Idle surge

[ontherun]

Just bought a 81 fi 2000, just put in a new gas tank, pump, filter, and sendig unit.. got it started after finding the wire problem at the ignition switch, now it surges at idle.. adjusted the TPI, cleaned the TB. it will act right under load, anybody have a idea where to look. Thanks in advance...Landis

[So Cal Mark]

look for air leaks

[ontherun]

ok I started replacing hoses but have'nt laid hands on all of them...thanks..L

[rlux4]

Our FI system is very finicky about air intake for mixture control. Make sure you don't have air leaks in the air intake boot, or the intake plenum. Any air that doesn't go through the Air Flow Meter (AFM) is unmetered and so isn't accounted for by the ECU. Also make sure the flap in the AFM moves freely throughout it's range of motion and that it snaps back to closed position. Check that you don't have a blown diaphragm in the vacuum advance module, this would be a vacuum leak. See if you hear a sucking sound at the brake booster. This would also be a vacuum leak.
The sensor that sends the most critical signal to the ECU is the temp sensor in the coolant T at the front of the head. If it's faulty it could cause all manner of weird running issues.
Let us know how it goes.
If you don't have it yet, download Brad Artigue's maintenance manual, it contains a section on our Bosch L-Jetronic system.
http://artigue.com/?page_id=3
He also has excellent wiring diagrams for us on his site.
Also, download Thad Kirk's manual for the FI system (scroll down to the FI 2000 engine section)
http://www.angelfire.com/wa2/fits/index.html#ljetguide
Ron

[ontherun]

WOW..thats just what I needed..the brake booster is good without leaks. the air box works freely, have to check the advance, thanks again guys... will let you know what I find out tomorrow..L

[So Cal Mark]

also make sure the idle speed is correct. Do you have the ability to check a/f ratio?

[ontherun]

No. measuring a/f is out of my of leage... way out.. but I can handle the rest..thanks...L

[ontherun]

Auxilary air regulator was stuck and loose injector connectors..took it out for a test run and barked the tires in two gears... this car is fun. my wife will love it... thanks for all the help guys..now on to the A/C..it's HOT here... still more to do, but now I can stretch the job out a little now that it runs so sweet.....Landis

[rlux4]

Those were my next suggestions!
Good going Landis.
Ron

[ontherun]

Right.................. Q; should the aux air reg, block the air going through it once it has warmed up..or just some of it? ...L

[rlux4]

The orfice should close completely. It works in conjunction with the cold start valve to introduce extra air and fuel during start up. After a few seconds the cold start valve stops injecting and then as the car warms up the auxilliary air valve closes.
Ron

[ontherun]

sweet. have to check it to make sure it's working properly....thanks...so much great info...L

[ontherun]

Alright,...I took the Aux Air Reg off again and a bunch of carbon fiber looking pieces fell out, so i am thinking it's shot....now I need to find one so this thing will idle properly....looks like this thing is like working on our early Bronco, full of surprises,...off to the wanted section...L