1990 TSi problems

[xlMcMlx DsM]

Im starting this new thread because my last one was getting off topic. Heres the other one, you can read up on it to get the info on whats up.
http://dsmtuners.com/forums/showthread.php?t=255119
I removed all the vacuum lines, the FPS, the EGR is blocked off, the ports on the TB are blocked. ive got a full 3" turbo back straight pipe.....which is causing boost creep like crazy. If i try to hold a steady rev, like just give it some constant gas, it cuts out, and surges, if you will. It will rev up a little like it wants to rev, then go back to idle, like idle surge, except im giving it gas. Now, the guy i bought the car from had the BOV vented to the atmosphere, and the MAS unplugged. If i leave the MAS unplugged , i dont get idle surge(which the car has if i plug in the MAS and recirculate the BOV) but only at operating temp. I have my boost gauge hooked up properly(i know i do) It read around -19 to -20 ay idle. But i rev it, and it wont go past 0psi(im gona replace the hoses with all new ones) Now, i built a boost leak tester, the RTV should be dry when i get home, and im gonna give it a quick test. Now, my ideas are to weld up a Magnaflow High flow cat to get rid of the boost creep. this is basically my only option, because im short on $$$, my mom wants it on there to be legal, and the cops around here will really get you for that. My other proposal is to get a GM MAF and translator. I can get the 3" MAF for basically free off a junk car, then put that all in with a Dejon tool UICP so i can actually vent my BOV properly w/o it running rich. Your input and suggestions are apreciated, any ideas or thoughts are also helpful. Its my first Turbo DSM, so im open for suggestions.

 

[JayRolla]

First off you need to make sure the bov is recirculated if its not, that will cause tons of problems.

With the boost creep, the cat wont stop it. It will be more work but pulling the turbo and properly porting it will fix your problem with creep.

You should not see any boost on the guage unless the motor is in gear. So its normal for it to go up to 0psi only when reving.

The maf-t will not fix your idle surge, if it did its just hiding a leak at the TB somewhere. Check your ISC and make sure its working properly. Also your boost leaks may be causing all your problems.

 

[xlMcMlx DsM]

so i got home today, and i went and boost leak tested it. NONE what-so-ever. didnt hear anything, held pressure perfectly. I havent had a chance to drive it with the new boost guage, so i took it for a spin around the block. pulled REALLY hard. To my suprise, it held 10psi!! all the way through the gears. No creep, or spike, or leaks. This is with the BOV recirculated, but the MAS was disconnected, so i wouldnt have to deal with idle surge. It ran perfectly, no surge, pulled hard, held boost. I dont know if this is just a one time thing, but we'll see on friday. Im ordering my MBC today, and hopefully a hard UICP next week.

 

[JayRolla]

PLUG YOUR MAF BACK IN NOW. Do not run the motor like that. The maf is NEEDED to read the air flow and insert the right fuel. You are going to kill your motor.

 

[xlMcMlx DsM]

i only ran it once just to see if the boost guage was working right, and if the bosot creep was gone. But of course i plugged it back in. Im gonna wait a while to drive it b/c im going to the salvage yard next weekend and get a GM 3" MAF and then order the translator so i can vent my BOV the right way. It's be a good starting mod, too. I could start tuning my fuel as soon as i rewire my fuel pump,

 

[JayRolla]

i only ran it once just to see if the boost guage was working right, and if the bosot creep was gone. But of course i plugged it back in. Im gonna wait a while to drive it b/c im going to the salvage yard next weekend and get a GM 3" MAF and then order the translator so i can vent my BOV the right way. It's be a good starting mod, too. I could start tuning my fuel as soon as i rewire my fuel pump,

Dont think this will fix your idle surge if thats why you are doing it.

 

[xlMcMlx DsM]

noooooo, i know it wont. It just stopped it so i could test my bosot guage. I know i need it in. Im gonna pull the TB off over spring break and completely rebuild it. New seals, block the FIAV, all that good stuff. But im gonna leave the old ISC on, and if its still surging after that, then i know its the ISC that's bad. But the thing is, i disconnected the ISC while the car was running so it would stabilize the idle, as said in Terry's Idle surge page, and it didnt do anything. It kept surging. So that means it couldnt be the ISC, right?

 

[xlMcMlx DsM]

i just did the 6V battery test on the ISC, and the ISC motor didnt even move. so i dont know whats up, but that just might be part of my TB rebuild.

 

[ekanddsm]

If you did the test and the motor didnt move you need a isc motor. I does more than just hold idle.
It helps your car return to idle so that it doesnt stall on deceleration. Another question, why junkyard parts?

 

[xlMcMlx DsM]

theyre cheaper. thats why. plus i can bring a 6V battery and ohm-meter out there to test them and see which ones are good. And i know that the ISC on the 2.0 NT will fit, and the salvage yard(my mistake, not a junkyard) has tons of them, so thast a plus.

 

[xlMcMlx DsM]

well i just finished with my TB rebuild. I replaced everything, the shaft seals, the BISSS screw o ring, the TB gaskets, and theres still idle surge. And again its after it warms up. I positive its the ISC. I found one for $25 and im gonna pick it up this week sometime