INPA fuel system Diagnosis

[Curtis135i]

Anyone know how to check your fuel system using INPA?

Having a intermittent idle surge issue.. no CEL yet.
Rpms go way down almost stalling.. 400rpm
then rpms jump up to 1100 then goes back to 600.

It started bucking lightly during cruzing speeds.

My HPFP has been changed at least once in the 114k miles of its life.

But if someone could help me out with how to navigate the fuel system test in INPA that’d be great.

[Dackelone]

Maybe try cleaning your throttle body. I know it's a pain but this sounds like a classic dirty throttle plate. MightyMouseTech Any thoughts ?

[Curtis135i]

It’s brand new actually. My original one died.. lots of throttle valve CELs.
The brand new one fixed it.
It’s has a few thousand miles on it too.
I’m sure it’s fuel.
Had a light hard crank after sitting 10 minutes. Engine was at operating temp. I drove it about 50 miles. Parked it 10 minutes.. then a light hard crank/start.
I have all new index 12 injectors as well.
Those have been working fine too.

[rowsdower]

Sounds exactly like my issue:

http://www.1addicts.com/forums/showthread.php?t=1490882

[MightyMouseTech]

Originally Posted by Dackelone

Maybe try cleaning your throttle body. I know it's a pain but this sounds like a classic dirty throttle plate. MightyMouseTech Any thoughts ?

Sounds exactly when I took my car out of storage last year, and used Seafoam as a dual stabilizer, which doesn't work apparently. Good fresh gas cleared it up.

Are you using top tier premium only? Is it fresh?

[Curtis135i]

Yeah. Put fresh gas in it, shell 93, topped off and a bottle chevron Techron complete fuel system cleaner.
Drove fine on the tank for over 100miles.
Then a little blip at crusing speed yesterday, 20 miles later light bucking at crusing speed.
City traffic on my way back at idle at the light dropping rpms..then bucking while shifting sometimes on take off. It’s intermittent yet consistent. I’m glad I made it home. Then in my drive way idle drops while sitting there.

I’m prepared to replace the HPFP if needed, but also wondered if it could be pre failure vanos solenoids.

I’m going to check random connections and start it up later on.

I kinda hope it just stalls out at idle to get the CEL code,

[Curtis135i]

Also noticed at crusing when it did this, the boost gauge normally in about 15 HG while crusing.. jumped more towards 5 when it was bucking/cutting out. The needle would jump toward 0... so I was losing vacuum.

My normal at idle is 20, sometimes 22 in HG

[rowsdower]

My issue is ongoing, but resetting adaptations in INPA makes the car run perfect. That may be a way for you to eliminate mechanical component failures vs sensor failures.

[Curtis135i]

Which adaptations do you reset? Also do you reset while engine is running? Or just with ignition power on and engine not running?

[rowsdower]

Originally Posted by Curtis135i

Which adaptations do you reset? Also do you reset while engine is running? Or just with ignition power on and engine not running?

I don't think INPA will let you reset with engine running. You press start twice with your foot off the clutch / brake so that it turns on but the engine is not running. I reset all of them because I don't know which ones to reset, maybe someone else who knows more can chime in before you reset.

[Curtis135i]

Swapped in my spare set of VANOS, no change, idle is choppy.. really nasty from a cold start.
Somewhat smoothed out, but still not right.
I really hope its not one of the new index 12 injectors.. I got them from FCPeuro.. so it’s LT warranty, but still.

[Curtis135i]

Yeah that’s how I’ve done it before.. ignition on but engine not running. With my throttle body being bad.. I tried the reset throttle adaptation before buying a new one.. took apart and cleaned it up too, before the reset. Oh man.. the engine sounded like it was going to die after the first time resetting it and starting it. Turned off immediately, let it sit, then tried again.. engine ran normally.. but later on showed up original Throttle valve CEL codes again.
So that experience made me nervous resetting anything unless I replace it.. it’s probably okay to reset adaptations, I’m only cautious after that experience.

[Curtis135i]

Originally Posted by MightyMouseTech

Sounds exactly when I took my car out of storage last year, and used Seafoam as a dual stabilizer, which doesn't work apparently. Good fresh gas cleared it up.

Are you using top tier premium only? Is it fresh?

I believe you were right, after at under 1/2 tank, I filled it back up, this time with Sunoco 93...and the engine did smooth out after 20 miles.. it’s possible the additive was too strong I initially put in with the Shell 93 full tank.. and that gas I got wasn’t the greatest.. weird.. but seems fine now. I didn’t reset anything, nor had any codes stored in DME.