Black smoke CEL Frustration

[NAVAJOMATT]

Hello out there everyone well I just got back from living under the ocean and am ready to go out and play!! But while I was gone my 91 Navajo started acting up running rough no power black smoke and poor poor gas mileage, Well I have changed the o2 sensor fuel filter air filter and the Fuel Pressure Regulator but still the black smoke! Engine is running much better but as I said Still smoke though much less. My questions are A. has anyone had this problem replaced the FPR and it just takes some time to burn off all the crap built up in there or any more suggestions? From what I have read there is no EGR Valve on the 91EFI but any help would be appreciated. Thanks in advance...Matt

 

[TDG]

Is it also emitting a rotten-egg smell? If so I would suspect that it is still running too rich, maybe a bad fuel injector or a combination of things. If it was running rich enough to produce black smoke I would question the condition of the catalytic converters, they don't handle raw fuel and extermely rich conditions very well and I have heard of some plugging up. Depending on how long it was being driven in the overly rich condition could cause a lot of carbon build up in which case could take some time to "burn off" leaving you with a little bit of black smoke. By the way are you still getting a CEL?

 

[NAVAJOMATT]

Yes so far it has only come on once and cleared when I shut it down...Smoke seems to be less and less so I am keeping my fingers crossed......But I am moving back out to San Diego and don't want to have this problem going on next month when I go! Don't want to break down halfway across the country or miss any runs once I finally get out there!!!!!!!!

 

[jimbo74]

if it is black or blue smoke it could easily be an oil problem.

 

[TDG]

From what I have seen if it has blue in it then it is oil, not to say that oil can't produce black smoke but black is more commonly seen when overly rich conditions exist. Back when I was doing light vehicle and power generation maint for the military we used to run the piss out of the diesel engines to get all the carbon out that came as a result of not putting enough load on them, and they would billow clouds of black smoke but then again diesels are a different world. Do you know what the code was for the last CEL you got?

If you are coming to SanDiego you might want to check out http://www.explorerforum.com/forums/showthread.php?threadid=29978 for a possible SoCal explorer club.