HELP!!

bigfrog3 · Sep 5th, 2006, 05:35 PM

I just bought a 1987 nissan d21 with a 3.0v6. All of the sudden the engine started running very rich ( black smoke coming out of the exaust pipe). I had a scanner hooked up to it and no codes came up. I ever tried hooking a new computer in and it also did nothing. I check the o2 sensor and the fuel regulater ( check vacuum line for gas ) and everything seemed to be fine .. please somebody help me figure out what is going on. Truck is running so rich that i keep stalling out.

dvdswanson · Sep 5th, 2006, 06:13 PM

check the MAF sensor

bigfrog3 · Sep 6th, 2006, 09:27 AM

Quote:

Originally Posted by dvdswanson

check the MAF sensor

already have and replaced it along with the o2 sensor and catalytic converter.

**88pathoffroad** · Sep 6th, 2006, 10:24 PM

Have you run the ECU error codes?

bigfrog3 · Sep 8th, 2006, 08:55 AM

yes i ran the self-diagnostic test with obd1 and i came up with a code 13 which is cylinder head temperature sensor and i replaced that and truck is still running rich or at least that what it seems because it's boggin down when I hit the gas and shooting out black smoke from the tail pipe. thank you guys so far and in advanced for replyin to my posts.

**88pathoffroad** · Sep 9th, 2006, 01:30 PM

Your remaining options for fuel delivery problems would be the mass airflow sensor, the throttle position sensor and the O2 sensor. I'd pull the MAF sensor and make sure the heater wire is intact first. Check here for how to take off and clean the MAF sensor...

NPORA forum thread, click me

bigfrog3 · Sep 9th, 2006, 02:24 PM

yes i ran the ecu codes and got a code 13 which is cylinder head temp sensor and i replaced that and im still running rich.

Fred S · Sep 9th, 2006, 06:13 PM

The next thing you should do is pull the sparkplugs and look at them. Are they all black and sooty, or just some of them? Since it's running pig rich, one or more plugs should be pretty sooty.

If it's just one plug, suspect a stuck fuel injector.

If it's all of them, then something's causing all the injectors to flow too much fuel. Get your fuel pressure tested.

Either way, check the plugs and post your results.

Fred

bigfrog3 · Sep 10th, 2006, 02:03 PM

Quote:

Originally Posted by Fred S

The next thing you should do is pull the sparkplugs and look at them. Are they all black and sooty, or just some of them? Since it's running pig rich, one or more plugs should be pretty sooty.

If it's just one plug, suspect a stuck fuel injector.

If it's all of them, then something's causing all the injectors to flow too much fuel. Get your fuel pressure tested.

Either way, check the plugs and post your results.

Fred

i checked all the plugs and they are all very sooty with carbon and they are brand new plugs, also the link fred gave me wont' let me look at it because i need a password. thanks so far guys for all the help, I also checked the fuel pressure regulator and there was no gas in the vacuum line. How do I go about checking the o2 sensor for functionality?

**88pathoffroad** · Sep 14th, 2006, 09:46 PM

Have you even tried cleaning the MAF sensor yet? I've seen quite a few problems solved by doing that...