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Thread: Some turbo/motor help

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2011-07-01 01:27:37
Some turbo/motor help
Hey guys. I'm experiencing some issues. Here is my setup first. 99 p11 with a w10, gtir t28, stock injectors, z32 maf, and a jwt ecu tuned for 4bar pressure and what I have. Also want to throw in that I have an ACT extreme with a 6 puck spring.

1.The first problem I want to clear it out. Its about stuttering of the car after warming it up. A friend of mine said this is normal due to the ecu being 4bar and I did notice it goes away after warming up, but now its doing it under 3k rpms at all times and sometimes when I'm climbing rpms to 7k. The only thing I can rule out is I need to clean the maf maybe. Also like to throw in that sometimes I hear popping coming from the filter when I rev or even switch gears normal driving. And when its done warming up, and I rev the motor, the air suction is loud and I can hear something like the filter is acting like a bov. I do have my bov recirc'd.

2. I noticed about a month ago(after the swap) I'm burning out my tires on high boost from 2nd and even on 3rd when boost kicks in. My high boost is set at 14-15psi. Now I noticed that at higher rpms, the rpm climb isn't steady as if the clutch wasn't grabbing at some points(it better not be my clutch). The car still burns out 1st and now only chirps 2nd. I can't think of anything what happen there unless its just me or need a simple tune up. But I know my car and I do feel a little power loss.

3. Idling issues. Had this problem ever since I was N/A and tried to adjust the timing. When I dc the tps, rpms stay above 1200rpm. I know how to time the car and the procedure by heart. I even cleaned out the iacv and checked for vacuum leaks. Now that I switched over the iacv, its doing on the turbo motor as well. If I dc the iacv, turn the screw all the way down, and turn off the car and try to start it, it dies, but one turn of the screw it will idle, but above 1100rpms even with the iacv dc'd. Only thing I can think of is replacing the iacv.

4. I have a wideband. I do keep track of the ratios. I know JWT runs ecus rich, but the rich I've seen during full throttle was between 12.2 to 12.4, isn't 11.9-12.0 better? I want to know also, is the a/f ratios suppose to be moving around from 13-16 when idling? or is my idling problem causing the mix a/f ratios? Also is the wideband suppose to move back and forth between 14-15.7 when crusing? or is it suppose to stay at one number?

Some help will be appreciated. And I will respond to anything you guys say. Thanks
2011-07-02 16:51:59
Boost leak? haha. I myself was amazed at what a boost leak can do. Even a small one.
2011-07-02 17:32:51
Reading your A/F gauge and your Boost/vacuum gauge and watching them constantly is important with these cars. Not so much so to watch teh A/F ratios. But just to know where they are supposed to be normally. If you do that you can actaully see a boost leak at idle. With cams your vacuum should be at about 13-15 without 20. If its lower at idle then somethings wrong/leaking air. The Air fuels at idle should be close to stoich or around 15.0:1. I like to lean mine out during the cold months to save gas and richen it up during hotter months to keep the motor running a lil cooler. During cruising it depends on how you set it up also. Normally if im doing a road trip and not boosting at all really then I like the a/f's to be around about 15:1 also. If its cold ill sit it around 15.5-15.9 cruising. Your a/f's sound fine. WOT you need to drop that down to 12.0:1. I had mine sitting at about 14:1 wot until about 3500 for good spool up time. Then I gradually drop it to 12:1 by the time its touching 3800 where the turbo hits full boost. You have a wideband so its gonna move depending on whether or not your going up a hill or whatever. I know in my car its damn near impossible to keep your foot steady and the A/f's steady unless your on smooth, level highway road. Otherwise anybump you hit will make your foot slightly move on he gas and that affects your a/f's directly. A/f should be pretty steady once the car is warm though and its just idling.

Start by cleaning the maf. It cant hurt. Get the maf cleaning can from any auto store. Replace and ZIP TIE EVERY single vacuum hose on your motor. Yes this cost money. But its piece of mind knowing that you can rule those hoses out. If you dont have tbolts then you need to get them. RTV grey ANY and EVERY place you can and skip the gaskets. They leak over time with boost. Or you can rtv grey over the gaskets.

Also one other thing that Ive noticed with these car is that I can always tell when I have a coolant leak no matter how small because my idle will start becoming bouncy. Im guessing this is because of the coolant running over the CTS only sometimes making the ecu go crazy. Replace your coolant temp sensor (like $14 anywhere) also just in case. Our cars are really sensitive to the CTS's.

Check your spark plug gaps and make sure they are gapped propperly for whatever plugs your running. With my Iridiums i run the gap bigger.

Last...stop flooring it until you figure out your issues or your gonna break something or mess something up.
2011-07-02 18:17:47
*Forgot to add that I have an SAFC-2 also with all the settings not touched.

Thanks johnny. that basically sums up somethings. And it all makes some sense. I do have tbolts all around for the intercooler pipings. Also, I had doubts about the coolant temp sensor cause that fixed my long idle issues with my 240sx before. I'm going to change the plugs out again, I checked them out and they have tan tips telling me the motor is burning right. I have the ngkr7e plugs and gapped them to .30.

I have an AEM boost controller that is a gauge and controller that reads in psi.
When idling sometimes its at -18 and moves around between -20 to -15 when my idling gets all werid. My car was idling perfect and getting very good gas mileage up until 3 days ago, its idling between 1k to 1300 after driving for a mile or so and coming to a stop. For some reason, when I do warm up my car, and drive and come to a stop I'm idling good at 830 to 900 and my a/f ratios are a little steady at 15.1 to 15.5. But after driving for awhile and coming to a stop it high idles and a/f ratios are at bouncing between 15 to 15.8. I havent smashed on the pedal for awhile..hehehe..

I'm going to rtv most of the things cause that kinda makes sense and it does sound like a better idea. I do have gaskets mostly everywhere where they can be placed except the bov, so I'm going to put rtv over the gasket.
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