This is probably a dumb question but I was just curious, I have a 2.8 PFI memcal from a 730 ECM is the limp home stuff the same as my whats on my 5.0 TPI memcal with the 730 ECM?

 

The same in function, I would doubt the RFD stuff is exactly the same. There is also a hardware select for cylinder select in the memcal, plus the K/S filtering.
BTW, RFD is redundant fueling devise.

Maybe Need4speed will help with more specifics.

 

The "limp home mode" comes from the network resistors pack (netres) on the memcal as you've indicated.

From what I know of the netres function, it takes the spark info from the ignition module and uses it as the basis of firing the injectors, ie without ECM control of fuel or spark.

This means that a 4 or 6 cylinder memcal won't work with an 8 cylinder motor (and vice versa) because the module timing will give the wrong fuel.

John

 

i wouldnt realy get to worried about the RFD. if the ecm blow up that bad 90% of the time your not getting home. trust me on this. anyways the 90% of ecm failures are usually injector drivers and if those are toast well it doenst matter what network resistors are in there its not gonna move.

 

Funstick- you know too much, and this is a newbie question No doubt you've got over the dumb errors problems, but a few of us are still making them!

I've relied on the netres a few times recently when I've had a badly-soldered home made low-profile ZIF adaptor and again with a used ECM that was unreliable. It's best to have the correct memcal if you're still learning.

John

 

really 2 weeks ago i mixed the pushrods on a late model 3.4 in a unspecified vehicle( knowing they were different lenghts) and head to pay for a cylinder head job. mistakes are human. ooh i also had to due the cylinder head job ahh free.


get a moates adapter and a good ecm. like i siad if its really going bad the netres arent gonna get you home with an engine in good condition. those RFD devices are designed for each engine and running it lean/rich will just tear stuff up. get a moates adapter and a good ecm. youll feel better in the long run.

 

Must be ignoring the 1227165s to come up with the blown 90% blown injector driver number.

Actually upon reflection, I haven't seen a blown injector driver other then in distructive testing on the bench.

 

well lets consider that i might poosiable work on car for a living. i can tell you the number one ecm failure i see is fried drives. mostly injectors. in the newer dodge neons the coils short and blows out the ign module in the ecm.

but the reason i siad that is becuase even if the a/d were to fail the backup values in the ecm for the trouble codes would take over. also if the MCU fails what the likely hood you would actually want to drive a 10k motor for an extened period ?

and btw the vast majority of the injector drivers i see blown are cuase by corroded or fualty wiring.

 

Does anyone know how this network resistor is made? I assume this is the little removable chip next to the 2732 PROM on my 1227747. I have a four barrel TB, and when mine goes into limp home mode, It runs really really rich. if there is a way to parallel or series a resistor and change this, I would like to do it.