Alright I am at my wit's end. I have a Red 94 Sport with a 5.9. I have tried everything that I can think of and its still pinging. I have changed out the plenum gasket and siliconed both sides of it as well as torking it and the manifold to the specs given to me by alldata. I even moved my IAT back to the #2 runner in hopes of quelling the problem. The timing chain is a cloyes double roller with less than 10k since I changed it out. The motor doesn't burn oil and is in very good condition for 120k. There are no cracks between the intake and exhaust valves and the seats are fine so I am not getting excessivly hot chambers. It is under load of course at about 3k when I tip in hard that it pings. The truck has many mods so I am not sure if something is giving me an issue.

The mods are Throttle body, Ported beer barrel intake, Ported heads (not decked to increase compression), Hughes Performance cam, Headers, Gutted cat, Flowmasters, mopar pcm(one of my suspects), msd coil and wires, crane gold race roller rockers, hardened pushrods, springs and retainers from hughes, and heavy duty roller tappets from mopar.

Any thoughts or new idea's would be of great help. I love the truck but right now it is frustrating the crap out of me. Oh yeah and PCM isn't throwing any codes as far as it's concern everything is just dandy. So thanks in advance for any help.

 

try this..its worth a shot!!!

http://dodgeram.info/tsb/2000/09-05-00.htm

its a tsb to show you how incorrect routing of the wires can cause spark nock or pinging

 

Both my brother and me have 94's that came right off the lot, both pinging suckers unless we ran the highest octane fuel available which is 92 here in Utah.If you got the manifold from Hughes is it the one with the egr on the back? If you ported the stock manifold I assume it has the egr on the back of the manifold.Just a thought but if you have the egr make sure it is not letting hot exhaust gases by during acceleration,that will cause pinging,best way is to plug it off and try running the truck.I believe the egr should only open at de-acceleration or low rpm. With all the mods you have you may not be feeding the engine enough gas.Some of the performance cams are not compatible with a computer controlled engine but Hughes is pretty good about setting you up with the right stuff although some of them will require a PCM re-program for the new cam.Some brands of spark plugs will cause pinging on the magnum motor,if you have a hi energy ignition system then stay away from the platinums,you may want to try some Autolite #3923's gapped at .035.Carbon build up on the pistons will cause pinging to.PCM not correcting the timing under load.Just some thoughts,that can be a hard problem to fix.

 

I appreciate the input. I am currently running autolite 3924's and I was thinking that I might want to go colder. I run only premium amoco gasoline and run chevron fuel system cleaner through it after every oil change. The things that I forgot to mention is that under heavy throttle it runs on the rich side. I take off WOT and I can see black smoke behind me. I am not sure about the egr closing or not I replaced the egr a while ago along with my o2. Will plugging the egr throw any wierd codes if so is there any way to trick the computer or would it have to be reprogrammed. Also it is a mild cam and I never bring the motor over 5500rpm so I'm pretty sure that the engine isn't leaning out although you never know one cylinder may be.

I have a question though, seeing as you are running 24lb injectors how are you keeping it from knocking even with the timing retard. I am just curious because I have been in the process of trying to locate pieces parts to supercharge my truck. Although I have heard the the plenum gasket will blow if much boost is seen in the stock intake so I guess that was wasted money.

 

i run champion series truck plugs .. witch are good in the cold side and gapped to about 35 and ive never ran into problems with pinging unless the tb is dirty or a bottle of injector cleaner

 

180 degree thermostat WILL stop it.

 

Yes, the PCM will set a code,but for testing purposes it is insignificant,you would be able to tell if that was your problem or not,repair it then re-set your PCM to clear out the code.


Just changing the octane of the fuel cured my ping/knock problem. On my ignition system I can set the "ignition retard" starting point and a stand alone MAP sensor monitors manifold pressure at boost and progressivly retards the timing from my pre-set starting point.Amount of timing retard versus boost psi.My stock injectors were 19#'s which were to lean under higher rpm and boost.The FMS 24's were a flow matched set and pretty much cured the lean condition,I may have been able to go to #26's,but it's a rare day I get it above 4200 rpm.

I have a few questions tho,I am no expert at "pinging" problems but....

#1- what is your engine operating temp?
#2-Do you have a Air/Fuel meter/guage installed? I ask this as I have one in my truck,several years ago I ordered a Hi Flow cat as I had already replaced my stock one once before and it was rattling to beat all he** again.The one I ordered got back ordered so I gutted the stock one until my Hi Flow came.My truck ran like crap after that, sounded crappy and ran even worse.My a/f guage showed the a/f mixture bouncing around like crazy all the time and my gas mileage dropped to 8.5 mpg,[normally 14ish on the hiway].When I recieved my Hi Flow cat I installed it plus the original 02 sensor and it's been fine ever since. Your rich running condition I believe you need to investigate to find the problem and you may or may not find your pinging problem along with it.
#3-By Mopar Pcm do you mean the Hi performance one?If so,have you tried your stock one again?
#4-When did this problem start,after a certain mod?Did you do several of these at one time?Did you reset your pcm after doing these mod's?[It should re-learn but stranger things have happened]
#5-What is your vacuum at idle?
#6-Have you tried a different brand of gas?

For the running rich problem,you may want to check your fuel psi[regulator bad],leaking injectors[is there still pressure on the schraeder valve on the fuel rail after the truck sits for 15 min or 1/2 hour],vacuum leak[won't take much for the pcm to increase fuel rate] or map sensor[check your electrical connection,on the 94's the harness pulls on the connectors and the female end receptacles get opened up where they don't always make a connection,had this happen to my tps twice already,had to crimp them somewhat to get a good connection,make sure the map sensor isn't cracked anywhere also],just a few thoughts for now but I am thinking it probably doesn't like the gutted cat.

 

I repeat. 180 degree thermo

 

my 2cents i just got a 99 with a 360. when i got it it had a sllight spark knock. my best friend is a dodge freak with a highly modified dakota with a 318. he told me to buy a MSD 6A box, and get autolite plugs #3923 gapped at 50 thousanths. the pinging totally went away. and i run 87 ocatane **** gas.

 

I had not thought about the gutted cat being an issue. My o2 is before the cat so I don't see how it could be affecting my reading. I put it on a friends snap-on scan tool and my o2 reading was solid. I am running a 180 degree thermostat it is actually one of the first things I did on the truck, by the way don't try the 160s they screw with the egr on these things big time and keep them in open loop, big no go. The fuel pressure stays in the rails no matter how long I wait, I shut down the truck and pulled the fuel line to remove the manifold and I still had full pressure about three hours later. It started when I put in the cam and added the mopar performance pcm but it wasn't till about a month or two later that the problem arose.

I just pulled my plugs and its looks as though #8 is running leaner than the rest so I am going to order a new injector to see if that may be the culpret. Seeing as there is only one o2 if one cylinder is running lean then it will through off the signal just enough to make the rest of the cylinder run richer but that one cylinder may very well still be running lean. I always knew I hated the great idea of a returnless system and no proper fuel filter. Well I will keep you posted I hope that this may be the cure for the pinging sob.

I do think that running an a/f gauge is a good idea I think I will invest in one either way. I checked the connections on the tps and they did seem to be on the loose side thanks for the tip. By the way 94champ did you reprogram your computer to get the 24#s to work on your truck. Do you think and inline or intank is the way to go for the extra fuel. Also are you running the stock short block or have you changed the pistons to forged. I have read mixed results on the durability of the stock cast pistons and I would like to have your opinion. That is the main reason I have held off on supercharging it, I don't want to turn a perfectly good truck into a grenade.