Brief dieseling sound when accelerating
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From: Pater, Maine
Brief dieseling sound when accelerating
I have a 1985 F-150 2wd w/C-6 and when I first accelerate it sounds somewhat like a diesel. It also makes the same sound when I first start it up after it's been sitting a while. I thought it might be pinging because I am unable to set the timing. The balancer/pulley moved so the timing marks don't line up. I set it by ear and it runs fine except for an intermittent large miss when idling (happens maybe every 30 seconds or so). Unfortunately I can't tell whether it makes the sound under heavy load or not because it's just to loud in the cab. But if accelerate (like when turning onto a new road) it makes the sound for about 2 seconds and then fades away. I just put a new oil pressure sending unit on and the pressure seems fine.
My thoughts were maybe rod knock? Piston slap? Pins are loose? Oil starvation? Oil filter (it's not a motorcraft), air pump? I just don't know. The engine has 212,000 miles on it and it was neglected by the previous owner. I just had the oil changed with 10w-30. Possibly with the wear on the engine by the neglect that the oil is to thin now and I need to run something with more weight.
Any ideas? I want to get it running well enough so that I can trust it to make the trip to the junk yard to pick up another 300 to rebuild. And right now I don't trust it to go 20 miles.
Thanks!
My thoughts were maybe rod knock? Piston slap? Pins are loose? Oil starvation? Oil filter (it's not a motorcraft), air pump? I just don't know. The engine has 212,000 miles on it and it was neglected by the previous owner. I just had the oil changed with 10w-30. Possibly with the wear on the engine by the neglect that the oil is to thin now and I need to run something with more weight.
Any ideas? I want to get it running well enough so that I can trust it to make the trip to the junk yard to pick up another 300 to rebuild. And right now I don't trust it to go 20 miles.
Thanks!
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Brief dieseling sound when accelerating
Stange symptoms. Your post sounds like lifter noise. Sounds like ice cubes in a deep glass? Check the condition of the push rods. I've been told that worn valve seats can lead to greater pressure pushing down on your rods -> lifters, hence the noise. Mine's been making a bit of noise also, but only at startup. I hope to rebuild my head within the next few months. The miss is strange as well. I'd begin by checking the plugs and wires. Look at the cap and rotor. Then, check out the egr. Maybe a vacuum leak somewhere. They're just ideas, it takes a while to work out the bugs!
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From: Pater, Maine
Brief dieseling sound when accelerating
The ice cubes in a deep glass is pretty close. It definitely doesn't sound like the 'ol "marbles in a can" description.
Is there an easy way to check the lifters? This is my first 300 or inline 6 for that matter. I noticed a small cover on the side of the block where the distributor and fuel pump is. Would this cover the lifter area?
I've replaced the fuel pump, plug wires, plugs, dist cap and rotor, air filter, pcv valve, coil, oil pressure sending unit, all fluids changed, catalytic converter and muffler. I have to install the O2 sensor tomorrow. Guess I will give it to Ford and see what they say.
When I am done with this truck sucking money from my wallet it is going to run like a scared rabbit and look darn good doing it.
Shawn
Is there an easy way to check the lifters? This is my first 300 or inline 6 for that matter. I noticed a small cover on the side of the block where the distributor and fuel pump is. Would this cover the lifter area?
I've replaced the fuel pump, plug wires, plugs, dist cap and rotor, air filter, pcv valve, coil, oil pressure sending unit, all fluids changed, catalytic converter and muffler. I have to install the O2 sensor tomorrow. Guess I will give it to Ford and see what they say.
When I am done with this truck sucking money from my wallet it is going to run like a scared rabbit and look darn good doing it.
Shawn
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Brief dieseling sound when accelerating
This could be nothing more than timing advanced too far. With your h-balancer having moved, this will be tough to correct. Try retarding timing first, 2 - 4 deg, then test.
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Brief dieseling sound when accelerating
spshultz:
At 212,000 miles the engine has some looseness. The ice cube sound at start up could be caused by the type of oil filter you are using. The top end of the engine is dry and certain oil filters allow the oil in them to drain back into the pan when you shut down. Thus, when you start the engine the oil pump has to fill the filter first before it reaches the top end of the engine causing the rattling noise. Use a motorcraft FL-1A oil filter with 10W40 or 20W50 weight oil.
On acceleration, the ice cube sound may be the lack of enough octane on your higher mileage engine. Carbon does, and will build up after all those miles causing a higher compression ratio. Remember how the muscle cars of the 70's with high compression engines only ran good with high octane gas?
Try using 92 or 93 octane. It melted my ice cubes! My 81 sounded like a baby rattle with the 87 and 89 octane.
The large miss could be attributed to an ignition tuneup or a fuel related cleanup.
1981 F-150 2WD STYLESIDE P/U
4.9L 1 BBL CARB
C6 AUTO
2.73:1 LIMITED SLIP REAR AXLE
STABILIZER BARS FRONT & REAR
6100 LB GVWR PACKAGE
ORIGINAL OWNER
199,935 PLUS MILES
100% STOCK & UNREBUILT
BUILT FORD TOUGH!!!
At 212,000 miles the engine has some looseness. The ice cube sound at start up could be caused by the type of oil filter you are using. The top end of the engine is dry and certain oil filters allow the oil in them to drain back into the pan when you shut down. Thus, when you start the engine the oil pump has to fill the filter first before it reaches the top end of the engine causing the rattling noise. Use a motorcraft FL-1A oil filter with 10W40 or 20W50 weight oil.
On acceleration, the ice cube sound may be the lack of enough octane on your higher mileage engine. Carbon does, and will build up after all those miles causing a higher compression ratio. Remember how the muscle cars of the 70's with high compression engines only ran good with high octane gas?
Try using 92 or 93 octane. It melted my ice cubes! My 81 sounded like a baby rattle with the 87 and 89 octane.
The large miss could be attributed to an ignition tuneup or a fuel related cleanup.
1981 F-150 2WD STYLESIDE P/U
4.9L 1 BBL CARB
C6 AUTO
2.73:1 LIMITED SLIP REAR AXLE
STABILIZER BARS FRONT & REAR
6100 LB GVWR PACKAGE
ORIGINAL OWNER
199,935 PLUS MILES
100% STOCK & UNREBUILT
BUILT FORD TOUGH!!!
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From: Pater, Maine
Brief dieseling sound when accelerating
Hood
You know I think I'll try that. Very easy to do so I know I can do it.
Going to go purchase a code scanner tonight also. Did try retarding the timing just a bit but the sound was still there. Performance seemed to drop just a bit.
Going to the junk yard tomorrow. Going to put a lot of faith in this old truck. She'll do OK cause she knows where going to go get her an engine to rebuild. Wife is going to follow in her car just in case.
You know I think I'll try that. Very easy to do so I know I can do it.
Going to go purchase a code scanner tonight also. Did try retarding the timing just a bit but the sound was still there. Performance seemed to drop just a bit.Going to the junk yard tomorrow. Going to put a lot of faith in this old truck. She'll do OK cause she knows where going to go get her an engine to rebuild. Wife is going to follow in her car just in case.
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Brief dieseling sound when accelerating
If you have lifters that are sticking or going flat, you may not need to rebuild you head, Just the lifters. Remove the lifters from the engine, with a bench vise very gently blead the oil out of them (Padded, plastic or brass jaws) then put them in a shallow bowl (you have to cover the inlet hole) full of marvel mistery oiland use a push rod and pump them back up. Do this a couple of times and they should be clean enough for a leakdown test. If they don't pass, take them apart and clean every piece with marvel mistery oil and a Q tip. put the lifter back together, pump it up and reinstall it. A lot slower, but much easier way is to run a quart of marvel mistery oil with every oil change until the lifters are quiet. then run a quart with an oil change about every 20,000 miles or so. I have a bronco with 350,000 miles on it, never been touched, I'm just in the process of replacing a 300 in a 66 F100 with 290,000 on it. (first rebuild) It works. Herman
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Brief dieseling sound when accelerating
spshultz,
Just a bit curious, but why are you going to get another engine for the ol'gal. she has a running one in her. or why not just rebuild the one she has in her now??
Just a bit curious, but why are you going to get another engine for the ol'gal. she has a running one in her. or why not just rebuild the one she has in her now??
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From: Pater, Maine
Brief dieseling sound when accelerating
ooooo! Old post! Yeah, I was going to do that and almost had a complete and well running 302 for $450.00 but life hit and I had to let the deal fall through. I miss the deep rumble of the V-8 (I have the FlowMaster 40 series Delta Flow 2.5" muffler on it now) plus performance parts are so much more available and in mass quantities than there is for the 4.9L. I actually have a Excel spread sheet file with everything I will need (with prices) for a complete tear down and rebuild of the 4.9.
The truck has been running terrible for the last 2 months (since I got it back from the Ford dealer). But I rebuilt my carb yesterday and for the first time I felt good about working on this thing. It went from an extremely bad and lopey idle to a slight miss idle after I rebuilt the carb. So my faith in this thing has been renewed somewhat.
I haven't given up on it just yet. It's just a matter of what information I can get on how to rebuild it before I decide what I will really do.
Shawn
Yeah, I was going to do that and almost had a complete and well running 302 for $450.00 but life hit and I had to let the deal fall through. I miss the deep rumble of the V-8 (I have the FlowMaster 40 series Delta Flow 2.5" muffler on it now) plus performance parts are so much more available and in mass quantities than there is for the 4.9L. I actually have a Excel spread sheet file with everything I will need (with prices) for a complete tear down and rebuild of the 4.9. The truck has been running terrible for the last 2 months (since I got it back from the Ford dealer). But I rebuilt my carb yesterday and for the first time I felt good about working on this thing. It went from an extremely bad and lopey idle to a slight miss idle after I rebuilt the carb. So my faith in this thing has been renewed somewhat.
I haven't given up on it just yet. It's just a matter of what information I can get on how to rebuild it before I decide what I will really do.
Shawn
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Brief dieseling sound when accelerating
I have that exact same deisling sound coming from my engine and it happened after I changed the oil and filter. It actually sounds like fluid running around behind the firewall. I'm guessing my deal is the oil filter. Its a Fram. I was going cuckoo over that one
Ron
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1987 - 1996 F150 & Larger F-Series Trucks
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