New to dsm's and having problems

[PhenomGSX]

I bought a 97 GSX a couple weeks ago. Im in high school and this is my first car, i love it, but im having some doubts on its condition. The guy i bought it from did some work on the engine, as far as i know or believe, he put on a td05h 20g turbo, 3" exhaust, and an Injen Cold Air Intake. I had to remove the boost controller he had put in because it was cheap and made the car overboost horribly for the stock block (30+psi at times). My problem is this: when i get into the boost and it hits 10psi + the ecu causes the engine to start cutting out, or so ive been told thats what it is. The guy i bought the car from told me to buy a new MAF translator and sensor but i do not want to spend $350 on parts that may even ruin the engine by making the fuel even more lean. Any advice? (keep in mind im not entirely knowledgeable in mechanical jargon).

 

[spyderturbo007]

and i have no clue what an EPROM ecu is, but im sure its something that will cost enough to stop me from going this route -_-

This will explain everything you need to know about the EPROM ECU that you need. I was able to pick up a DSMLink package on Ebay for $640 that included the cable, software and EPROM ECU.

 

[PhenomGSX]

man if you just want your car to run right and dont no much about tuning and fuel management i would just sell your after market parts and buy some used stock parts, you can put the stock injectors back in and fuel pump and get a manual boost controller and turn your boost down to like 10 psi and it will run fine.

It runs fine now, i want it to be fast without sacrificing what i have now. I probably wouldnt have bought it stock tbh.

 

[PhenomGSX]

Ok, so I have a couple options here, I think. I could either go with some 550cc injectors and an AFC, or so,e 780cc injectors, DSMLink, and an Eprom ECU which i will probably have to socket. Im thinking i have to go with the DSMLink though because if a lack of fuel is whats causing my cutouts, wouldnt 550cc be too small?

 

[PhenomGSX]

KEYDIVER Chips - 2G DSM ECU Tuning

Im thinking it may just be easier to skip the tuning process and buy a chipped ECU for my 780cc injectors. Opinions or suggestions?

 

[boostin92awd]

Chipping it would be the easiest way for you from the sounds of things (if you already have an E-prom ECU).I ran 880s on my 1g with a chip and had no problems.

 

[CTP]

How about some engine bay pictures? Worry about getting all the issues fixed so it's running correctly before you worry about tuning it and getting chips and injectors. You need to get the boost under control first. Some pictures of the engine bay so we can see what you're working with would be great. A video of the boost gauge during a 3rd gear pull would be ideal. You have a good amount of work ahead of you. I know what it's like to buy someone else's modded disaster.

 

[PhenomGSX]

Ill try and get some pictures today. But im not tryin to get it tuned really, it does run right now, i just cant get into boost without the CU cutting out and thats all im tryin to fix before i go further into modding.

 

[PhenomGSX]

Anyways, I think the problem with the boost spiking is that my wastegate doesnt completely open up. my uncle told me that a new vacuum modulator would allow the wastefate to function properly which would then allow me to use even the cheap MBC that i had and it wouldnt cut out, but i am really unsure, i was already leaning towards that chipped ECU

 

[CTP]

Anyways, I think the problem with the boost spiking is that my wastegate doesnt completely open up. my uncle told me that a new vacuum modulator would allow the wastefate to function properly which would then allow me to use even the cheap MBC that i had and it wouldnt cut out, but i am really unsure, i was already leaning towards that chipped ECU

Fixing your boost problem by adding fuel is like fixing a broken leg by taking pain killers and ignoring it.

You need to determine why you're overboosting and make it stop. Didn't you say before than you tested the actuator and it was working properly? How exactly do you have it hooked up? You should have a dedicated line running from the intake manifold to the wastegate actuator, no where else.

If you were to go WOT at 2,000rpm in 3rd gear and make a pull all the way until redline, what would happen? Would the the boost gauge get burried as soon as boost came up or would it start out at lower boost until you reached 5,000-6,000rpm and then start climbing out of control? At what point would you hit fuel cut?

 

[PhenomGSX]

Fixing your boost problem by adding fuel is like fixing a broken leg by taking pain killers and ignoring it.

You need to determine why you're overboosting and make it stop. Didn't you say before than you tested the actuator and it was working properly? How exactly do you have it hooked up? You should have a dedicated line running from the intake manifold to the wastegate actuator, no where else.

If you were to go WOT at 2,000rpm in 3rd gear and make a pull all the way until redline, what would happen? Would the the boost gauge get burried as soon as boost came up or would it start out at lower boost until you reached 5,000-6,000rpm and then start climbing out of control? At what point would you hit fuel cut?

We took the wastegate off the car and it worked fine, which is why i am really not sure if its the problem, but they seem to think that the way the turbo was installed may have inhibited the ability for the wastegate to open completely.

At WOT it wont start overboosting until about 4-5k rpms, it stays at about 10-15 psi until then, then it jumps almost instantly to 25-30. Currently I hit fuel cut before i overboost, so at about 10-12 psi it starts to cut out, but not to the point where the car bucks.

 

[CompuBob_TSi]

yeah i didnt explain right, that is what we did. We removed the controller from the system but connected the rest back together. We took the wastegate off and tested it with a pump and found that it opens up completely at about 16-18 psi yet for some reason im still over boosting

ok, so you took the actuator wastegate off and tested it and it works fine.. try to test it connected to the turbo and flapper.. the wastegate flapper it's self might be seized.. did you check to see if it moves freely? that could be causing your overboosting problems.. if the wastegate actuator works good off the car, it might not have enough power to push the seized flapper open..

thats the only reason I can see it over boosting so easily.

 

[PhenomGSX]

ok, so you took the actuator wastegate off and tested it and it works fine.. try to test it connected to the turbo and flapper.. the wastegate flapper it's self might be seized.. did you check to see if it moves freely? that could be causing your overboosting problems.. if the wastegate actuator works good off the car, it might not have enough power to push the seized flapper open..

thats the only reason I can see it over boosting so easily.

We tried that before we took it out but it was hard to tell just how far it was opening. We hooked the pump up to where the MBC was and it seemed to open alright but it may have been stopping at a certain point. Ill take another look tomorrow though

 

[CTP]

We took the wastegate off the car and it worked fine, which is why i am really not sure if its the problem, but they seem to think that the way the turbo was installed may have inhibited the ability for the wastegate to open completely.

That's very possible. Are the housings clocked correctly? Try testing the wastegate on the car and make sure the arm is able to move all the way without binding.

At WOT it wont start overboosting until about 4-5k rpms, it stays at about 10-15 psi until then, then it jumps almost instantly to 25-30. Currently I hit fuel cut before i overboost, so at about 10-12 psi it starts to cut out, but not to the point where the car bucks.

If it's staying down to near wastegate spring boost until 5,000rpm then IMO the wastegate is probably working correctly. If it simply shot up and never stopped at lower boost I'd say you have a wastegate problem. What it sounds more like is a very bad case of boost creep which I don't find surprising on an internally gated 20g with a 3" exhaust.

The fact that you're hitting fuel cut at only 10-12psi almost guarantees that you have a large boost leak. The MAF is reading a whole lot of air that isn't actually making it into the engine and that's why you're fuel cutting.

HOWEVER, what you described doesn't sound like fuel cut. Fuel cut is extremely abrupt and unmistakable. It's like crashing into the rev limiter (actually it's more like hitting a speed limiter because those are fuel cut, rev limit is spark cut, but let's not get technical). If you're truely hitting fuel cut during a WOT pull, you'll know it because you'll probably go flying through the windshield if you aren't buckled up.

It sounds more to me like the car is just running crappy under boost. I can't remember if you covered this already and I'm too lazy to look back, but are the plugs in good condition and gapped correctly?

 

[PhenomGSX]

That's very possible. Are the housings clocked correctly? Try testing the wastegate on the car and make sure the arm is able to move all the way without binding.




If it's staying down to near wastegate spring boost until 5,000rpm then IMO the wastegate is probably working correctly. If it simply shot up and never stopped at lower boost I'd say you have a wastegate problem. What it sounds more like is a very bad case of boost creep which I don't find surprising on an internally gated 20g with a 3" exhaust.

The fact that you're hitting fuel cut at only 10-12psi almost guarantees that you have a large boost leak. The MAF is reading a whole lot of air that isn't actually making it into the engine and that's why you're fuel cutting.

HOWEVER, what you described doesn't sound like fuel cut. Fuel cut is extremely abrupt and unmistakable. It's like crashing into the rev limiter (actually it's more like hitting a speed limiter because those are fuel cut, rev limit is spark cut, but let's not get technical). If you're truely hitting fuel cut during a WOT pull, you'll know it because you'll probably go flying through the windshield if you aren't buckled up.

It sounds more to me like the car is just running crappy under boost. I can't remember if you covered this already and I'm too lazy to look back, but are the plugs in good condition and gapped correctly?

I guess i wasnt quite sure about fuel cut when i mentioned the 10-12 psi. At 10-12 the engine makes a sputtering noise, somewhat like backfire only constant. Im not sure if its really bad or normal, being my first car, but it doesnt seem right. When i continue to boost through that is when it cuts out, and yes, it bucks really hard when it cuts out, scared the hell out of me first time it happened

 

[PhenomGSX]

So i tested the wastegate while it was on the car and it looks like the arm only opens up about 1/3 of the distance it should. Problem with the actuator maybe?

 

[CTP]

It could be binding. Are the housings clocked correctly or the is the arm trying to push at a weird angle? If you disconnect the arm can you open the flapper all the way by hand?

Sputtering isn't normal. Check the plugs.

When you do make a full pull you definitely are hitting fuel cut when the boost skyrockets. You just need to figure out why it's sputtering before that point.

 

[kenamond]

If you still have the stock injectors, you're not doing your motor any favors running 30psi. It may seem like everything's okay (aside from fuel cut), but the motor isn't getting enough fuel, running lean, running too hot, knocking, and potentially consuming itself with all that extra oxygen+heat+aluminum.

A sure-fire boost controller in the time-being is your foot. Watch the boost gauge and use the throttle to regulate boost.

Did it sputter when you first started driving it, or has this developed since then? I agree that you should pull the plugs...take pictures if you or your dad or uncle aren't sure. And find out what plugs it has.

You can measure the throw of the WGA easy enough both on and off the car. Mark the arm where it comes out of the WGA, apply pressure until it stops extending (don't overdo it or might rupture the diaphragm) and measure how far it went. If you do this on the car, also note how far the lever on the turbine housing rotates and check for interference between the arm, heat shields (if you have any), and turbo. If you pull the WGA off and repeat the test, see if it goes farther or the same. While it's off, do as CTP and others suggested and try turning the WG lever by hand to see how far it goes and how easily it turns.

Many of the WGAs don't have enough throw to run low boost. The WGA might be working perfectly fine, but it can't open the WG enough, not enough exhaust bypasses the turbine, and the boost goes higher than your current setup can tolerate.

And you really do need to get/make a tester and check for boost leaks. That's part of the normal maintenance and one thing you should check fairly regularly.

If everything checks out and you still can't control the boost, you've got options, but the only one I can think of that won't cost money would be to sell the 20g and get a smaller and cheaper turbo that won't creep on you.

 

[PhenomGSX]

ok, today I got some NGK Platinum plugs and 10.2mm wires, put them in and have absolutely no more sputtering. I ofcourse am still getting fuel cut at a certain psi (sooner than before it seems) but the major issue is fixed. I will be putting in the stock turbo because I have found out that mine is actually en eBay 20g This should put things to normal.

I do have a question though, do I need to recirculate my BOV? This is an automatic 97 GSX and someone said that with an automatic recirculating wasn't entirely necessary. Other opinions?

Thanks for all the suggestions thus far, led me in the right direction.

 

[CTP]

I do have a question though, do I need to recirculate my BOV?

Yes.