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iTrader: (17)

I am running very rich, car back fires, flames will shoot out some times, smell of fuel.

Here is what has been replaced,
oxygen sensor,
tps,
Iac,

I am running out of ideas, wtf is making me run rich as hell? i have no cats or anything. could my MAF be bad?

i did a search and found the solutions to everything I have already replaced. I differenately need some help. thanks!

pmpn

Any codes? What is your base timing set at? Do you have an AFPR? If so, what is it set to? You could also have a combustion problem (burnt wire, fouled plug) on the left bank causing the ECM to dump more fuel in.

Toxinz

could be a computer problem and is in limp home mode. Coolant temp sensors have a very profound effect on air/fuel. It could be the maf sensor. It also could be missfireing really bad because of a bad coil,arching wires,plugs, etc. However you should really get a scan tool and see what the pid lists says. Any trouble codes come up?

Vader

If the MAF were reporting an out of range intake air flow, the ECM should set an error code within 600mS. I would disregard that as a possibility for now, but if you really want to prove it to yourself you can disconnect the MAF electrical connector and see if the engine starts/runs any better. Don't get your hopes up...

You probably should test fuel pressure with both the engine running and after shutdown. If pressure is within the normal range, and does not drop off rapidly after the pump shuts down, look elsewhere. If the pressure does drop off rapidly, check for leaking injectors and/or a leaking fuel pressure regulator.

TPeye

check the resistance of each of the injectors. they should be around 16-17 ohms

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iTrader: (17)

well, I have replaced the coil as well along with the wires. I have no engine light on. How do i check for the code? I have that key thing. As for the coolant, the previous owner hardwired the fans to run at all times.
As for timing, i do not know what it is set at yet, I have only owned the car for a week. What is the factory setting suppose to be?
Also, what is the fuel pressure suppose to be. I believe the previous owner said something about an afpr. If I know what the psi is suppose to be in the ball park, then I can adjust accordingly. thanks

8492bird

"Ballpark" pressure is 40-45 psi. I think specs are 42-43 psi.

pmpn

6-8* is standard base timing. If your not getting an SES light, I would, like Vader mentioned, assume O2 and MAF are operating. CTS is a good idea, you would have to check that with a scanner. It could be leaky injectors but I would imagine you would get an SES light for it- "O2 too rich" if it were anything serious. I think you have a vaccuum leak or a misfire. Are you using the stock PROM??

Which direction is the engine backfiring?
-If it is out the exhaust- it is too rich because extra fuel is igniting in the exhaust.
-If it is in the intake- it is too lean. You may smell fuel only because it's not consumed. (Timing is too retarded or completely off)

I would look really good at your timing, make sure the wires are in good condition and in the proper firing order.

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iTrader: (17)

I will check the timing tomorrow, however, I doubt the car is misfiring, it idles okay, It is a little rough, but when you get up on it, it has no problem hauling ***. But, I will check it anyways. I will also take all the plugs out? Any recommendation on plugs for TPI? just standard bosch coppers? Plats?
How do you even adjust the timing on a tpi? Regular Hei is easy, how does this system work?
Also yes, the car as far to my knowledge has a stock prom. If the injectors were leaking you would think I would smell gas in the engine bay right? And the backfire is definately through the exhaust. However, I do have alot of exhaust leaks that do need to be addressed.

pmpn

When does it back fire? Mostly at idle, wide open throttle or deceleration; all? TPI is HEI, you will just need to disconnect the brown connector on the passenger strut mount, it is the ESC- computer controlled timing. That way it isn't advancing when you try to set the timing, then set it as you normally would a carbed vehicle with a timing light. It will prolly run like crap with the ESC disconnected... not a problem as long as you can adjust the timing to be close. It would be a good idea to pop out your ECM and verify that you have a stock chip, could save lots of troubleshooting now and later.

From personal experience I would recommend AC Delco, they don't advertise like the others but they are good. I've had Bosch plugs foul after 30 mins of run time. Exhaust leaks in itself will cause backfiring, fresh air being introduced to hot fumes can ignite. Especially if it's a header leak.

When we say leaky injectors, yes they can leak externally but specifically internally. Old injectors wear over time and the pintle does not hold fuel pressure as well causing fuel to leak into the cylinders.

3.8TransAM

Run delco ignition compenents and save yourself some trouble.

Also hardwiring the fans on all the time is a waste and will make your car run cold and waste fuel, although it more than likley isnt causing your current experiences.

Ohm the injectors out. You should have 17ohm if good and stock. Above 12 ohm is serviceable per GM, this only verifies electrically, not mechanically.

Pull the vacuum line to the AFR and see if its wet inside, if it is , its bad. Hook up a FP guage and block off the feed and return lines immediately after u prime the pump. Watch and see what happens, it should hold pressure for an extended period of time. Like an hour or two.

If it doesnt hold pressure, remove the plenum and lift the fuel rail up with clips attached and reprime the system and lay paper towle underneath and watch for leaks.

Also your car has acold start setup. failures of that injector and switch are fairly common.

later
Jeremy

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iTrader: (17)

The car only backfires when you are driving and if you shift pass 3k rpm. As soon as you shift it backfires, then accelerate, shift, backfire. I am replacing the trans tomorrow. I wiill try and time the motor as well and check the ohms of each injector.

pmpn

Sounds like a leaky injector to me.

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iTrader: (17)

I havent had a chance yet to tear into the car, I am new to the Tpi world, but what gaskets would I need to do this injector replacement? plenum gaskets? then obviously the new injector and orings? What is the time frame on this work so I can plan accordingly?

pmpn

You'll have to remove the TB, plenum, runners and fuel rail. I would just reuse the runner and TB gaskets. Orings come with injectors. It takes me about an hour to swap injectors, piece of cake. Before you do, you really should hook up a pressure gage, see what your fuel pressure is. Turn off the car and watch your fuel pressure, it should hold pretty steady for a few hours. It's the best way to check for leaking injectors.