Not sure how my last thread was combined with another one, but thought I would start a new one since the other thread changed titles and, therefore, subjects.


First, the car is a '92 awd with 2g mas, 550's, new isc, blocked off fiav and rerouted coolant because the spring broke, s-afc, refurbed ecu, and some other stuff but I think that's all that matters.

Now my problem (from watching the 02 and low fuel trims): My car is running very lean at idle, to the tune of +17 on my s-afc at 1k after the car warms up. The o2's seem to start out fine and then start to get more and more lean as the car warms up. If the car is rolling while it's out of gear (coasting to a stop) the rpm are under 1k and the car is rich on the logger but as soon as the car stops it goes to lean again.

Also, today when I was testing some things I had been driving the car but shut it off for about an hour. When I checked to make sure the new isc was working I started the car and it idled fine at 750 rpm. I then turned on the ac and the idle dipped and there was a click from under the hood. This continued until I shut the ac off - the idle would drop and there was a click, repeating about every 2 seconds (sounded like the ac compressor was making the click, at least near that area). After the car idled for a few minutes I tried the ac again and the idle dropped a bit and then caught at about 600 rpm and stayed there. Turned it off and the idle returned to 750rpm.

If you need any other info, just ask. I appreciate the help.

Ok first off,do you have an afpr,and/or a aftermarket fuel pump?

Also for the car to idle lower when you bring the a/c on is normal so i wouldn't worry to much about that.now for the clicking noise.Did you check and make sure it wasn't a solenoid?Is the clicking noise repetitive?Can you pinpoint where the noise is coming from?Have you done any new installation of any kind?Has this been happening for a while or just out of the blue?

My a/c will kick out if the engine reaches a low rpm as well. If I pick the rpm's up a tad it will quit. I don't really think that is a major issue...

I have a 190lph fuel pump without a new afpr. I removed the solenoids that are designed to aid at startup. The egr is blocked off. The pcv is routed to a catchcan with a breather filter on it.

I also pressure tested the intake to 10 psi before it blew the coupler off that I had attached to the intake pipe.

Glad to hear the ac is working fine. I was hopeful when it acted normal when the engine warmed up, but I didn't know for sure. Good news!

To answer the question about a new install: I just blocked off the fiav and coolant passages because I had to have the s-afc at about +9 at 1k and thought it wasn't normal so I checked the fiav and saw that it was broken. Now the correction seems to be worse.

Another question that seems like it would be related: Wouldn't high fuel pressure make me run rich? I just bought a fuel pressure tester and it reads 51psi at idle with the vacuum line removed - 45 psi with the vacuum line attached like normal. Isn't it supposed to be at 37psi? The fpr sure looks stock. Should I replace it with one that I just picked up from an 1g nt?

I'm interested in knowing if you found out the problem. I have the exact same issue.

Every single stock to moderately modded 1G I have ever logged has run incredibly lean at idle. What's it going to hurt? It's just idling, you aren't going to knock and hurt the motor or anything. Unless you have to pass emissions and are getting high NOX from it, I wouldn't worry about it.

Are you insane?
I'm getting like 43 counts of knock <b>off the line</b> and thats pulling timing like a mofo so I think its a problem worth looking into. If the knock starts from a lean condition at idle it tends to carry that knocking right into boost.

RiceKiller_TSi said:

Are you insane?
I'm getting like 43 counts of knock <b>off the line</b> and thats pulling timing like a mofo so I think its a problem worth looking into. If the knock starts from a lean condition at idle it tends to carry that knocking right into boost.

Click to expand...

Then you do have a problem. But like I said, I have seen many, many 1Gs run lean at idle, including all 4 of mine, and all of them have run just fine at WOT.

Don't worry about the O2 sensor. What do your fuel trims look like?

IHeartTurbo said:

Every single stock to moderately modded 1G I have ever logged has run incredibly lean at idle.

Click to expand...

Mine don't, but then I correct for the difference in injector deadtime and injector global in the EPROM. On a SAFC2 you can try to adjust by setting a 800 RPM low throttle NE-point and tune your idle better.

Almost all aftermarket injectors have quite a bit of additional deadtime over the stock injectors. That extra deadtime means that time the ECU though fuel was spraying isn't and since the injector pulses are shortest at idle a larger percentage of fuel is lost than at WOT causing the car to be leaner.

Steve

So Steve, is this something that could be corrected using just the maft? Or would I have to have my eprom flashed? Currently I have no safc and I'm not tuning in rpm mode with the maft. What do you think?