Hey guys so I have an automatic 91 305 TPI. I recently found that 4 of my fuel injectors where bad (after my car was stalling out, lacked power, and would not shift gears smoothly) by testing and finding the injectors were well below 11 ohms...so I bought a set of Bosch III injectors for South Bay Fuel Injectors and installed them smoothly as per the instructions I found on this site. After that my car was a night and day difference with the smoothest idle, solid shifts, and a lot more driving power. However, a day later the car began running rough and stalling. It was not as rough as before, but rough enough to stall out when idling. After giving it gas a bit it would go back to running perfectly. Then the next time I run it it misbehaves and idles rough. What might cause it to run perfect sometimes and horribly other times after this injector swap?? There are no gas leaks that I can see or smell and all the injectors tested ~15.6 ohms...any ideas?

 

Just curious...did you reset the ECM?

 

I had the negative battery cable disconnected during the swap and reconnected it after, so I'm guessing it was reset.

 

So another note about my issue...when the car is idling rough it chugs like a diesel truck engine and pours smoke out the exhaust ans spews out black carbon...if I rev the engine into the redline range the idle smooths out and the engine operates like brand new...no carbon spewing out n barely any visible smoke. Could this be a vacuum leak? I suspect my TB gasket....

 

Generally, black smoke = mixture too rich. A vacuum leak will generally result in a lean mixture. My first thought is maybe one of the injectors is sticking open. When you had the rails and fuel lines loose, maybe you got a little bit of debris in the system that's gotten in an injector. Check it with a fuel pressure gauge and see if it holds the prime after the ignition is turned on for a few seconds then off.

 

I was hoping this would not be the case as the fuel line connections had quite a bit of corrosion and its possible while reconnecting the metal lines that some rust could get in....however I do not have a fuel pressure gauge, if there is debris in the injectors what can I do to avoid having to pull the injectors out and clean them? I tried seafoam in my gas tank and that didn't help much...would lucas injector cleaner or chevron's techtron actually help dissolve crud? Any other alternatives?

 

I was suggesting that as starting point. It could be a number of things causing your problem. A pressure test is an easy way to ether confirm or eliminate the injectors as a probable cause. I wouldn't go taking out the injectors again without testing them. Auto Zone will lend you a fuel pressure tester (have to leave a deposit) free. If you intend to keep the car and drive it, I would suggest you spend the $30 or so for a basic test gauge. The pressure test is the starting point for a lot TPI diagnostics, so it's an absolute must have tool when your trying to figure out what's wrong with a TPI system. Believe me, this wont be the only time you'll need one if you keep the car

 

Thank you very much for your advice lonestar7. I did realize I was losing fuel pressure and decided to change my fuel filter. Upon changing the fuel filter I found that the solid fuel line from the tank to the fuel filter had rusted through and would drip/mist in a few places when I pressurized the system by turning the ignition on. So I bought a replacement line from JEGS (part no. 965-FGL8507)...I am hoping this is the correct line and hope that it would not be too difficult to reach/change myself.

 

Did you find the problem???

 

if there is rust or debris in the injectors I don't think seafoam or any other injector cleaner is going to work at this point. Another way to check for a leaky injector is to run the engine and then pull the plugs. If you have any wet cylinders then you have a leaky injector. If that is the case you may just have to pull them. Send them in to us and we will clean them for you....no charge.
You need to make sure that your entire fuel system is clean.

 

I though I solved the issue with the new fuel line...but I did not...my issue continues in this thread:

https://www.thirdgen.org/forums/tech...ml#post5661506