Knock sensors

[Chikar]

Here's comes a probably dumb question.

I'm having a pre-ignition (knock) problem with a 99 Explorer Sport 4.0L OHV automatic on hills (and even gentle inclines if the weather is hot enough).

I've put a couple of cans of Sea-Foam in the gas tank over the past month or so which seemed to improve the situation a little.

But then I noticed the ping ONLY seemed to be coming from the passenger side! I had read somewhere this engine has two knock sensors, one on each side of the block, and I'm thinking the passenger side sensor might be bad.

But, all the on-line catalogs I've looked at show knock sensors only for the SOHC engine.

So, the dumb question...does the OHV valve actually have knock sensors and, if so, does anyone know where they are?

Thanks all.

 

[waskly]

have you tried a higher grade of gas see if the knock goes away?

 

[Chikar]

I have, and the knock goes away.

But, their is a Ford service bulletin that says the problem is a "driver issue" and advises the vehicle should be accelerated hard daily to get the RPM above 3500. That's supposed to break loose the carbon buildup in the cylinders and blow it out the exhaust. Apparently carbon buildup is a problem with this engine if it's not driven hard frequently. The trouble with that driving style is gas mileage goes out the window.

The bulletin also says NOT to use higher-octane fuel as the engine isn't designed for it and the fuel will make the carbon buildup problem worse.

Getting it above 3500 RPM is almost impossible if you don't floor it and keep it floored otherwise it upshifts before 3500.

Ford puts a V6 in an SUV to improve mileage then tells you to drive the snot out of it to make it run properly, blowing the gas mileage. Go figure.

 

[deweyville65]

There are no knock sensors on the OHV engine. If you want to get over 3500 RPM, why dont you just shift the trans to 2nd gear. I guarantee you can see 4500 or better.

 

[waskly]

I have, and the knock goes away.

But, their is a Ford service bulletin that says the problem is a "driver issue" and advises the vehicle should be accelerated hard daily to get the RPM above 3500. That's supposed to break loose the carbon buildup in the cylinders and blow it out the exhaust. Apparently carbon buildup is a problem with this engine if it's not driven hard frequently. The trouble with that driving style is gas mileage goes out the window.

The bulletin also says NOT to use higher-octane fuel as the engine isn't designed for it and the fuel will make the carbon buildup problem worse.

Getting it above 3500 RPM is almost impossible if you don't floor it and keep it floored otherwise it upshifts before 3500.

Ford puts a V6 in an SUV to improve mileage then tells you to drive the snot out of it to make it run properly, blowing the gas mileage. Go figure.

im a going to go and re read tsb for your year. I have never heard of this tsb.

for a 99 explorer all listed tsb's.

06-26-01 - MERCON ATF IS BEING REPLACED BY MERCON V AS A SERVICE FLUID FOR SOME MANUAL TRANSMISSIONS
06-24-13 - 5R44E / 5R55E SERVICE PART LEVEL CHANGE / COMPATIBILITY
05-06-20 - FRONT AXLE LEAKS FLUID FROM VENT TUBE - VEHICLES EQUIPPED WITH 4X4 OR AWD
05-04-18 - FALSE PARKING AID WARNINGS
04-24-19 - REVISED PROCEDURE FOR ADJUSTING ALIGNMENT ON ALL SUSPENSIONS - NEW RIGHT HAND UPPER CONTROL ARM DESIGN FOR TORSION BAR FRONT SUSPENSIONS
04-24-05 - REAR WINDOW DEFROSTER GRID/INTEGRAL ANTENNA DIAGNOSIS AND REPAIR - TERMINAL TAB REPAIR
04-15-04 - RATTLE NOISE FROM PRIMARY CHAIN DRIVE AREA 2000-3000 RPM - 4.0L SOHC ENGINE
03-24-01 - ELECTRICAL - AIRBAG LAMP ILLUMINATED - DIAGNOSTIC TROUBLE CODES (DTC'S) B1994 AND/OR B1998
03-22-10 - TRANSMISSION - 4R44E - 4R55E - 5R44E - 5R55E - LOW LINE PRESSURE READING AT WIDE OPEN THROTTLE (WOT) - POSSIBLE DIAGNOSTIC TROUBLE CODES P0732, P0733, P1762 - VEHICLES BUILT BEFORE 12/1/2001
03-20-03 - DRIVEABILITY - MALFUNCTION INDICATOR LAMP (MIL) ILLUMINATED WITH DTC'S P0442, P0455, P0456, P0457, P1442 OR CHECK FUEL CAP LAMP ILLUMINATED WITH DTC P0457
03-19-09 - ENGINE - 4.0L SOHC - BUZZ, RATTLE, OR EXHAUST NOISE FROM UNDER THE BODY|NOISE - BUZZ, RATTLE, OR EXHAUST NOISE FROM UNDER THE BODY - VEHICLES EQUIPPED WITH 4.0L SOHC ENGINE ONLY
03-18-01 - ELECTRICAL - REMOTE KEYLESS ENTRY (RKE) - SERVICE TIPS
03-14-08 - TRANSMISSION - NEW TRANSMISSION COOLER FLUSHER - SERVICE TIPS
02-25-08 - ELECTRICAL - NEUTRAL TOW AVAILABILITY|TRANSMISSION - NEUTRAL TOW AVAILABILITY
02-22-01 - DRIVEABILITY - SURGE/ROLLING IDLE - GEAR DRIVEN SYNCHRONIZERS - INCORRECT INSTALLATION - CAMSHAFT POSITION SYNCHRONIZER (CMP) INSTALLATION TOOL CORRECT APPLICATION|ENGINE - GEAR DRIVEN SYNCHRONIZERS - INCORRECT INSTALLATION - CAMSHAFT POSITION SYNCHRONIZER (CMP) INSTALLATION TOOL CORRECT APPLICATION
02-21-13 - ENGINE - STRAIGHTEDGE PROCEDURE FOR CHECKING CYLINDER HEAD AND BLOCK FLATNESS
02-17-06 - LAMP - BRAKE - INADVERTENT DISABLING OF BRAKE SHIFT INTERLOCK
02-17-01 - PAINT - PREMATURE CLEARCOAT CRACKING - SERVICE TIPS
02-16-04 - FUEL SYSTEM - FUEL PUMP "WHINING"/"BUZZING" NOISE COMES THROUGH ENTERTAINMENT OR TWO-WAY RADIO SPEAKER|RADIO - ENTERTAINMENT OR TWO-WAY COMMUNICATION - "WHINING"/"BUZZING" NOISE IN SPEAKERS CAUSED BY FUEL PUMP|NOISE - "WHINING"/"BUZZING" - COMES THROUGH SPEAKERS OF ENTERTAINMENT OR TWO-WAY RADIO

which one is it?

i still never heard of this over 10 years in a dealership.

if you have a ping, i hate to say it, but you need to up a grade of gas.

 

[Chikar]

TSB
01-19-7


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



Publication Date: SEPTEMBER 24, 2001






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 Cleaner.
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.




PART NUMBER

PART NAME



PM-3

Motorcraft Carburetor Tune-up Cleaner




OTHER APPLICABLE ARTICLES:

NONE

WARRANTY STATUS:

Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage



OPERATION

DESCRIPTION

TIME



011907A

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

1.6 Hrs.


DEALER CODING



BASIC PART NO.

CONDITION CODE



6108

42


OASIS CODES:

497000, 615000, 702000, 702100

--------------------------------------------------------------------------------

Copyright © 2001 Ford Motor Company

 

[Chikar]

Thanks deweyville65;

There's a 4 block long and VERY steep hill on the way home so I put it in 2nd and went at it today. Turns out even in 2nd I'm breaking the speed limit at 3500 RPM

 

[my98nnj]

TSB
01-19-7

Seems you've found the answer to your problem.
Although I disagree with Fords statement regarding the use of a higher grade of fuel.

 

[Chikar]

Yeah, I wonder about their octane recommendations too.

 

[waskly]

i doubt this tsb still even exists, i ran 2 ohv vins and didnt find it.

i will say one thing, when the tsb was printed, ethanol was 1-3% now its 10% in gas. i would just go up a grade till the ping stops.

 

[deweyville65]

Try using StarTron fuel additive. Found at WaL Mart in the sporting goods section. I found it in the local KMart for a dollar less than Wal Mart. I use it all the time in my 96 OHV. Buddy of mine uses it in his generators all the time too. Claims better fuel consumption. Good when you live off the grid.

 

[Chikar]

Hi waskly;

Your ethanol content comment is interesting.

You're in the States, I'm in Canada.

To the best of my knowledge ethanol is not normally used in our gas but there is a station just out of town that does have an ethanol blend available. I've tried it when I've been out that way but that hasn't been very often.

I did notice two things, it's octane rating is 89 as opposed to the normal 87 of regular, and the ping stopped with just that small octane boost. Even better is that it's priced the same as regular 87 octane gas.

Buying "mid-grade" at other stations is expensive. the price jumps 12 cents/liter or about 46 cents per U.S. gallon. And it's 89 octane.

Since I never have the ping problem in the colder months I guess I'll just drive out of town for gas when the weather is warmer. AND make sure I go up the hill on the way home in 2nd with the Explorer floored to blow out the carbon

 

[waskly]

Hi waskly;

Your ethanol content comment is interesting.

You're in the States, I'm in Canada.

To the best of my knowledge ethanol is not normally used in our gas but there is a station just out of town that does have an ethanol blend available. I've tried it when I've been out that way but that hasn't been very often.

I did notice two things, it's octane rating is 89 as opposed to the normal 87 of regular, and the ping stopped with just that small octane boost. Even better is that it's priced the same as regular 87 octane gas.

Buying "mid-grade" at other stations is expensive. the price jumps 12 cents/liter or about 46 cents per U.S. gallon. And it's 89 octane.

Since I never have the ping problem in the colder months I guess I'll just drive out of town for gas when the weather is warmer. AND make sure I go up the hill on the way home in 2nd with the Explorer floored to blow out the carbon

just my 2 cents, the price in fuel, to use during the summer, heat days to not ping, vs an engine, head job etc, its just easier to go up a grade.

engine temp, vary while the needle wont move, combustion temps are higher, which is why you are getting pre ignition up a hill, hence why 89 stops it, it needs more heat then 87, yes 2 octane means more then that, its also why different octanes exist.

if it was carbon, i would say grade of fuel means little to it. it would be setting 89 and 87 off at the same.

to me you have pre ignition from heat, very hot out recently, as you said it, the vehicle does not do it during cooler weather. the 2-3 months, for fuel will never equal a repair job. and you don't need to change anything.

 

[Chikar]

Have to agree with you there waskly, a liitle more for gas a few months of the year is way cheaper than a rebuild.

I bought the truck new and noticed ping was a very occassional problem starting around 100,000 kms (60,000 miles). It's slowly becoming more sensitive to heat and hillls (more likely to ping). Not surprising I guess as it now has 285,000 kms on it or 177,000 miles.