Barrystheman

Could someone please take a look at this datalog? I am very new to this and this is my first log. The car runs like crap and I am not sure what I am looking at 100%.

http://www.mediafire.com/download/7t.../first_one.uni

My car has only ran for a total of about 90 minutes on a fresh 383.

Sorry, forgot to include..... 95 Camaro, LT1 now 383, AFR 195 heads, Edelbrock LT4 intake, 4L60E, Erson 584 lift cam, TPIS 58MM throttle body, Kooks headers and catted Y, accell 40 lbs injectors, PCMforless tune.

Thank you,
Barry

Barrystheman

What would cause the IAC pos to stay at 160?

Injuneer

Idle air control valve is wide open (at least the PCM is telling it to open 160 counts) and the engine is still idling too low (at end of log - target idle is 850 rpm, actual idle is varying 650-850 rpm). Check IAC valve.

After 3.5 minutes the coolant is only at 122*F and seems to be warming up very slowly. Are you running a thermostat?

The low coolant temp is probably causing the very rich idle mixture on both banks - 900+mV on both O2 sensors. Assuming you have deleted AIR system.

It went into closed loop at 206 seconds like it's supposed to, but you do not have enough run time in closed loop for anything to happen with the long term fuel trims. At the very end of the log the short terms are starting to drop, in response to the overly rich O2 sensor readings. Little doubt the long terms would be dropping if you had run it longer in closed loop.

Are you unable to drive the car? Sitting at idle for 3 minutes, with a couple revs of the throttle doesn't produce a lot of useful data.

What exactly are the problems the engine is exhibiting? "runs like crap" really doesn't tell us much.

Things that look normal:
-system voltage
-closed TPS volts
-barometer
-MAP is normal for a decent cam. What are the full specs on the Erson cam?
-inlet air temp
-spark advance

Questionable:
-MAF is showing 13+ grams/per second.... very high
-5 to 6 millisec injector pulse width very high
-almost always a fraction of a degree knock retard, up to 9* retard when you tweak the throttle. Running that rich with a cold engine should not be producing knock. What is you static compression ratio? What fuel are you running?

Excuse any typos - I'm working with one arm in a sling.... PITA

Injuneer

-IAC valve not working:

http://shbox.com/1/iac2.jpg

-IAC passages blocked. I thought the TPIS throttle body was supposed to be one of the aftermarket TB's without IAC problems.

The IAC "count" you see in the data log is what the PCM is telling the valve to do, There is no feedback to show if the valve is actually in this position.

-bottom plate on TB not tight, or leaking coolant into IAC system - if you still have coolant to the TB.

Barrystheman

I have a new TPIS throttle body, do I need to ajust the idle screw first?

Here is the short story. I put the new engine in started it up with open headers. It seemed to be running very rich. I called PCMforless and Keith said to close the exhaust back together and try it again. Did that. After I put it back together I took it for a ride. For about a half block it ran great! I stopped at a stop sign and it died. It started right back up. Tried to drive it back home and it was popping and I thought it wasn't going to make it back. Again I called PCMforless, Keith said the LT1's are known for vacuum leaks and to start there. I found four of the NEW injectors leaking. I replaced all of the orings on the injectors and the leak was gone. I rechecked for a vacuum leak, I didn't find any. After I put it all back together it doesn't want to idle. When sitting in the garage and I break torque it I do not get any popping or misfiring. I really don't want to drive it if it doens't want to idle. Once I get the idle back I will try to drive it again.

My compression ratio is about 10 3/4 to 1 and I use 93 octane fuel. Erson cam is 584 and 236/224 I think 112 LSA. I don't have the card in front of me.

I did some reading last night and found that I may have to ajust the idle screw since it's a new throttle body??

I hope you arm gets better and thanks for the help.

Barry

Injuneer

Bring the throttle stop screw out and see if it lowers the IAC counts. Problem when you do this is the TPS closed throttle voltage is going to go up. You don't want it to go above 0.90V.

How good is the valve adjustment? If you have them to tight it's going to make it difficult to get the engine to idle. I suspect the cam is 224/236 but you need to get the correct numbers.

Barrystheman

226/234 is the correct cam. I tried to adjust the screw out and it didn't make a difference. As soon as it goes into closed loop it starts popping and doesn't want to stay running. The popping is out of the exhaust not the intake. I am at a loss... I hear a very faint tick like maybe a small header leak. Could this make this happen? I am not sure if it's a header leak but it's the only thing I can think of that's in that area.

I trust the valves are adjusted correctly. The guy I use is very detail oriented and has built many LT1's.

Injuneer

Exhaust leaks before the O2 sensors cause the engine to run rich. But the limited closed loop data in the log indicates it's running rich WITHOUT the elevated LTFT's that an exhaust leak would cause. Does the coolant ever warm up to normal levels - 180*F?

Barrystheman

I have a 160* thermostat and pcmforless has tunned the fans to come on sooner. I will run a new datalog today or tomorrow and make it stay running in closed loop for a few minutes. Maybe if I gave you more to work with you could help me more.

Thank you for all of your help Injuneer! I will repost this evening or tomorrow.

Barry

Injuneer

A 160* t'stat begins to open at 160*. Isn't fully open until about 180*. It's
purpose is to allow the engine to approach operating temp before the coolant starts to flow.

Barrystheman

Injuneer, take a look at this one. I ran it for a while. Let me know what you think..


http://www.mediafire.com/download/n9...econd_test.uni

Thanks a lot for helping me out!
Barry

Barrystheman

Update!!

I called a guy near Nashville, sent him my tune and datalog, he made a couple changes, and told me to change my plugs. I started the car up and it ran great!! Once I resend him my new datalog for some final adjustments I will post what shop and a phone number.

Fred, thank you for all of your help!! You're the best man!

Barry