Minor Idle/boost problems

[2plus4plus0eq6]

Hello,

I have an '89 with a s14 sr20det. I tried searching, but couldn't find anything specific for my situation. I am still learning this stuff, but don't really know what air/fuel ratios are normal. I want to install my manual boost controller and turn it up to 12psi, but want to fix a couple things first.

I just recently got my car back from an auto shop. They installed my air/fuel (with wideband sensor) and boost gauge. At idle I am reading about 25hg vacuum (Too high - too low?) and only hitting about 5 psi of boost at WOT. The factory boost solenoid is gone so I thought I would be seeing around 11psi if not at least 7psi.

A/R is reading between 11-15 at idle and hitting like 22 at WOT. Is this normal? I know 14.7 is a magic number, but better to run rich in an induction application to avoid leaning out because of the turbo. 22 seems really lean. I don't want to blow something up before I turn up the boost.

Coming to a stop will stall the engine if not slowing down real gradually. I kinda have to feather the pedal. I am wondering if a boost leak is causing this. I will do a leak test when I get sometime.

Please let me know what a/r numbers I should be aiming for. I am running 94 octane btw.

Thanks for the help

[2plus4plus0eq6]

Update:

So I did a leak test by plugging the pipe where my air filter is and hooked an air compressor up. There seems to be a decent size leak somewhere near the turbo. Not a slow leak.

For the life of me I cannot seem to find it. I tried soapy water. I think I can feel it with my hand.

I am surprised my car seems to start and idle fine. I can only hit a max of 5 psi boost so I assume it must still be a small enough to be able to hold boost still.

Anyone with experience or a little trick that can help me find this leak? I don't really want to start ripping things apart yet because I think I should identify exactly where it is first. Its just a tight spot.

Someone please help!!

Thank you

[Fuego]

First your afr at idle should be around 14-15 and generally hold around there. WOT should be much closer to 11 than what you're seeing. The boost solenoid was there to hold the pressure at 11lbs. If it failed, the wg actuator would hold 7lbs (which is what you should be seeing).

Once you're stopped and feather for a second does it idle fine? My initial guess is your BOV for the idle, but that wouldn't explain it leaning out at WOT. Check seals between your MAF and the turbo inlet, it sounds like you're getting unmetered air.

[2plus4plus0eq6]

Thanks for the reply. I'll check that area again and report back. Thanks

[2plus4plus0eq6]

Update:

Still can't find the leak as of yet, but noticed black soot in the turbo right where it connects to the hot pipe. Is this normal? Doesn't seem to be any oil. I have a catch can so I know its not blow by.

[blksylv]

do you have a gasket in between the turbo and the outlet for the hotpipe?

http://www.enjukuracing.com/products/oem-3-bolt-turbo-outlet-gasket-for-nissan-sr20det.html

[2plus4plus0eq6]

do you have a gasket in between the turbo and the outlet for the hotpipe?

http://www.enjukuracing.com/products/oem-3-bolt-turbo-outlet-gasket-for-nissan-sr20det.html

I assume I still have the stock one in there, but i'll double check that. At one point I know I took everything apart and put it back together. hopefully it was OK to reuse the gasket. Thanks

Edit:
Just to note that when I put everything back together, soon after I did a boost leak test and everything held no problem at 15psi

I also did a little research on how turbos actually work and where boost is held. Sounds like I can narrow my leak locations:

1. Gaskets on turbo compressor side
2. Silicone couplings connecting to compressor
3. Maybe by chance if its possible. Boost could be leaking through from the compressor side where the turbine is to the exhaust turbine side. Is this the reason for the soot?
4. Wastegate

[2plus4plus0eq6]

Update:

I took the 2 fittings off the compressor side of the turbo. The one that connects to the hot pipe of the Intercooler and the other one is the air intake. I found oil in the fitting that connects to the intercooler. It doesn't look like it spread any further than the connector. Its not in the intercooler.

here are 2 pictures.
http://imagizer.imageshack.us/v2/150x100q90/673/yFJrD1.jpg
http://imagizer.imageshack.us/v2/150x100q90/912/hj1eOZ.jpg

Sorry for the small pics. For some stupid reason they display small.

At this point, I am assuming I need to rebuild my turbo. I cleaned up the fittings and put some gasket maker in between the original gasket just to make sure its sealed. I will hope for the best and update tonight.

[Kaifd3s]

If you pressurized the system from the air filter, and you can sense a leak by the turbo area; The only parts that are pressurized is the intake and turbo compressor elbow. Those would be the only two areas by the turbo that would have a leak.

Change both gaskets, and do another pressure test.


As for the car wanting to shut off when coming to a stop. Check the idle adjustment on the IACV. Just search on how to adjust it. That is most likely the problem.

[2plus4plus0eq6]

If you pressurized the system from the air filter, and you can sense a leak by the turbo area; The only parts that are pressurized is the intake and turbo compressor elbow. Those would be the only two areas by the turbo that would have a leak.

Change both gaskets, and do another pressure test.


As for the car wanting to shut off when coming to a stop. Check the idle adjustment on the IACV. Just search on how to adjust it. That is most likely the problem.

I did another test. Still have a leak near the turbo. Still won't boost past 5 lbs. I put some stuff called 'stop-a-leak' to help thicken up the oil. The last time I noticed my boost leak test was good was when I had some normal crappy 10w-30 in the engine. Now I am running 20w-50 royal purple so I thought the synthetic was passing through the turbo seal. I notice the engine runs quieter now. My air/fuel ratio numbers seem a little better. While boosting at WOT, I am getting 12-15 a/r. When I let off the throttle, my a/r is like 22. Is that normal when letting off the throttle? This is all new to me

I will check the IACV to see if thats causing any issues and report back when I get the chance.

[Ka-t in progress]

Engine oil will have zero effect on a boost leak,two totally different things. Lots of factors could be causing your lean issue. Finding that leak and fixing it should be first,you know one is there so get that under control, and stop trying to get over 5 psi until you get it fixed. Check for more leaks, I'd hate to see your vacuum line come off the wastegate and you over boost. Take your time and research/ask for help. Good luck!

[2plus4plus0eq6]

Engine oil will have zero effect on a boost leak,two totally different things. Lots of factors could be causing your lean issue. Finding that leak and fixing it should be first,you know one is there so get that under control, and stop trying to get over 5 psi until you get it fixed. Check for more leaks, I'd hate to see your vacuum line come off the wastegate and you over boost. Take your time and research/ask for help. Good luck!

I know what you're saying. I am beating around the bush with this turbo leak. I think that is what it is. I am just hoping that its something else... but I don't think so.

I did clean out my IACV today. It seemed to have made it worse. I don't get it. Maybe I have to adjust the screw since its cleaned out. It now dies on me when I start it up unless I feather the pedal for a bit. Before it started up no fine with no hesitation.

Any suggestions with the IACV screw?

Thanks

[Ka-t in progress]

I believe I have mine set to 3 turns out from all the way In. You could check the voltage if it would ease your mind. There's a write up on here but I can't get the link. I'm betting on it being a leak of some sort. If it's not a leak, the lean issue could be from a dirty fuel filter,or a pump going out. I'm assuming your on the stock fpr. But first things first with that leak good buddy.

[2plus4plus0eq6]

I believe I have mine set to 3 turns out from all the way In. You could check the voltage if it would ease your mind. There's a write up on here but I can't get the link. I'm betting on it being a leak of some sort. If it's not a leak, the lean issue could be from a dirty fuel filter,or a pump going out. I'm assuming your on the stock fpr. But first things first with that leak good buddy.

I will have a search to see how to adjust the screw properly. I have a stock FPR at the moment. I have a megan racing one kicking around, but a local shop said it was too cheap and shitty to put on. They said it was a ghetto way of adjusting fuel cause it just forces it through the injectors. I am not sure if I totally agree with that. Anyways. I also have a brand new HKS air filter, and new fuel filter, and a new walbro pump.

[Kaifd3s]

Search on how to properly adjust the IACV. You have to disconnect the TPS and stuff when adjusting it. Also when you cleaned it out did you replace the gasket for it? IF you didn't, that would just make your idle problem even worse.

Find that boost leak. Try pressurizing the system and just spray a soapy water mix around the pipes. Look for bubbles.

[2plus4plus0eq6]

Search on how to properly adjust the IACV. You have to disconnect the TPS and stuff when adjusting it. Also when you cleaned it out did you replace the gasket for it? IF you didn't, that would just make your idle problem even worse.

Find that boost leak. Try pressurizing the system and just spray a soapy water mix around the pipes. Look for bubbles.

I found a decent write up here. http://www.zerotohundred.com/newforums/nissan/327316-diy-how-to-cleaning-iacv-maf-throttle-ecu-set-setting-base-idle-and-timing.html

I had no idea I had to disconnect the TPS first. Anyways.. I think that boost leak I am experiencing is the root of everything. I probably wouldn't even have any idle problems if it was fixed. By adjusting the idle, I could be just putting a temporary band aid on the problem.

I tried soapy water but just couldn't see anything. The only indication of a leak near the turbo is that I can hear it. I plugged the air filter inlet, plugged the neck fitting on the compressor that goes to the intercooler, plugged the small hole on that same fitting that goes to the valve cover and hook my air compressor to it. I can hear the leak. I cannot feel any air around the turbo. That's why soap water won't work. It sounds like a big leak. My only thoughts are that its leaking air through the turbo seal into the turbine side of the turbo.

How likely could this be happen? Anyone with experience on this? I would hate to rebuild the turbo to find out that the problem was something else that's still there. If air was escaping into the turbine side of the turbo, I guess I could disconnect the turbo elbow to the downpipe and check to see if compressed air is felt in there.

Edit:
I have a good feeling that my wastegate could be stuck slightly open. The leak sounds big so if it was the turbo seals, I doubt it would be a big leak.

I have a TurboXS manual boost controller I haven't installed yet. By putting this inline with the wastegate, could this potentially fix my problem?

Thanks to everyone for all the help so far. I'll check tomorrow and report back.

[2plus4plus0eq6]

Update:

Good and bad news. Good news is I found the leak. Bad news is that its in between the turbo turbine and compressor. This is self inflicted. When I took the turbo apart long ago, I didn't seal it properly with new RTV. I've got no one to blame but myself. I also tested the wastegate and it works perfectly.

Soon here I will start the long ass process of ripping the turbo back out and sealing it up properly. What a PITA.

Quick question. should I drain the oil and coolant before disconnecting the lines going to the turbo to avoid a shitload of fluid coming out onto my face while I am under the car. Or.. will just a little bit come out.

Thanks

[Kaifd3s]

A ton of oil should not flow out of the lines, so you shouldnt have to drain the oil. If you are going to fix the turbo, you should want new oil flowing into the turbo for the first start tho. Coolant, I would drain. It could develop an air bubble in the system. I wouldnt risk it, just drain it and refill the system.

Glad you found the leak homie.

[2plus4plus0eq6]

A ton of oil should not flow out of the lines, so you shouldnt have to drain the oil. If you are going to fix the turbo, you should want new oil flowing into the turbo for the first start tho. Coolant, I would drain. It could develop an air bubble in the system. I wouldnt risk it, just drain it and refill the system.

Glad you found the leak homie.

Perfect. Thanks for the tips. I guess I'll update back when I get it all put back together with no more leaks. See if that fixes my idle issues. I would guess yes.

Thanks to all who helped me out.

EDIT:

I forgot to mention in this whole thread because I didn't think it could be a problem with the idling and stalling, but I have a HKS SSQV BOV installed (non-recirculating). I'll fix the boost leak first and see how that goes before I decide to recirculate the BOV

[2plus4plus0eq6]

New thought on fixing this. Let me know what you guys think.

I believe my leak to be right where the turbine housing connects with the CHRA. Instead of disconnecting all of the fluid lines and such. Is it better and easier to disconnect my turbo elbow, exhaust manifold and wastegate so I can readjust the turbine housing? I mentioned earlier about putting some RTV on it once I get to the housing, but I don't think its supposed to be used. I think there is an o-ring that seals it. Maybe I just need to tighten the bolts more.

Maybe even leaving the exhaust manifold on and disconnecting the turbine from it.

Any thoughts on this from experience?