Ford Fuel System :: Flat Spot When Accelerating Off Idle
Jun 15, 2009
I have a 4160 on a 351 Ford. I confess, it's a boat!
I had a major flat spot when accelerating off idle. I found it wasn't pumping on the accelerator circuit.
I replaced the accelerator diaphragm and cleaned the squirts and the passages. It squirts great now, but if I floor it, it completely bogs. If I baby it really carefully, once the engine gets over about 1800 rpms, it acts fine.
I thought it over, checked the travel on the arm that presses the diaphragm, and figured my pump cam was worn. It "seemed" like the duration of the squirt was not long enough.
I got a new cam kit. The orange cam on my carb was not a bit worn compared to the cam in the kit. Not encouraging. I put the only other cam in the kit that I thought might work. It was blue, and it gave more lift but no greater duration. It did not make any difference that I can tell. Is there a transition circuit I might have problem with? I don't know enough to go any further.
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My 2.0 recently had some problems with the coil pack so I replaced it. Now my car hits a "flat spot" when accelerating around 2000 RPM and then another around 2600 RPM. If I am in 3rd gear going about 20MPH and I press the gas about 25-30% it sort of shakes and won't accelerate and when I take my foot off the gas and slowly ease the pedal down it accelerates fine.
My car also runs pretty rough at a cold idle(misfires). When I press the gas it sounds smooth until it gets back to idle. At any temp my car runs really rough with the A/C on. I also hear a rattle/Buzz around my relay panel when the A/C is on. My car is a 1999 2.0 AEG. I don't have VAG-COM just a generic scanner and the last codes I got were:
P0134
P0135
P0141
I replaced both O2 sensors and the beginning of this year and those codes came back right after I did them. I will scan tomorrow and post any new codes.
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Engine is a late 60's 390 with a C6 auto in good shape with a purported rebuild of about 10-15K miles on it. I picked up a nice condition Autolite 4100 and rebuilt it. Original tag states "C5AF AV" and below that in smaller font: "A 5AC" The base is stamped 1.12. It has the auto choke and auto tranny kickdown.
Truck has been sitting for 4 years so I drained the gas, primed the oil and added 5 fresh gallons. Started up on the second try!! But it won't idle and wants to die unless I feather the gas until it warms up. Also has a bog when accelerating up past 1200 RPM. I've been checking for vacuum leaks but none so far found.
I have a number of questions. But one of the areas I believe I need to correctly adjust is the float level, and here is where I can't get a clear answer or clear explanation of the correct procedures. What is the correct float level? My Sorensen rebuild kit actually had multiple values and the one that looked best had different primary and secondary values. I tried setting it "dry" by the upside down check with the cardboard supplied gauge. Good news is that it is not overflowing so needles and floats seem to be working correctly.
However, how do you do a more accurate wet setting? Appears to be two methods - one is the float setting and the other is the fuel depth. One good thread seems to state that both wet floats should be at 11/16". An engine builder locally said they should both be about level/parallel. Autozone says the primary should be 20/32" and the secondary should be 1 1/16". My rear wet float is almost level and it measures about 15/32". NONE of the data I've been able to find agree on the right setting nor do they explain in detail the correct way to measure using the wet float method.
I've got more questions like the choke settings and the vacuum port for hot air intake (currently open) and only getting 14 inches vacuum (I believe it should be 18 inches) etc., but I'd like to get the floats right before tackling them.
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2003 7.3 Sd Has a flat spot from 2700 - 3000rpm especially when it changes down, say going up a hill , if I decelerate and let it change back up it will pull again but if I leave it changed down it will not rev anymore. No CEL , put it on the scanner , only code that came up is " intake temp Low " which would not effect it. Have just installed new up pipes , new HPOP hoses , in the past it has had a new IPR and HPOP . It had this flat spot before and it would bring up low boost pres hence the up pipes . Have checked all flanges and intercooler boots etc.
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I had these things wrong in the first 12 months
Tire shake: took 4 trips to find one bad tire. Replaced 1 tire
Squeaky front end: 2 trips to find front coil rubbing on the frame due to bad mount or something. Fixed under recall
Squeaky front end part 2: bad upper strut mount bushing. I won't even count the dealership nicking my hood and it has to be repainted.
I have never had a perfectly smooth riding car. Frankly, the loaners drive better. I documented this with the dealer I bought the car from and then with VWoA a month ago. I told them the front tires are shaking again and need a balance. I even had the front tires balanced at an Indy shop. Before my 1100 vacation. Now it needs balancing again. The back has always had a slight bumping
Now at the 10k service, I get a free alignment check and find my car is moderately out if alignment.
I originally mentioned it to my purchase dealer asking if it needed the alignment after all suspension work. They said it was not needed. EVIDENTALLY IT WAS.
So now I have a tire with a flat spot which they should have replaced when I had one replaced. Evidently, this car says before I leased it. I used my free alignment I had with my extended warranty which I should have been able to save for down the road AND I still need a tire balance.
I told VWoA a month ago I shouldn't have to pay for a balance if it kept going out of balance. Obviously, something was causing the tires to be out if balance. It was pretty far out on the front left. Camber was out .58 and the toe .02.
I am highly annoyed. Norm reeves never put the effort in to make it smooth.
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About 3 weeks into the new 13 Elantra. Liking it pretty good. I seem to be hearing a noise of some sort. Almost sounds like a flat spot on a tire. Seems to be more rapid the faster I go and more or less noticeable on different types of asphalt. Didn't really notice it at first. The only thing I did was let some air out of the tires. They had almost 40 psi when I got it. They call for 32.
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I have a 07 Sonata 2l crtd, Its been running fine for about 6 years, But for the last couple of months, when setting off gently, as it reaches approx 1400rpm, I get a blip/hiccup/flat spot/miss. It ONLY happens at 1400rpm, and irrespective of what speed I am doing.
For example, as above, (setting off) but also, if cruising gently at approx 50mph ( which equals approx 1400rpm) then it does it again. It only does it at 1400rpm.
Also (maybe related) the orange engine warning light has now come on ( twice in past 2 weeks ) it stays on for a day or so,,,then goes out. its not flashing.
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I have annoying problem with the car feeling flat while driving it braking into a corner then coming out of the corner I feel I get no response from the pedal unless I push it down further. While pushing down a little further it roars out of the corner. I have noticed it more now because of the icy roads when I have traction control turned off. Push pedal down slightly with no response, then push 1mm further and the tires spin slowly.
I performed my own test in neutral of the auto transmission. While idling at usual idle speed, push pedal slowly and stop, kept doing this a little further each time to see what the rpm was reading. Finally it went from Idle speed under 1000 rpm and shot up to over 3000 rpm? I tried this dozens of times and could not rev the engine to anything between idle speed and roughly 3 grand. Took to dealer "no codes" I believe this will affect fuel consumption.
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I have noticed several times when leaving my driveway (backing out OR driving out) that it feels like I have a flat spot in my passenger front tire. The first couple times I pulled over to check the tire pressure to make sure it was ok, and it was. It doesn't happen every day, but I have noticed it 4-5 times in the last 5-6 weeks. I was talking to a guy from work and he has the same issue.
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When I first got my car it had a flat spot while driving hard at higher rpms. Almost as if something were actually holding the car back, it would pull nice up to that spot and then just almost die off. I eventually got unitronic flash and it seemed better but it was still doing it. Later companies started coming out with dsg flashes and this seemed to be the remedy but I now have hpa dsg flash and it still does it from time to to time. Could this be a faulty coilpack, or an issue with the intake manifold valve that changes over at higher rpms?
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I got a 4180 carb and at the accelerating pump I got a leak I wound up putting in the wrong screw so I had to retap the hole put a heli coil for 8 32 screw and now that its tight it has a leak don't have a lot of funds right now so I'm trying to find a solution that is not going to cost to much and forgot the count on pri needles and I got a backfire as of right now and not sure what adjustments need to be made or locations of what to adjust. I need to get back to work and its hard to do without transportation.
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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?
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I rebuilt a 1963 ford 2B crburetor with manual choke. Put the carburetor on and it runs very rough. Won't go below 800 rpm or it dies and I need to choke it to start. Thought it was a vacumn leak so sprayed WD -40 and no change in idle. So pulled off the carburetor and put on the previous carburetor (with electric choke) and it runs great. I want to use the manual choke to hook up the cable though. I replaced everything in the carb. What do you think it is?
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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?
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I have a 1984 Ford F-150 with an I6 engine and a motorcraft carburetor. The truck absolutely will not idle. So I got to looking at the carburetor, and found this red hose going from the carb to a metal pipe, the pipe was just dangling there not connected to anything, and the end it rusted off. I'm pretty sure I know where the other end is supposed to go to, I just don't know how to get there as obviously I am missing some parts and I can't find them so they must have been lost on the road somewhere.
Here's how it looks:
The end of the pipe:
Where it is supposed to end (I think)???
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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.
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I have an ambient temp switch connected to the vac port on my throttle emissions control solenoid for my 2150 carburetor. It's a 78 F-150 with a 5.0L 302, automatic 2WD. Would a bad ambient temp switch screw up my idle? I've disconnected the vac hose and it won't idle at all, and it does the same thing when I disconnect the two wires from the ambient temp switch. If I leave everything alone, I can get the idle down to around 1800rpm, but any lower than that and it stalls.
Is it possible to swap out this throttle emissions control solenoid with another type? I've looked everywhere and can't find an exact replacement, and I have no instructions on how to tune it.
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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?
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I have an 07 F150 with the 4.6L engine and i was wondering if theres any need to clean my injectors at 30,000km the truck seems to vibrate at idle but not very noticeable seems like a regular v8 rumble but two ppl have pointed it out recently and have riden in my truck a bunch, should i be puttin some injector cleaner in my fuel?
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I bought a new Holley 600 CFM 4150 with electric choke for my 79 ford F 250 with 400 engine. If I start the truck cold the choke works as it should and after driving 10 or so minutes it runs fine off choke. When I restart the truck after stopping for gas or food it goes back on high idle even with the engine temp at 180 degrees. Should it go on high idle even on a hot day fully warmed up every time i start it? I don't remember my last 600 doing it.
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1993 f-150 with 1988 5.0 with no pollution stuff fuel injected. here's the problem. Starts fine and idles great for about 5 minutes , check engine light comes on and it very nearly stalls at which point it begins to miss and surge and basically tries to die.
If I feather the Throttle i can keep it running but not smooth!! Can't find and vacuum leaks and the egr seems to be working (push plunger up - trk). dies. Ran fine when I bought it this way about 1 year ago and all of a sudden this. note.... It started doing this after it ran low on coolant but did not over-heat.
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