Running rich and fouling plugs

[kpate]

1990 Bronco II 2.9.....had it running good and it started fouling plugs BAD. I replaced oxygen sensor, fpr, injectors, map sensor, and tfi. It does run, but extremely rich like its in safe mode. Could it be the ecu????

 

[RustedRanger]

Check for codes first....you can find how to do that in the Tech section. It could be a number of things. I had replaced a bunch of things,was running good then all at once wouldn't want to start hot and ran rich...it was the ECT sensor (engine coolant temp) that I had changed,went bad again.

 

[robertc1024]

+1 with ^. I had the same problem. You can check it if you've got an ohm or volt meter. Here's a link to test it: http://oldfuelinjection.com/index.php?p=28

There is also a ground wire from the firewall to the passenger side of the back of the engine. I've heard a lot of people say that if it isn't making good contact on both ends, it can cause the engine to run rich.

 

[kpate]

Checked for codes. Get a code 11 and (pass test) everytime. Will look for that ground wire when i get home tonight.

 

[cmr2]

Have you broke the coolant line ? If so possible air pocket sits at the coolant sensor

Grounds also like mentioned

 

[a31ford]

Fuel pressure regulator is leaking into the vacuum hose... would be my guess, inspect the back of the stem, look for crud or the smell of gas, or even liquid.

Greg