Mass Air Sensor ?

[Azuris]

   Hello All. My first post here. Been lurking here since I got my truck. I really enjoy some of the builds Im seeing here. Im sure Im in the right place to keep my little jewel running like a top.

 

   I bought myself an 85 720 4x4 with the z24 engine. Good solid truck just needing some TLC. I was driving my truck when out of the blue the truck dies. Then there after it wouldnt stay cranked under 2000 rpm. I was thinking fuel issues so I checked the fuel filter and pump. All good there. Then Im thinking clogged injectors so I got some seafoam and a can of injector cleaner. That didnt help. Carried it to a shop. When the guy started to work on it it ran fine. So I had him do a good tune up on her. When I picked it up It ran like crap sputtering and blowing blk smoke. So I left it with him again. Now he is thinking MAF sensor but isnt 100%. I have been looking for a sensor but can find one. There cant be to much wrong with the engine. Just hoping one of you fellas might have answer for me. Thanks in advance.

[datzenmike]

Does the air filter have one or two wing nuts holding it on???

[Azuris]

 It has 2 . this is also a Z24i.

[84720FourWheel]

http://www.nissanpathfinders.net/forum/topic/5194-how-to-cleaning-your-maf-sensor/

[Charlie69]

Pictures of the engine please as I have a Z24I and I am trying to identify what year it is.  I bought it used.

[Azuris]

Charlie. No picture as of yet. My truck is at a garage right now. Once I get it back I will be glad to post some pictures of the engine.

[Azuris]

If it is indeed the MAF I have read somewhere  to only get  a Nissan OEM replacement. Seems the aftermarket one are problematic. That being said the OEM MAF is obsolete. Ive been looking around for one but havent found one yet. The MAF was cleaned but that didnt help. At this point we are not 100% sure its the MAF but it does seem likely.

[datzenmike]

That's why I asked. This is a throttle body injection. It also has a diagnostic function that stores fault codes.

 

I only have the Z24i info for the next gen truck the D-21 Hardbody so not sure if exactly the same as the late 720. The EFI computer is located under the driver's seat. There is a Red and a Green LED. you can ask it and it will display a code by flashing. Red is 10s and Greens are units. For example 4 Red and 4 Green is code 44 a sign that everything id OK.

 

Warm engine (if possible) turn engine off in neutral.

Turn ignition to ON

Both LEDs should light

turn the diagnostic selector to the ON position

should display code 24 and 31

turn headlamps  and heater fan on high

Turn them off.

Only code 24 should show

Depress clutch and shift into any gear and release clutch

Depress clutch and place back into neutral release clutch

Should show code 44

 

If any other codes... wright them down

[84720FourWheel]

Also if you get the Maf out, be sure that the o ring that seals it to the throttle body isn't cracked. Extra air leakage would give you the over rich condition.

 

Remember, the wiring to the Maf is 30 years old, it may have broken internally. But as far as getting a new Maf, I'd go to a junkyard and pull some off of any 89 and older Pickup or Pathfinder. They use the same throttle body on the 4cyl or the 6, so it should all be compatible.

[Azuris]

Thanks everyone for your responses.Have a new Maf on the way. Hadnt thought of a broken wire. I will be looking closer at this. I will let yall know how things progress. Thanks again everyone.

[datzenmike]

It's going to get expensive buying parts.

 

Did you look at the throttle position sensor? It tells the ECU if idling or full throttle. Full throttle ignores the built in fuel map and goes extra rich for max power.

[Azuris]

Datzenmike. You sure are right about getting expensive. Ive got it in a mechanic shop. The guy is doing me right as he is stumped. Im not going to get my truck back until its running right. I work alot of hours so time isnt there for me to mess with it right now. Also it isnt a daily driver so no worries there. I do need it running to keep it in the drive as Im alway playing musical cars. Ive past on all the good information to my mechanic so with a bit of luck I will be running again this weekend. Thanks again for your help.

[datzenmike]

Try the fault codes. It's a self diagnostic and will point to the problem.

[Azuris]

 Just wanted to Thank everyone for there help. It was the MAS. I had it tuned up and put a new muffler on it. Runs like a top. Now  on to a new windshield and some shocks. Cant say the old truck need much. Just a little here and there. I will post a picture when I can get home before dark to take one. Thanks again!