85 idle problems
Thread Starter
Burning Brakes
Joined: Jan 2005
Posts: 847
Likes: 1
From: spring branch texas
85 idle problems
just got a 85 4+3 a couple weeks ago and it runs ok but the idle is a little irradic, varies from 700-1100. I've missed placed my code definitions, I'm getting a code 44. I thinking 44 was something to do with a lean condition but the car smells pretty rich at idle.
Can someone verify the code for me and point me in the right direction.
Thanks
Can someone verify the code for me and point me in the right direction.
Thanks
Burning Brakes
Joined: Jun 2002
Posts: 1,001
Likes: 1
From: sd
Code 44 is fuel injection lean exhaust indication. This is from the Helm manual:
Sensor. A Mass Air Flow MAF Sensor output that causes the ecm to sense a lower than normal air flow will cause the system to go lean. Disconnect the MAF sensor and if the light flashes closed loop (field service mode) and the lean condition is gone, replace MAF sensor.
Lean injectors. Perform injector balance test
Fuel Contamination. Water, even in small amounts, near the in-tank pump inlet can be delivered to the injectors.
EGR. Possible stuck EGR valve will cause the system to go lean.
Fuel pressure. System will be lean if pressure is too low.
Exhuast leaks. If there is an exhaust leak, the engine can cause outside air to be pulled into the exhaust and past the O2 sensor.
O2 sensor pigtail that connects to the O2 sensor may be possibly hitting the exhaust manifold causing it to ground and give a false reading.
Could be any one of these according to the factory service manual. Hopefully this gets you close to tracking down your problem. Good luck!
Sensor. A Mass Air Flow MAF Sensor output that causes the ecm to sense a lower than normal air flow will cause the system to go lean. Disconnect the MAF sensor and if the light flashes closed loop (field service mode) and the lean condition is gone, replace MAF sensor.
Lean injectors. Perform injector balance test
Fuel Contamination. Water, even in small amounts, near the in-tank pump inlet can be delivered to the injectors.
EGR. Possible stuck EGR valve will cause the system to go lean.
Fuel pressure. System will be lean if pressure is too low.
Exhuast leaks. If there is an exhaust leak, the engine can cause outside air to be pulled into the exhaust and past the O2 sensor.
O2 sensor pigtail that connects to the O2 sensor may be possibly hitting the exhaust manifold causing it to ground and give a false reading.
Could be any one of these according to the factory service manual. Hopefully this gets you close to tracking down your problem. Good luck!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Code 44 IS set by a lean exhaust reading. Whenever I hear of an erratic idle I think of the IAC. It and it's passages should be clean. That won't cause a rich smell or a check engine light, however. You may have an air leak and/or a vacuum leak that leans the exhaust and causes the ECM to try to compensate. Of course the FSM will have a step by step trouble shooting chart for each of the codes.
RACE ON!!!
RACE ON!!!
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Manual should have mentioned a faulty air pump circuit too - clamp off the air hoses to the headers and see if the problem goes away. Remove the check valves and make sure you can only blow air through them in the direction of the headers.
Thread Starter
Burning Brakes
Joined: Jan 2005
Posts: 847
Likes: 1
From: spring branch texas
thanks guys, that gives me a start. Unfortunatly I won't be able to work on it till next week, Christmas rush and all.
I'll let you'll know what I find out.
Merry Christmas and Happy Holidays
I'll let you'll know what I find out.
Merry Christmas and Happy Holidays
Team Owner
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Does anyone know what the tiny square opening is on the top side of the TB bores? It's right at the closing position.... is it some sort of minimum idle setting.
My idle went up 300 rpm (and turned to crap after trying to reset it) all this because I cleaned out the IAC and tb bores. I presume it's because the TB is now leaking air from the loose shaft that is now clear of grime. Either that or I damaged the IAC somehow.
My idle went up 300 rpm (and turned to crap after trying to reset it) all this because I cleaned out the IAC and tb bores. I presume it's because the TB is now leaking air from the loose shaft that is now clear of grime. Either that or I damaged the IAC somehow.
Drifting
Joined: Mar 2005
Posts: 1,923
Likes: 0
From: GA
Originally Posted by CentralCoaster
Does anyone know what the tiny square opening is on the top side of the TB bores? It's right at the closing position.... is it some sort of minimum idle setting.
