Ford Fuel System :: 1988 F150 - Cuts Out Under Load?
Apr 28, 2009
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
Advertisement
cant figur this out have no signal to injectors and no power at fuel pump 88 f150 5-0
View 2 Replies
I have an 88 E350 With a 460 EFI . Problem is there fuel is coming out of the ecs canister . It has the dual canister set up fuel comes out of the rear one after the engine starts. I have never seen this before. What would cause this ?
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 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
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
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
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
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
I have a 1988 f-250 with a 460 motor. I have fuel and I have fire. And the truck starts with I prime it. I tried looking for the crank sensor but can't find it. I looked behind the balancer and I didn't feel any wires or anything. I checked on the sides of the motor nothing. It has a new coil pack and ignition mod. Fuel pump and starter. What else can it be?
View 4 Replies
Its an 88 F-250 4x4 with a 302 EFI 5-speed. Fair compression, runs smooth. When I press the gas pedal it takes about 5 seconds for the old girl to return to idle. I know nothing about EFI. My buddy,s out of town with the hand held mechanic. Is there anything I could check till he gets back.
View 6 Replies
I have a '88 F250 with a couple of dual tank issues, first of all if I'm running on the rear tank the fuel returns in the front tank.... not an isssue if trhe front tank is empty, but if both tanks are full the front tank will overflow. If the front tank is empty I run on the back tank until I'm out of gas and switch to the front and I"ll have about a half a tank in the front tank.
Second issue, running the front tank the fuel gauge stays on full until I have about half a tank, then it works OK. If I'm running the back tank it stays on full, even after the tank runs out of gas??
View 14 Replies
1988 F250 351 5.8
I've worked for months on this truck and I now have it in the shop. The truck shows a 41 code and has a lean miss at idle that get worse during acceleration and cruise. The injectors were refurbished 6 months ago and the ECM was replaced 3 months ago. All sensors are new and within specs. Fuel pressure is good and there are no vacuum leaks.
The mechanic has verified that the condition is not electrical related. The O2 sensor will react if carb cleaner is sprayed into the throttle but other wise shows constantly lean. He's now checking all pins at the computer for any off condition. He is suspicious of the refurbished injectors. I'm wondering if the computer somehow went out again. Which way to go or what/how next to test?
View 9 Replies
I have an 1980 Ford F-150 with an inline 300. I just installed a new egr valve on. Here is the problem:
After the engine warms up with everything connected, the engine starts to cut out and die while idling. This is due to the VCV opening up and allowing vacuum to the EGR. My question is why is this happening? The EGR is not suppose to open up during idle.
View 4 Replies
