Just started this #@%$^(&^% backfire from throttlebodie.Mild built 5.9 360.Whats up and how to fix this problem? It's not a full time issue,just when I hammer it on sometime.

 

Check your compression. A sticking valve, even open just the slightest ammount can cause this.
Any major exhaust restrictions maybe?
Running lean? Do you have any pinging? Especially when you give er the beans?
Have you replaced the timing chain? They can have a lot of slop in them after 100k.

 

Please define "Mild Built".

 

Timing, burnt valve or lifters not adjusted right. The distributor is 1 tooth off or not set right. 1 tooth off on the timing chain. Did this just start on a good running engine or after the rebuild and in the truck?

 

Thanks to all that gave suggestions to my problem.Did a topend teardown to check everything from distribitor to timing chain.And everything in between.Heads clear(ported assembles)With all apart re-degreed cam while it was open.I did a vid,but can't find the cable for upload for show & tell.Finally got to use the inspection teardown gasket kit that hung on the peg board for over a year.The PCM didn,t have any code for what happened(OBD 1)system.IN my youth this job,a few hrs.Now 70 takes 2 days,getting old sucks.Just a Grimelin to entertain me.Shake down cruse, PERFECT!! NO sign of any problems,Motor has 7k miles.Pulled the 408 stroker to install in a project .But Thank you again to PRJAWRet HeyYou CJSUHR.

 

Getting old may suck, but, it sure beats the alternative.

Glad ya got it goin' again.

 

Hey You, About mild built motor or drive train? Well 1994( OBD1) MOPAR 5.9 now 0.20 bore for 363 ci. NA motor.All parts are MOPAR& ARP fasteners,Stage8 header bolts.These parts, in boxes and shelves for a few years bought when I was working for dealer.Employ discount.Never knew when I,d need parts for the 94.ANY WAY. fORGED CRANKSHAFT,3.58 WITH 360 MAINS.Magnum Stroker pistons-4.020 bore RT CAM 467/482 with roller rocker Factory Ported Head ASSEMBLY(CAST IRON)2.0IN iNTAKE-1.6 EXHAUST INT.PORT VOL 153CC INT.FLOW230 CFM 8MM VALVE STEM. M 1 INTAKE,53 MM fASTMAN ThROTTLEBODY. mOPAR HEADERS 17/8 CERAMIC COATED IN AND OUT,TOO 3 IN COLLECTOR WITH 3IN TUBES ALSO COATED.40 LB venom INJECTORS.pcm FROM ARRINGTON PERFORMANCE itcovers all needed performance for OBD 1 motor TRans is Stage 4 from FAIRBANKS/ 5 speed.MILD built 94.TUNES with Laptop

 

Have you done much work on your tune? You are a long way from 'stock' there. The OBDI computer wouldn't have a clue what to do with it. Various performance problems wouldn't be any surprise.....

 

Sounds like quite a number of engine mods. Did you confer with Arrington regarding your build before you got their PCM? You also mentioned that you tune via the laptop. Are these with canned tunes provided by Arrington or do you have full tuning latitude with your laptop?

Lastly, have you performed a leakdown test on the motor to ensure a piston didn't bend a valve or bend a pushrod?

 

Yes to all inquires.And API Calibration Survey,before sending unit to them,you've been there so you must know all that's. asked about the motor.OBD 1 systems is not supported with handheld turners or canned.API cracked the case for upgrades. My daugther and some of her Programer,ENgineer computer nerd friends(All MIT students)asked me Why I didn,t ask them.I had already sent it too API.So upon re-installing and fired it up.I was soooooo happy.So responsive.On demand and delivered without any hesitation.The kid & co-horts as a gift for a favor built a program to work with the API.Nothing real out of the park,race mode performance stuff.Kind of like Red key, Black key in the HellCATS.I'm old school,cant begin to talk Nerd stuff .Just really happy with the results!!!