Ok, I have been running very rich lately and have fixed the exhaust leaks,I think, yet still running rich. I believ it is a sensor telling the computer to fatten it up.At initial start up it is not rich.after a couple of minutes, raw fuel starts dumping out of the tail pipes. I have ommited the rear 02 sensors(programmed out) and the front two are brand new bosch. I changed out the mass air flow and map and it made no improvement. We took a scanner reading with both the old parts and the new and they both seemed to reading in the same range(don't remember) so I returned the new ones and put old ones back on. I am having a problem with the valves but no hesitation or miss and I did turn the fuel pressure down to right at 40 PSI(which should be fine) fuel advance per Chiltons. If it was a problem with the tunning,I believe that at idle it would do it the whole time, not just after a couple of minutes. Help please as I am only getting 200-230 miles out a tank and I am babying it. I used to get at worst 275.

 

Looks like we double posted? Mine has been getting 170miles per tank and it sucks. I don't drip fuel though and it smells normal. Are you fouling plugs? Are you holding fuel pressure when you turn the engine off?

 

no havent checked the plugs in a couple hundred miles but engine is brand new, 3k miles? Fuel pressure is perfect throught all operating ranges.

 

Are your injectors stock? What size are they?

Are your o2's switching at idle in closed loop?

I'm thinking either your injectors are too big and dumping raw unatomized fuel down the intake causing too much air to get by the chambers. This would give you a lean condition at the o2 causing the computer to dump even more fuel. You shouldn't get this problem with the hot cam cause its supposed to be a mild stock cam.

The 97 has heated wideband o2's right? I've heard many times that people who install headers loose enough heat in the exhaust to not let the o2's come up to temp. Make sure the fuses are good for the o2 heating elements.

 

I was told by the guy I bought the car from that the injectors were not stock, but either way when I bought the car it was stock and I did not have this problem before. Since new engine and flash I have.

I didn't know that about the heating element to the 02 sensors, never heard of that. So I don't know. I'll check the fuse block, what would it be labeled as? I don't remember seeing anything labeled 02 sensor heating element or anything like that.

 

But like I said, a 97 wide band may not have this.

 

There are no wide-band O2 sensors used in any stock 4th Gen engine, so scrap that idea. The only 4th Gens that do not have heated narrow-band sensors are the 93's. They have single-wire unheated narrow-band sensors, so there can be a problem with the sensors getting hot enough on a 93, but not on the 94 and newer models with the 4-wire heated sensors. There are trouble codes and an SES light for faulty heater circuits.
If I'm reading this right, you have been told the car had non-stock injectors. Appears you then had the engine rebuilt, and the PCM reprogrammed. In order to get the PCM tuned, they have to know the size of the injectors. What did you tell them about the size?

Many people here have found that the Bosch O2 sensors do not give good results. Most recommend that you stick with the OEM AC/Delco sensors.

You mention you are having a problem with the valves..... what is that problem? If something is increasing overlap dramatically, or if the valves are not closing fully, it could result in unburned air in the exhaust causing a false lean condition.

 

Just that, not sure valves are set right, I have been thinking this was issue but no one else would confirm it as a possibilty. Thanks injuneer and 89. will check tonight

 

oh and in regards to the injectors I told him they were stock and he confirmed not programmed any different in the computer

 

update. Just set the valves and some were nto set right,but now they are set right, 0 lash. car runs and drive much better....but. Still running rich,a little white smoke, only in open loop. Once the car warms up and it goes to closed, the smoke stops and doesn't smell AS BAD but still rich.This is seeming more like a tunning issue....am I thinking right?

Also scanner at friends work has not said anything wrong with 02 sensors or heating element to rule that one out. I appreciate alls help very much

 

Good to hear its running better at least.