4.0 engine timing

[F150hybred]

After reading through NUMEROUS threads on engine pinging and detonation, I do have a question... Is it possible to "adjust the timing" by moving the cam shaft position sensor? Kinda at my witts end here trying to figure out the root of my engine pinging. Any help would be greatly appreciated.

94 Exploder 4.0, A4LD 200km

 

[Bob Ayers]

No, the reference signal for the timing comes from the crankshaft position sensor, not the camshaft position sensor. If you have a pinging problem,
find the route cause of the problem (vacuum leak, wrong plugs, dirty MAF sensor (a definate possibility if you have been using a K&N air filter), or carbon deposits in the combustion chambers).

 

[F150hybred]

The saying "done that... been there" is fitting to what you told me. Did the plugs with Motorcrafts... did the air filter... no vacuum leaks... new MAF... upper and lower intake gaskets... sealed the cooling system... changed grades of fuel... replaced the fuel filter and regulator... had a code scan done by a competant tech... the list goes on and on.
The tech even hooked it up and had me drive him around! (you know it didn't do it then... never does).
I dunno, maybe I'm missing something here. Any other ideas?

 

[Bob Ayers]

The saying "done that... been there" is fitting to what you told me. Did the plugs with Motorcrafts... did the air filter... no vacuum leaks... new MAF... upper and lower intake gaskets... sealed the cooling system... changed grades of fuel... replaced the fuel filter and regulator... had a code scan done by a competant tech... the list goes on and on.
The tech even hooked it up and had me drive him around! (you know it didn't do it then... never does).
I dunno, maybe I'm missing something here. Any other ideas?

De-carbonize the combustion chambers would be the next thing to do.

Here is the TSB:

Article No:
01-19-7

10/01/01

^ ENGINE - 4.0L OHV - CARBON KNOCK ON ACCELERATION

^ NOISE - CARBON KNOCK ON ACCELERATION - VEHICLES EQUIPPED WITH 4.0L OHV ENGINE ONLY

FORD:
1990-1997 AEROSTAR
1990-2000 EXPLORER, RANGER

ISSUE
Some vehicles equipped with the 4.0L OHV engine may exhibit an engine noise which may be perceived by the customer as a piston/connecting rod bearing knock. This carbon knock is heard only under load during the drive cycle. Carbon knock is a customer drive duty-cycle phenomenon that cannot be repaired with an engine exchange. This may be caused by carbon build-up within the combustion chamber.

ACTION
Verify condition. If normal diagnostics fail to correct the condition, de-carbon the combustion chamber to help quiet the carbon knock noise. Refer to the following Service Procedure for details.

SERVICE PROCEDURE

1. Use Motorcraft Carburetor Tune-up Cleaner PM-3.

2. Carbon removal:
a. Disconnect canister purge line from throttle body.
b. Attach a vacuum line to the canister purge port.
c. At hot engine idle, allow the engine to ingest 1/2 to 2/3 of a can of Motorcraft Carburetor Tune-up Cleaner. Use caution not to ingest too quickly due to potential hydro-lock issues.
d Shut engine off and allow it to soak for one hour.
e. Start engine, allow engine to ingest the remainder of the Motorcraft Carburetor Tune-up Gleaner.
f. Remove vacuum line and re-install canister purge line.
g. Road test vehicle at 3500 RPM for 2-3 miles.
h. Repeat above procedure two times for a total of three times.
i. Change oil and filter.


3. Review the customers' driving habits. The recommended drive cycle should include daily periods of engine operation above 3,000 RPM, such as a brisk acceleration from a stop position. This will break/burn the carbon off the piston head.

4. Use regular unleaded fuel, 87 Octane. Mid-grade and Premium fuels may increase the probability of carbon buildup, leading to a knock noise.



PARTS BLOCK

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage

OPERATION DESCRIPTION TIME

011907A Remove Carbon From 1.6 Hrs.
Combustion Chamber
(Includes Time To Perform
Procedure A Total Of
Three Times)

DEALER CODING
CONDITION
BASIC PART NO. CODE
6108 42

OASIS CODES: 497000, 615000, 702000, 702100

 

[F150hybred]

De-carbonize... did that too. And for what it's worth, I'm not easy on it so it's getting the "brisk acceleration" treatment too. As I said, I'm at my witts end.

 

[madman_2]

did you try upgrading to a better fuel instead of regular? sometimes gas is watered down enough that youll here a pinging sound when your going up a hill. you know... putting under a load

 

[F150hybred]

I went from regular.. to mid grade.. to premium. No change. The one thing I can recall is this... if you remove a battery terminal so you can do some welding, once you re-connect it, it works great untill you get about a half a tank through it. Does that make any sence to you???

 

[F150hybred]

Any one else wanna pipe in with an idea? I'm open to any suggestions.

 

[Big Jim M]

pinging?

Any one else wanna pipe in with an idea? I'm open to any suggestions.

As we all know pinging is caused by one or more of three things..
1. Too much timing
2. Lean fuel condition
3. too much compression..

I would go thru these three one at a time looking for what it is that I havn't adjusted yet. Yeah, in these engines sometimes it takes time and persevierence..
In my case my son has a 3.0 and it pings on regular! So he uses mid-grade fuel and that works for him. He doesn't wish to spend the time to find what the problem really is with his ride.. I kindasorta agree with him. As the repair, in his case, is so easy.

Could be as easy as the fuel has just a small amount too little pressure and is causing the ping from the lean condition...
Big JIm

 

[Bob Ayers]

If going to premium fuel doesn't change anything, maybe the noise isn't pre-ignition (pinging), maybe it's "marbling" that your vintage of 4.0L was known for.

 

[Yellowsplash]

Higher octane is only a bandaid....as said you need to find the root of the problem. There isnt a way to adjust timing, but there is an harness under the hood that lowers timing advance by the installation of a jumper wire...I believe it is near the firewall on the drivers side. Cleaning your MAF with CRC's MAF cleaner and seafoam treatments are a start. btw, are you sure its not an exhaust leak at the collector?...many people mistaken this for pinging under load.

I went from regular.. to mid grade.. to premium. No change. The one thing I can recall is this... if you remove a battery terminal so you can do some welding, once you re-connect it, it works great untill you get about a half a tank through it. Does that make any sence to you???

Interesting...almost sounds as if the adjusting of fuel trims is making the problem worse. How old are your o2 sensors? Any check engine lights?

 

[F150hybred]

To update... I did a test of the MAF with an "high end" (Mac tools) VOM and the voltage was steady when operating and within parameters. So that eliminates any thought of there being a vacuum leak. I have done the Sea Foam in the combustion chamber as per the TSB from Ford. I have also unplugged the MAF while the engine is running and drove it like that to verify it's operation... no change, still pings. I know what an exhaust leak sounds like and I don't have one... I even went as far as going to an exhaust shop for a free inspection and they found nothing. The O2 sensors were thought of when I had a scan done by a competent tech and they were showing the correct voltages while running.. so, no sense if changing what's not broke (besides... this is all starting to get expensive).
This is quickly becoming a real head scratcher and the joy in fixing my own truck is getting real stale.

I'm about ready to drop it off at Ford and tell them I don't want it back till it's fixed.

 

[Bird]

If going to premium fuel doesn't change anything, maybe the noise isn't pre-ignition (pinging), maybe it's "marbling" that your vintage of 4.0L was known for.

The only way it's the 'marbling' problem in his 94 is if someone swapped in a 4.0 out of a 98 or 99 - that's the 'vintage' that had the problems with it. Need to study up a bit more there, Bob.


As previously alluded to, there's a standalone 'octane adjust' jumper over by the underhood fuse / relay box - unplug the jumper from the plug and it'll drop your timing by 4 degrees. If it still 'pings' after unplugging the jumper, it's not timing or octane.

Bird

 

[F150hybred]

If your referring to the gray one that located near the firewall on the same harness as the diagnostics plug, then I know where it is. Now, if I unplug that and things sort them selves out... what's next??? Do I just leave it out or do I need to replace it?

 

[Stardust]

Well I seem to be in the same boat except that changing my oil seems to be a temporary ''fix'' (and yes I know it makes no sense).

I have not tried the wire jumper.
What color is this wire??? A pic would be Great!

Thanks.