Engine running lean 96 supercarged series II

Thank you. The car is very responsive with the throttle. I dont have any farb cleaner but i will get on that test. The cars idle does fluctuate but very smoothly like i were doing it with the thrittle and only about 200-300 rpm difference. I havent dine a oressure test because i dont know where to put the connector. Anyhow. I will do these tests. And my car does shift funny. Itbstays in the torque converter gear constantly amd doesnt lock gears unless it it under a heavy load like going up a hill or accelerating.

dtrumbo wrote:

Thank you. The car is very responsive with the throttle. I dont have any farb cleaner but i will get on that test. The cars idle does fluctuate but very smoothly like i were doing it with the thrittle and only about 200-300 rpm difference. I havent dine a oressure test because i dont know where to put the connector. Anyhow. I will do these tests. And my car does shift funny. Itbstays in the torque converter gear constantly amd doesnt lock gears unless it it under a heavy load like going up a hill or accelerating.

I do not remember if you removed/cleaned the throttle body.

If not, you might find that if you remove it and clean it well (and use MAF sensor cleaner on the MAF and be sure the IAC port is cleaned out as well) you may find your idle fluctuation goes away. There is write up on that on this site. You will need coating-safe TB cleaner, and sensor-safe MAF cleaner. GM dealers sell a great TB cleaner in tin bottles (instead or/in addition to spray cans). Ironically, *my* dealer uses the Castle TB spray (you have to be REAL careful with it though it is a very very aggressive solvent).

Albertj

I havent removed these things to clean them because of all the fuel lines going iver them. It seems to be a complex job. Not difficult just alot of small parts but i did clean the maf sensor.

dtrumbo wrote:

I havent removed these things to clean them because of all the fuel lines going iver them. It seems to be a complex job. Not difficult just alot of small parts but i did clean the maf sensor.

You don't have to remove any fuel lines but you do need to detach the throttle cable and cruise control cable, and you need to let a little coolant out of the coolant drain because the TB is water cooled on these cars. You also need to get a replacement TB gasket, about $4-$6 if you can buy it right - shop around. You could get them cleaned on-car at a shop with Wynns or BG machine BUT on these cars the IAC and EGR passages will stay dirty if you do it that way and eventually the car will turn the SES light on anyway.

Cleaning the MAFF sensor - easy thing to do, nice job getting that out of the way.

Before you take your TB off for cleaning, I'd do the carb cleaner check, and the fuel pressure check if you can acquire a fuel pressure gauge. Make sure it's the type special for checking fuel. Fuel pressure is checked from the valve on the front rail. You need to remove your engine cover and the valve has a little plastic cap on it. The gauge threads onto this valve.

Okay, thank you. I am prettyvsure i can rent a fuel pressure gauge from the parts store. And i will get carb cleaner and spray around to check for a vacuum leak.

AA wrote:

The supercharger coupler won't cause anything like your experiencing.

Before we decide a vacuum leak is causing your lean condition (I'm not sold on it), are you experiencing any obvious symptoms of a vac leak? A serious vac leak should make the engine RPM fluctuate at idle, and hesitate under throttle application, but then things will seem fine once you get into it. Are you experiencing a rough idle situation? If so, you haven't told us about it. It also effects shifting of your trans. I once had a cracked vac line, which made my some of my shifts feel "harder" than normal.

Have you tried spraying your vacuum connections with carb cleaner with the car running? A leak might respond with a change in idle RPM when you find the leak area. This same test can be done for the intake gasket, and I assume the LIM gasket too, if it's that bad that it's leaking to the outside air.You can also combine this test with the use of a scan tool to check changes in STFT (short term fuel trim). STFT should change quickly if you spray the leak area. If you're not able to get a response from spraying the carb cleaner around the engine, I wouldn't start tearing apart and replacing gaskets just yet.

Another test you can do is use a scan tool to simply watch STFT & LTFT (short/long fuel trims) while running the engine. If you are truly running lean, your STFT & LTFT numbers should be very high (above +8 or 9). If this is only the case at idle, and the STFT gets closer to zero at higher RPM, it suggests a vacuum leak. If the STFT continues to stay high at higher RPM, it probably represents a fuel related condition.

You say there is a starting problem, or delay. Here is a big clue that makes me think fuel delivery (although a vacuum leak could also cause this). One thing to try is to take a fuel pressure meter and mount it to the pressure valve on the fuel rail, with engine off. Start the engine and get a reading - should be above 40 PSI at idle (mine showed 44). Turn the car off and watch the needle. Does it lose pressure quickly? If so, one of your injectors may be leaking fuel, which might explain all of your problems. BUT.. you can't know this until you perform the test.

i forgot to ask if a leakey injector would cause a lean reading on the diagnostic.

In theory it shouldn't, but you are assuming there is a single problem. You could have a few different problems causing your symptoms (example: one leaking injector and one stuck, or leaking injector and vac leak).

I see. Thqts a good pont. I will have to check all of it.

When i sprayed the carb cleaner around i didnt notice any change in idle but after a few seconds it started to smoke white.

dtrumbo wrote:

When i sprayed the carb cleaner around i didnt notice any change in idle but after a few seconds it started to smoke white.

That sounds like a different problem, more like when the thermostat opened up then coolant began leaking into a cylinder. Time to pull the plugs and look for fouling.

I am not loosing coolant thoug. And i almost never get any smoke except from gas.

The carb cleaner was smoking white? Or the exhaust? Or what?

It was going through to the exhaust. . Sorry.

dtrumbo wrote:

It was going through to the exhaust. . Sorry.

smoke coming off the exhaust pipes under the hood, or coming out the tailpipe?

Lol. It was coming out of the tailpipe. I think i did things wrong i put the little straw on it instead of misting it around

Well that's good info - if the carb cleaner you sprayed on/around the intake area made it into the exhaust, you very likely have a vacuum leak of major proportions, which just backs up the whole lean code. Now you can spray carefully, one place at a time, and see where it causes the engine to stumble or race briefly. Spray a little more scientifically and you will narrow down the point of leakage.