Tech Support Forum - View Single Post - [SOLVED] 95 Chevy S-10 4.3L TBI

dgoad · 09-03-2007, 04:28 AM

I would like to ask some of you to take an educated guess at this problem(s). My son's has a 95 S-10. Was running great, until one day a couple of months ago, it started running really rough at a red light ( as he tells me ) and he had to work the throttle to keep it running and then about a block or two later it quit and hardly would start. When it does, it will not stay running well even with throttle work. My son was told by one of his buddies that he thought the Catalytic converter was plugged up. So, my son took it off only to find that it was not plugged and the truck still has the same trouble. So, he had it towed from his house to mine. I know! I Know! Anyway, I got a chance to help him with it the other day and boy what a job. I will tell you that this truck has a little over 200,000 miles on it and the only thing that has been replaced was the altenator a few months back. Yes, it is in need of some help. Anyway, I started by looking for vacuum leaks and I found a couple and replaced the fitting and hose. The engine is still loping really bad. I read the engine codes and got an EGR and RICH code. Looking at the Throttle Body I noticed that both injectors were dripping. So, basically I rebuilt the TBI. New injectors, fuel pressure regulator, cleaned the IAC and the ERG valves. Installed new plugs, wires, cap, rotor, fuel filter, and O2 sensor. I checked the fuel pressure and it is reading 11psi down to about 7psi. The pressure moves down and back up slowly as you race the engine and basically is pretty stable most of the time around 9-10psi. I was told that this is normal and that while the fuel pump is old ( and I will more than likely have to buy one of those too! ) it is still working and it should not be what is causing the running at idle problem. I am saying an idle problem. I figure that when I find what is stopping it from idling correctly, I will be able it fix all the problems. ( well maybe not ) I reset the codes and now I have none showing. Computer does show that it is in OPEN LOOP MODE and O2 Sensor shows RICH and while working the throttle and watching the code meter, the reading will move from RICH to LEAN and back to RICH again. While all of this has helped the engine somewhat, it still barely idles and it still lops really bad. Throttle aceleration is smoother ( not a clean smooth note by any stretch ) when going up with NO backfires up or coming back down, but the engine still hunts, misses and lops. There are only a few things that I think that I might have missed, other than my brain, and I might not be able to find it either. I have not looked at the igniter module for the ignition and I don't know if this could even cause this kind of trouble. I have not done a compression check. The head gasket comes to mind, but I have no water or oil issues inside, outside or otherwise. And come to think about it I have not checked for water in the gas. But, that would have to be a lot of water. We have burned, spilled, sprayed and or pumped out and use several gallons during our fuel system adventures and the tank is still half full and problem is still there. Anyone with any insight and comments other than "just shoot it" , I would like to hear your ideas and they would be appreciated. Oh, and I did kick it in the right door panel because it got in my way, still no luck. Thanks.

09-03-2007, 04:28 AM	#1 (permalink)
dgoad Registered User Join Date: Sep 2007 Posts: 10 OS: wVista	[SOLVED] 95 Chevy S-10 4.3L TBI - Idle troubles I would like to ask some of you to take an educated guess at this problem(s). My son's has a 95 S-10. Was running great, until one day a couple of months ago, it started running really rough at a red light ( as he tells me ) and he had to work the throttle to keep it running and then about a block or two later it quit and hardly would start. When it does, it will not stay running well even with throttle work. My son was told by one of his buddies that he thought the Catalytic converter was plugged up. So, my son took it off only to find that it was not plugged and the truck still has the same trouble. So, he had it towed from his house to mine. I know! I Know! Anyway, I got a chance to help him with it the other day and boy what a job. I will tell you that this truck has a little over 200,000 miles on it and the only thing that has been replaced was the altenator a few months back. Yes, it is in need of some help. Anyway, I started by looking for vacuum leaks and I found a couple and replaced the fitting and hose. The engine is still loping really bad. I read the engine codes and got an EGR and RICH code. Looking at the Throttle Body I noticed that both injectors were dripping. So, basically I rebuilt the TBI. New injectors, fuel pressure regulator, cleaned the IAC and the ERG valves. Installed new plugs, wires, cap, rotor, fuel filter, and O2 sensor. I checked the fuel pressure and it is reading 11psi down to about 7psi. The pressure moves down and back up slowly as you race the engine and basically is pretty stable most of the time around 9-10psi. I was told that this is normal and that while the fuel pump is old ( and I will more than likely have to buy one of those too! ) it is still working and it should not be what is causing the running at idle problem. I am saying an idle problem. I figure that when I find what is stopping it from idling correctly, I will be able it fix all the problems. ( well maybe not ) I reset the codes and now I have none showing. Computer does show that it is in OPEN LOOP MODE and O2 Sensor shows RICH and while working the throttle and watching the code meter, the reading will move from RICH to LEAN and back to RICH again. While all of this has helped the engine somewhat, it still barely idles and it still lops really bad. Throttle aceleration is smoother ( not a clean smooth note by any stretch ) when going up with NO backfires up or coming back down, but the engine still hunts, misses and lops. There are only a few things that I think that I might have missed, other than my brain, and I might not be able to find it either. I have not looked at the igniter module for the ignition and I don't know if this could even cause this kind of trouble. I have not done a compression check. The head gasket comes to mind, but I have no water or oil issues inside, outside or otherwise. And come to think about it I have not checked for water in the gas. But, that would have to be a lot of water. We have burned, spilled, sprayed and or pumped out and use several gallons during our fuel system adventures and the tank is still half full and problem is still there. Anyone with any insight and comments other than "just shoot it" , I would like to hear your ideas and they would be appreciated. Oh, and I did kick it in the right door panel because it got in my way, still no luck. Thanks.