Chrysler electronic fuel injection used on a big block?

[Ron Ward]

I have a buddy who successfully adapted a later model Mopar EFI (5.9L Magnum) to a 440 engine. The problem he is experiencing is that the big block distributor rotates in the opposite direction of that in a small block. Thus, as engine speed increases, the ignition lead decreases. Any ideas as to how to trick the distributor or pickup coil into thinking the distributor is rotating the same way as a small block?

[NewEnglandRaceFan]

shouldn't the timing be locked out of the bb dissy and advanced through the ecu?

[BBR]

I got nothing, but dang he must have REALLY wanted Mopar efi on his BB. If I was retrofitting something, Mopar's efi would be at the bottom of the list for sure.

I posed the same question some years ago about putting 5.0L Mustang efi on a SB Mopar. It was concluded that distributor rotation did not matter, but I still have my doubts. There might still be some good threads about that hidden on Moparts.

[BlueCuda340]

shouldn't the timing be locked out of the bb dissy and advanced through the ecu?

If it was mechanical advance he wouldn't have this problem. Because the dizzy is going the wrong way the electronic advance works backwards.

[BKBridges]

I have a buddy who successfully adapted a later model Mopar EFI (5.9L Magnum) to a 440 engine. The problem he is experiencing is that the big block distributor rotates in the opposite direction of that in a small block. Thus, as engine speed increases, the ignition lead decreases. Any ideas as to how to trick the distributor or pickup coil into thinking the distributor is rotating the same way as a small block?

Ron,
Sounds like pre 1991 EFI? TBI? The dist on the post 91 EFI stuff is just a cam sensor and spark distributor. The ECU controls the advance. I would say he needs to ditch the OEM ECU and go with an MS solution...
BKB

[NewEnglandRaceFan]

I'm guessing he is tuning the oem ecu somehow.. instead of inputing an Advance curve.. why not input a retard curve if the tables will allow it.. that way because the dissy is turning the wrong way. the retard curve is really an advance curve..

[Matt Cramer]

shouldn't the timing be locked out of the bb dissy and advanced through the ecu?

Yeah, that doesn't sound right to me either. The ECU should calculate the timing and command the coil when to fire based on the crank trigger.

[Z88Z]

Did he ever get anywhere with this?

I'm assuming/hoping he used the 96 and up OBD2 setup, otherwise about the only tuning option for OBD1 is a flash from B&G or a couple of others.

Assuming it is OBD2 did he incorporate the diagnostic port too I hope? Otherwise it will also be pretty impossible to tune and much harder to diagnose any problems.

I'd love to know how he set up his CPS for the cam. For the CKPS I'm assuming he notched the bell and used the Magnum type window wheel flexplate and a custom bracket for the CKPS?
I think it's Hughes that makes a CKPS bracket for LA motors but I don't know if that fits or adapts easily to the B motors.
Looked into aftermarket trigger wheels but so far I didn't find anything compatible with our system - good old Chrysler, ha ha.

What injectors is he running and what intake?

As far as the problem, I'm assuming he either made a custom one piece shaft for the diz or at least tacked the shaft to lock it out - otherwise the PCM isn't going to be happy at all, LOL.
I know the Magnum diz shaft is too short and the RB front rail for the valley pan interferes with the diz body - so I'm guessing he didn't use the Magnum diz.

So the basis for setting the "timing" when replacing a Magnum distributor is actually setting "fuel sync" which is done through the diag port with the DRB/factory scanner - although a lot of high end SnapOn type scanners can do it if they have the right software.

I'm looking into the same thing now working with my tuner and the next step is to determine whether the CPS is phased 'straight up' for cylinder #1 or whether there's any 'lead or follow' (advance/retard) to it's initial setup.
If it's other than straight up you, then with the reverse direction rotor you should theoretically just set it up the same degrees on the other side of #1.

But from everything I'm hearing this should be a viable setup.

(I didn't see a vendor section and I hope I'm not stepping on any toes of forum rules here, but...) For SCT tuning I'd recommend Ryan at [email protected] He's got some of the best results with SCT

[Z88Z]

Did he ever get anywhere with this?