Re: RE: (Fwd) JET Module for 97 Dakota

From: William Blount Arthur (m990198@nadn.navy.mil)
Date: Mon Oct 26 1998 - 14:59:31 EST


I heard, after I bought the Jet II, that a Mopar performance computer for
a '96 ram would work on a '97-98 model. I think the same was true for
dakotas. I wish I could get rid of my Jet. I do think it works ok, but I
bet the Mopar is more aggressive. Also, I was thinking that anything that
costs 250 dollars should take the stupid speed limiter out. (I know
something else that would cost $250 and would take it out and it has 4
barrels)

Confused in MD.

Bill
'97 SS/T

On Mon, 26 Oct 1998, Bridges, Bruce wrote:

> Yikes,
> sounds like a scam!! I know my JET II is doing something, but I was
> un-impre4ssed with their front line "workers"... (knock sensor my Butt...)
> Thanks for the computer sciences reverse engineering! An expensive
> investigation no? Did yKRP ever put the resistors back in and try it??
> BKB
>
> -----Original Message-----
> From: KRP [mailto:krp@interaccess.com]
> Sent: Monday, October 26, 1998 8:37 AM
> To: dakota-truck@buffnet.net
> Subject: DML: (Fwd) JET Module for 97 Dakota
>
>
> Just a story you all might find interesting. I bought a JET module for
> my 97 Dakota, and had nothing but problems with it. I found that with
> the module , the check eng. light would come on and my 3.9 V6 would no
> longer idle. Further, I could be cruising at 65 MPH and the engine
> would die. Mashing the accelerator seemed to get it going again,
> sometimes right away and sometimes not. The fix was to unplug the JET
> module and plug it back in again or disconnect the battery. I quickly
> got tired of this and returned the thing to the shop to have it sent
> back to JET and replaced. JET was prompt in getting me a new one. Just
> one problem. The new one did some of what the old one did. I again
> returned the unit and had my truck analyzed and found that it indeed
> is healthy. The third module arrived and the truck ran great. No
> dieing or rough idle or check engine light. Now there was a whole new
> problem. This module didn't even improve performance. I was a bit
> puzzled and not sure I got what I paid for. I figured that I wasn't
> going to get one ofthese things that worked, and I wasn't going to
> get my money back. So I carefully disassemled it. I used an exacto to
> cut all arround and seperated the two plastic parts. I then seperated
> the header on the interface card from the PIC16C711 microprocessor
> board and drew out the complete schematic of both the interface card
> and the board. I then went to the Chrysler deeler and looked at the
> servise manual to find out the pin out of the 97 Dakota 3.9 V6
> computer. Pimarilly the pins that the interface card connected to.
> By the way, none of the pins are interrupted by this circuit. I simply
> piggy backs or inother words is in parallel with the existing wires.
> It turns out that not all of the pins they tapped were sent to the
> PIC16C711 and not all of the inputs/outputs on the module made it to
> the vehicle computer. However, +5 volts, +12 volts, and ground did
> connect.The following is what was available at the interface card...
> pin 2=fused B+
> pin 8=crankshaft position sensor
> pin 23=throttle position sensor
> pin 4=sensor ground
> pin 17=+5 volt supply
> pin 27=manifold absolute pressure
> pin 16=engine coolant temp sensor
> pin 15=intake air temp sensor
> pin 31&32=ground
> I can't go into great detail about how the software works, but
> basically the microcomputer is supposed to look at different sensors
> and compare the reading to a programmed look up table that only JET
> know the contents of.depending on the code feeding a cheap digital to
> analog converter, a buffer amp hammers on the correct pins with a new
> voltage based on the look up table. They use the same pin onthe
> microconputer as an input and an out put. All bit to zero=
> digital-analog converter to turn off and allows the microcomputer to
> sample the real reading and then compare to the lok up table and then
> the buffer is told to hammer on the existing voltage with the new
> voltage again. This all sounds good except for one thing. There are
> two resistors labled as R7 and R2 there is also a capacitor labeld C10
> C10 is no big deal just a filter, but R7 and R2 are in series with the
> traces from the module to the only pin being sampled or changed. These
> two resistors are not even present on my third module.there is no way
> it can do anything ! I do believe that the folks at JET thought that
> they would send me an incomplete unit to see if I would still
> complain. Sure enough, here I am. I am not even sure that there is any
> code on the PIC16C711 because you can't read these once the lock pins
> are set. I would appreciate it if JET would work with me on this, but
> a call to them resulted in me being accused of removing these two
> missing risistors myself.What a joke. I can't tell you not to puchase
> one of these, but beware.Also, one of the claims of this devise is to
> improve the shift of the auto trans. It doesn't even connect to the
> trans pinws located on a different plug of the vehicles computer.
> Hope someone enjoys this.
> John.
>
> Cat, the OTHER white meat.
>
>
> Keith R. Phelps
>



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