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Nick
Dodge Dakota
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6/15/2002
10:33:31
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 Subject: Backfiring
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Anyone know what would cause a a 5.2L to back fire through the throttle body? I have a cam, roller rockers, MPI intake, and computer. Could it be a bad plug, or timing? Can you adjust the timing? THanks.
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blued
Dodge Dakota
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6/15/2002
10:44:50
|  RE: Backfiring
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I had that happen years ago after me and a buddy put a new set of rockers in one. Turns out that we had over tightened one of the rockers on the intake side and as a result it floated, got hot, and burned up on us, after that it started to backfire periodically and I noticed a decrease in power. (duh) No you cant adjust timing at least on the newer 5.2's. What year model is yours? I dont think a bad plug would cause a backfire unless so much gas was pouring down the exhaust that it fired inside the exhaust manifold or tailpipe. Had a guy bring in a ford that had that happen last week. If thats the case it probably wouldnt be coming out of the throttle body it would more likely blow your catalytic converter or muffler apart. Good Luck hope this helps...
How long ago did you put on your Rockers?
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Nick
Dodge Dakota
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6/15/2002
12:28:06
| RE: Backfiring
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I put the rockers on about 1000 miles ago, I hope that I didnt burn one up, that would suck. It got worse after I put my new MPI intake manifold on last week. How would I inspect the roller rocker to tell if one was burned up? Thanks.
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Nick
Dodge Dakota
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6/15/2002
15:18:57
| RE: Backfiring
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My truck is 97
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blued
Dodge Dakota
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6/16/2002
01:46:26
| RE: Backfiring
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The first thing I would do man is to check the compression of all cylinders for several revolutions. If you did float one then it should show a lower preasure on that cylinder. If that does not reveal anything or if you are uncertain the only way to know would be to take off hte head. I would recommend however if you are not sure what you are looking at or for that you take it to a mechanic for the compression check. Valves themselves are not expensive but getting them put in can be a costly pain in the arse. Let me know how it goes
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HSKR
Dodge Dakota
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6/17/2002
00:05:51
| RE: Backfiring
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Since you say you've done the cam, I woudl check the timing, and fuel sync signals. Also, make sure the cam was installed properly. Depending on when/how it backfires, it oculd just be an overly rich condition. Mine did this because the fuel sync was not set correctly causing a rich condition.
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handi2
GenIII
6/17/2002
00:55:25
| RE: Backfiring
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I'm not familiar with the 97 but if might want to check for a cracked distributer cap.
http://photos.yahoo.com/handi254310
2002 Quad Cab SLT Plus 4.7 Every Available Option
Access Tonnoue Cover/Bedrug/360 Air Intakez/Jet Stage 2
180 Robertshaw/Roadmaster Active Suspension
Street Scene Grill Inserts
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Nick
Dodge Dakota
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6/17/2002
12:15:35
| RE: Backfiring
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I will definetly try the compression thing, I can get my hands on a tester so I will try that first. I just ordered a new excell cap and rotor so I will try that to. I also have a set of big Valve R/T heads that I will be putting on soon, which will be good if my heads are done in.
thanks
Nick
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Nick
Dodge Dakota
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6/17/2002
13:19:33
| RE: Backfiring
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WOuld a worn and stretched timing chain cause a backfire, the truck only has 26,000 milies on it but some have been really hard. How would I check the full sync?
thanks
Nick
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Jeff
Dodge Dakota
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6/17/2002
17:48:16
|  RE: Backfiring
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I have been having the same problem with my 99 R/T. I am running Crower 1.7 rockers with the stock cam and mopar PCM. I noticed a ruffer idle with the 1.7's and have done about 5 compression tests to make sure the valves were closing. Each time I got 150psi in each cylinder so I figured it was Okay. Then I installed the 2bbl M1 and now I sometimes get a backfire out the throttle body as the engine warms up if the throttle is snapped wide open. I'm lead to believe that is being caused by the Mopar PCM adjusting the fuel curve. Does this sound possible?
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HSKR
Dodge Dakota
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6/18/2002
00:04:25
| RE: Backfiring
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Fuel sync needs to hbe checked with a DRB scanner.
Jeff, this is a problem with some R/T's. The fuel sync is off from the factory, but doesn't become apparent until it gets a few mods on the motor. I saw one a couple weeks ago that was at +7V from the factory. You want it as close to zero as possible. The fuel sync being off will make the PCM throw more fuel in and cause a rich condition which will cause backfiring when the trottle is mashed from a roll, or blipped a few times.
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Nick
Dodge Dakota
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6/18/2002
10:06:13
| RE: Backfiring
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Thats exactly what my truck does, when you give it gas from a stop or blip it a few times, BANG. I will have to get the checked out, my cap and rotor came in today, I'll try that first. thanks Nick
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MikeD
R/T
6/18/2002
10:58:06
| RE: Backfiring
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I get the same sound coming near the TB...I think on mine its cuz I can't seem to get my air hat to sit right near the back...the lip of the airhat doesn't sit flush w/ the rim of the TB so when I punch it it lets out a big pop. I had this problem when I first swapped my TB but I finally got it sitting flush but now I can't seem to get it back to the way it was.
So Nick look under the airhat and look to make sure there is no gap between the rubber TB seal and the bottom of the hat. If theres not then its probably the fuel sync like those guys said. Just a suggestion.
~Mike~
'01 R/T
.512/.512 Kammer Cam, MP 2400 Stall, True Duals w/ Flowmaster 40 series, M-1 2bbl, F&B 52mm TB, Airaid, JBA headers, JBA 9mm wires, Kenne Bell Optimizer II, 160 t-stat, 3rd cat removed, Chrome R/T badges
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Nick
Dodge Dakota
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6/18/2002
21:29:09
| RE: Backfiring
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Ya I thought that it could be something like that, so I popped the hood the other day, and blipped the throttle the other day and it backfired so loud it sounded like a gun shooot. Im planning on getting the fuel sync checked soon! Thanks for all the help.
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Jeff
Dodge Dakota
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6/24/2002
02:30:14
| RE: Backfiring
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Mine is doing this with the fuel sync set dead on with the DRB. Any more ideas?
M1 2bbl. Mostly when cold and warming up.
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blued
Dodge Dakota
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6/24/2002
22:20:05
| RE: Backfiring
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Jeff,
You say yours is still doing it??? What exactly have you done to the truck as far as mods go? What year is it and how many miles? Do you still have the original PCM to put back in for comparison sake... Might try that to make sure that something isnt wrong with the "brains"
Good Luck
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Jeff P
Dodge Dakota
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6/26/2002
20:07:00
| RE: Backfiring
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There must be 2 Jeff's with this problem. I responded early with the 99 R/T. Today I spoke with my mechanic at the Dodge dealer and he said that the only sync that is adjustable is the distributor sync. He says by turning the distributor this will result in changing the fuel sync value on the DRB. The fuel sync is in the PCM program and cannot be altered according to him. Does this sound right? I'm having the fuel sync checked in a couple days.
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Nick
Dodge Dakota
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6/26/2002
20:18:25
| RE: Backfiring
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I spoke with my local dodge dealership today about the fuel sync, He said that it is adjustable if you have your truck on the DRB, you can turn the distributor and change the sync, optimal setting is 0.
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Jeff S
Dodge Dakota
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6/28/2002
05:26:32
| RE: Backfiring
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Mine still does it. I need to get this resolved before my supercharger install.
Mine is a 95 5.2 and like stated above, it got worse with the M1 install. Hardly did this with the factory intake. Hmmmmmmmm
Thanks for the info.
The other Jeff with this problem.
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Matt
Dodge Dakota
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4/14/2004
09:00:38
|  RE: Backfiring
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My truck is a 92 5.2l and it is backfiring when i just step on the gas but if i floor it it doesn't backfire i changed the cap rotor distributor plugs and wires and the problem is still there. I was wondering if it could be the distributor because i had it changed now it backfires worse. The mechanic said it could be the rockers and if it is would anyone know how much it costs to get that fixed. I would appreciate this help alot.
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