ok, i got my car running https://www.nopistons.com/forums/pub...#>/biggrin.gif , but one of my turbos went out https://www.nopistons.com/forums/pub...DIR#>/ohmy.gif (the back one) and also my RPM's jump around and rev high.



if i let it idle for a while (usualy sits at about 1000) the RPM's will raise to 1200 and then to 1500 back and forth.

if i move the stick shift a little (auto trany) then it stops for a while, and goes back to about 1000 RPM

it says that it should sit at 720 RPM's in "P" (park). at idle



also is there an easier way to check and make sure your turbos are good? without taking off all that crap? https://www.nopistons.com/forums/pub...IR#>/wacko.gif

you can pull the elbows off the front of the turbos where is goes to the filters and grab the compressor wheel and see if there is alot of play, and also look for alot of oil in the intercooler and/or intercooler pipes.



The idle problem could be the ISC, (the black thing with white connector on the UIM) unplug it and see what happens, it could be sticking.

i took off the down pipe and messed with the turbo that way. the down pipe was all melted inside (or the honey comb stuff was) so i knocked that stuff out and replaced the down pipe (turbo spu freely) and now she screems.

but she also smokes really bad when you start it, and idles wrong.

so ill check the ISC and the UIM



thanks for all your help,

cody

ah yeah thats very important to get rid of the precat, it will extend the life of your turbos and help open things up alot.



If your interested i have a couple different aftermarket downpipes, one is the HKS one that works with right hand and left hand drive rx7s. I had it on the car before i went single turbo, and the other is a brand new 3" stainless one i got second hand. I dont remember what it was but its a really nice unit.



An aftermarket downpipe will be less restrictive then the stock precat and help further with spool up and the volumetric efficiency of the engine.



These cars tend to smoke more then other cars anyways... they do burn oil by design. The stock fuel maps are also quite rich. It's hard to say if your car is smoking more then it should though, but it's possible the oil seals in the turbo are leaking. You can try replacing your o2 sensor, its a relatively cheap and easy thing to do, if your old one is bad it could cause it to run even richer.



You might also check for vacuum leaks to fix your idle.

k, i am actually looking for a down pipe, will one of them fit a stock pipe setup, and whats your lowest price cause i need something cheap.

and when it smokes it puffs out a BIG cloud of it and its not even gas its oil. and once its running its like its cold outside and smokes a little for a while.

could be the oil seals on the turbo, they do tend to smoke more when they are cold.. keep an eye on your oil level and see how much it goes down. I think a quart of oil every 3000 miles is about what they normally use.



I know the HKS is for a stock exhaust system, the other is 3" i think, i never had it installed so im not sure if it will bolt up to the stock exhaust or not.. ill send you a PM with the price.

rx7's tend to smoke more when cold ***

Whether turbo oil seals would leak more or not im not sure?



Was the car flooded at all while you were trying to get it running? If so maybe there is excess fuel in the oil causing it to be thinner..



Since it's been sitting so long the car probably is anxious to be driven around, and things might start clearing it up the more you drive the car.

well the problem is that it wasn't cold out, it just smoked like it was a cold day (like when its about 30 deg. out and you start cold engine).

and thanks for that tip.

its been running good it just smokes and the RPM's jump around at idle (in park) from 1000-1500 back and forth, until i move the stick around then it stops for a while.

check your TPS it could be out of adjustment. there are several places on the net that show how to adjust the TPS correctly. other things to check would be the dashpot, but thats usually sysmtoms caused when you get off the gas the rpms jump around or stick, and also the ISC, a black thing with white terminal mounted near the throttle body on the side closest to the firewall on the UIM. This is what the ecu uses to control idle under different loads such as when the A/C is turned on. Unplug it and see if they settle down. it could be sticking.

Check your boost sensor on the fire wall near the drives side. There should be a vacume line attached to it. What makes you think the rear turbo is no good? They are sequesntial and on one shaft so if one is bad the other could be on its way out too if there is any play that will deteriorate the seals. Check from the intake side, pull off the lower hose the connects to the front of the turbos and pull back and forth on the nut that holds the compressor wheel in place. This would tell if you have any end play. If your not smoking like crazy your trubos a probabley fine. I bet that the clogged melted cat is the culpret of your problems. I could also change becasue of that messed up cat becasue the O2 sensor will be getting readings that fluctuate from the exhaust not working properly. I bet there is a lot of back pressure being built up from the cat too slowing down the flow out of the turbos.

yes, the turbos work great and the problem was the cat we knocked it out about a week ago....but when we take off the turbo kinda bogs then goes....kinda like flooring a diesel engine (basically there is no acceleration for about 2 sec.)

Turbo cars always have a certain amount of lag, the stock sequential turbos have less lag but it's still there, You have to have enough rpms for the exhaust to be there and spin the turbos.



and actually the front turbo usually wears out sooner because its always being used, and the rear one comes on after 4500 rpms so it gets less use.

ya i know...but could tha lag be from the empty pre cat? i knocked everything out of the pre cat...all the crap inside, and put it back on/

well the precat is still smaller then an aftermarket downpipe, so you could gain so you could reduce the lag some more with a downpipe. And then even more with a midpipe, and more with a catback. The less back pressure you have the less lag, but the more noise and emissions. the precat is bad for the car though and stores extra heat so its good you at least knocked it out. If you're cruising at 4500 rpms is there any lag when you punch the gas? Or is it only coming from a stop light or somthing? Do you have a boost gauge?

no its only from a dead stop, it works pretty good when were going, we never really floored it at a constant speed. we kinda have a boost gauge but it really a pressure gauge, still works. it only seems to lag when we floor it off the line, like the turbos are delayed.

thats normal. at idle there isnt enough exhaust gases to spin the turbine thats why there is a lag. New turbos would be the same way.

no its not like what you think, its like flooring it in a stock van and then after about 3 sec it kicks in. i know theres a little lag but you can really tell the difference.

hmm i'm running out of suggestions. maybe the main cat clogged?

My NA was exhibiting similar symptoms. Check all of your cats. If one has failed it might have caused a chain reaction.



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My exhaust system became a virtual potato canon after I flooded the motor. Once I put fresh plugs in and got it running it backfired violently five or six times. Platinum plated strips of metal were propelled out of the tailpipes like a shotgun. Afterwards idle was high and no amount of adjusting could bring it down consistently. Amazingly it still ran and could squeal tires with cat as pictured. https://www.nopistons.com/forums/pub...IR#>/blink.gif