I did the LT1 cam swap when I pulled my engine for a rebuild and now I'm more than frustrated. Since then I was able to datalog and tune my bin so that my car runs pretty well when at temp.

The problem is that it runs like S**T when cold and will randomly go into limp home mode 20 mins into a drive. Also I'm getting like 10 miles to the gallon which tells me my tune is waaaaaaaaaay off.

I'm toying with the idea of just putting my old cam back in and seeing if I can get the car running well with that cam then later on doing the LT1 cam swap again.

I realize this is a step backwards but am so tired of not driving my car! I know tuning for a new cam isn't a "quick and easy" thing, but I just can't seem to get to the next level of tuning.

Will installing a wide band 02 sensor and tuning with it cure all my problems or is it just another can of worms?

Any thoughts or suggestions?

 

WB is a desirable tool but cost is a consideration. Are you getting an CE light? Intermittant CE light? I did with my cam swap(intermitant).
Sounds like you will need to tweek the OL coolant compensation tables. How does car run shortly after it is cold started? IOW does it have most issues 140-165F on coolant?

What was BLM reads after cam swap? where did you see BLM off the most?

 

Tackle the ECM limp mode issue first. It may be that the ECM is bad, or that the chip is coming loose in the socket. But can't tune until the ECM is working OK.

Then work on the VE tables to get the driveability back. As this is done the cold running issues should subside. May not go away entirely, but should be better.

Since the intake was off double check that the distributor timing is set correctly. And if bumped (say to 6* BTDC) that the calibration is changed to match.

RBob.

 

When I first started tuning, I was getting the CE light more frequently. After my 10th chip or so I got it less frequently. Now I get it on longer drives on occasion. So I have to pull over and restart the car so it gets out of LHM, then I am fine for a while again.

When cold, the car runs ok right after it starts (while the choke is on?). But once that is over I have to pedal the crap out of it to get moving and have to drive like an old lady till it gets to CL.

I've attached one of my first datalogs and one of my last if anyone cares to look.

Thanks for the responses!

 

I haven't checked the timing since i first got it running again after the rebuild, but if I recall i have it set to 8* BTDC. I didn't change the calibration to match. I don't remember reading about that anywhere before, I will search for info on that.

Thanks for the response!

 

A good possibilty. I'm fighting this right now, but mainly because I was screwing with tables before I knew what a huge impact they have. Now I'm slowly getting them working again. It's amazing how much more fuel a cold engine requires. Not to mention a cold modified engine.

 

if u have a MAF set up the LT1 cam shouldnt have caused the problems. i would get the stock tune back on the chip and u should b happy!

 

I think he's running TBI.