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#436331 - 08/12/09 09:57 PM 408 Magnum efi tuning issues. HELP!!!

I finally got my 94 Dakota together with the 408 magnum efi motor that I built earlier this year. Basically here is whats going on. The truck is a 1994 318/5 speed originally. When I bought the truck, it had been wired for an OBD2 style computer and rine fine. I built this 408 based on what Marty at KRC performance suggested, so it is pretty beefy and has a monstrous hydraulic roller cam in it. Anyways, he sent me a SCT tuner with a program designed around my engine and a 1997 Dakota 318/auto pcm. This is the PCM that the truck ran on when I bought. Well, I started the motor on this PCM before the flash and it idled and ran ok. I then flashed his tune into the PCM via the SCT tuner and fired the truck back up. It ran for 2 or 3 seconds and stalled. It only does that now when you fire it. The next day, My friend who works at a Dodge delivery came by with his scan tool and he checked it out. Apparently, after I flashed the PCM, It through the truck into theft mode which cuts off the fuel supply. I called Marty at KRC after that and told him what happened and his response was that my PCM had been previously modified and the new flash wasnt able to overwrite the existing one completely. His answer was to purchase a new PCM from the dealer matching the vin to the truck my PCM originally came from. I called the dealer and got a quote at around $500. Yikes! All I want to know is if there is anyone out here who is savvy with PCMs or flashing custom tunes. I would prefer to have this repaired before I drop another $500 on this project. I have read about a member named hemifever who is good with this type of thing. Im between a rock and a hard place and now I really wish I would have just slapped a carb on this thing! Thanks for any help.

5414313-mydakota3.jpg (107 downloads)

#436332 - 08/13/09 09:49 AM Re: 408 Magnum efi tuning issues. HELP!!! [Re: ]
Dragula Offline

Registered: 05/02/04
Posts: 10148
Loc: Taxes R-US, NY
Can't help with a PCM, but if you choose to go carb or switch to aftermarket efi, we can discuss that.

Don't know if I would ever mess with something like that from the factory for a street/strip application. Factory computers are just that, and they get a little fussy when you mess with them. I would have ditched it entirely for a stand alone set-up as mentioned above. I recently purchased a new unit that could keep you in EFI, but much of the factory sensors would likely have to be changed if they were out of the range of this little units parameters, but I am pretty sure it could be easily adapter to your intake and basic set-up with a little luck. That would get you away from a factor type set-up....

Edited by Dragula (08/13/09 09:51 AM)
'71 Duster Pump Gas 512LD for sale now too (6.19) (9.70 at 138.5mph)

'70 Cuda, Plan C.... (6.31) (9.9)

#436333 - 08/13/09 10:34 AM Re: 408 Magnum efi tuning issues. HELP!!! [Re: Dragula]
gdemon Offline

Registered: 10/02/03
Posts: 387
Loc: Almont, MI.
Have you tried B & G in warren. They specialize in mopars. They flashed my computer for my hemi conversion.
69 Barracuda 70 Cuda 70 Cuda 70 Cuda Conv. 70 T/A Challenger 70 Sport Fury GT 71 Demon 5.7 Hemi 72 Demon

#436334 - 08/13/09 05:45 PM Re: 408 Magnum efi tuning issues. HELP!!! [Re: gdemon]
Wedgeman Offline
pro stock

Registered: 05/03/04
Posts: 1475
Loc: Ste-Sophie, Quebec, Canada
I swithched PCM like I wanted on my '94 5.9l, don't need the VIN until '96 I think or later...

I just foud out it costs $$$ to flash a comp ? ouffff


#436335 - 08/13/09 06:03 PM Re: 408 Magnum efi tuning issues. HELP!!! [Re: ]
blk00rt Offline

Registered: 01/27/08
Posts: 377
Loc: Michigan Troll
contact hemifever he is a good guy and is does the tunes for KRC. I believe he is somewhat affiliated with them. Have you tried to teach your truck to idle again. Mine looses its idle from time to time when the computer has been unplugged for a while. You simply start the truck and hold the accelerator at 1500 rpms for about 30 seconds, then let your foot off, if it dies try it again at 1700 rpms. repeat, I have never had to go above 2200 rpms doing this but after I do it, the truck idles fine.
Rob Dunn
1976 Dart Sport 360
2000 dakota RT 408 with 150 nitrous
2013 Dodge Ram 1500 Hemi
2009 Jeep Patriot

#436336 - 08/14/09 05:36 AM Re: 408 Magnum efi tuning issues. HELP!!! [Re: ]
360view Offline

Registered: 01/18/06
Posts: 4294
Loc: USA
Is the original factory 1994 OBD-I PCM for the 318 manual still around somewhere ?

#436337 - 08/14/09 02:06 PM Re: 408 Magnum efi tuning issues. HELP!!! [Re: 360view]
Wedgeman Offline
pro stock

Registered: 05/03/04
Posts: 1475
Loc: Ste-Sophie, Quebec, Canada
I think Jeg's has some.........


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