Diagnostic port under hood 97 fzj80

[Cruiser nancie]

Hey guys,
I have been having a constant cel for system too lean. But thats all i get.
Ive gone through all basic system lean replacements and checks. No results.
Will the diag port under the hood on the firewall tell me more then just system to lean?

 

[Joshwho44]

Your truck is OBD2 so the under dash connector is what you're looking for...the firewall connector won't tell you anything really... If you don't have one already, you should pick up a cheap Elm327 OBD2 reader. That way you can check fuel trims, air flow, etc, in addition to just pulling DTCs.

 

[NLXTACY]

It'll tell you what code you have and then you can fall down the rabbit hole of remedying the issue. Without that CEL you are just chasing your tail.

 

[LINUS]

I'm not sure all the other uses for that port, but I've only used it to reset my SRS warning light in the cluster. I kicked it of my own fault, but if you have a FSM in whatever form, maybe there's more functions - seems it comes up semi-regularly for other issues but I am less a bowl & more a strainer of 80 info anymore. Meh.

You could, -as Joey stated, drop into the rabbithole & start with checking things like your MAF, or if say your intake tube has a crack (getting common now), -things like that.

Maybe you're getting unmetered air in the system, hard to say.

Not sure the real world usefulness of them, but those bluetooth OBD2 port dongles you patch into your phone are a item a buddy with a forced intake Audi A4 thinks is the greatest thing since sliced pie.

 

[Joshwho44]

The smartphone OBD2 readers are great. For $20 the BAFX brand on Amazon is hard to beat. If you don't mind spending a little more, then the OBDLink brand is awesome. I think you need Bluetooth for Android or WiFi for iphone.

 

[BILT4ME]

Or you can go to O'Reilly Auto Parts store and check and reset for free as many times as you want.

 

[Joshwho44]

Yeah, but that only lets you pull / clear DTCs, which won't tell the OP anything more (already have lean code). Being able to view the live data can be pretty invaluable when troubleshooting. That and you can make custom gauges/displays with an app like Torque. It's pretty cool if you've never played around with it before!

 

[TrickyT]

Said rabbit hole:

P0171: System too Lean (Fuel Trim): Trouble Areas: air intake (hose loose or cracked); fuel line pressure low / leak; injector blockage; heated O2 sensor malfunction; mass air flow meter; engine coolant temperature sensor.

So yeah, the problem can be caused by many things.

 

[OGBeno]

Said rabbit hole:

P0171: System too Lean (Fuel Trim): Trouble Areas: air intake (hose loose or cracked); fuel line pressure low / leak; injector blockage; heated O2 sensor malfunction; mass air flow meter; engine coolant temperature sensor.

So yeah, the problem can be caused by many things.

And finally, ECM.

 

[cruiserdan]

The first thing I would look at is the air intake hose. Very fragile and brittle when old.

 

[LINUS]

The first thing I would look at is the air intake hose. Very fragile and brittle when old.

Intakes are getting old & cracking, electrical gremlins (sockets, insulation degradation) are setting in - all due to the overall age of the materials & heat cycles they've seen. Nature of the aging process.

1997 models are all 2 decades old now.

 

[ridgeback rig]

The first thing I would look at is the air intake hose. Very fragile and brittle when old.

I have a 93 with a cracked air intake tube. Where should I look for a replacement at a decent price?

 

[Hornd]

I have a 93 with a cracked air intake tube. Where should I look for a replacement at a decent price?

ebay intake tube

 

[Cruiser nancie]

I have all new hosing for intake. Anf ibe done everything you guys have listed
Are there any vacuum lines that are under the dash that i may have missed?

 

[Dragos80]

I would also start with the air intake hose.
@Qball just replaced his, bought off amazon (generic one, but so much better in red).
Had to replace mine due to the same issue. Found an OEM part off eBay for about the same price as HPS brand Qball got.

 

[shocktower]

It'll tell you what code you have and then you can fall down the rabbit hole of remedying the issue. Without that CEL you are just chasing your tail.

You will be at Wit's End