graniteguru

iTrader: (1)

Got a quick question. I am battling the last of this rebuild. I am having a problem with Idle and acceleration. When I tap the gas, it hesitates big time, backfires through the intake. When I adjust the set screw down on the idle to below 1300 rpm or so, it revs ever so slightly and then immediately dies. I have tested the plugs on the afm, and I am supposed to be getting around 1 volt on pin 2b at idle. Since it won't idle, I can't really test this voltage. As it sits with the engine off and the ignition on, I get zero volts out of this pin. Is this normal. If not, what could it be? The TPS is set to exactly 1volt. Whether they are related or not, the CEL will not light and I can not get any kind of timing light to give me a signal on the engine. So right now, the timing is very questionable.

HAILERS

Pin 2B is the output of the AFM. You seem to have none.

See the BR/W wire at the AFM? It is what is called ref voltage of approx 5vdc. More common to see 4.5vdc. Seems it isn't there at the AFM OR the AFM internals are dragging it down.

Pull the plug off the AFM and check for 4.5vdc approx on the brown/white wire on the plug. If it's there, leave that plug off and go to your boost sensors plug. Check for 4.5vdc on it's brown/white wire. IF you see 4.5vdc on the boost sensor plug, leave the meter on that wire and go put the AFM plug back on. Now recheck the voltgage on the boost sensors brown/white wire. IF it dropped waaaaay down, then the AFM is messed up in my humble opinion.

IF you never see more than approx 2vdc on the brown/white wire in the plugs with them disconnected.............bad ECU in my opinion. There's other checks to see if that's true or not.

Ah, wait a minute, your car idles so you'll see at leadt 4.5 on the brown/white at sometime. So it couldn't be a bad ECU in that case.

HAILERS

Have someong push the cone in the afm aft while you look at the meter on pin 2B. See if anything happens. I doubt it will. Normally you'd see approx 4.5 vdc and as you push aft the voltage would decrease to close to zippity.

graniteguru

iTrader: (1)

Thanks Hailers for the information. I have checked the br/w wire at all of my sensors and they are reading at 4.95 volts. I also checked to make sure that they are not going to ground. I guess that Pin 2b where I am supposed to be getting approx 1volt is an INPUT TO the ECU from the AFM. There must be something that is preventing this from happening. I had an AFM that I had purchased on this site, thought that it was bad, bought another one found out that it was bad. I finally ordered a re-conditioned one from Black Dragon Auto for $269.00. They asked for a core of 65.00. I should ask them which one they want me to send. LOL. I sure hope that this fixes the problems I have been having. I am ready to surrender.

HAILERS

PIN TWO BEE should read what is in the attached jpg. All elect plugs on the ECU, backprobing the 2B wire. Color of the wire is in/on the other jpg above. EDIT: GREEN wire.

graniteguru

iTrader: (1)

Update. I found several problems in the harness itself. I had redone this harness to accomodate the JDM motor and looking back, I had done a pretty sloppy job especially when it came to the shielded cables. I had taken the outside shielded part and braided them together, but left them too close to the signal wires inside the shielding. I found a few places where it was probably grounding and eliminating the voltage signal back from the sensors. I am in the process of cleaning and THOUROGHLY inspecting ALL of the wires and connections back to the ecu. I am fairly sure that the AFM was bad, so I bought a re-manufactured one from Black Dragon Auto for $269.00 and a 65.00 core charge. I should have everything back in this weekend and report back on whether it worked or not.