Howdy,

I have a 1995 F150 302CI engine with 143,000 miles. Engine runs great but lately I noticed a small knock in the engine. Oil is at full level. I have switched to high octane fuel and even added octane booster but the small knock is still there.

The engine was recently serviced at a Ford dealership where throttle body parts were cleaned among other things. When I crank up in the morning there is no knocking, it appears that the knocking begins after the engine comes up to temperature.

Oil pressure guage always reads pressure. The needle is a little to the right of center above the half-way mark.

Have any suggestions?

Thanks and best regards,

Matthew

 

Check ignition timing. Pull the codes. How old are your spark plug wires? Fuel filter replaced recently? Just what pops up off the top of my head... Oh, and check fuel pressure. Keep us posted.

 

I get the same thing, especially when speeding up and it's trying to torque upto speed rather that the tranny downshifiting.......I am doing plugs/wires this week and thinking about timing but I don't know what I am doing with that....Fuel Filter is on the list as well, LoL......

 

your problem sounds somewhat like an oil pump. when an oil pump is on its way out, the motor wont knock until its warmed up.

 

Sounds like when your engine warms up, the oil pressure is lower which is normal, but it may be too low. When the engine is cold the pressure will be high and therefore high enough to supply engine OK.
I would first install a good pressure gauge right into the engine block and monitor it while driving.
If the pressure drops considerably, or is too low to begin with then the engine must be overhauled, or the oil pump replaced.

 

if the oil pressure drops a bit or you r hearing knocking when it is warm and the oil is thin it probaly needs a overhaul, bottom bearings or piston clearances are too much, and or the valve train starts tapping, 302 are good motors but are hit and miss, you either have a good one or you dont, mine had 120000 on it when it needed overhaul, my father in laws has 143000 and runs as good as a few months after it was bought

 

First of all, thank you for the speedy and insightful responses.

Here's the scoop. I changed spark plugs, wires, air and oil filters, oil, thermostat, and anti-freeze. Oh yeah, changed the power steering gear box as well, and yes, I am tired.

I did not check timing because I do not have the tools and I haven't pulled codes yet, the truck was on the rack most of the day.

Tomorrow, I will pull codes, get an alignment, and check timing.

Right now, I have a little more pep out of the engine which was peppy enough to begin with but I still have that little knock.

Oil pressure does not drop after initial crank, guage stays steady. I will have to figure out how to attach an oil gauge directly to the block, not sure that I have ever done that. What should the oil pressure be?

Will look into fuel pressure as well tomorrow?

Is a bottom end overhaul a complicated process? Are there any docs on the process posted here?

Thanks and best regards,

Matthew

 

if you pull out the sending unit on the left side of the block u can attach the tube from the gauge there, may be a easier spot but that is the only one i can think of
bottom end only involves pulling the motor and dropping a crank kit in it or having the crank ground and fresh bearings installed, but it is recommended if it is out alreay to pull the top end, have the heads freshened up and pistons checked and/ put on new rings if you dont have to bore the block and or install new ones, also have the rods checked for out of round and new rod bolts installed, new timing chain, new oil pump, and if it interests you a quality cam that may give better performance than that stock one. also new cam bearings, this is some bucks but worth it if it is already out, but might be able to get by with just putting a crank kit in, but if the pistons are worn, you did all that work for nuthin, there are some vehichles where the bearings can be replaced in the vehicle but i dont think this is one of them. if it is i would like to know, b/c it will save me a days labor just replacing the bearings on my fresh rebuild that spun one. any guys out there know any other tricks to keeping the bearings from spinning, my clearances are dead on when i had everything ground and reworked, i should glue them things with a drop of j/b weld or lock tight...lol if it wont be too thick?....ummm, ive heard of brass dowel pins drilled and tapped in the hole in the bottom cap through the bearing but i want to know more about it from any racecar engine builders out there
though sometimes it is just as easy and just as expensive to get a reman from a reputable dealer that way u get a warranty usually 3 years or 70,000 mi and that is sometimes well worth it if you are accident prone or have a string of bad luck like me

 

What is a good company/site to buy reman's or even brand new.....If I have a 5.0L and want to buy a 5.8L, how hard of an upgrade is that???

 

Dottyematt, it sure sounds like a timing problem which is a simple fix make sure that it is between 10-12 degrees of initial advance no more, no less. Do the simple free stuff first. Find a friend with a timing gun and basic knowledge and be sure to unplug the spout connector, which on your model is next to the firewall on the drivers side. Small .5"x1"greyish white plastic block @ end of black wire loom. Your timing marks are on your crank pulley behind where the belt rides and your arrow just above the crank pulley on the left. Sure hope this helps you! I would time it for you for free but I dont know where you live.

 

You know that that oil pressure gauge is just an idiot light with a needle, right? It either shows just over half or nothing because it's wired off of a pressure switch. That switch triggers OK at just 6 or 8 PSI, IIRC.

There's a fix in the tech section on here or on dieselstop.com that discusses pulling the instrument panel, jumpering across a resistor on it, and replacing the oil pressure switch with an actual variable oil pressure sensor to at least make the stock gauge show changes.

The best solution is to get a real gauge/sender in addition to or instead of the stock gauge.

I have a "T" (1/4" pipe thread) into the block and have both the variable stock sender (asked the guy at the parts store for a sensor for an '83 with a 351) and an aftermarket sender.

 

Once again, thank you for the feedback. And, thank you adamk1974 for the offer.

Here is what has changed. I had the front-end aligned yesterday but the tech suggested that I change the caster bushings at 70 bucks a piece installed. Eek! He added that they were not that bad but to bring the tires into full alignment they would need to be changed. Is there any process docs here that explain the procedure? Is this a difficult/dangerous thing to do?

This morning, I had the timing checked and it is sitting right at ten degrees. The mechanic indicated that the knocking sounded like pre-detonation and that running some simple fuel injector cleaner through the system would probably clear it up. He added that the knocking was very slight and probably would not hurt anything if left as is. Also, he suggested that the knock sensor could be failing. But, I found that the knock sensor is located at the rear of the engine below the intake. There is not much room back there. Any suggestions on how to get at it without removing any parts from the top-end?

And now, here is the real bummer. After the fluid and spark plug change, the engine ran great. It even squeeled the tires upon heavy acceleration. But I checked the oil and found that I had accidently put one too many quarts of oil into the crank case. I only drove it 70 miles before I figured that out and made the adjustment. Now, the engine idles and runs rough and no longer squeels the tires. Did I foul the plugs? Is there something else I can clean/replace that will get the pep back and clear up the roughness?

Gatesj, thanks for the info. I did not know that about the oil pressure guage. I will research the fix and check the actual pressure.

I still have fuel filter to replace and fuel pressure to check.

Thanks in advance. ...Matthew

 

I sure am sorry to hear about your bum luck and hope that it isn't getting you down. But on the bright side "every dark tunnel has a light of hope." I think that you are on the right track by replacing your fuel filter keep us posted.

 

I am having the same problem only on a 351 from 95. Its fine when its cold but after it warms up it knocks. I thought it is a spark knock but I have had it checked out a couple of times and no one can find anything wrong. Have replaced egr system plugs wires cap rotor fuel filter. I have also checked the timing its dead on 10 degrees have tried to retard with no luck. The only thing that gets rid of the knock in my engine is to leave the spout out. So ia m wondering if the oil pump could cause this problem. Oh ya it has ben going on for about a year.

Thanks Kevin

 

Folks,

Thanks again for the responses. I have collected additional information. Here is a summary.

Indication: [list=1][*]Slight knock when engines comes to temperature[*]Intermittent rough idle, rough running[/list=1]

Diagnostic Suggestions and Results:[list=1][*]Timing: 10 degrees[*]Codes: 565[*]Spark Plug Wires: Changed[*]Fuel Filter: Today[*]Fuel Pressure: Monday[*]Oil Pressure Gauge: Today[/list=1]

About the rough idle etc., I removed the idle motor and cleaned it thoroughly and the engine ran great for about five minutes.

Upon suggestion from the guy at Autozone, I disconnected the battery for about 40 minutes. After reconnection, everything seems in order. Engine runs great. It appears that the excess oil did no damage.

I did put some 536 highway miles on the vehicle and it ran great but I noticed that it consumed about one quart of oil during that time. Is this a bad thing?

What should the fuel pressure be?

Thanks again, Matthew