Hello. I just replaced the head and intake gaskets on my 4.0 engine. After hooking everything back up it runs rough but if I disconnect the MAF it runs fine. Could it be just dirty or is it bad? Also the alternator doesn’t show voltage or charging. I had it tested and the auto parts store said it was good. The regulator was cracked so I replaced it. Before I did the engine work it ran ok just misfired when at cruising speed or under 45 MPH. I have checked wires, fuses, links, vacuum lines and found no leaks anywhere. Can I get some help and advise please? It’s a fantastic little truck that’s in solid shape. It has 411165 miles on the odometer. I also have tuned it up. Plugs, wires, coil pack is two years old. Thanks in advance from an old shade tree!
i found a ground wire that I didn’t connect and now have 15v out of the alternator, 16.8 V on the fuse able link by the black fuse box under the hood and 14.6 bolts on the other side that goes to the battery. The charging gauge is down on the low end and not moving even at high revs. Battery had 11.68V and running the engine for 30 minutes dropped it to 11.57V I can’t tell if it’s charging the battery but it all seems to be working. I will clean the MAF and see if it changes when I plug it back in. If not I’ll replace it. Any ideas on what I might have missed? Thanks!

 

Welcome to the forum

What year Ranger?

A car/truck battery should be 12.3v to 12.8volts, so your battery is drained or bad
Test battery after it has been sitting for a few hours, over night is best, do NOT start engine
12.8v new battery
12.5v at 3 years old
12.3v at 5/6 years old

12.2v or lower is a drained or bad battery

Vehicles Charging system's are very easy to test, test battery first, and remember its voltage
Key OFF
Use alternator's metal case as the ground
Test B+ terminal, the stud/nut terminal on the back of alternator, leave wire attached, should read Battery Voltage exactly(you remembered it right, lol)
If not then fuse or fusible link is blown

Unplug 3 wire plug on voltage regulator
Test the yellow wire, should be Battery Voltage exactly, if not then fuse or fusible link is blown

Test the light green wire, should be 0volts
Turn on the key
Retest light green wire, should now be Battery Voltage, can be a little less<< this is the ON/OFF switch for alternator, also the Battery Light circuit, so important

If all wires test OK then plug back in 3 wire connector and make sure the White jumper wire is plugged into its single terminal

Start engine
Test battery voltage again
Should be 14.3v to 14.8volts, UNDER 15Volts!!!!!!, over 15volts will fry a battery
After 5 minutes of idling test battery volts again, should now be 13.5v to 13.8volts under 14volts, that means voltage regulator is working

If battery voltage is under 13volts after start up and the wires test OK, then alternator is bad, period, doesn't matter it is new

Charging system is just not that complicated, test 3 wires and your done

 

Thanks Ron I’ll recheck it tomarrow. It’s a 2000 ranger. I cleaned the MAF and it still ran rough so I’ll get a new one. I’ll post my results when I go over it all again.

 

If vehicle voltage is under 12volts engine running that may be the reason for rough running, so get alternator system fixed FIRST

 

Thanks Ron. The fuseable link by the engine fuse box was bad replaced it and it’s all good. Now just a new MAF sensor and it’s good for another 500K miles! (With regular maintenance). Thank you so much.

 

Good work

Thanks for the update and THE FIXES