Ford Fuel System :: Hiccup And Stumble When Get On It Real Hard From A Standing Start
Jan 10, 2009
My 302 runs pretty good when all warmed up. It has some cold start issues every now and then, but is easily dealt with. My question is how to best "tune" the carb. It's a 600 cfm 4150/60 style Holley single pump, vac secondaries and electric choke. About as basic as you can get. I think I have the fuel level set correctly. I also think I have the "idle mixture" set right. I used a vacuum gauge and moved back and forth between screws till I got the highest vacuum. Is there a better way than that? I have the idle set correctly. the fast idle is a little high, but I can fix that.
Now, my real question is how to fix the hiccup and stumble I get many times when I step into it pretty good. I assume that this is the point the carb is going from idle circuit to main circuit. It stumbles when I get on it real hard from a standing start. I can roll slowly and step into it and it stumbles as well. I also like to blip the throttle when I down shift (it has a manual tranny by the way), and many times I'll blip it and get nothing. Now, it runs fine after the stumble all through the rpm range. That's the only time it stumbles. so, do I need more accel. pump shot?? To compensate on the transfer of circuits.
I also notice when I on it real hard, during the shift right when I jump on it, under the heaviest load, I hear a bit of spark knock. It's not running hot, and the timing is good. Do I need a bit bigger jets? I'm thinking it's going a bit lead during that time, but I don't have any real way to measure it.
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What would make a FI engine act like its flooding out and dying after a short run on the freeway?
Details:
1994 F-350 351W (just overhauled this winter)
has new TPS, ICM(?).
Dual exhaust dumps right before the tires
new filters in tanks, new fuel filter on frame rail
All fuel lines have been opened and blown out from the tank to the engine compartment fitting near firewall.
Fuel pumps hold good pressure when tested.
Symptoms:
smells like its running rich most all the time
after a short hiway run @ 70MPH it will stumble and die when returning to surface streets.
fuel smell near engine sometimes, but no obvious puddles or leaks anywhere.
May be related?:
When on a longer highway run, I can't use the FWD tank for a long period without the engine stumbling and cutting out or popping at times. But I can swap to the rear tank for a bit then run the FWD tank again for a while. driving up hills it seems to be worse, but I'm in the panhandle of TX right now..good grief!
I am having to drive this truck for work long distances. While I dont expect a vast fuel range, it would be nice if I could go a couple hundred miles on 20 gallons of gas....
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460, stock RV motor with LT headers, Alum Stealth intake. Carb is brand new, Holley 600 cfm, out of the box.
Elec choke, vac 2nds. Timing is set to 12 BTDC.
Truck idles beautifully. Drop it in drive, it will ever so slightly stumble/hesitate then go liked a raped ape. Has great acceleration (for a 8k dually crewcab). In my mind, I'm thinking a slightly larger than stock accel pump to give a bigger shot.
However, it does have a 1" carb spacer. That and the hi rise stealth, is it leaning out for a sec and causing the stumble? Would pulling that 1" spacer work? I was thinking the higher the carb the better to get less heat dissipation from the engine's heat. Replacing the heater core now. So I have some time to sort it out. I'd like to road test a tank of gas through it, but gotta fix the heater 1st.
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I have a recently rebuilt 400 with a mild cam and Tmeyers flat top pistons. The carb is a 600cfm edlebrock that was bought new and installed a few months ago.
The issue I'm having is if I'm driving around and shut it off to run in the store its hard to start when I come back. I end up having to floor the gas to get it to start. When it's cold I tap the gas and turn the key and she lights right off. Could this be an issue with vapor lock? Why does it go away if I floor the gas?
Only other thing going on is when accelerating the engine runs noticeably smoother above 2700rpm. It's a little boggy below that. Probably two different problems but I figured I would throw it out there.
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I have a 2001 Lincoln LS V8 that runs rich and no one can solve the problem that's been going on for close to a year. The fuel sys pressure tests fine. The fuel regulator sensor has been replaced. First start in morning is normal but after that I need to give it gas to get it to turn over. Also, car has a fuel smell.
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06 F250 6.0 with only 65,xxx miles on it. This has happened twice and both times the engine was warm and had been cut off for less than 10 min.. When I tried to crank it back up it stumbled and idle roughly then cut off. After several attempts to re-crank it still would idle rough and I tried to give it fuel but no change, even with pedal fully depressed. Then it would die.
After sitting a few minutes it starts normal. Both times I didn't have my obd2 adapter for my torque pro. The last time it happened I went home and hooked it up and got no codes. Everything looked fine. What could it be, where should I start looking. Batteries are1.5 years old. Oil, oil filter, and both fuel filter changed about 1000 miles back. I have had the truck for 1.5 years and the oil has been changed twice.
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I have a 96 aurora that has been giving me alot of problems. It started with the car being real hard to start and very sluggish upon acceleration. I had an engine code of 0300 (multiple cylinder misfire) I had a full tune up as well as an intake manifold gasket done. This seemed to fix the problem for a short time. The problem then started again. this time i was told that it was a fuel pump so i went ahead and changed that as well. Again this fixed the problems for a short time. Now i am having the same problem again. I now have 2 engine codes 0300 as well as 0151(bank 1 sensor 2 o2 sensor) This started after it rained and i notice the problem always seems to be a little worse when its wet out. Also the car is really only hard to start when it has sat for awhile. m If i drive it and come back 5 minutes later it will start right up though it still idels really rough and has no acceleration. Can the o2 sensor be causing the misfires and if so will that make it hard to start. Also if i changed the fuel pressure regulator about a year ago.
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09' Auto accent developed an issue that I haven't been able to sort out. Car began experiencing a condition where it was harder and harder to start, over about a 2 day period. As well, when stopped at a light it would idle fine, but almost stall when you tried to accelerate. Once above about 2k rpms it was fine, but then near 4k rpm it felt dead, didn't want to pull.
Only code was P0171.
Here is what I have checked thus far.
All injectors ohm out exactly at 15.1
-Fuel pump primes at key on like it should
-Verified cam/crank are timed properly (timing belt didn't slip a tooth)
-Car is MAP based, so no MAF to deal with. It's totally stock down to the paper air filter.
-Purge solenoid is closed and appears to be functioning properly.
I was checking things last night and this time it didn't want to start at all. I haven't checked for injector pulse or spark (it's coil on plug), but this didn't seem like part of the issue it was experiencing. Almost feels like a cam or crank sensor going out (timing is acting weird). Is there a relatively easy way to test the cam or crank sensors other than just trying new ones?
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i have a 1994 mitsubishi diamante 3.0 sohc hard to start and idles real rough. it has new plugs,wires,cap,rotor button,fuel filter,and air filter.fuel pressure is between 45 and 50psi which is good i have good compression on all cylinders timing belt is good and i am getting spark to all plugs. with the car running i pull the plug wires off and cylinders 1 3 5 makes a difference but 2 4 6 their is no change.the car was setting for two years.it dose have new gas.the check engine light is not on and has no codes.
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2002 E-250 with the 4.6 V-6. Pulled the 30 amp fuse, replaced the fuel filter, replaced the fuse, now the truck wont start. Checked the fuse and the kill switch under the passenger kick cover, all ok. Cranks and cranks but wont fire. No problem prior to changing the filter. Even swithed out the relay with another, no luck.
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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...
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4150 Holley 532BBF float adj issue . I think i have it close, but its so hard to tell because the engine shakes the vehicle so much its hard to set the floats so that it just trickles out of the float holes. (532 kasse P51 heads, big roller cam) Is there an easier way to do it say on the bench?
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03 F350 7.3PSD... A/C blows cool on max only but does not blow real hard on high.
Blower motor is loud like it is blowing but just not coming out of vents. On reg A/C blows hot, actually blows hot on all other settings.
A/C compressor is on but blows hot through vents. I am thinking blend door and or something else. Thing is I am not sure what or where to look and how do I check?
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My 2000 ranger in 4x4 high never did this. And in 2wd it doesn't pull at all...
When in 4x4 high it pulls hard to the left ?????? is left not working? It has automatic hubs ...
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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).
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I am currently working on a 97 ranger with a 4cyl and 5 speed. its having some idle issues that i cant seem to pin point, you can start it and it will idle rough then when you rev it up it chugs real hard then dies. used my scan tool and all the sensors are good, fuel pressure is good, good compression, all 8 plugs are firing good and no codes. The other deal that has me a little confused is when I unhook the hose that runs from the air intake tube to the valve cover, I get a lot of vacuum at that port on the valve cover that the hose hooks to. Also when I plug it and pull the dipstick, I get vacuum at the dipstick tube. never seen this before but at the same time I've only messed with very few of these trucks so I don't know whats normal.
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I have 1976 F250 with a 352 That will start and run for about half a second and then die. If I give it gas as soon as it fires up it sputters HARD and then dies after a total of about one to one and a half seconds. Is it getting to much fuel?
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have just put a motor in this truck. She will start when cold but will not start when hot. problem with the fuel injector maybe????
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115,000 miles, adult driven. Hard cranking, took into dealer. Replaced 4 injectors - cylinder 2 misfiring. Showed me return gas line clogged with brownish material. Dealer stymied.
Now, Subaru headquarters diagnoses replacing all steel fuel lines, fuel rails, fuel pump...full of rust from inside. Tank looks Ok, as does filler neck. Premium gas used always, added Drygas seasonally as needed.
Question: where the heck would rust come from? What can I do to prevent this problem again? Love the car...would like to get 200,000 from it.
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I have a 2007 F550 with a 6.0. Truck started running real rough and stalled. I was able to start it back up after a bit but within a few blocks it did the same thing. Was very similar to problems I had with clogged fuel fuel filters before I changed the tank to a plastic one. I pulled the filter and housing on the rail and cleaned and replaced the filter. There was no debris in there. Changed the filter on top of the engine too. Cycled the key 5-6 times. I could hear the pump running but the filter housing on top of the engine did not fill up; all I saw was a very little bubbling and gurgling sound.
I opened the drain on the rail filter housing and a little fuel came out but not as much as it should have. Cap is tight, don't see where I could be sucking air. I'm thinking the pump may be shot? Only other thought I had was maybe I switched the plugs on the housing on the rail but I really don't think I did. There are 2 plugs on the right hand side. Black plug is plugged into the lower position parallel to the ground while the gray plug is in the higher position.
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Went out to start my 150 last Wednesday. It started up, then quit, and then wouldn't start again. Later that night, it started up and then kept running. Called up a couple of auto parts stores and was told it was probably the fuel pump. The next day, we got it running and took it into the shop. They couldn't figure out what the problem was, so we took it back on Friday. On Saturday, I drove it about 40 miles, then parked it for about an hour, then it wouldn't start up again.
The mechanic came and checked it, said it almost certainly was the fuel pump, then he got it started with some brake cleaner. I drove it home and then later drove it again. I made a stop and it wouldn't start again. Had to get it towed to the shop. They spent all day Monday changing the fuel pump and filter and thought it was fixed. I picked it up and had no problems that night. My wife drove it Tuesday about 50 miles and had no problems with stopping or starting it. I went to start it up Tuesday evening and it died again and wouldn't start up.
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