replaced MAF and O2s, now worse codes!

[virgil's ranger]

replaced MAF and O2s, codes got WORSE

After my CEL came on on my 94 ranger 4.0, i read it and replaced the MAF and O2s now i get these codes....

179 Fuel system was rich at part throttle Single, Right or Rear HO2S - Fuel control
114 IAT sensor out of range - IAT
116 Engine Coolant (ECT) sensor out of range
157 Mass Air Flow signal is/was low or grounded
173 Oxygen sensor not switching - system is or was rich - Single, Right or Rear HO2S
188 Fuel system was rich at part throttle - Left or Front HO2S - Fuel control

What's wrong?

 

[Runnin'OnEmpty]

I'd first check to see that everything is plugged back
in after the work was done. Especially the IAT and ECT.

Might have a vacuum leak at the plenum O-rings...?

 

[virgil's ranger]

All Plugged In And Good

 

[virgil's ranger]

Bump. please I Need Some Help. One Thing I Have Been Thinking Is About 2 Years Ago I Put In Some 24# Injectors From A Lincoln v8 But Haven't Had Problems Yet.

 

[UrbanRedneckKid]

Does it run bad or lack power? Usually MAF and O2 codes point towards a plugged converter...(referring to why parts were originally switched out)

Check your 5v reference signal, its possible one of the sensors you put in was either wrong or shorted.

Remember, New part doesn't mean good part. Manufacturers pump out thousands of parts daily, and don't test every single one.

 

[kimcrwbr1]

Did you reset the computer and erase the memory. Disconnect the battery for at least 1/2 an hour. Clean the MAF with rubbing alcohol and check all vacuum and electrical connectors. Do a KOEO test and when it starts sending codes end the test to erase the memory then run it for 20 minutes and run the codes with the engine hot. You need to reset the computer every time you clean/change a sensor. Allways fix one code at a time starting with the lowest number first, reset the computer and erase the memory to confirm the repair. One senser can set off multiple codes that is why you fix the lowest number first and confirm the repair.

 

[virgil's ranger]

I Did Check The Cat. All Good. All Connections Are Good. Cleaned MAF .Reset Computer.
Better, But Still Sporadic CEL code Flash And Poor Performance.

 

[UrbanRedneckKid]

Did you check the computer's ground?

IIRC, it comes from the fender harness, there is a plug-in under the fuse box, the other end runs to the negative battery terminal.

Should be .02 ohms from the ecu to the terminal, with both ends disconnected.

 

[virgil's ranger]

That Would Make It Flash Those Codes?

 

[mfkcbk]

Possible computer malfunction?

Similar (runs rich) code problems with my 93 4L, with 270k mi. Ran terrible. Going up hill I couldn't go more than 35mph. Cleaned the map,replaced o2 sensors and fixed a potential vacuum leak but didn't help

Ended up changing the engine control computer yesterday with a reman. from cardone for $100.

No cel and truck runs great again!

Only hard part was getting the lower nut off the ecc housing since it sits so low on the wheel well; at least on my truck.

Don't know why the computer messed up. Maybe 20yrs is the reason or who knows.