at the shrader valve at the top of the motor on the fuel rail and I get no pressure at all when I turn the key. The relay in the engine compartment seems to be working to as I can hear it. I put a new on of those on to to be sure. Leads me back to the pumps again. I replaced the external pump on the fuel rail and I know thats working. I replaced the fuel filter to while I was there.
Is it possible to have BOTH fuel pumps in the front and rear tanks go at once? Seems unusual. My other F150 with dual tanks worked great and when the back tank pump went I could just switch it over to the front tank.
View 2 Replies
1991 F150XLT, 5.0, E4OD....Should the EFI system bump up the idle speed when the AC system is operating to compensate for the compressor load? Obviously I'm asking because mine sure doesn't. With AC on, the idle speed will drop to around 300rpm in Drive, like when sitting at a red light for example. Surely this isn't normal operation...is it?
View 4 Replies
My 88 F150 (300 six, 5 speed, dual tanks, 176,000 miles). The truck has the low pressure fuel pumps in the tanks and the high pressure pump on the frame rail setup. Truck starts fine, but cuts out severely under acceleration for the first 30 seconds of driving. After that I only notice the problem when applying a lot of throttle (does not cut out under gradual acceleration) or climbing steeper hills. If I kill it for a few minutes and then take off again the problem is back for the first 30 seconds or so. I have replaced all the tune-up type stuff (all filters, plugs & wires, dist. cap & rotor, ignition coil, o2 sensor, cleaned throttle body, replaced IAC valve, numerous sensors). Timing is dead on at 10 deg. BTDC with SPOUT unplugged. My FPR was bad so I also replaced that. Condition exists regardless of which fuel tank I am using (no problems with tank selector).
Getting no KOEO codes, but getting KOER code 41 and plugs do seem to show a lean condition possibly. I'm still averaging around 16 MPG since this became a real problem about 3 months ago.
I removed the bowl from the reservoir between the tanks and the high pressure pump on the frame. No filter in there, but it was clean with no gunk or sediment found. I removed the line from the inlet side of the high pressure pump and found that while cranking the engine I have fuel flowing freely (same amount of flow regardless of which tank I've switched to). The flow was steady, but not extremely strong. If I understand right the in-tank pumps are not designed to provide much pressure? Below is what I found at the schrader valve:
key on, engine off - high pressure pumps runs for about 1 second, brings gauge up to 48 psi
idle, FPR connected - 40 psi
idle FPR disconnected - 52 psi
revving throttle with FPR connected - 46 psi maximum
Connector, where fuel pump relay plugs in, seems to be clean and not corroded at all.
View 14 Replies
I picked up a 90 f150 with the 302. it wont idle without a little throttle, so after a quick look under the hood i noticed alot of broken torn and missing vacuum lines. Where I can get some sort of diagram for routing?
View 1 Replies
I have an 87 f150 inline 6 efi. The truck will not rev over 2000 rpm even when idling. It has a new fuel filter. What this could be?
View 2 Replies
