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Turbo Ii Issues....

Old 04-04-2005, 01:47 PM
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Okay.



First some background for anyone who hasn't already heard:



It's an '87 Turbo II with a fresh engine from Mazda with less than 600 mi on the engine. Everything is stock except the HKS intake, the Racing Beat downpipe and the straight exhaust into APEXi N1 Duals.



The idle is now relatively steady give or take 200 rpms, it is idling around 1250. It still sounds kinda rough though.



Secondly the smoking is definitly noticeablle. It doesn't really stink like burning oil or coolant, its a light colored white/blue smoke. It doesn't seem to smoke as bad when you rev it up but once its revs down it smokes again. The engine seems to be running okay though, it isn't shaking or stalling. My dad says it might be running rich.



Thirdly under moderately hard(spirited) accelleration it kind of misses or bogs down or something. It starts to pull quite nicely but then, right when rotarys start to really shine, it just has no power and misses. You can feel the car just lose power when it "misses".



I'm thinking these issues are all related. I'm guessing the TPS needs to be adjusted....but I really don't know. Its needs a new blow off valve but this wouldn't cause these symptoms right?



My major concern is the rough idle, the smoking and the power loss under hard accelleration.



Here is what has been replaced : all vacuum hoses, belts, lights, motor mounts, gaskets, lines, injectors, seals, plugs, wires, battery, alternator, brake master cylinder, clutch, p-plate, throw out and pilot bearings, rebuilt rear, Racing Beat downpipe, new 2 inch y pipe into APEXi N1 Duals, fuel filter, diamond cut headlights, o2 sensor, factory stereo, HKS intake, tires(less than 500 mi on them), brakes and wheel bearings.



There is also a "screaming" or screeching sound that comes from the read end when you give it gas while driving.



Please reply with any/all ideas, comments, suggestions, questions or ideas. Thanks alot guys. I'm gonna see what else I caqn find on the forum.
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Old 04-04-2005, 04:38 PM
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Ok, i'm not an expert but if you are using your stock ECU with a racingbeat exaust, your backpressure changes significantly. The boost raises up to around 12psi and the ecu cuts off fuel to the rear rotor. You need to purchase a fuel cut controller from mazdatrix or racing beat, or buy an hks one configured for your car on ebay. They are around 100 dollars and might be just what you need.



Now i'm 18 and only starting on my rotary rebuild.. and i would double-check what i said with someone of more experience.



Also on that screaming noise.. my transmission in my 83 gsl did that, screamed very loudly. It only gets worse. I ended up replacing my tranny with one from a salvage yard, worked beautifully.



Also, before you hurt your engine, you should read how to break it in from somewhere.



Good luck,

Shawn Brown
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Old 04-04-2005, 06:24 PM
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first the idle is too high, your idle should be at or around 750 to 800 second the smoke sounds like a rich mix , check the metering oil pump for proper operation also. and seeing is it is an s4 check to see if the twin scroll is operating properly now i have sean alot of broken control rods on the twin scroll. but of up most importance go to a dealer and get that compression checked and then if you do not have one get that mentioned fcd.
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Old 04-09-2005, 04:11 PM
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the miss could be from fouled plugs since you says it runs rich, a plug swap could be very useful



they can foul out pretty easy on newly built motors too



and yeah, without a fuel pump and fuel cut defenser i WOULD NOT boost around on that car w/ full exhaust and intake, you will blow your car up because of the rear rotor fuel cut.



you should look on ebay for a used HKS F-Con. This way you can adjust your fuel. They also come with FCD's. Run about $225-260 used. Make sure its for your year of RX-7 as the F-Con is pretty universal and has plenty of different chips and harnesses
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Old 12-20-2006, 07:38 PM
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Update anyone???



Well some things have changed since last post:



The smoking has stopped entrely, it only did that one day shortly after getting it home from maryland. The car was driven for some time after that, keeping it under 4,000rpms, mostly under 3,500 rpms. Boosting has been avoided like the plague.



I was driving it one day when something "happened" to her, I was at like 3,500rpm in 3rd shifting into 4th, when I let off the gas and pushed in the clutch it the rpms dropped only slightly and then bounced back up on their own, it kept bouncing around 2,500rpm no matter if the clutch was in or out as i was coasting down the road. I drove like that, "bucking" kinda, only for about 200 yards and then parked in my driveway and shut the car off. As I parked, the car it stalled with the clutch still depressed.



The next day I started the car and it immediately revved up to about 3,500rpms and stayed there, without my foot on gas pedal, it wouldn't drop even when I blipped the throttle, I only let this ahppen for about 2 sec before shutting the car off. it did this once or twice more in a row. and then I cleaned the throttle body and the throttle linkage. I also installed a Rtek7 Stage 2.0 Ecu( to help with necessary fuel management and tuning later) at this time.



I started the car and it didn't spike to 3-4000rpms, it revved up to 2,500 and then fell like normal after a second, only now the rpm is bouncing ~200rpms all the time. It starts cold and idles at 2,000 for a minute or two and then falls to 1,750 then to 1,500 then to 1,250 down to maybe 1,000 as it warms up but always bounces about 200rpms every couple seconds.



You can easily hear/see the motor revving up and then revving down every couple seconds though as it warms up it gets a little smoother, with a little longer pause between "rpm pulses".

It's just really wierd, I have checked the TPS, replaced it with another one from my '88 GXL donor. Checked for vacuum leaks as best I can, tested the resistance of the BAC and other vlaves, I just don't know what else to do.



There was obviosly something that happened that day, although it is better now it isn't fixed, why won't my TII idle like a good girl? There are still only about 1,000 miles total on the new motor. I am addresing fuel mods/tuning/wideband monoitor installation/turboupgrade soon but need my baby to idle first.? I don't want to have tot otake it to a mechanic if I dn't have to but I will if it is necessary to fix her.Thanks for the help everyone. happy Holidays



--EDIT-- It revs up to 3,000 just fine, it sounds great, runs cool, won't stall, still drives around driveway but does this 200rpm revving idle thing.
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Old 12-21-2006, 09:17 AM
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Thermowax system on the throttle body will keep the idle higher until the engine coolant has warmed up. That 3000rpm warm up deal I believe is ecu related, AWS sensor and BAC. All of the high idle stuff is normal when its cold out. Idling bouncing around sounds like TPS misadjusted or vacuum leaks.
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Old 12-21-2006, 08:32 PM
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Originally Posted by 1Revvin7' post='849798' date='Dec 21 2006, 10:17 AM

Thermowax system on the throttle body will keep the idle higher until the engine coolant has warmed up. That 3000rpm warm up deal I believe is ecu related, AWS sensor and BAC. All of the high idle stuff is normal when its cold out. Idling bouncing around sounds like TPS misadjusted or vacuum leaks.




thats the typical answer i get on rx7 forums.....



TPS was replaced, installed and adjusted to within spec.



I am aware of the Accellerated Warm-up System does, or at least how a normal rotary starts and idles high for a bit when cold then drops or kicks down to a normal idle., my situation is nothing like that. When the rpms stuck that one or two times, each time you hit the gas and tried to blip the throttle to get it to kick down, the rpms just went up and stayed there....much different than normal operation of AWS.



BAC valve has been checked and it operates apparently as it should, it's resistance is within spec and it clicks when 12v is applied.



I've checked as best i can for leaks, found a small leak in the intercooler piping by the Blitz BOV, tightened that and it didn't help make a difference. Also found a small exhaust leak by downpipe, fixed with impact gun, result is just a little less fuzz in exhaust note.



Also the Rtek7 2.0 , installed during the period i was trying to fix this problem, eliminztes the cold start AWS procedure so it doesn't subject the poor motor to something like that.





As mentioned before, the car isn't doing that thing where the rpms climb to 3,500 -4,000 rpms when started and stay there, forcing me to shut off car. That just happened twice after it started bucking that one day. Now its just that teh idle bounces, like the motor revs up and down every couple seconds. I'll have to take a short vid and post it on putfile or something so you can see what i'm talking about.



Anybody from the NJ area wanna help a guy out???
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Old 12-22-2006, 09:30 AM
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Sticking throttle plates or cable?
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Old 12-22-2006, 04:44 PM
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mine does something like that

if I try lower the rpm to 1000 or lower it dies

then sometime it floods

compression is 90/87 with 20 miles on the rebuild



then one time I drove it and got to a light, tried drving away and the engine just started bouncing up and down... no matter if I floored it....it stayed doing the same thing at the same up and down rpms



Put four rebuilt injectors

walbro 255 H/P

Racing beat full exhuast



Think the AFM is f'd

going to put a megasquirt EMS and be done with it
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Old 12-22-2006, 05:19 PM
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revvin,



I clean the throttle body as best i could without taking it too far apart, the throttle body throotle plates are not sticking and are within tolerances. The cables don't bind and I don't see how the throttle cablre could be causing such a consistent pulse like rev that i have. I don't know but keep thowing the ideas out there, I might not have tried something you know about. Thanks so far though,







...,

Thats does sound similar to my problem. I am going to replace the fuel injectors anyways soon whether or not I have resolved this issue. My exhaust is pretty new, and i just tightened the only leak in the whole exhaust i could find the other day. Mine doesn't stall, it doesn't flood, it just does that surging idle, whether it is in a different throttle position or not.....I'm gonna check my compression tomarrow morning with a standard compression checker, just to make sure.



The afm, how do you check for operation? resistance, volts????

MyRtek7 2.0 ecu is all i need for now, I like it anyway. I just need to fix this idle/surging and then upgrade fuel system /ignition /turbo + wastegate/ suspension/ brakes and paintjob. Thats all........ I have all the pieces at my house cept upgraded turbo, just want to get her running well before going further with mods.



Thanks everyone for your help and ideas, please don't be afraid to offer a suggestion or share similar situations for advice. Take care, have a great holiday season.
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