Knock Not MAF Related?

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J

J Browning

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I posted a week ago about the engine knock issues I have and how the Ford techs said it was more than likely the MAF sensor when I took it in for a diagnostic.



I bought a brand new MAF sensor and it seemed fine until yesterday afternoon when I heard the clinking noise again, 4th gear about 2200 rpm with engine under load about 90 degrees outside.



The nosie is only noticeable when its hot as hell out? 90+



89 octane gas helps



tech said it was not timing chain (01 4x4)



tranny was recently flushed and serviced. (just ruling out options)



Do we have a intake temp sensor that will effect the ECU and casue knock, or is it highly unlikely that the temp sensor would casue detonation?



Im pissed off and freaking out because my brother had the exact same nosie with his jeep a year ago and a month later it blew a hole though the wall and shattered a piston.



I cant figure out what is wrong!
 
If you are using an after market air filter like K&N, etc., you need to clean the MAFS with CRC electrical cleaner that can be purchased from most auto parts stores. I'd also clean the Idle Air Control Motor (see projects- maintenance); check your fuel filter and possibly timing chain depending on how many miles on your ST. I'm sure others will more input.
 
Fuel filter is new, tried cleaning the old MAF with CRC like 10 times but it never helped.



IAC, TB have been cleaned several times as well. The new MAF was only in for a day before I noticed the clinking noise again.



Spark plugs are new. Battery is new. Fuel pump is new. I have replace a barage of parts based on the dealers suggestions.





And as for the timing chain, its internal. There is nothing I can do about that.



Im at 4500 ft elevation. It gets really bad when I take the drive from here to PHX AZ which is about 1500 elevation. Once I get near PHX the noise is constant which still leads me to believe air temp and elevation are part of the problem.



I never hear the noise in first or second gear though :unsure:
 
The timeing chain can stretch, and I said possibly needs to be replaced due to high milage; over 100k. Have you put in a good fuel additive like Techron or Royal Purple? It couldn't hurt. There's a member of this site, Hal, that's a Ford tech in the Tuscon area; you might see if you can connect with him.
 
If 89 helps It sounds like a lean fuel issue, or octane issue . There are 2 temp sensors. One is a sender for the Gage and 1 sensor is for the computer. I would look toward those...



the correct thing here is to hook the truck to a snap on scanner and drive the truck and make it do the rattle, It could bad 02 sensors as well...

heck It could even be carbon build up in the engine...



Todd Z
 
yep tried that too. Several Times. as well as differnt oil viscocities (10w-30 and 10w 40)



Lets look at the timing chain issue for a min. Dealer claims the timing chain problem is only heard at start up and since my noise occurs while driving after the engine is already warmed up then it cant be my timing chain.



Is this true, does the noise everyone is hearing only occur in the first 5-10 mins of driving around the 2-2.5k range. I never hear mine then. It only rattles after the engine is warmed up completley.



second, is all 01's get the recall or only job 1's? He said my 01 was not covered.



thanks, jason
 
Todd, the comp temp sensor? Where is that located?



I have been using engine cleaning products for the last 6 months now. About 5 bottles worth but maybe the store stuff is not strong enough? the engine only has 65k on it. I wouldnt think it would be that gunked up.



As for the scanner thats what I believe the tech did that did the diagnostic. he commented "that he hooked it up to his tester and after starting the key and driving it around the numbers got worse and worse." i was assumed he was talking about engine knock readings.



No CEl lights. im not sure what the fuel pressure is, and I assume thats what you mean by lean condition. as in its probably not getting enough fuel pressure? thats why i replaced the pump because he said to try that as well.



do the fuel pressure regulators go bad?



would you say keep the new MAF since i already bought it becasue its bound to go bad soon or keep my old on put that 135 to something else?



i have $600 plus in parts and still no solution
 
My truck does the exact same thing. Higher octane fuel makes the noise go away. A couple of people that I work with have other Fords with the same engine, one is a Ranger and the other is an Explorer, and have the same issue. I've also known others who have older Rangers and they just accept it as being "a Ford thing".



I've asked Ford about it several times and they always tell me to use the higher octane fuel. I quit asking becasue I got tired of them making stuff up when I asked why the truck doesn't run right on the fuel that Ford specifies. Frankly, I've given up and just use 93 in the summer time when I go out of town.



I would like a resolution to it though.
 
The temp sensor for the ECU input dont cost much. I would try changing it out. Our 4.0L motors have close to 10 to 1 compresion, (9.7 to 1 exact)..It appears that the ECU is not pulling the timing back at higher temps. Since Higher octane fuel seems to help, this is just a educated guess on my part. I know that the temp sensors can be bad but not out of enough parameter to throw a CEL...
 
I agree, i hate having to pay for 89 plus when it should run on 87.



Further if this thing blows up becasue of detonation i've really got problems then.



And this is just one more thing to add to the list of problems I have had and the truck barely has 65k on it.



I have easily spent 4 grand in replaement parts alone by now. just sitting around waiting for the damn tranny to blow like others.



i bought a truck to haul things and im afraid to put any load on it because of this problem.

 
I looked and the only one I find, is under the throttle body, behind the thermostat housing..I cant see the back side at the firewall..maybe the the same one is dual purpose..normaly not...maybe someone is mre familar with the 4.0L than me will chime in..
 
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What sensor is this? I was looking around for the temp sensor and I noticed this had vac line connections to the intake mani. (Which mean it could be gunked up) Possibly my problems.



Anyways so I take a little drive....(88 degrees at 12 noon) and no nosie. Wait an hour, pull off this sensor, spray some CRC in the two little holes and the elec connections, reinstall and take another drive (1pm 94 degrees) and presto there is my knocking noise under load.



Now im not sure if monkeying with that sensor is the cause becasue im leaning more towards temp as the culprit. I never hear the knock until after it gets 90+ degrees.



Hey eddie, as for those two sensors under the TB i saw those as well, but I assume they are coolant temp sensors since they go into the block. I figure if there is a intake temp sensor like on my Mitsu Eclipse then it should be tied into the mani somewhere. I just cant find out where either.
 
My past knowledge with dealing with the Ford OBDI ECU, they use the coolant sensor for various things. Among them timing control. I maybe wrong but I think,on our tracs, the inlet air temp is part of the Mass air sensor...Our tracs are OBDII ECU's....They dont have the seperate air temp sensor as the pre '96 Fords OBDI ECU did...
 
Timing control.....



My temp guage guage does read below the half way mark all the time. It is using the stock thermostat. So maybe the sensor is saying the engine is cooler than it really is and not retarding the timing for when the air temp gets hotter?



Or was that function only with the older fords?



I think im going to return the MAF sensor if i can. No point in wasting 140 dollars if its not going to solve the problem.



So this sea foam stuff? is it suppost to clean valves better than your over the counter FI/carb cleansers?
 
On the right of your throttle body, the red circled screws, that is your throttle position sensor (TPS). Sends a signal to the ECU of position, so the the injectors and also timing can be adjusted acordingly. It can be tested with an ohm meter. It is just a varible resistor with a 5vdc load. What you do is to unplug it and hook your ohm meter to it. Look for a smooth change in resistance as you slowly rotate the throttle..
 
I'll check it but im sure its fine. Ford said they checked the TPS. So I left it alone. I just dont think it would qualify since my my problem seems to be ocasional (usually high outside temps) and not all the time. If it was TPS related wouldnt it be every single time, in every gear.



maybe it does happen in 1st and second but i have never been able to hear it.
 

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