Hi everybody, I have a 2002 chrysler t&c 3.3 flex. Last Monday wife drove it twice it was fine then i got in it and it acted like it was flooded, put it to the floor and will fire up spit and sputter blow black smoke out the exhaust keep revving it up and it will clear out, runs fine after that and starts fine but gets bad mpg. sometimes it wont start just cranks. when it is running I can put it to the floor it will rev up to like 5 grand the just fall on its face like its being choked out. here's what I've done. New fuel filter,map sensor,temp sensor,tps sensor, timing chain cleaned out the cat left the exhaust unbolted didn't run any better. Has gas in the oil, pulled up the injectors looked at them and when it cranks they seem to firing like they should be. Has spark, has from 50 to 60 psi on fuel. I have been reading on internet about the sbec being bad or oxidized. Unplugged the pcm and the plugs looked good. where is the sbec and what does it do. I am usually pretty good with diagnosing vehicles but I am going crazy with this. Any and all help will be greatly appreciated. Thank you.

 

SBEC or Single Board Electronic Controller is a design description of the PCM or Powertrain Control Module. They are one in the same. PCM is the term most use today.

Rings or an injector stuck open. The later would explain the hard starting too. Have you check fuel pressure before the first start of the day? Have you checked compression. Vacuum leaks?

 

I have not done a compression check but when id does start and stay running it runs fine. I did check for a vacum leak and no leak. when i first turn the key on first start of the day it jump right up to 55 psi for fuel. pulled up the injectors and turned the key and let it prime up and the injectors do not leak at all while I was holding them up and watching them.

 

What is the pressure before you turn the key for that first start. Looking for at least 40 psi.

 

it will bleed off down to like 10 psi before i turn the key on. Before I the key on for the first time it smells like gas through the intake. The thing that gets me is even if i turn the key on like 2 or 3 times before starting it to prime the pump, it still will not start. I was wondering that if after it sits for a extended period of time the injectors cant keep holding the pressure and they start to bleed off into the valves then they leak down into the cylinders and it floods out when i start it for the first time. But why when I take it down the road and put it to the floor and it revs up then just falls on its face and wont go at all and no matter how long i hold it to the floor it just keeps bogging down until I start to let up on it then it will start to pick up again.

 

Check the fuel injector harness, just outside the intake manifold (driver's side) where it passes near the exhaust cross-over. Many people have found degraded wire insulation. Search for some good posts w/ photos. Mine looked just like the photos. I wrapped each wire w/ self-fusing silicone tape (good to >500F) and no problems since. The harness weave is held w/ a longitudinal Velcro strip so is easy to peel open.

The fact that your fuel pressure leaks down to 10 psi suggests you might have a leaky injector. However, that could be due to a bad check valve in the fuel pump too. There are many companies that will test your fuel injectors for flowrate and spray pattern, and ultrasonic clean if needed. They are pretty reasonable here (~$15/injector) and often have a booth at auto shows.

 

I did try and rub the wire harness between my fingers and while it was running and it would not stumble or die or anything and when it wouldn't start i tried messing with them and it didn't do anything but i think I'm just gonna just start pulling the wiring harness apart and looking at it. I have whole different harness from another van i had to put a motor in for a guy so maybe I will just put that one on my van and try it. I think I may even have a whole set of injectors and rail from the same van too. Think I might try those. Its down to trial and error now. Gonna mess with it some more tomorrow I think. I'll keep you guys updated as I work on it and ideas will still be appreciated. I am gonna double check every thing you guys suggested just to make sure I didn't over look something. Thanks guys