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turbo-1
Dodge Dakota
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4/17/2004
13:50:02
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 Subject: Help Severe Detonation
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i have a '99 ram 318, a few months ago it started
detonating slightly so i put 89oct. in and it was fine. until two weeks ago when it started to detonate on 93oct. then thanks to this site i found that the plenum gasket blew. so i bought the plenum cover kit from hughes engines. after installing it i still had some 93oct in the tank and it ran great. i am running a 180 t-stat, 3923 plugs K&N filter and a hypertech programmer, programmed for 87oct. however, the next day i filled up with 87oct. and it started detonating again really bad. so i reprogrammed it back to stock and it still detonates. are the mods that i am running a bad combo? i have never messed the distributor, its in the stock location, i couldn't find any info on what the timing should be at idle but it is at 11 degrees advanced is this O.K?. is it adjustable? i also checked for leaks all around the intake and all vacuum lines. and i also checked the fuel pressure which is fine (45psi) and listened to the injectors and they are all uniform. pulled the plugs they are all normal no hot ones or oil soaked. the computer isn't throwing any codes ether. i thought that maybe i blew the plenum gasket again but it doesn't appear that way. is it possible that my computer is messed up? i do have a bad ring on cyl#7 120 psi i put a little oil in and it went up to 165psi. the rest are 160-170 psi i don't think that would cause detonation though. any help would be great i am out of ideas. thanks
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daffydak
GenIII
4/17/2004
15:49:04
|  RE: Help Severe Detonation
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I believe you are supposed to run "mopar combustion chamber conditioner" (or sea foam) to remove all the built up carbon from your cylinders. I don't think the injector cleaner stuff will work, you need a product that you let sit in the combustion chamber for several hours.
Hope I helped...
Dan
mopar=mopower
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GTO/Kota
Dodge Dakota
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4/17/2004
20:30:36
| RE: Help Severe Detonation
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Hey Dan...I saw your truck on SummitTruckStyle.com! I got mine up as well on the site. It's about time some more Dakotas got their pictures up :)
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daffydak
GenIII
4/18/2004
01:23:21
| RE: Help Severe Detonation
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sweet!!! this just goes to show it's a small world LOL
are you the 01 on the site?
that hood ROCKS!! i like the clean look, and those boyd coddingtons! NICE
Wanna trade?? :-P
Dan
mopar=mopower
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gen1dak
Dodge Dakota
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4/18/2004
11:31:50
| RE: Help Severe Detonation
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Reset your computer. The computer has been steadily adjusting to the vacuum leak. Now it's fixed, but the computer doesn't know this. At worst, it'll give you a clean slate to work with.
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GTO/Kota
Dodge Dakota
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4/18/2004
15:45:18
| RE: Help Severe Detonation
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Hey Dan! No, mine's not the 01, that's a sweet truck though. Mine is the 98, red sport a few pages into it. I had a friend put it up for me because I couldn't get the picture to upload, and I forgot to have him list all my mods. Ah well. I like what you've done to your Dakota so far by the way!
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turbo-1
Dodge Dakota
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4/18/2004
20:59:35
| RE: Help Severe Detonation
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I tried the sea foam, didn't seem to help much. and about reseting the computer i have already tried that a couple of times. what do you guys think of getting the pcm flashed? all i have heard is bad things. any other ideas????
thanks
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WipLash
R/T
4/18/2004
21:15:49
| RE: Help Severe Detonation
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Have you checked to see if your injectors are all functioning properly? It's hard to tell without the proper equipment, but you can check the injectors by yourself with just a long screwdriver. With the engine at idle, stick the tip of the screwdriver to the injector and put your ear against the end of the handle. You should hear a sharp clicking noise. Compare all 8 injectors. They should all sound the same. If one or two sound weaker than the others then you are probably running lean and that will cause detonation.
It's a long shot, but it appears you have already checked/tried everything else.
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gen1dak
Dodge Dakota
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4/18/2004
21:17:18
| RE: Help Severe Detonation
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10 degrees initial timing? That's fine on good gas, but 87 octane? I don't see it. Back it down to zero degrees TDC and see how it does.
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turbo-1
Dodge Dakota
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4/22/2004
15:28:47
| RE: Help Severe Detonation
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checked the injectors and they all sound the same. gen1dak. isn't 11 degrees stock for the initial timing? i also thought the timing was none adjustable unless you messed with crank position senser or by a computer mod?? am i wrong??? thanks for the help
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gen1dak
Dodge Dakota
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4/22/2004
18:52:45
| RE: Help Severe Detonation
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Didn't you say you were using a Hypertech programmer? Aaaaand can't you adjust the timing with it? The initial timing wasn't what I was thinking about so much as what comes in addition to it. That initial timing, in and of itself isn't too much, but timing advance would have to be pretty limited and slow to avoid ping, which is how it's programmed from the OEM. I'm still hanging on the programming having been adjusted. How did you reset the PCM?
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Rob C
Dodge Dakota
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4/22/2004
22:17:18
| RE: Help Severe Detonation
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I know you have a 180 degree thermostat but, is your engine actually running cooler? Have you been monitoring your operating temperature throughout your troubleshooting? Hot engines love to ping.
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Sephiroth
Dodge Dakota
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4/22/2004
22:46:54
| RE: Help Severe Detonation
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Rob, a 180 runs the 318 MUCH cooler! I have one in mine and it ownz. I run around 195 average. Unless you have a leak or your radiator is damaged/clogged, a 180deg thermo is a sweet yet cheap addition. Just don't run the engine below about 175deg, or it may damage it/wear it out faster.
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sam
Dodge Dakota
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4/23/2004
01:08:31
| RE: Help Severe Detonation
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Your PCM needs to be flashed to get rid or the detonation. The intake leak usually causes this problem because of the soot build up on the spark plugs combined with the buildup on the top of the piston. I don't know why some of these posts are talking about ignition timing because you can NOT change it. Go ahead and turn the distributor and all it will do is throw you fuel sync off, unless you turn it too far and then you will get a nice backfire. The PCM is what controls the ignition timing and you can't change it. The PCM flash will pull back some of the advance to get rid of the ping and without a dyno not one person can tell it has any less power. If you dont want the PCM flash just keep filling her up with the premium fuel. I would change the plugs and try the mopar upper engine cleaner, spray the whole can in the t-body with the engine running (at full operating temp) shut off the engine and let it sit for about three hours, then start it up and idle it for a few minutes (it will smoke a LOT) and take it out and do a few full throttle accels and closed throttle decels, keep it in low gear for compression braking. This will clean it up pretty good. If this does not work, you will need a flash to get rid of the detonation problem. I have reflashed many of these trucks including my own and have not had any performance issues other than the absence of the pinging from the engine. Good luck.
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Sephiroth
Dodge Dakota
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4/23/2004
18:08:02
| RE: Help Severe Detonation
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Actually sam, you can modify the timing without the CPU on engines like my own 318. Granted, if i modified mine right now, without any changes that warrant the need for advancement, I'd probably do mroe harm than good, but it can be done. Now on the newer models I do believe it's all controlled by the PCM.
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gen1dak
Dodge Dakota
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4/23/2004
23:40:30
| RE: Help Severe Detonation
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Sam, the timing can be changed. What do you think the Hypertech programmer is all about? Ignition timing and fuel curves. It is not accomplished by turning the distributor, and since you're the only one who's mentioned it, it further underscores my next statement. The reason you don't know why some posts mention timing, is because you really don't know as much as you think you do. Also, while carbon buildup in the cylinders will increase the compression ratio over time, a blown intake gasket will cause immediate pinging. How can it be then, that sooty buildup is the cause? Like I said, it can contribute over time, but the pinging is caused by a lean-out condition that occurs from the loss of vacuum. This throws off the whole deal. The O2 sensor sees a lean condition, which causes the PCM to boost fuel flow, which only makes things worse. All engines experience carbon buildup, and this is taken into consideration in the OEM programming so they will run without pinging as they "carbon-up."
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sam
Dodge Dakota
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4/24/2004
03:08:08
| RE: Help Severe Detonation
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I was referring to timing changes people were trying to make with rotating the distributor. I know that the hypertech and other add-on modules will change timing. The sooty build up on the spark plug will glow during compression and ignite the fuel before the spark has a chance to. When the lower plenum pan leaks it is more likely for the engine to suck oil and crankcase vapors than to actually cause a vacuum leak. A lean out condition will definately cause a detonation problem, but when the plenum pan leaks the engine is not sucking atmospheric air into the combustion chamber and will not cause an air/fuel ratio lean enough to cause a detonation. The crankcase vapor contains hydrocarbons that will burn in the combustion chamber and will not throw off the oxygen sensors. The pinging problem is caused by oil ingestion. The adaptive memory can more than compensate for the slightly leaner air/fuel mix caused by the burning crankcase fumes. You also contradict yourself in your statement, if the o2 sensor sees a lean condition it will cause the engine controller to inject more fuel which would kind of disprove your lean mix detonation theory, right? I may be wrong and if so, you should call chrysler and have them take away my mastertech gold certification because I may just think I know more than I really do.
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Dakota52318
Dodge Dakota
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4/24/2004
07:57:17
| RE: Help Severe Detonation
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OH that was funny Sam.... I dont think that they will take it away from you. I was having a slightly smaller pinging and oil consumption issue, but my intake is sitting on the floor right now and there is about a 1.5" section where the gasket was pushed to the outside when they put the belly pan on from the factory... been like that its whole life probably. Only problem is dodge gave me a gasket set for a V6 instead of an 8... now Im really pissed cause I was hoping to have my SCer on this weekend!!!!!!! DAMN!!!!
TJ
dakota52318@toad.net
1992 Dodge Dakota 4X4
3.90 Gears, Long Bed
318, 46RH Auto
DT Headers, Functional RamAir Hood
K&N FIPK, Flowmaster Muffler
Custom Throttle Body
MP Computer
Viper Electric Fan
15.74@87.59 b4 fan.
4350lbs
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gen1dak
Dodge Dakota
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4/24/2004
22:37:27
| RE: Help Severe Detonation
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Okay, let me connect the dots for you. I skipped over a few things, but I didn't know I was dealing with a "Mastertech...whatever." The loss of vacuum causes an over-rich condition. The O2 sensor sees this, and leans out the mix. Then, the mix is too lean, the O2 sensor sees this, fattens the mix, the vacuum leak persists, causing over rich, O2 sensor leans,....left-right, left-right. Do you get it yet Mr. Master-legend-in-your-own-mind? Try connecting the dots. Once again, ALL ENGINES CARBON UP. Ever seen an engine with bad valvespring seals? It smokes from a lot more oil consumption than a plenum seal leak, but it doesn't ping. The fact that a vacuum leak causes carbon buildup to happen faster is nothing new and exclusive to Magnums. Ever heard of bad piston rings? Burn a quart a week, but no pinging. Yeah, it's that little drop of oil like you say. NOT! Also, like I said, as far as I have noticed in an admittedly brief scan of this thread, YOU are the only one referencing twisting the distributor as a method for initial timing adjustment on Magnum engines, not those of us whom you claim are in error. Hydrocarbons that burn. Hmmm, now there's a concept. And what, pray tell, are these hydrocarbons carried on? Would it be, oh, I dunno....AIR? Air, that isn't metered by the throttle body? Air that isn't in balance with what the PCM is seeing relative to the TPS and engine speed sensor? Oh, and Mastertech man....there are plenty of people with degrees on the wall, that can't find their ass with both hands. You appear to one of them.
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gen1dak
Dodge Dakota
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4/24/2004
23:01:36
| RE: Help Severe Detonation
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According to the MP Magnum manual, the oil-sucking explanation is considered a secondary probable cause of detonation. Note the wording: secondary probable, NOT the primary reason, and it goes on to mention that this can be seen if the leak exhists, and an aggressive timing schedule is used. So, there is some validity, but the PRIMARY reason, as stated, is as I have already stated. This chain reaction will ultimately lead to the shutdown of cylinders as the reaction-response goes further and further out of balance.
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Sephiroth
Dodge Dakota
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4/25/2004
11:01:44
| RE: Help Severe Detonation
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Hey gen1, how much did that engine manual cost you? I've been thinking about getting one for my '95 CC 4x4.
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