foolmoon_design

Another WTF for the ECM. Most of ya'll know I try and race each weekend. This past weekend I thought I completely screwed my motor up bad! I made five or six runs all in about an hour. The car was fine. So I let it sit for an hour so I could sit in the stands and watch 2 rails go at it for a while.(rails at the 1/8 make me laugh, since their burnouts almost cross the finish line.LOL) So after sitting the car for a bit, I get in crank her up, and pull into the staging area. It starts to rain... so they close the track. Well, I wasn't done getting my fix, so I decided to open it up on the interstate on the way home.

At WOT it was driving like it hadn't been tuned. Only boosting to 15PSI, and never throwing a code. Freaked me out bad! But I never suspected it could have been the ECM pulling power, because right before I left the track the Low Fuel light came on. So the next morning, I start it up to go fill up the tank, and it is still not boosting past 15psi. After four or five key cycles though low and behold the power is back and boosting again to 24-25psi.

So after I got the power back, I tried data logging, and dug up P2187 Too lean at Idle.... So I did the troubleshooting. I started by checking all vac lines for cracks, tears, etc. Nothing found. I then switched my efforts looking for problems with the wastegate. Nothing found. Then I cleaned the MAF, nothing found. I then applied pressure to the intake and looked for leaks around the gasket, nothing found. Finally checked compression on all cylinders, again nothing found

This was all rectified by Saturday, and the car is running fine, so my question is this. (maybe Mike or ChevyMgr have an answer for this) Will the ECM cut back on power once the Low Fuel light comes on, or could I have sucked some junk through one of the injectors, from running a low tank at the track?

The possible culprits are: dirty MAF, too much oil on intake filter, bad gasket, vac leak after the MAF, Intake solenoid, fuel filter, low fuel? I pretty much rulled all of those out except the intake solenoid, and I think cleaning the MAF was the true problem, although when I replaced the exhaust solenoid, I begged the dealer to replace the Intake, they didn't.

Anyone have any thoughts? Again car is running fine.

Another tid-bit that might explain... My last run, the guy in front of me was purging a ton of NOS, any chance I sucked some up and caused the ECM to react to it?

LawDog88

I can't speak for the SS, but I have run my HHR down to the low fuel light to basically on fumes, and not had a problem with it robbing power..

I did however have the Throttle Body control go bad, and that caused it to "limp" or lose power...

2005HHRauto

I have heard that there's 'protection', that kicks in with low-fuel on DI motors.

Have also heard that when you get down to your last gallon, the ECM won't even let the engine crank over at all.

Breadfan

I dunno about all that. Yesterday, the wife ran it below 1 gallon and I didn't notice any difference on the way to the gas station.

bigjacksauto

Not sure about what you where experiencing but oddly enough about 2 weeks back
It was lightly sprinkling out and I could not boost over 15 psi even with traction control off
the car would start to spin then it just felt like it had no tune in it.
It was almost as if the car cut the power back.
Later that day it ran great.
Almost as if the car was saying what are you trying to do the roads are damp?
I am going to guess it was the the tune cutting back on power for some reason just not sure what that reason is.
How is that for a meaningless answer?
All kidding aside as some have mentioned before sometimes the cars with tunes need a wake up call.

RobSSTurbo

To lean at idle would means less fuel. Its not good to run below a 1/4 of a tank that's how you burn out pumps. You can get away with couple times but that's why you got a lean code is the lift pump couldn't keep up with the hpfp. You may want to check the fuel psi on lift pump side to make sure its pushing I think 60psi.

foolmoon_design

Yeah, I went through all the possibles, couldn't find a fault. I ran it low on purpose, for weight savings, must have been really low.

I know when I'm at the track the DIC reads 8mpg. Lol.
I think I ran it bone dry. Opps.

But the preventive maintenance, was overdue any way. No harm no foul.. Yet.

2005HHRauto

The day that I bought my car, got in it for a test drive, it wouldn't start,
Or even turn over.
The salesman used a portable jump -start battery, still nothing.
A tech came out to try it, still wouldn't turn over.
Another tech came out to look at it & stated that the tank must be down to one gallon.
They dumped some gas in it, & it then turned over & started.

Dieselracer

When you tired running less fuel did you notice the hhr lose MPH on the top end? This weekend I ended up at the track with less fuel then i thought. The first 4 passes were dead on. But then after that I noticed I was losing top end. I couldn't feel a difference. But noticed it on my time slip I lost anywhere from 1.5 to 2.5 MPH. And the HHR became inconsistent. I noticed this started happening as the gauge hit 1/4 tank. Later in the night I was getting much better 60ft. "cooler weather", But over all running slower because I was losing MPH. My only guess what that with the Lower fuel the pump couldn't keep up the same. I usually run my tank at 1/2.

foolmoon_design

Come to think of it, yeah the car got its best times with above a 1/4 tank.