New 99 GSX with Mods need help..

[KrazyRob]

Ok so I bought this 99 GSX with 51k original miles, the thing is in great shape but the kid who had it put alot of mods on it. He had a credit card and went crazy with it.. fortunatley he had a shop do all the work. And luckly he saved all the stock parts.. Im considering putting this gem all back stock but I love the power that it has now, its pretty insane. This is my 4th turbo eclipse but this baby by far is the quickest. And here in CA i need to smog it before i get my tags and with all these mods there is no way ..

Any how i am having some problems with the car and im not sure where to start, I was a truck mechanic for a while but not up to par on DSM mods.. Ill start with the problems im having then tell you the mods it has..

1. Getting code PO300, just went on the freeway at normal speed and the car started a slight spudder and the CIL came on with 2 of these po300 codes.. its a missfire code.. I checked the easy stuff like plugs and wires and they are good im wondering if it is this after market MAF..

2. Over heats at idle, bubbles in over flow bottle.... has alum toyorad rad and FAL fans.. The fans were not coming on enough.. So I heated the probe with a lighter and the fans came on like they should.. I removed the temp probe from the top of the radiator and installed it in the bottom of the radiator and it ran at normal temp and never got hot but the overflow bottle still bubbled when I shut off the car. Had to fill the rad a few times after it overheated, hopefully its not a HG, but there is no oil in coolant, or no coolant in oil, no smoke out of pipe or sweet smell, no miss in the motor, compression test reads 168,160,165,163 and all holds steady..I might have fixed the overheating problem with the fans but why is it overflowing at the bottle, just bought new rad cap today as well..

Ok mods: It has a different MAF on it that looks like its off a chevy or something or GM.. It has MAF Translator 2.02 HP in a box it says .. TIAL performance wastegate kit, DNP header, large alum radiator with FAL electric fans, new ACT extreme clutch, new large injectors, top of the line intercooler, Blitz BOV, Nology hotwire plug wires, NGK plugs,Dejon polished pipe with K&N air filter,Optima battery, Aeromotive adjustable fuel pressure valve and guage, 3'' custom exhaust with Apexi muffler all wide open no cat, undercarriage neon lighting kit , Greddy turbo timer, top of the line viper alarm, new tires..

The car came with alot of stuff .. just want to learn more about it and get it running right...I need a reliable car that I can take on long drives 5-6 hours, thats why I was debating putting it back stock, dont want to be on the side of the road wrenching on a race car .. but this things rocks

 

[Travisgsx96]

If its your main car and the one you need to be reliable id say go back to stock. If you have another car though you can use if something does go wrong id stick with mods. As long as things are done right theres usually not a problem. But as soon as something goes wrong it goes very wrong most of the time. Dsm's like to be tempermental.

 

[WES_393]

First off, thanks for doing some tinkering before posting! That's a good bit of information. Posts like this help us out a ton when it comes to helping you.

1. Make sure you spark plugs are gapped correctly and maybe even pull the gap in a tiny bit. This will make it easier for the ignition system to fire at higher RPM's. Also try checking the coil pack both visually and with a volt meter. Visually you want to make sure it looks okay. No blisters on the coils, the spark plug wire terminals are clean, etc. For testing with a volt meter here is a good little guide:

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You may also want to run a boost leak test. Here's a good link for that. But rather than "listening" for leaks, spray soapy water on the pipes and watch for bubbles. Bubbbles = leaks.

http://www.dsmtuners.com/forums/art...-boost-leak-test-how-boostpro-net-tester.html

2. It's possible that this is a bad thermostat. When the car is running, grab the lower radiator hose and see if it's much colder than the top. If so, then you thermostat is shot and stuck in the closed position. Lack of flow causes the coolant to boil and push through the over flow tank. The compression is pretty OK. Factory limit is 130psi with no more than 10% difference between cylinders. So I'd say you will get quite a few more miles out of that engine before thinking about a rebuild.

3. You are most likely correct that the MAF you have is a GM MAF. They are a blow-through MAF that work much better than the stock one. The MAF Translator (HP in a box) is what converts the signal so you ECU can use it to control the fuel. If you haven't noticed, it has a few adjustment knobs so you can "hide" or "show" airflow to the ECU. This is a pretty old school way of tuning known as a "piggy-back". You are tricking the ECU into giving the amount of fuel you want. You could look into DSMLink which will let you tune without the MAF Translator. It's easily the most popular way for DSM owners to tune, but pricey. Does the car have an A/F Ratio gauge? If not, it's definitely something to look into. You really can't use the MAFT without one. Wideband is the only way to go for A/F gauges.

I know it's a lot to soak in, but that should get you started! I think your problems could be easily cured so I wouldn't go through the trouble of putting back to stock. In all honesty, you have a pretty kick-ass setup. Some of us started with empty shells and are still nowhere near your level. Post some pics of that beast when you get a chance.

Here are some other links that would be good to check out:

These guys wrote the book on DSM's.
VFAQ Site - Visual Frequently Answered Questions

Everything about MAFT.
http://www.dsmtuners.com/forums/fre...-you-want-know-about-maf-translator-maft.html

DSMLink. Just to give you an idea.
ECMTuning, Inc.

Best A/F gauge on the market.
MTX-L Wideband O2 Digital Air/fuel Ratio Gauge

 

[johnovision27]

Good morning and welcome to the DSM community. Luckily for you, you came into the game with some mechanical experience under your belt. If you didn't, you'd either go broke paying the shop to do it all or become one anyway, so you already have that going for you.

Ok, lets take a look at the P0300. Unfortinatly, I have zero experience with the GM-MAF and the translator but rest assure it is a very common mod for these vehicles, so at least the "kid" wend down the right path there. Judging by the mod list you posted, I'm willing to bet he swapped out the stock T-25 turbo for something with some more balls. Could you take a look on the compressor housing and write the code you see on here? Could be something like TD05, TD04, Garrett, Holset (should have a place card with the model), etc. When we know that, it'll give us a better idea of where to start thinking. However, if he has larger injectors there must be some way to tune it or else it'll be running PIG rich all the time. The MAF translator you see there is only for the swapped out MAF to the best of my knowledge, but don't take that as gold. I'm sure someone else will pipe up and give you some more info on that subject.
But lets get back to the tuning. Does the engine light come on and then go away right away?? Did he give you an OBDII - USB cable with the car? (ie DSMlink) Is there anything with a screen anywhere in the car? If he isn't tuning it with anything and there are larger injectors, I'm surprised the sputtering at cruise is the only issue you're having. So, see whether or not you can contact him and ask him whats the story there and let us board dwellers know so we can point you in the correct direction. But as for now, all I can suggest is that you're running so rich at cruise that you're drowning the motor. Any other symptoms of this sputtering? Under heavy acceleration? At normal cruise? All the time or only when the car is warmed up?, etc. On an initial search, it appears the the P0300 is a common issue. Give the search button a couple of goes and see if anything comes up as a similar occurance.

As for the over heating issue, you seem to have it under control. My only question is, your coolant temp proble is on your rad? 0_o....... O rly....

1G

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2G

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These are the only places I know of temp sensors being located.

check out VFAQ Site - Visual Frequently Answered Questions A LOT of excellent information there to get started.

Good luck and hopefully we get an update soon!

These guys wrote the book on DSM's.
VFAQ Site - Visual Frequently Answered Questions

, beat me to the punch.

 

[IHeartMyHonda]

@Johnovision
You may have missed that his car has flexalite fans, which sometimes can use their own temperature probe to control them. These are pretty much just thermistors on a wire that stick into/zip tie to the radiator fins, and when they reach a certain temperature, they cut the fans on. When you use that system, you bypass ECU control of the fans.

 

[thomcasey]

Bubbling coolant in the overflow can also mean bad head gasket.

 

[johnovision27]

@Johnovision
You may have missed that his car has flexalite fans, which sometimes can use their own temperature probe to control them. These are pretty much just thermistors on a wire that stick into/zip tie to the radiator fins, and when they reach a certain temperature, they cut the fans on. When you use that system, you bypass ECU control of the fans.

Oh cool! My car came with the FAL fans on the rad and still used the ECU. I was unaware and stand corrected. Thank you kind Sir.

 

[nek]

Bubbling in the cooling system can be
1) HG. Dont need coolant mix with oil for this to be the issue. Also compression can be normal. Does it overheat while driving?
When you say overheat at idle you mean maxed out gauge?

2) Burping your coolant system for air pockets. If air is trapped it will slowely bubble out

3) Simply your coolant is boiling. If you check your cooling system with the rad cap off then there is no pressure which will cause boiling coolant. Also, an inproper mix of coolant - water can cause premature boiling.

And overflow doesnt mean there is an issue unless you keep needing to fill it up. Also make sure the seal under the cap is seated properly.

 

[KrazyRob]

Thank you all for a good information. Yeah i need a reliable car to get back and fourth to LA with my band. Its about out a 5 hr drive and i dont want be stranded . Im selling my stock 97 gst with 180k miles, and i upgraded to this 99 gsx with 51k miles. I love this gsx but these mods are a bit of work to keep dialed in but super fun to drive! Lol .......

Yes it has a big turbo in it, i was looking for a stamp but didnt see one i will look again its gotta be there. The sputtering is not severe but you can hear it change in the exhaust and then the cel comes on...... Its not like its running on 3 cyls but kinda like something electronically goes hay wire it still maintains power on all 4. It seemed to happen just driving normally on the freeway steady at 65 mph.. And on the cooling issue its like the motor is pushing out all the coolant into the bottle and then it would overheat cause the radiator was empty.. oh man i have done 2 head gaskets on these cars already and one motor rebuild and its not a HUGE job but still a pain in the a-- . Gonna drive it later and see if it keeps coolant in the rad after fixing those fans last night.. thanks again.. i will keep status posted..

Ok i took the car out on the hwy and put 15 miles on it and it has not over heated. When i left my house the overflow bottle was half way full and when i got home it was full and there was constant bubbles coming up in the bottle but it was not overflowing hot just up to the top and bubbling. I left the car idling for 10 mins and it never overheated on the gaige but for some reason the bubbling stopped as it was idling. It was the same temp as when i pulled into the garage kinda wierd ..

Ok now the spuddering problem..... i cleared the po300 codes with my scanner when i left the house and it drove fine for about 7 miles and then while taking off slowly and turning at a stop sign the car started spuddering and the cel came on. I guess it actually did feel like it was runnong on 3 cyls for about 8 seconds then it cleared up but the cel stayed on. Its like itwas clearing its throat for a few seconds... maybe it does just get drenched with too much fuel for a few seconds the it clears its self up.. i left message with guy i bought the car from and asked. What turbo is on here and how do you tunebthis set up.. im waiting.on a reply.. if this is a maf problem could it be fixed since its intermittant? Car seems to be tuned well and does run rich out of the pipe. I hate intermittant problems ...

 

[johnovision27]

Good stuff. The turbo should have something on it somewhere, hopefully....
The overflow bottle will fill up and empty as coolant is pushed and pulled from the motor so that part is normal.

As for the bubbling, I've never had an issue with it before, but the simplest solution or something to try as mentioned above would be to burp the system. Personally, I let the car cool down all the way, pop the rad cap off and run the car for a couple mins. This allows the air to work through the system and vent. That or you can physically squeeze the top rad hose (maybe it helps, maybe it was a matter of timing when I did it but it seemed to work. )

The sputtering issue sounds like something I encountered while driving from Calgary to Toronto. Highway speed, and it came out of the blue. I had to turn off my car and wait a couple mins, some time even having to pull the -ive on the battery. Unfortunately, I never found the culprit as my engine toasted itself before getting to Toronto and just did a full rebuild.

However, shortly after that my CAS bit the dust. I suppose that could be an issue. If it's not telling a cylinder to fire, then you'll feel like you're only firing on 2 or 3 which is exactly what mine felt like. When it's sputtering, do you try and accelerate and you just feel it bog down? If it is running rich, you could be right, just too much fuel could also cause that. Any estimates on MPG?

 

[KrazyRob]

Oh man that sucks about your engine.. that kind of worries me about taking my car on long drives .. I put about 60 miles on the car yesterday and the light never came on and it never sputtered.. but then this morning I did it randomly. It will do it driving normally at a steady pace ,it will do it taking off from a stoplight slowly, racing, seems like it doesnt matter when. The CEL will pop on and then you will here the spuddering missfire through the exhaust then it clears up a few seconds later and runs fine but the CEL stays on with the codes... totally intermittent..

As far as the overheating issue it has not overheated on the guage since i moved the temp probe on the radiator for the fans, actaully now the car seems to run cooler on the gauge and sits below the halfway point on the gauge.. But everytime i turn it off the is contant bubbles coming into the bottom of the overflow bottle. I will try to burp it today... im wondering if these cheap autozone/ oreily rad caps are no good... do they make caps that hold more than 13lbs for these cars? What would happen if i put a 16lb rad cap on the car? Lolb

 

[macks96boltdsm]

if the car is a 6bolt swap which you need to find out then the p0300 code is the random misfore code that is a common problem with the 6bolt swap and dsmlink is what you need to fix it or you could unplug the tps sensor as a temporary solution until you get link

 

[KrazyRob]

It has a factory 7 bolt motor with 51,000 miles... but the mods have been added.. and I bought the car with the mods already on it.. I am not setup for the dsm link.. it has the old school maf translator box on it and gm maf. Cel comes on randomly and the motor misfires for a few seconds and then clears up...

As far as the cooling system I bought a new performance 1.3. 19 pound rad cap. And it seemed to work for a while but then after driving the car on the freeway and checking it back in my driveway ..I noticed there are still bubbles coming from the overflow bottle and the bottle was full. Damn! Could this be a blown HG? How can i check for it.. there are no normal symtoms of a blown.HG.. and its not overheating..

 

[KrazyRob]

Ok the car is overheating now. When i came to a stop it went into the red.. the fans are working all the time but it doesnt matter... its like the motor is pushing out all the coolant into the bottle leaving the radiator empty and then the car over heats.. frustrating! I have had over heating problems with all 4 of my turbo 2gs in the past.. just want a fun reliable 2g.. but these cars are so temperamental... .. sorry venting.. and drinking beer! Lol

Oh and the spuddering is getting worse and lasting longer now. It used to last about 8 seconds and clear and now it lasts 30 seconds.. im almost ready to pull this motor apart and put it all back stock.... opinions??

 

[johnovision27]

Can't help you with the sputtering problem.... I just rebuild mine and that solved the issue. haha.
As for the cooling issue, have you flushed the whole system? You might have a clog somewhere, or as you already mentioned, the HG.
I sit around 190-200 degrees in hot summer traffic. rarely goes over that.

 

[importracr317]

Sounds like a random misfire. Is it the stock engine? It hasn't been swapped? Also, any ECU mods? Is the ECU stock or is it an eprom ECU with a modified chip?

 

[MY1GDSM]

if the car is a 6bolt swap which you need to find out then the p0300 code is the random misfore code that is a common problem with the 6bolt swap and dsmlink is what you need to fix it or you could unplug the tps sensor as a temporary solution until you get link

They don't need DSM/ECMlink to disable the code for Random misfires. they can do that with the ECU that came in the car as it's flashable(if that's what is still in it).

OP
Pick up a Copy of EVOscan and a logging cable and post so logs and people will be able to help more. I'm in a bit of a hurry if you would like Email me directly and I'd be glad to help and give you some more details some time when I'm not so busy

 

[jjaycxj]

I had the exact same problem with the sputtering and CEL. It turned out to be the wrong spark plugs were in it when I bought it I would redo the plugs and wires and see of that fixes it.