Engine Problem on a 93 4.0L OHV

[theBlurr]

hey folks,

I am in some need of help, I have tried everything I can think of with out access to a scan tool.

Problem is this... intermittent hesitation, black smoke from exhaust, CEL is on, and intermittent rough idle. I believe the engine is running rich, and causing the engine to bog down and hesitate.

What I have tried... checked plugs, all were wet with fuel. Compression on all cylinders is with in 5psi of 150psi. Fuel pressure is constant 40psi and holds for 15min after pump shut off (test was done with out the mymengine running using the Data Link Connector). Checked vacuum line on the pressure regulator and no sign of fuel. Air filter is clean. Finally the ignition coils are all capable of putting out approx. 20kV using an air gap tester.

So... does anyone else have other thoughts or suggestions on what to check. Any help is much appreciated.

Cheers
Blair

 

[tobyduck]

Check your MAF sensor

 

[4.0 power]

coolant temp sensor

 

[Nhaz]

scan tools for OBD1 (which you have) are dirt cheap.

http://www.therangerstation.com/tech_library/OBD_I.html

Look at the MIL section. this allows to to get a code without a scan tool.

Oh and its also maybe a O2sensor. Its old enough for it to be bad.

 

[theBlurr]

thanks everyone for the suggestions, I was able to fix the problem after some probing with my multimeter, it was a MAF low voltage. So a trip to the wrecker and all is good.

cheers
Blair

 

[xentris02]

sound like your timing could be off