brothers4.3

Hey guys, New here, I am trying to help my brother fix his 1995 chevy 1500 4.3 vortec tbi. The past few weeks it has been running super rough, and he finally got tired of the way its running, so he brought his truck to me. I pulled the codes, and tripple checked the codes, the codes we got were : code 32 EGR failure, code 44 lean exhaust, code 67 tq converter clutch solenoid, and code 83 tq converter clutch.

So, I ended up replacing his egr valve with a brand new unit, dropped the a/t pan/filter and replaced the torque converter clutch solenoid, replaced the o2 sensor and reset the computer.

Now, after replacing the 3 parts that the codes said to replace, the truck will run fine untill it gets up to operating temperature, and then starts studdering and missing etc....

What else could it be? We checked the codes, replaced the 3 parts pertaining to the codes we got, reset the ecu, and still have the problem.

What else can I do?


(We replaced the dizzy cap, wires, plugs, fuel filter, pcv valve and a whole bunch of other stuff a few months ago before the problem arose, the truck ran perfect for about a month after doing the tune-up, then started sputtering and missing, idk what else to do)

nkh34

Did you do the Rotor under the cap now the codes dont match up but i had a cracked rotor in my other car once and it sputtered out everywhere she went

brothers4.3

yes, we replace the rotor along with the cap, wires, plugs, pcv, fuel filter, air filter etc etc etc....

A month or two later, his truck threw a CEL for the first time ever.
We got: code 32 EGR failure, code 44 lean exhaust, code 67 tq converter clutch solenoid, and code 83 tq converter clutch.

We since replaced his EGR valve with a brand new unit, dropped his a/t pan and replaced the torque converter clutch solenoid and replaced the a/t filter/fluid as well, and then replaced the o2 sensor with a brand new Bosch o2, then reset the ecu or pcm...

Today, we re-re-rechecked everything, re-reset the ecu/pcm and then drove 50 miles. The check engine light came back on, so we pulled off the road, cut the truck off and pulled the codes via paper clip. All codes are gone except code 44 lean exhaust, so we fixed everything else, just need to figure out this lean exhaust problem.

You guys have any suggestions? I am stumped. Plz help me fix my brothers truck!

brothers4.3

any suggestions? i realy need to fix my brothers truck

brothers4.3

Any ideas guys? I am a Honda guy, I dont know too much about Chevy's (next fav car brand), but I need to fix my brothers truck. PLz help us

nkh34

Alright i have reseached this for ya (my brother always helped me with my truck but he got stumped on my clutch wont touch my truck anymore so i know how it goes. this is what i learned.

1. DTC 44 is set when the Oxygen Sensor (02S) signal (02S) voltage on CKT 412:

•  
  • Remains below 0.1 volt from 70 seconds.
  • The system is operating in "Closed Loop."
  • Maximum air fuel ratio 14.6.

Diagnostic Aids:

Using the Tech 1, observe the long term fuel trim values at different RPM and air flow conditions. The Tech 1 also displays the long term fuel trim cells, so the long term fuel trim values can be checked in each of the cells to determine when the DTC 44 may have been set. If the conditions for DTC 44 exists, the block learn values will be around 150.

• Oxygen Sensor (O2S) Wire - Sensor pigtail may be mispositioned and contacting the exhaust manifold.
• Heated Oxygen Sensor (HO2S) Wire - An oxygen supply inside the 02S is necessary for proper O2S operation. This supply of oxygen is supplied through the 02S wire. All 02S wires and connections should be inspected for breaks or contamination that could prevent reference oxygen from reaching the 02S.
• Check for intermittent ground in wire between connector and sensor.
• Fuel Contamination - Water, even in small amounts, near the in-tank fuel pump inlet, can be delivered to the injectors. The water causes a lean exhaust and can set a DTC 44.
• Fuel Pressure - System will be lean if pressure is too low. It may be necessary to monitor fuel pressure while driving the vehicle at various road speeds and/or loads to confirm.
• Exhaust Leaks - If there is an exhaust leak, the engine can cause outside air to be pulled into the exhaust and past the sensor. Vacuum or crankcase leaks can cause a lean condition.
• AIR System - Be sure air is not being directed to the exhaust ports while in "Closed Loop." If the block learn value goes down while squeezing air hose to left side of exhaust ports,
• CKT 413 - If CKT 413 is open, the voltage at terminal "C14" will be about 0.45 volt. This may also cause DTC 13 to set.
• If all check OK, the Oxygen Sensor (O2S) is faulty.

I hope this helps

nkh34

It almost seems to me like you just got a faulty o2 sensor i know it was brandnew but faulty parts happen alot

brothers4.3

It was a brand new Bosch oem replacement with the correct plug, Im pretty sure the o2 is fine, the truck is running much better now, but we think there might be a crack in the oem exhaust manifold. Instead of paying $100 for a new cast manifold, hes thinking of maybe spending 2-300 on a pair of decent tubular shorty headers that will bolt up to the stock Y-pipe/cat section, but all I can find is 96+, will the obd2 96+ 4.3 vortec headers work with his 95 4.3 vortec 1500? Hes also thinking of getting the Magnaflow bolt-on direct fit Y/cat while we are replacing the exhaust manifold...

also, not so related, he wants a cheap intake, and all I have found are cheap intakes for 88-99 5.7 1500's, will one of those intake work on his 95 4.3 tbi 1500?

nkh34

With headers i know with these trucks you want to go with long tubed headers if you want a gain. Intakes also you wont get much out of everything i read says not to change the stock air box its already set up better than most cold air intakes. Either get the tube from airaid or just put a K&N in the stock air box. here is some good holley headers for the truck Holley Performance Products Ceramic Headers 31508FLT
Then this web site has a couple different brands Parts Bin - Auto Parts and Accessories Catalog - Headers
It looks like they all run from about 300.00 up

sonorakid

Great thread