MS3Pro Ultimate Weird Fueling Issue

indyjonn · Post by **indyjonn** » Thu Apr 20, 2017 6:43 am

Ran into an issue the other day and I would like to try and rule out the ECU being the cause. The car had been running great for a few hundred miles with no issues at all. Then one day last week I went out and tried some new idle control settings and it fired right up no problem. Then out of nowhere it just started running like crap. Super fat AFR everywhere, idling in the 10s. I started pulling fuel out of the WUE and VE and it would still be in the 10s AFR.

MS3Pro Ultimate
4.8L LS engine (twin turbo)
58x crank / 1X cam
210lb bosch injectors

Tried three widebands (all show the same thing), reflashed firmware, reloaded old tunes, new plugs/wires, compression test (155 across the board), output testing was all good, no loose rockers, every exhaust runner gets heated up just after firing the motor.

Main issues is that is runs crazy rich no matter what I do and acts like its not hitting on all 8, but I have not found anything conclusive to show its not running on all 8.

I have tried a bunch of things but haven't found a root cause yet. I can take the VE, cut it in half and AFR will hardly move out of the 10s.

Any information helps. Would like to rule some things out before I tear the engine apart.

Thanks!

indyjonn · Post by **indyjonn** » Thu Apr 20, 2017 6:57 am

Composite log looks fine as well. I have also verified all grounds. Every ECU ground goes right to the battery, all coil grounds are good.

billr · Post by **billr** » Thu Apr 20, 2017 9:54 am

Is the logged "fuel pressure2" your FP? Is that psig, psia, or psi-delta across the injector? Regardless, it looks kind of odd.

indyjonn · Post by **indyjonn** » Thu Apr 20, 2017 10:14 am

billr wrote:Is the logged "fuel pressure2" your FP? Is that psig, psia, or psi-delta across the injector? Regardless, it looks kind of odd.

A friend of mine pointed that out as well. I am currently not logging fuel pressure. There is a gauge on my regulator, pressure is rock solid.

Reverant · Post by **Reverant** » Thu Apr 20, 2017 11:26 am

Your MAP values are really high, look for vacuum leaks.

LSXCutty · Post by **LSXCutty** » Fri Apr 21, 2017 5:37 am

Just wonder why you have stoich at 10 in your tune?

Lxmodguy · Post by **Lxmodguy** » Fri Apr 21, 2017 6:17 am

Yup yup.....what he said. Stoich values gonna override all the fuel targets.

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93supercoupe · Post by **93supercoupe** » Fri Apr 21, 2017 7:27 am

Car is on e85 and that value did not change from when it was running well to running like crap.

GrannySShifting · Post by **GrannySShifting** » Thu Oct 26, 2017 10:27 pm

Did you ever figure this out?

vw_chuck · Post by **vw_chuck** » Fri Oct 27, 2017 4:19 am

Stuck open injector?

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