With the PFC in Idle F/B control mode OFF, what are the minimum sensors required to run? I don't mean run correctly, just start and idle. I am guessing:

CAS, CKP
Water thermosensor
Air temp sensor
TPS
MAP sensor

?

What else?

I am trying to troubleshoot the source of my crappy/nonexistent idle/stalling that has been going on for months, by eliminating everything that I can and moving from there.

 

There is no Idle F/B control. Only O2 F/B Control and Idle IG control.

The idle IG is to keep the ignition at certain timing during idle.
O2 F/B is the oxygen sensor feedback to cycle the injectors on/off for fuel efficiency and smog.

Make sure you got the right one. Usually without Airpump, you want O2 F/B off. But you always want Idle IG ON, not off.

 

If the PFC is modeled after the stock ecu, I assume you wouldn't need the air or water sensors. I believe with the stock ecu if there is a short or open (in the wiring) or the sensor is bad the ecu uses a default value. You can verify this in the service manual.

 

I meant O2 F/B on/off, sorry.

I am having problems maintaining a run condition. When started, after a lot of cranking, it will eventually "catch" and fire up, but only with me manually holding the throttle open. It will rev to 2k or so RPMs with throttle input, whilst belching smoke (very rich), and will not idle at all. I have checked the ignition & compression, both are ok. I have replaced the ignitor. Fuel pressure is ok. Injectors are stock. Plugs are stock. Engine has stock ports.

Currently I have connected in the engine bay the following:

CAS 1 & CAS 2 (CKP)
Water thermosensor (back of filler neck)
Fan thermoswitch (back of filler neck)
Primary injectors 1 & 2
Air temp sensor
TPS
MAP

Secondary injectors are disconnected. All other sensors and ancillary equipment is disconnected. T/B is open to atmosphere (no intake piping, intercooler, etc). No exhaust (open downpipes). O2 sensor is disconnected. Plugs are new/replaced/have been checked. Injectors/fuel system does not leak. Double throttle removed. TPS has been calibrated. Idle adjustment screw has no effect. Wiring harness is new (no breaks, etc). All sensors on PFC check out in sensor chk mode. As you can see I have carefully and repeatedly worked through the obvious.

After fully warming up, the engine will idle, although very badly. Timing light shows a constant perodic cycle of the ECU advance then retard then advance then retard... about every 10-20 revs. Occasionally it will stabilize.

Re: the PFC wiring harness mod for PFC install; I was told that this was for A/C control only. Hence I have not modified my wiring harness; both A/C and power steering has been removed. If I am wrong please let me know.

Basically I am trying to get a bare-bones motor running and work forward from there. A six-pack of the beer of your choice and a large pizza to whomever figures this one out. I've been working on this for months with no progress (you may have seen my other threads).

 

I think there are a few of us DIY'ers that could help you thru this if we were there.

The two items that come to mind that you didn't mention is the ISC and AWS. are these installed and wired up? Is the AWS tube capped?

Other concerns are vacuum leaks and PFC settings. The PFC should do a sensor check for you but you need to have the commander.

Also curious if you have the fuel pressure solenoid hooked up or did you also bypass it and run the fuel pressure regulator reference line straight to the manifold?

Too many questions.

 

The ISC and AWS are both installed. The ISC is hooked up and appears to be functioning correctly. The AWS is not connected and is not capped; (actually the tube is gone) but the solenoid seems to be closed when no input is applied - am I correct?

I am positive there are no vaccum leaks. At this point, I even have the brake booster line removed and capped off in case the brake booster was leaking.

I do have the commander, so I have reset the unit as well as gone through the usual sensor check process. The only thing that is highlighted on the sensor chk screen (other than the switches) is the VMOP - I have no MOP installed (premix). The injectors are stock, and the PFC is calibrated for stock injectors.

The FPR solenoid is also gone. I have a standalone regulator that is calibrated to the factory spec rail pressure. The FPR takes a reference off of the inner vacuum nipple that the stock FPR uses (under the rear secondary injector).

Thanks for your help.

 

Are you sure the water, fuel, and air temp connectors are not swapped?

ISC could cause idle instability but not the black smoke. Sounds like a **** load of unburnt fuel. Leaky/stuck injector, too high fuel pressure, wrong injector in primary slot, ignition issue (are the plugs saturated with fuel when you pull them?), fubar MAP sensor, how much pre-mix are you running, something simple is not right on the car.

What is your inj duty at idle?

 

Good call, that's what I thought

Smoke is more white than black; perhaps I have a premix problem; I am not burning crankcase oil however; I know the difference in smell...

- injectors are not leaking or stuck (three weeks of testing, I am abso-effing-lutely sure of it)
- water, fuel, air temp sensors are not swapped (fuel temp is unplugged for now)
- fuel pressure is ok
- primary injectors are 550s
- ignition verified ok, but the engine is flooding (obviously)

If I

- remove EGI fuse
- crank it with the plugs removed until no more fuel vapor emerges from the plug holes
- replace the plugs with NEW plugs
- add premix to the chambers to lubricate them
- crank

It will fire RIGHT up, smooth as expected for the first several revs (1-2 seconds), and then as she tries to settle down and stabilize the idle it will start cycling the ignition advance/retard/advance/retard as I mentioned, and either stall or if it manages to stay alive, it's very rough. Max vacuum is about 10 mmHg.

Perhaps a bad coil pack? I have spark on L/T1/T2, verified with timing light and also by removing wires and checking for spark to ground... ignitor has been replaced with a known good ignitor.

As you can see I am certainly fresh outta ideas...

 

That vacuum is kinda low. Sure you don't have a vacuum leak? Tough to tell without having the car idling. With the car idling, spray carb cleaner at every possible leak path, it it makes the car stumble you've found your leak.

The lower vacuum will put more fuel in the mix if using stock PFC maps but not enough to make it smoke. Suggest you get someone local to help you troubleshoot.

 

Where are you in Alabama??? Do you have a Datalogit? Have you checked all of your PFC settings? stock pfc map...borrowed map? new or used PFC?

You put the stock ecu back in to see if it still has the same problem?

 

Last night I got the car to run stably at 1.5k+ RPM. Idle is very rough. I appear to have a leaking o-ring on the rear secondary since the rear rotor flooded all to hell when I left the system pressurized for a while (I was pumping the gas to replace it by bleeding it out of my gauge port on my regulator - took just a few seconds!). Upon replacing the plugs with new plugs and restarting, the idle was crappy (as expected) and I noticed the smoke was *only* coming from the rear rotor (I have separate downpipes). I disconnected the secondary rail by bypassing the feed, since I have AN fittings. Things got a little better, but still very smoky. Vacuum was better. I am going to check out the primary sealing again by replacing all the o-rings. I don't think I have a sensor or igntion problem anymore, since things run great at higher RPMs. In fact, the cops showed up around midnight when I finally shut it down. Apparently a 13B with no exhaust is "loud". She sure does sound sweet tho.

SPO, I am in Huntsville. If you feel like dropping by so you can get saturated with gasoline smell, feel free!

Disclaimer: All of the above conclusions could be wrong, so this statement is here to avoid me making an *** of myself in a few days when I post something like "It was really a bad coil pack."

 

For the most part... I now smell more like exhaust than gasoline, which is a _good_ thing.

Last night, I

- took the primary rail out *again* and pressurized it; it did not leak, but I did have a broken isolator o-ring, which I replaced (fortunately I have spares, since I have broken them before).
- I didn't check the secondary rail, it's still bypassed
- I checked (again) for any and all vacuum leaks and verified correct fuel pressure setting on the FPR
- I added a PCV valve and a temporary line from the filler neck to the manifold to put a vacuum on the crankcase

And the PFC part:

I disabled O2 F/B control, unplugged the O2 sensor, increased the base idle to 900 RPM, and leaned out the idle map from 1.21x in the idle region to 1.000. I also zeroed the timing map in this region, but it didn't seem to affect the timing. I got this PFC used; is it possible that this map is "locked?". I am able to make changes to the leading and trailing ignition maps, but they don't really seem to affect the timing.

Since someone asked, after the inj map change my reported injector duty cycle is about 4.5% at normal operating temp (about 80-85 degC) at 850-900 RPM.

And in case anyone was wondering, the ICS does stay closed when disconnected.

I am now getting a semi-stable idle at about 15mmHg vacuum, and the idle will recover after the engine is revved without stalling. The smoke has all but gone away, and now I get a *combustion* smell instead! I also can restart the car reliably. I tinkered for a while with the T/B idle screws, and it's not perfect, but better.

I am wondering if this PFC had been tuned (contrary to what I was told by the seller). Of course I had done an init to get the settings back to stock but it looks like it was running **** rich at idle, and leaning it out improved things quite a bit. Perhaps the base map has been modified? Is there a way to tell, or am I pretty much just going to have to buy a datalogit? Can the datalogit set everything back to the out-of-the-box settings, or will I have to copy them from somewhere else?

Thanks for the help; sorry about the long post.