So, Dominick...A verdict???

[Paul Workman]

Kinda wondering how the saga of the fuel cutoff went (I may have missed a post or two of late - I B incredibly bizzy the last couple weeks ) Did it turn out to be a pump issue or ???? Sure would be nice to compare the fix to the data from the scanner; a good learning exercise to be sure!

Keep the shiny side up!

P.

[karterdon]

Paul - Dom posted some pictures of the fuel filter sock that he took out of his car - It was completely plugged and black- He replaced both pumps and the filter sock and he says the cars runs Great !!!!!

Don Yoakem
91 #267 Dark Red Met.

[XfireZ51]

Originally Posted by karterdon

Paul - Dom posted some pictures of the fuel filter sock that he took out of his car - It was completely plugged and black- He replaced both pumps and the filter sock and he says the cars runs Great !!!!!

Don Yoakem
91 #267 Dark Red Met.

Yep. I remembered this happening to my 84. So I pulled the pumps and lo and behold. Ockham's Razor is the principle proposed by William of Ockham in the fourteenth century: ``Pluralitas non est ponenda sine neccesitate'', which translates as ``entities should not be multiplied unnecessarily''.

[Paul Workman]

...the "KISS" principal!

Very glad to hear it is running well! I have a long tube for my fuel pressure gauge. Just for grins, I may want to hook it up and go for a ride.

P.

[XfireZ51]

Originally Posted by Paul Workman

...the "KISS" principal!

Very glad to hear it is running well! I have a long tube for my fuel pressure gauge. Just for grins, I may want to hook it up and go for a ride.

P.

Paul,

I think the key here is WOT. Pumps need to be able to provide much more volume. There may be enough at PT so pressure looks fine but then WOT
basically absorbs any cushion and therefore starves the motor.

[Paul Workman]

Originally Posted by XfireZ51

Paul,

I think the key here is WOT. Pumps need to be able to provide much more volume. There may be enough at PT so pressure looks fine but then WOT
basically absorbs any cushion and therefore starves the motor.

Dom,

You think a long WOT pull in what gear would be best...4th? Or mebby just 3rd, considering the speed one attains at 7000+ in 4th?? The point being, a worst case "stress test" for the fueling system would require WOT at sustained high-end of the rpm band, I would think.

P.

[Aurora40]

I'm not sure the LSx ECMs have individual cylinder monitoring? I imagine they still have one O2 per bank? And I think only the new ZR1 has the dynamic fuel pressure control?

[Paul Workman]

Originally Posted by Aurora40

I'm not sure the LSx ECMs have individual cylinder monitoring? I imagine they still have one O2 per bank? And I think only the new ZR1 has the dynamic fuel pressure control?

Bob, I wuz speaking in more general terms with regard to the exponential increase in tuning variables for today's "ECMs" and those that dabble in tuning them, compared to the OBD-I and the LT5s.

A tuner would know, but I seem to recall reading that the exhaust pulses from the individual cylinders across the respective bank O2 can be (and are in some cases) monitored with respect to the exhaust valve timing. Thus, the mix and even the timing can be or is tweaked on individual cylinders - one of the advances allowed by the faster computers and OBD-II - one of the big advantages of the LSx over previous (OBD-I) ECM limitations. This could make position of the O2 on aftermarket exhausts a bit critical, if correct indexing of the cylinder is to be maintained. (I don't recall the source - been a while back.)

As for variable fuel pressure, I was referring more to the variety of variables facing the tuners of the latest engines (LS9 to be specific - also an "LS" motor). Point being, with the monitoring and sensing capabilities available to today's tuners - to the point of individual cylinders, if needed, certainly raises the bar when it come to tuning (not that every tuner would need or even want to delve to that level).

P.

[Aurora40]

Originally Posted by Paul Workman

A tuner would know, but I seem to recall reading that the exhaust pulses from the individual cylinders across the respective bank O2 can be (and are in some cases) monitored with respect to the exhaust valve timing. Thus, the mix and even the timing can be or is tweaked on individual cylinders - one of the advances allowed by the faster computers and OBD-II - one of the big advantages of the LSx over previous (OBD-I) ECM limitations. This could make position of the O2 on aftermarket exhausts a bit critical, if correct indexing of the cylinder is to be maintained. (I don't recall the source - been a while back.)

They certainly seem to be able to infer things like misfiring on an individual cylinder. I didn't know they also made fueling decisions on a per-cylinder basis, though.

Using a more modern controller would certainly be interesting, and perhaps could eliminate some of the difficult to find electronics. Though I wonder if it would be hard to get these newer ECMs to work with the 9-slot crank ring?

[Paul Workman]

Originally Posted by Aurora40

They certainly seem to be able to infer things like misfiring on an individual cylinder. I didn't know they also made fueling decisions on a per-cylinder basis, though.

Using a more modern controller would certainly be interesting, and perhaps could eliminate some of the difficult to find electronics. Though I wonder if it would be hard to get these newer ECMs to work with the 9-slot crank ring?

I dabbled in machine language programming once. But, in a nick of time, I saw my own insanity looming ahead and veered away from "the dark side"! But, maybe some prison inmate (with that kind of time on his/her hands) can re-write the code so a currently available ECM would be able to be substituted for the (now up to 18 year old) ECMs in our cars.

Anywayz...I find engine design and the attendant control thereof to be a fascinating topic. (Maybe that afore mentioned insanity got me anyway, and I just am not sane enough to realize it! )

P.