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360 build update

33K views 301 replies 18 participants last post by  smity901 
#1 ·
OK so we got the fuel sync set at 0 it does bounce to -2 back to 0 now and again...idk how much closer we can get it to stay at 0 then that. Second when the truck is idling the timing the scan tool read was 14* from what i've read around with these cams that sounds about right.

now these test were under no load sitting in park this is what im getting.

My buddy jay was bringing the the rpms up by 100rpms at a time with the scan tool to test it, once the truck hits 1400 RPMs the timing jumps up to 30* and it starts back firing. So we backed the rpms back down to idle at 750, now using the gas peddle we bring it up past 1400rpms it back fires a little once you hit 2400 rpms the computer brings the timing back down miss fires go away and as you continue to rev the engine up in rpms hitting 3,000RPMs the computer has the correct timing and you can just bury the tack to 6 grand no back fires nothing the truck just sounds great. Its just that first couple hundred rpms the computer is tricked for some reason thinking that the truck is running wide open.

The TPS sensor isn't tossing a code so I dont think its bad to make the computer think its going balls to the wall.

Im going to email Sean and see what he thinks.

I feel like we have taken a step in the right direction though in getting this thing dialed in though.

Any thoughts or help let me know guys.

the truck sounds so good at idle and once you get passed the 2400 mark omg look out the 3 inch pipes thing sounds mean!!!! shes just a little confused still.

Was also thinking about taking the tune out and seeing what happens.
 
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#74 ·
maybe these will help you out...
 

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#134 ·
mine looks like this one. guess you got to click on his tab at the end of his name to see is display.

Spun you said a compression test will tell me if have a leaky valve?
 
#76 ·
seriously this weather better break soon...more snow coming......
 
#77 ·
Wish that snow would come to Ontario Canada. I wanna take the 800 skidoo out. :thatfunny
 
#81 ·
ok so we got the truck to jakes automotive....my god....this truck movesssss I love it once she is warmed up mannnnnnnnn that cam just lobes....we stopped at the gas station when we fired it up all eyes were on me....thats how I like it. Trucks just so weird man you just keep it out of that range and this truck gets up and moves!....second gear you brap that gas and it snaps your head back...this cam and intake are torqueyyyy! I love it.

So I show up at the place after doing 75 in a 45 yeah not good Idea with exhaust and a truck that big in a area like that but I finally got open road to opener up.....hehehe I get there and the guy says just get in the truck put it in drive with your foot on the break start bringing the rpms up....when I got to that crappy range he said enough park it...you got a dead spot somewhere...looks at me and says ill find this problem sir don't worry 90 bucks for a test ill have it back to you monday....I shook his hand and said thank you right on brother!

Bad news I guess they dont deal with SCT on there dyno he says Seans tuners dont data log and they dont have the software to do so? So im a little confused on that idk if they just let people come and put there car/truck on a dyno and just see the numbers they put down so thats pretty upsetting.

So going to email Sean and figure it out.
 
#82 ·
You don't need SCT to data log. Thats what the dynos for, most have a wideband built into the dyno to monitor fuel ratio across the RPMs.
 
#83 ·
IC, but what about timing adding or retarding to see what it likes how does one record that? I mean my truck might like a few more degrees and gain few more horsepower wouldn't it? Or it might like a little less how does that work?
 
#84 ·
You could email Sean and ask for more timing and try a new tune, then see if it improves. Sean will probably add more timing once he knows your air fuel ratio.
 
#85 ·
Ok makes sense
 
#86 ·
sct gives sean a recommended timing advance and fuel parameter amung other things. sct has tested extensively on their product and its not the first motor for sean to tune. i'm sure his base line for that cam is VERY close.
have the shop email over the dyno results to sean.
 
#87 ·
Yeah I talked to to Sean everythings good
 
#88 ·
Wow these people here at Jakes are scaring me now, I been so excited waiting for monday for them to call say bingo we fixed your problem, instead them call me and say hey were not even going to waste your time, we dont deal with SCT I got to take it to someone who does...and IM like well didn't you run a diagnostics test on it to see why it back fires??? He goes does it do it without the tuner in...im like yeah hello I told you guys that, I told you before I left that I would pull the tune out so if you fixed the problem it wouldn't make anything worse cause sean had changed a few things to try and fix it himself, its like they didn't listen to one word I said.....

Well after telling him that he said he was confused thought it ran fine without the tune in it....im like no still runs like shit in the early RPMS....then says what he said last time oh ok if its running like that without the tuner ill find it for sure....now im just waiting.

at least he wasn't going to charge me the 97 bucks and then tell me he can't change anything cause he dont deal with SCT....jeez people these days
 
#89 ·
u need to get a data logger. like the lm2. easier for your tunes from hemifever.
 
#90 ·
Sounds to me like maybe you have a bad Crankshaft Position sensor, or a bad ignition coil. Did you happen to use a screwdriver to turn the engine over as you tightened the torque convertor, and use the square slots in the outer edges of the flex plate to turn the engine over with? If you did, it can make a burr on the edge of the hole and catch the crank position sensor and bend it, throwing the timing way off. Dont ask me how I know this LOL.
 
#91 ·
They ran the diagnostic test, said all sensors are fine, didn't find any flaws. I have more and more people telling me that its running lean.

I just got some email into sean.

There has been some miss information here I been giving. More of less I have been letting my buddy drive the truck. Cause I know he has built engines and ran into problems and can tell whats going on. Well today after jake called and tryed to tell me the time and chain was off a tooth, i brought them a picture of the time and chain and let them look at it and its clearly not! I drove the truck home....I noticed something!!!! This thing only backfires if you try to slam the pedal down and gooooo. If you just slowly accelerate like your driving normal no hurry, it dont miss a beat. I has nothing to do with 1400 rpm its just if you pin it at any RPM and I think I got Sean to figure out whats going on.

Quoteing Sean here after I told him it only backfires when you punch the gas. I can daily drive it al day if I lay off the gas. Before I was telling him that it backfires in that 1400-2400 rpm range...which is not true.

(I ONLY made changes in the full throttle fuel multiplier)

Me - I asked him what that meant

Sean_ lol. There are 3 fuel tables. The bigdaddy main table, a full throttle table, and a part throttle table. The full throttle and part throttle add or remove fuel over top of the main fuel table. I made a change only in the full throttle section so there's no overlap with the same rpm/vacuum area of the part throttle table. Since you don't have a part throttle issue, didn't need to add fuel in that scenario. clear as mud? :)

Ill try the tune tomorrow hopefully this fixes it. But I still got allot of people telling me that its not getting enough fuel.


as far as timing. the time and chain is dead on, and Jakes Automotive checked the Dizzy.....said its dead on to at TDC the rotor is right on the notch...if seans new tunes done fix it im out of ideas.
 
#92 ·
Good luck, hopefully it works out. Whats the part number for the injectors your running?
 
#93 ·
Have you replaced the catalytic convertor?? If you have over 80K miles on it, its possible that it could be clogged up. It can cause backfires from the heavy backpressure. I've had one clog up and cause similar symptoms as you.

Also, have you checked your fuel pressure? The shop you've been going to should have a guage that will either go inline of the fuel rail's quick disconnect if you have plastic rails, or will connect to the fuel pressure schraeder valve if your fuel rail is the steel ones. Then you could watch your fuel pressure and see if it's dropping off when you stomp the gas, meaning you might have a weak pump or bad pressure regulator. If it were either you would just put a new fuel sending unit in it and be on your way, about 300 new from the stealership.
 
#94 ·
Not running a cat, and I got a fuel rail pressure gauge says 55 pounds and don't move when I stomp it so idk this is just crazy
 
#95 ·
Lee ill get you thee link later today
 
#97 ·
#98 ·
The new tune didn't help....seriously im ready to give up. why can't any of you guys live close to me so I can take you for a ride lol :p
 
#99 ·
was wondering if you guys know if there is any real difference in engines from 96 to the 2000-2002 blocks, I cant remember what year block I got but its in the 2000s and is a 5.9L but not higher then 02, all I transfered over from the 96 block I got was the flex plate.

Im seriously trying to think of what to do idk whats going on.

Should I just buy a new mopar performance PCM?
 
#100 ·
if it was mine, i would start messin with the fuel synch. thats what i think it is. not all motors fall n that +3 catagory. seen guys runnin +8 to below 0 before it was correct. i had to mess with mine 3 times. and think i need to advance it a little more.
 
#104 ·
At this point ill try anything, I got a wideban o2 gauge coming, do you think the fuel would cause backfiring? My fuel sync now is set to 0 once in a while it bounces to -2 then back to 0.
 
#101 · (Edited)
Those injectors are to big unless Sean knows and dialed them back. Those are 24lbs @ 43 psi, Dodges run 50psi which makes it around a 26lbs injector. stock is 23.5 @50psi.

Im justing using stock injectors on mine.

The 360 magnum blocks are all the same except for 02-03 they added extra engine mounts.

I would still like to see a picture of the distributer and rotor @ TDC.
 
#102 ·
i dont believe its the injectors. mine are tuned #26s at 43lb bar3 by hemifever. he got it right.
 
#103 ·
have you had the wide band o2 read yet?
 
#106 ·
Yeah dont make any sense, only thing I can think of would be if the cam was to advanced...but if it was why would it run so smooth at top end?? Or a Intake valve is slightly stuck open or the place the heads came from didnt set them up right? Is there a way to shoot air into the spark plug hole and see if I can hear it coming out the intake when the intake valve should be closed? lol did i just answer my own question on that last one about the air shooting lol, is there any trick to find out what side the backfire is coming from?

I just emailed Sean asking him to write me a list of everything he wants checked on the scan tool, both with the tune in and the tune out, the truck driving the truck sitting in park. I'm waiting for him to respond. If all checks out what Sean wants me to check, im going to buy some new lifters and while im at it take the heads off and check the valves out. If I find nothing im going to assume the PCM is shot or just wont accept a cam that size.

Did I mention the other day on the test drive it stalled as I pulled back into the shop? What causes that?

Were can I find a 96 PCM that I can have sent to me tuned for what I did?

Also few peolpe have said crank sensor! Now if it was bad it wouldn't send any spark. or if it was bad would it send spark at the incorrect time? If I remember correctly that is what a crank sensor does right if its bad it dont allow spark.

Lee when I get the truck in the shop at my dads im going to set it at TDC and take some pictures. The guy at jakes automotive I believe ripped me off, I dont think they really gave it there best to look it over, plus I asked the guy if he set it to TDC and seen if the rotor was on the notch...he said yeah...but I thought it was suppose to be just past it? If so he basically lied to me. I wasted 100 bucks there.
 
#107 ·
Seans Reply

I would suggest waiting on your wideband. I really can't speculate all of the different conditions that would cause a backfire. Lean condition can, ignition/crank can, and valve timing are the 3 most common. Since I added fuel at the issue area and you said it worsened, it probably just choked it down with fuel and still backfired. That would make sense as that would make 3000 rpms have more fuel than 5000 which isn't normal. But get a wideband and check.
 
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