420a (turbo) car stalls when stopped and bucks when taking off in 1st and 2nd

[glowryder]

check the voltage on the MAP, seeing boost kills those sensors.. id say get a missing link (to protect the map snesor) and run the FCD as well. perhaps an issue with the TPS/IAC? check the resistance of those and see if they are shot or clogged.

 

[dsmking101]

hey guys i just read this whole post and i got to bring it back..im mostly having the same problem...
i finished my turbo install 14b turbo ,255 pump,12:1 fmu,fcd set at 4.49 volts,smic,hks bov vacume line installed direct to the the intake manny,fmu vac line teed into the bov line,internal waistgate,manual boost controler set at 3psi at the moment,glowshift boost gauge,custom piping with home depot elbows and cups not the best for boost but doin the job right now intill i can get the silicone ones soon...for manifold i have the stock 420a manifold with a 14b flange attachment custom..

now the problem .... my car dies on me while driving as if i turned of the ignition afther only no more then 5 minutes of driving....when i start the car it idles for about 2 minutes then stutters a lil then shutts off but starts right back up afther a minute or two of waiting.. i dont know why this is happening i can drive the car it boost fine but wont let me boost above 5000 rpm itll start to boost then once i reach 5000 rpm itll drop down in rpms .....please help i need any info i can get thanks guys

 

[LD25Delta9]

Do a BLT. Sounds like you've got a leak somewhere and it's not showing your full amount of boost. Most likely you're maxing out your injectors and you didn't even know it. Whatever your Internal Wastegate is set at is what your boost level is. Your MBC will only regulate it above stock boost levels.

 

[dsmking101]

i think stock injectors can hold about 8 psi max /and im not pusing that much yet so maxing out the injectors are out the question...boost leak maybe but will know soon....so your saying i caint controle my boost with my mbc with an internal waistgate? i have a boost gauge and i have my mbc set at 3 psi at the moment intill i figure out this problem of the car shutting down on me/ and when i drive and hit boost my gauge shows me im hitting 3 psi and wont go over that i can see but then again it wont let me pass about 5200 rpm so maybe im wrong but i think everything should be fine when it comes to controling boost..some one told me that my 255 pump maybe be sending to much fuel and causing my car to drop in rpm at idle and stutter and shut down so they said to switch back to my stock pump... can this work if so would i run to lean with a stock pump or will i be ok with the stock pump and my 12:1 fmu ..thanks guys let me know

 

[LD25Delta9]

A MBC restricts air flow to your wastegate. No matter what your MBC sees pressure wise, your wastegate will only open at the set rate. So a MBC will only raise boost levels, never lower them. The 14b has a set IW rate of 11-14lbs of boost. Which is already enough to max out our 235cc injectors. This is what leads me to believe you have a boost/vac leak, because you are definitely not getting the right numbers via your boost gauge, or you have a faulty boost gauge. Do a BLT for your IC pipes, and a smoke test for your head.

On a side note, get a chiltons or download the service manual, and find the stock ohm and voltage for the ASD relays and test them. They are the two black boxes to the right of your Brake master cylinder.

Edit: After looking at your avatar pic more close-up, I'll almost guarantee a vac leak. You've got way too many vac lines and T's running everywhere. I'm not bashing, just trying to help. The most direct/shortest vac lines you can use are best. Also make sure they aren't oversize and just clamped all to hell, either. I'd also look into nixing your EGR system and getting a catch can instead of those breather filters.

 

[dsmking101]

thats a pic of my engine while in build it dosent look nothing like that now.....i figured it out fixed the problem thanks guys for the help ...is there anyway i can controle my boost with the internal waistgate......i dont want to over boost i juss want to keep a steady 6 psi right now

 

[LD25Delta9]

No. Not if your IW is set above 6 psi. You should also tell us what the problem is and mark the thread as resolved so that it may help out future Tuners.

 

[dsmking101]

ok i will but it wasent my thred...and if these internal waste gates are set to 11.5 stock on gsx and me having it on my car with an n/a ecu will make it to run about 6-8 psi right? because the ecu,s on gst and the gsx have a selinoid that helps it run 11.5 psi stock..since we dont have that selinoid then it brings it down to 6-8 psi stock right? thats what i read some where on a post is this true

 

[LD25Delta9]

No this is not true. The wastegate spring is what dictates the boost level, not the solenoid. The 420a ecu is completely different than the 4g63 and the 4g64, so you can't switch any of that theory over. If your gauge is reading 3psi, then you have a boost/vac leak or a faulty gauge.

Sorry I didn't notice it wasn't your thread....makes me wonder what happened to the OP.

 

[dsmking101]

im not running 3 psi i said i had the mbc set at 3 psi my boost gauge is reading what the internal waste gate is pushing 6-8 i did set my mbc to 6 and hopefully it stays that way......what do these waste gates come stock?

 

[LD25Delta9]

What kind of MBC do you have? Must be fancy.... the stock spring pressure is 11 to 14 lbs. It depends on which turbo you got from which year DSM. They all range differently from the 13b to the 18g.

 

[dsmking101]

nahh its not fancy i have a ebay one with the knob...and i have a 14b from a gsx i dont know what year really but it is pushing some where between 6-8 pounds i know what you mean about the 11-14 tho...since this one is puahing around 6-8 and up i just set my mbc to 7 this morrning and i hope it satys that way since i caint lower boost just raise it..