When I upshift into 2<SUP>nd</SUP>, 3<SUP>rd</SUP>, 4<SUP>th</SUP> gear (M5OD), I get a pinging-type noise between ~1500-2000RPM. It’s paired with quickly-pulsating hesitation (quite different from the one you get just before you stall the engine, when you stop while still in gear). As I accelerate the hesitation becomes quicker until in the low to mid 2000RPMs when it begins to run smooth again.<O</O

<O</O

Is it valves, fuel injectors, spark plugs, wires, etc.????<O</O

Can't seem to nail it down.

Thanks

 

What type of gas are you using? If you are using regular try mid grade.

 

If you have two tanks ... does it do it more from one than the other?

 

Pinging under load? I would think along the lines of not enough octane in the gas for the motor (not likely if its stock unless you are using the dirt cheap watered down stuff, I have heard that stuff ping in a stock motor), timing too far advanced, hot spots in the combustion chamber.....

 

Make sure you've got good plug wires on there. Also, make sure they are routed at least one inch apart from one another. Crossfire induction is very common on the 5.0. The 302 also has a knock sensor which may be bad. It can't hurt to run some SeaFoam through it or some other injector cleaner. If it's not the wires or sensor, it's probably carbon build up in the combustion chambers.

 

Remember from Mil days stationed abroad. Mechanic did an engine test, including measuring the resistance in the spark plug wires. Turned out they were bad.
Anything like that here? If so, what values should I see; good or bad?

Running Ford Motorsport wires; blue and individually numbered.
Spark Plugs: Motorcraft ASF42C
Gap: will have to check it


Alz,
the wire are routed correctly according to the Ford TSB on crossfiring. Had to correct the routing several years ago, when I installed the above mentioned wires.
Will check on the Knock sensor.

Eco & kcb37
I am running regular (87 Octane) gas. When the truck was new (back in 1991), I used 89 Octane for a while, until I had smoke and starting problems. The Dealer said, the engine was designed for 87 Octane, so that's what I've been running. Something about different flash points, don't quite recall the details.

 

It was designed to run on 87 when new. How many miles on that engine now? Try running a few gallons of premium fuel. If it goes away, I'd try running SeaFoam through the intake and in the tank. See if that doesn't help. If it's not crossfire related, it's probably carbon buildup, or the knock sensor.

 

Strange. I've never heard of it doing anything negative to the motor when running a higher octane.

 

Mileage is right about 210K.
Gotta fill up on gas tomorrow anyway.

Alz,
what's SeaFoam? and why run Premium Gas first?


Found a spec sheet @ AZ on plug wires, not more than ~ 5000 Ohms from the distributor cap to the wire's end.
Anybody know of the factory values on wire resistance?

 

The premium fuel will help with pinging(detonation, preignition). It is slower to ignite. Carbon build up causes hot spots in the combustion chamber as well as higher compression if excessive.

This is SeaFoam:http://www.seafoamsales.com/motorTuneUpTechGas.htm
I use it in the intake and also run it in the tank. Do a search on this forum for others who have used it.

 

Higher octane will not hurt the engine. Is the check engine light on? You can pull the computer codes with a paper clip and a haynes manual. The computer may set codes even though the light isn't on.
Check the fuel pressure. I had a EFI 5.0 that had similar ills and it was the fuel pressure regulator. A friend of mine checks his wires at night by spraying the wires with water (engine cold) from a plant watering sprayer! If a wire is leaking it will be VERY noticeable.
Even though several things can cause your problem its likely only one. A cheap digital multimeter, manual, fuel pressure gauge, and a couple of hours should reveal the problem.
Good Luck
rikard
old ride 83 F150 5.0 AOD 220k orig powertrain (rust in peace)
now 94 F150 4.9 5spd 178k

 

i have to run mine on 89 or else it pings and has no power

 

I would suggest you check the EGR valve. The 1988 with 302 I owned did this, and it turned out to be the EGR. Also check the codes as this problem did'nt trip the light. But did set some codes. Once fixed the problem quit. I recall reading that EGR problems are common on 1987 To 1990 302's.

 

The only time you should have a problem with gas is running to low an octane. The higher the octane rating the more resistane to detonation. (basically it takes more heat to make it burn) I asked cause low octane in some engines will make the engine try to run like a deisel. I think i would check the knock sensor too.

 

TX,

You may want to make sure your distributor hold down bolt is tight, because if it has loosened up your distributor can move on it's own and throw the timing off.
Believe it or not this happened to me on my 88' F-150 4.9L EFI and I had almost the same problems you are experiencing. It freaked me right out when I went to check my plug wires and my distributor rotated just by touching it. I was wondering why my truck had been running so wierd for a week or so. I warmed it up to normal operating temp, shut it off, disconnected the SPOUT plug going to the ignition module, set the timing to 12 degrees BTDC and locked down that bolt that had loosened up (dist. hold down bolt), reinstalled the SPOUT plug and then reset my codes. Fired it up and she was smooth as hell.
This may not be the problem in your case, but it sures doesn't hurt to check to make sure it's not loose.

Of course I would do all the other stuff too, new plugs if they haven't been changed in a bit and new plug wires. Cap and rotor. Maybe some Seafoam just for good measure.

Johnny


1988 Ford F-150 4.9L Custom 4 speed dual exh. glasspacks, alloy Ford wheels
1990 Ford Mustang LX 5.0 Hatchback AOD w/Bassani X pipe & Flowmasters
1993 Ford Mustang LX Coupe 5-speed


.............................God Bless Henry Ford..............................................