| From | Message |
Rob
Dodge Dakota
8/01/2001
08:13:30
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 Subject: Knocking?
IP: Logged
Message:
Has any one experienced any knocking with the magnum 3.9?
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E
Dodge Dakota
8/01/2001
11:38:45
|  RE: Knocking?
IP: Logged
Message:
Do a search for 'pinging' or 'detonation' on these boards... theres quite a few threads.
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Marc
Dodge Dakota
8/01/2001
21:46:02
| RE: Knocking?
IP: Logged
Message:
put in a 180 degree t-stat and it will quit. and you dont have to use a robert shaw like all over this site. i just used a heavy duty one, and when you go to get one they will try to give you a 195 degree for your truck. just ask for a 180 t-stat for a small block chevy since they are the same. the stant part number is 30108 i think or 34108.
but either way the small block stat will fit. and make sure not to drop the bolts when you are putting it back together, mine went under the ac compresser what a (female dog) to get out took longer to get it out than to change the whole thing. i also put 3923 autolight equivilant champion truck plugs in at the same time, but i am sure that the t-stat will cure the prob.
'99 rc 3.9lv6 2wd
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Zaurusman
Dodge Dakota
8/01/2001
22:57:39
| RE: Knocking?
IP: Logged
Message:
Marc, the t-stat is not always enough. Might have been enough for you, but mine pinged after my replacement same as it did before. The temp guage confirmed that the stat worked, btw. I just filled up with regular with my new Autolites and haven't had any pinging, but it'll take until the next tank has partially cycled to be sure they did the trick. My fingers are crossed!
Rob, follow this order and you can't go wrong, stopping wherever the pinging stops:
1. 180 degree thermostat. Jet one is great IME.
2. Autolite plugs (www.speedtweaks.net)
3. MSD timing adjuster (last resort ~ $100)
The problem is that the timing in the computer (the PCM in this case) is too advanced, and you have premature detonation. Your local dealership can "flash" it to change the timing software, but that saps power & mileage from what I've heard.
If you cannot do any of the above just yet, try switching temporarily to premium fuel; stopped my pinging. But the first two are cheap as heck; expect to pay $10-15 for either.
BTW - in case you're eyeing your distributor for a solution, the PCM controls the timing no matter what you do to the mechanics.
--
Zaurusman
'98 RC V6 5spd
http://www.tiborsrealm.com/Dakota/ModsList.htm
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MikeN
Dodge Dakota
8/02/2001
09:35:20
|  RE: Knocking?
IP: Logged
Message:
I wound up having to change the intake manifold plenum pan gasket (or belly pan gasket). Mine was so bad that I could see a coating of oil inside my intake manifold. It creates a vacuum leak which leans the mix way out, promoting knock. It took about $65 for intake manifold gaskets and $20 for the plenum gasket from teh dealer and about 5 or 6 hours to do the whole job. Combined with a 180 Tstat the result is that my truck rarely knocks except going through the mountains with a heavy load :-)
Mike N
1998 4x4 CC SLT 5.2l
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Tim
Dodge Dakota
8/06/2001
00:01:36
| RE: Knocking?
IP: Logged
Message:
Yes, check the manifold gasket first, then get the computer flashed, then put cooler plugs in(3923's). I had my 99 3.9 dakota's gasket replaced which reduced the knock considerably, then they flashed the computer when the update finally became available. Do the flash, it didn't affect my milage at all and caused a barely perceptable power loss (not much power to lose in a 3.9 so you don't notice it really...lol.....). After the flash, it will still ping for a split second when giving it alot of gas suddenly but then go away. Put the cooler plugs in and it will never ping again. I've towed heavy loads in mountains with the A\C on in 95 degree heat and it never pings a bit. After doing all that stuff, then mess around with the thermostat for more power and stuff but don't half-ass it and rely on just the t-stat to get rid of the ping cause it won't work.....at least it didn't with mine. (nor did high octane gas).
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Tim
Dodge Dakota
8/06/2001
00:02:14
| RE: Knocking?
IP: Logged
Message:
Yes, check the manifold gasket first, then get the computer flashed, then put cooler plugs in(3923's). I had my 99 3.9 dakota's gasket replaced which reduced the knock considerably, then they flashed the computer when the update finally became available. Do the flash, it didn't affect my milage at all and caused a barely perceptable power loss (not much power to lose in a 3.9 so you don't notice it really...lol.....). After the flash, it will still ping for a split second when giving it alot of gas suddenly but then go away. Put the cooler plugs in and it will never ping again. I've towed heavy loads in mountains with the A\C on in 95 degree heat and it never pings a bit. After doing all that stuff, then mess around with the thermostat for more power and stuff but don't half-ass it and rely on just the t-stat to get rid of the ping cause it won't work.....at least it didn't with mine. (nor did high octane gas).
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Tim
Dodge Dakota
8/06/2001
00:02:49
| RE: Knocking?
IP: Logged
Message:
Yes, check the manifold gasket first, then get the computer flashed, then put cooler plugs in(3923's). I had my 99 3.9 dakota's gasket replaced which reduced the knock considerably, then they flashed the computer when the update finally became available. Do the flash, it didn't affect my milage at all and caused a barely perceptable power loss (not much power to lose in a 3.9 so you don't notice it really...lol.....). After the flash, it will still ping for a split second when giving it alot of gas suddenly but then go away. Put the cooler plugs in and it will never ping again. I've towed heavy loads in mountains with the A\C on in 95 degree heat and it never pings a bit. After doing all that stuff, then mess around with the thermostat for more power and stuff but don't half-ass it and rely on just the t-stat to get rid of the ping cause it won't work.....at least it didn't with mine. (nor did high octane gas).
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