ran a/c and oil pressure dropped

[jamanrr]

I have some scoring on my cams. Is this a fatal thing? I run a/c in my car and my oil pressure dropped cause I do not have the idle up control for the a/c working? what should I do? Run it till it dies or be prepared to do something else? thanks

I can not notice it missing or rattling or anything. As long as I do not run a/c the oil pressure remains constant but there is scoring on the cam lobes and what will happen? can they wear back to normal with normal oil pressure?

I notice no loss in power or performance.

[jamanrr]

Not to answer my own thread but I went out turned the a/c off and ran the piss out of the car it maintained normal oil pressure through out the run and the scoring that was on the cam is not visible as bad as it was still can see it a little. So, I guess it was light scoring from when the oil pressure dropped from the a/c switching on and not having the high idle for it. I thought the apex pfc could control a/c -- screw it I probably will just pull it out since I do not need to run it anyway and I do not daily the car. anybody have any ideas that runs a/c?



crap 0000

[jamanrr]

come on someone has to know. Is there a way to control the idle on a apexi power f/c when the air conditioning is turned on? It should be raised when the a/c is on not lowered.

[DeatschWerks]

I haven't much experience playing with the Power FC, so my suggestion would just be a band-aid. You could alway bump up the normal idle a couple 100 rpm so when you do turn on your accessories, it idles a little higher.

When you saw scoring, is it just a color change on the surface from heat or is it actually gouged?

[jamanrr]

I haven't much experience playing with the Power FC, so my suggestion would just be a band-aid. You could alway bump up the normal idle a couple 100 rpm so when you do turn on your accessories, it idles a little higher.

When you saw scoring, is it just a color change on the surface from heat or is it actually gouged?


thanks for the reply -- it was not gouged or as in has chucks of the cam gone but it was surface color change. I have not run the a/c in a while and the cam lobe now has the normal oil smooth coating that it usually did. I ran the a/c cause it is hot as hell where I live. Just the idle drops when the a/c clutch is engaged and oil pressure tends to go along with idle so when I came to a stop sign the idle went like real low and the oil pressure went to 5 psi or so and almost died. I reved the engine back up and shined a flashlight in the number one cam hole and it had some scoring on the cam. I then turned the car on and ran it normal without a/c on and ran it on the interstate to a good 80-90 mph and came home looked inside the valve cover and the oil on the cam lobe was normal and the scoring was not as visible as it once was. Normally without a/c my car will run 15-20 psi at idle. A/c has a fast idle function I thought which is suppose to raise the idle not lower it.

[fliprayzin240sx]

I got this same issue on my Silvia and you got a couple of things to try. First, in the PFC, there should be an option to bump your idle in there when the AC is turned on. Check and make sure the PFC is sensing the AC turning on. Mine, for some reason, isnt seeing it so its not bumping the idle.

Next option is just bump the throttle plate open a bit. Figured its hot as fuck so its not like your gonna be cruising without the AC on. Start the car, get it up to temp, turn the AC on and then plate with the TB. Idle should be atleast 800 rpm, even as much as 1000rpm if you have decelleration issues.

[jamanrr]

I got this same issue on my Silvia and you got a couple of things to try. First, in the PFC, there should be an option to bump your idle in there when the AC is turned on. Check and make sure the PFC is sensing the AC turning on. Mine, for some reason, isnt seeing it so its not bumping the idle.

Next option is just bump the throttle plate open a bit. Figured its hot as fuck so its not like your gonna be cruising without the AC on. Start the car, get it up to temp, turn the AC on and then plate with the TB. Idle should be atleast 800 rpm, even as much as 1000rpm if you have decelleration issues.


yeah I called my tuner and he said to play with it in the idle settings but the shit is in Japanese? So, I was like wow. I have almost though about not running it at all but it gets hot where I live. Just need to get the idle up for the a/c when it is on? Does the PFC have the ability to tell if the air is on or off they have a sensor check for everything else. I guess I could just set the idle up for a while till it gets to where it holds a constant idle with the air on. I guess this is why 99% of the sr20det swaps do not run air conditioning ---- it is a PIA.

What does this mean?

http://img28.imageshack.us/img28/7610/idlez.png

I just looked at the settings and there are like 6 different settings for the idle? I see f/c idle a/c and idle a/c it is confusing as hell. I probably will not touch it unless some body has some proven values they would like to share? there are some smart guys here that should be able to answer this?

also note -- I do not have all those idle settings. My just shows F/C idle A/C I guess ON since it is Japanese and off as well as idle a/c on and a/c off. Wonder why I do not have electrical load idle settings? maybe they did not need them on the Silvia motors?

[fliprayzin240sx]

yeah I called my tuner and he said to play with it in the idle settings but the shit is in Japanese? So, I was like wow. I have almost though about not running it at all but it gets hot where I live. Just need to get the idle up for the a/c when it is on? Does the PFC have the ability to tell if the air is on or off they have a sensor check for everything else. I guess I could just set the idle up for a while till it gets to where it holds a constant idle with the air on. I guess this is why 99% of the sr20det swaps do not run air conditioning ---- it is a PIA.

I just looked at the settings and there are like 6 different settings for the idle? I see f/c idle a/c and idle a/c it is confusing as hell. I probably will not touch it unless some body has some proven values they would like to share?

I'm in the states right now so I cant just go out to my car and check. But IIRC, if you go into the Idle/Rev menu in your PFC, there should be something in there for the AC.

Then if you go into sensor check, it should tell you what its sensing. If you turn on the AC, the PFC should show that its sensing it in there. If not, then you have the same exact issue as me.

[jamanrr]

I'm in the states right now so I cant just go out to my car and check. But IIRC, if you go into the Idle/Rev menu in your PFC, there should be something in there for the AC.

Then if you go into sensor check, it should tell you what its sensing. If you turn on the AC, the PFC should show that its sensing it in there. If not, then you have the same exact issue as me.


got a better idea of it now. My idle with a/c on is something like 1100 rpm and with it off it is 850 rpm. The ecu is not reading the a/c switch when it is the ON position. So, this has to be wiring or a problem inside with the ecu? Since you are having the exact same issue maybe we can solve it together? You could just raise the base rpm up to 1000 or so from 850 (which mine is at now) but this would just be a band aid. I can hear the clutch engage and disengage when I hit the a/c switch but the little block dot will not turn black so it is not reading it.


Think you can find the answer? and you have a factory sr20det car with a plug and play Power FC the real thing and not a swap?

[fliprayzin240sx]

Same issue, no my shit is not factory. I'm running an S15 Spec R setup into a Zenki S14 Silvia. I've had my tuner go over the wiring and he said it was good, he said he has no clue why the PFC isnt seeing the AC turn on. I didnt bother chasing it again since I just adjust my idle for the summer since I figured I wont be driving around with it off. Plus I'm running 270 procams, bumping my idle to 1k actually helps my car idle a bit better and help with the lopey cams.

See if you can find a wiring diagram for the AC, I'm curious to see how the ECU sees the signal when you flip the switch on the console. There has to be a signal that goes from the AC unit to the ECU. The ECU detects that signal and it then sends a signal to the IACV to open up to bump the idle when theres a load. The IACV actually has 2 valves iirc (atleast on S14/15 SRs), one for the AC and the other is for the the electrical load (not really just that too, I think the Power Steering also bumps the idle up when its under full lock), hence the reason you got 2 different adjustment on the PFC.

[jamanrr]

Same issue, no my shit is not factory. I'm running an S15 Spec R setup into a Zenki S14 Silvia. I've had my tuner go over the wiring and he said it was good, he said he has no clue why the PFC isnt seeing the AC turn on. I didnt bother chasing it again since I just adjust my idle for the summer since I figured I wont be driving around with it off. Plus I'm running 270 procams, bumping my idle to 1k actually helps my car idle a bit better and help with the lopey cams.

See if you can find a wiring diagram for the AC, I'm curious to see how the ECU sees the signal when you flip the switch on the console. There has to be a signal that goes from the AC unit to the ECU. The ECU detects that signal and it then sends a signal to the IACV to open up to bump the idle when theres a load. The IACV actually has 2 valves iirc (atleast on S14/15 SRs), one for the AC and the other is for the the electrical load (not really just that too, I think the Power Steering also bumps the idle up when its under full lock), hence the reason you got 2 different adjustment on the PFC.


sent you a pm. You would not happen to have an s14a sr20det ecu pin out diagram? I have one it will take me a while to find it since my harness was done by yuri at wiring specialties.

[Darius]

Oil pressure varies directly with idle. The faster the rev, the higher the pressure. When the A/C kicked on and put extra load on the engine without the ECU knowing about it, the rpms drop and so does the oil pressure. It isn't a bad thing unless it is dropping below 15 psi when this happens. Just bump your idle settings up couple hundred rpms and call it a day.

[jamanrr]

Oil pressure varies directly with idle. The faster the rev, the higher the pressure. When the A/C kicked on and put extra load on the engine without the ECU knowing about it, the rpms drop and so does the oil pressure. It isn't a bad thing unless it is dropping below 15 psi when this happens. Just bump your idle settings up couple hundred rpms and call it a day.


I bumped it up by 80 rpm seems to be fine right now.

[DeatschWerks]

Good to see the issue is under control. I know what you are talking about with the heat. The A/C went out in my DD last Sunday. I need to get that fixed fast, and in a hurry.

It's no fun being in stop'n'go traffic when the temps are 100°+!

[auk113]

If you are running PFC I can imagine that your ether an SR or RB. With that said JDM engine harness setups use different wire to start AC. In US a/c is controlled via chassis harness. You have to find a pin out for your ECU and trace trigger wire for AC... That way PFC can automatically bump up your idle when it comes on.

[Darius]

Look on NICO for the "Keeping A/C on an S14" thread by 300Plus. He has a writeup on how to wire it. I also posted a wiring diagram on another thread there titled "RB---->A/C".

[jamanrr]

Look on NICO for the "Keeping A/C on an S14" thread by 300Plus. He has a writeup on how to wire it. I also posted a wiring diagram on another thread there titled "RB---->A/C".

I read his article and he knows his stuff.

I really think my problem also can be attributed to a atmosphere vented BOV which causes my idle to stumble. I have all the heat shielding on the lines like he does and I have even read what he states about grounding the a/c switch to pin 46. I do not know if this is the correct pin for an sr? It would seem that they would have them the same but I do not know if I want to risk it since it takes me 3 seconds to raise my idle on my handheld. If I could see an actual wiring diagram of what he is talking about for his RB and see if it matches up to what an sr runs then I would know. I raised the idle 100 rpm and it takes cars of the low oil pressure and is a normal running car with cool a/c. It would be neat to figure out that wiring and if any of you guys know for sure if that works on a sr then I might give it a shot.

I think a lot of my stumbling idle can be attributed to an atmospheric vented BOV. Will be switching to a recirculated system once I get some money. Should not be that expensive though and hopefully the car can run even better. thanks for the replies