[KingLT1]

A friend just finished up his build and went with one of these SMG drop in pumps for the low side.

2016 SS A8

Mods:

Rods/Pistons 377
Ported Heads
Btr stage 2 38% lobe cam
LPE HPFP
+30 FIC injectors
P1x stage 2 w/ 3.9 upper 8" lower. Makes 12 psi on this setup.

on E50 this low side pump will not keep up on its own. Tried the SMG settings and everything in-between still no dice.

Hooked the JMS up since it was previously installed with a LT4 pump and low side pressure holds great.

SOI- 366
EOI- 190
5.3ms injector
2600psi rail
.84 lambda
101lb/min dynamic airflow

The problem is the FSCM doesn't like this SMG/JMS combo. It literally throws a CEL for insufficient fuel even when cruising part throttle and the JMS isn't active. Unplug JMS no codes. Logs show fuel system is fine but pressure won't hold.

Old setup with the LT4 low side pump and JMS no issue.

Tried lowering JMS voltage...same issue.

Not sure what's up but it looks like this pump has to come out since it won't play nice with the JMS...shame because there is plenty of fuel with this combo but no bueno with the codes.

Either way the claims of 900whp using this pump only with no other assist appears to be false...at least targeting .83-.84 on E blend. Might be ok running leaner or race fuel.

Just sharing info.

[SOCAL.M6.ZLE]

Great info KING... thanks for sharing... another reason why I am waiting for KATECH's drop in solution...

[LloydK]

Mine just failed, I’ve been tuned 4-5 months , lost pressure with boost on way back from Camarofest

[rcoe]

Originally Posted by SOCAL.M6.ZLE

Great info KING... thanks for sharing... another reason why I am waiting for KATECH's drop in solution...

Same here and with them being local would like to drop mine off get their new low side and do port injection at the same time.

Maybe this winter.

[NicKey]

What code is it triggering?

[KingLT1]

P2635- Fuel Pump 1 flow insufficient.

[ZLRob]

This is a dumb question because I know you know your stuff without question, but have the parameters in the FSCM been changed to match that of the JMS on HPT? I had to change quite a few values over OE in mine in order for that JMS to function as it's designed to.

[KingLT1]

The JMS was installed with a LT4 pump prior working flawless for 2-3years. It didn't start throwing codes until this SMG pump was installed.

[ZLRob]

Originally Posted by KingLT1

The JMS was installed with a LT4 pump prior working flawless for 2-3years. It didn't start throwing codes until this SMG pump was installed.

Was the JMS installed and run as is, or were parameters and tables modified in HPT like what is normally done to make the most of it?

[KingLT1]

It was all adjusted just like my car is or any other car I have worked with that has a JMS and no issues.

Basically if I disconnect the JMS, command 70psi, pressure drops around 5500rpm. High side tanks once pressure gets below 50psi. I lowered commanded pressure in 5 psi increments. Once I got down to 50psi all pressures will hold to 6250rpm then falls off.

Now turn the JMS on, pressures hold all the way to 7k rpm.

Here is some log screenshots First pic is with JMS off. Second is with it on. Now if this was a setup issue causing the bypass to dump pressure as SMG claims, the JMS shouldn't be helping.

It looks like a classic case of the pump itself not being capable enough.

Just need to figure out why the JMS triggers a CEL soon as the power connector is plugged in and the car is started. It's looking like a communication issue between ECU and FSCM or the pump itself. Need to do some more testing.

[ZLRob]

Originally Posted by KingLT1

It was all adjusted just like my car is or any other car I have worked with that has a JMS and no issues.

Basically if I disconnect the JMS, command 70psi, pressure drops around 5500rpm. High side tanks once pressure gets below 50psi. I lowered commanded pressure in 5 psi increments. Once I got down to 50psi all pressures will hold to 6250rpm then falls off.

Now turn the JMS on, pressures hold all the way to 7k rpm.

Here is some log screenshots First pic is with JMS off. Second is with it on. Now if this was a setup issue causing the bypass to dump pressure as SMG claims, the JMS shouldn't be helping.

It looks like a classic case of the pump itself not being capable enough.

Just need to figure out why the JMS triggers a CEL soon as the power connector is plugged in and the car is started. It's looking like a communication issue between ECU and FSCM or the pump itself. Need to do some more testing.

Sounds like SMG is trying to place the blame on the JMS instead of their own faulty hardware. From what you posted it certainly seems like the pump is the problem child here.

I'm not there so I don't want to assume either though.

[KingLT1]

So we ended up removing the SMG pump, reinstalled the LT4 along with adding a DSX Aux pump. The car now has plenty of low side.

[radz28]

That's a bit of a bummer in some ways. At least you guys are back on track.

That Katech set-up has my attention though.

[KingLT1]

Originally Posted by radz28

That's a bit of a bummer in some ways. At least you guys are back on track.

That Katech set-up has my attention though.

Yeah, he didn't want to risk trying something else that hasn't yet been proven. The Katech is also on my radar for my car if I ever move forward with more mods.