1989 Nissan Hardbody Z24 Need Help!

[baggednissan1989]

Hello I have a 1989 Nissan Bagged Show Truck

Straight to the issue!

I can drive it fine no problems until! 3500 Rpms. It will hit 3500 rpms and start bucking. I will shift and no problems until 3500 Rpms. Its a 5 Speed so I can drive it but only about 7 miles. It burns rich and when I pull the plugs they are soaking wet in gas. When I bought the truck the vacuum lines where a mess I found a diagram and they are set correctly. At idle its extremely quiet and smooth. Rev the engine no problems. The Maf sensor has been replaced so says the seller. I feel embarresed one being ASE Certified but I never thought I would own a carburated truck. Please Help! Thanks God Bless glad I can be apart of a great well know club.

Also for the air bag mini truckers out there I have a firestone 2 switch set up front and back. Its S L O W to raise and lower it has a 5 Gallon tank and one compressor would adding another tank and compressor help the issue??

Names A.j. [email protected]

[Ace2cool]

As far as the fuel issue, it's certainly in the carburetor. Likely needs a good cleaning/lubrication of moving parts and float adjustment. (I'm assuming it has a carburetor, anyways, cause my buddy's 90 had one) Possibly could be a jet issue, but most likely it just needs cleaning/adjusting. I'll let the truck guys verify with that.

[baggednissan1989]

Thanks bud will give it a shot and let you know going out now to remove the Carb

[Ace2cool]

Actually, on second thought, it could actually be a jetting issue. You're minitrucking, so obviously you modify it. I'm assuming intake/exhaust? That changes the airflow of the engine, and without adjusting the carburetor, you'll be running either a rich or lean mixture. Just food for thought.

[Dattebayo]

Hey, maybe this is kind of a "big duh" statement, but carbureted trucks don't have MAFs... Not to mention they didn't offer the carburetor in any '89s. You probably have the TBi engine.

NICO has a manual for the '89 TBi in it's FSM cache... --> http://www.nicoclub.com/FSM/Hardbody/d21_truck_1989.pdf

[baggednissan1989]

Dattebavo thanks your right....... OK here is where im the truck has spark in time and getting fuel but way way too much! I noticed on the Tbi that it has four spots to adjust they are hex key slotted.... Any idea what they need to be adjusted to. I have tested everything Injector etc for the last three hours....

[Dattebayo]

Have you tested the fuel/vapor return lines? If it's pinched, the injector will direct all pressure into the TB.

If you've tested that already, then I would look at the fuel pressure regulator first before looking to adjust things. At any rate, the first thing I would look at is your fuel pressure. Both of those sort of failures can cause higher than usual pressure.

The other possibility is that you simply have a large air leak somewhere after the MAFs. That could be responsible for extra fuel and for a computer error that would cause it to go into limp mode, aka 3500 rpms or so.

What, may I ask, are you certified for under ASE?

[baggednissan1989]

Tested fuel pressure everything checks out fine.... Now that said testing the injector in the throttle body it is constantly spraying... Im picking up a new one in the morning... I can go from there keep you informed...

[Dattebayo]

Yeah, a stuck open injector can do that. Hope you get lucky!

[Ace2cool]

Ah balls. missed the maf comment in the original post. Good catch Dave.