76 PTO

Hi guys, I need some ideas on what to do next. I have a stock 96 vortec engine with a 92 tbi on top. Brian at TBI chips burned a custom chip for me and it has run great for more that a year. My problem is it is running so rich it fouls plugs and blows dark grey smoke. Gas is getting in the oil. I have a new
GM heated o2 and a new cts. The timing is spot on with the tan wire unpluged. I watched the o2 last night on winaldl and it was at .960v before it went to closed loop. Then it jumped between .860v-.960v and around zero. Im running Brians fpr spring at 17psi. Im thinking about throwing in the other spring I have to get to 15psi and replacing the map sensor. The injectors are not dripping. I'm going to datalog and video it tonight. I will post the video tommorrow.

I need some ideas!

Thank you,

Eric

Schurkey

Did the engine EVER run "right"?

Proper vacuum supply to MAP sensor???

What is scan tool data for coolant temp, and short- and long-term fuel correction?

76 PTO

The engine ran great. Dont know the vacuum reading. I'm going to datalog tonight and post the data.

ex-x-fire

Is the ign. timing advancing when you rev it? That'll cause a low vacuum reading.
You need to check the fuel pressure, maybe a restriction in the return line is causing high pressure.
Check the ecm grounds.

76 PTO

Yes the timing advances when i rev it. I put a vaccum gage in line with the map sensor and it read 18" at idle. Put new coil in last night before i data logged. I 'm posting several pictures and data. See what you guys think.

76 PTO

pictures

76 PTO

20130319_193334_LOG.txt

20130319_193806_LOG.txt

some data

76 PTO

20130319_195121_LOG.txt

20130319_200153_KNOCK.txt

20130319_201244_BLM.txt

More data, The plugs are black again, even got a cough of flames through the tbi. There is some of water coming out tailpipe, but no bubbles in radiator. when you hit the throttle you cant see anything and the fuel smell will make your eyes water.

Ronny

iTrader: (1)

A defective coolant temp sensor will cause car to run rich. It thinks it is -20dF.

76 PTO

I just changed it. I dont know by looking at the data if it is working or not.

morgsie

iTrader: (1)

If it was running good and now it's not it's most likely a mechanical issue. Any recent work done on the truck? Is firing on all cylinders? If it's missing it can cause a rich condition. Injector leaking maybe? You can hook a timing light up and point it at the injectors while it's running to check the spray pattern. Start with the basics I bet this will be something simple.

76 PTO

Injectors look good. I put a different spring in the regulator to get the fuel pressure down. I got it down to 13 psi and it still smoked. It would barley run. I had to unhook the map just to get it to idle. After it warmed up i saw bubbles in the radiator. Little confused because the smoke is grey and im fouling some plugs. Looks like headgasket. I'm going to rent the tester from the parts store tonight and make sure i burp the radiator good.

morgsie

iTrader: (1)

I think you are over complicating things.

lozantius82

iTrader: (1)

I had a tbi stage 2 chip tune until it washed my cylinder walls of oil and wore my rings so bad that my engine would smoke 24/7. His tune ran great but it gave me the exact symptoms you have and destroyed my old engine in a year. Your better off burning your own chip.

76 PTO

thanks, i'm thinking I might have to rering.

RFmaster

Run a compression check before jumping to this conclusion...