2g: Mo clipse, Mo problems

[kingcoyote]

Hello everyone,

I recently purchased a 95 GST and I've noticed some problems that I can't really identify the source of. For one, there seems to be a dead spot in the powerband around 5,000-7,000 RPM; it starts boosting and really pulling around 3k but then seems to drop off quite a bit of power and stop accelerating by 5k. Pretty frustrating.

Car has 170k on it, previous owner claims that the motor was rebuilt about 70k ago. He said that he recently did a full tune up, but maybe I should look at the plugs and wires. So what does this problem sound like to you guys ? Boost leak ? O2 sensor ? MAF ?

After driving it for about 30 minutes last night and then parking I noticed a ticking noise coming from the motor, the infamous lifter noise ? I plan to seafoam the car this weekend and see if it goes away.

Also, the car's SRS light as well as an icon which looks like a carousel or perhaps a crown is lit up on the dash. I'll have to find an owners and service manual to look those up.

Any help or suggestions would be greatly appreciated; I'm somewhat of a noob to working on cars in general and this is my first DSM.

 

[blakmoondsm]

What boost are you running ? was the car still running when you heard the ticking ? you may just need an oil change. Its been said before but don't rely on the previous owners maintenance, at this point it's all hear say. Do your own maintenance.

As far as the crown, carousel looking light that means you're low on coolant.

 

[Squirrel8811]

The SRS light is the airbag system. As for the other light its your low coolant light. Check the coolant in the engine but dont forget about the over flow tank. There is a sensor in there also that detects low coolant. Make sure that is filled also. Drove around for a week with that light on until I found out what it was.

 

[zack4g63s]

The srs light is for the seat belts and airbags. The carousel looking one is the low coolent level light(I guess it supposed to look like a radiator). Not sure wut would cause the srs light but the lcl light may just be it is low or the sensor on the bottom of the overflow tank is bad. Fill the tank and see if the light is still on. If it is try unplugging the sensor, if it goes off replace the sensor.

 

[GTOJohnny67]

You need to fill out your mod list. Even if it is stock it will help others help you. If your running the stock t25 it starts to die off at 5000 rpm. From my experience if the boost is turned up on the t25 the harder it drops after 5000 rpm.

 

[kingcoyote]

The car is stock aside from exhaust headers and lowering springs. As far as I can tell I'm running stock boost and the turbo gauge typically is in the half to 3/4 range when driving.

Sorry about the lack of details; I just purchased the car yesterday and haven't had much time to drive or look at it.

I checked the radiator cap and overflow tank earlier. The overflow tank was empty so I'll fill that up.

I also found that one of the two radiator fans had become somewhat melted and nonworking. The previous owner seems to have disconnected the cable leading to that fan, though whether that was the cause or 'solution' to the problem is anyone's idea.

Oh and the fuel consumption is pretty high; I used about 1/4 tank going no more than 25 miles. The CEL isn't on, does that definately mean no codes are being thrown or would it be worth a trip by autozone ?

 

[zack4g63s]

The melted fan should be on your drives side right? Had the same thing happen to mine, just took it out. It's for the a/c and should'nt effect anything unless you run the a/c(mine didnt worked pulled it out to). Im guessing its bc you have no heat shields.

Also invest in aftermarket boost gauge. Its hard to get a good reading with the stock one.

 

[Squirrel8811]

Also the car is a 95. This is pretty much the caveman stages of OBDII. No light means no codes but that doenst mean much of anything. Probably the only time that light will come on if something is unplugged or totally out of whack. I have no cat whatsoever and the car doesnt even pick that up. Besides checking for boost leaks and the obvious stuff. Check anything that is going to control your fuel like the tps,ect,o2s,maf, or anything like that.

 

[blakmoondsm]

You will not be able to tell anything from that stock boost guage, get a boost guage. As far as your fuel consumption goes 25 miles of normal driving and 25 miles in boost will make a difference. But as stated before get all your maintenance out the way. Your air filter could be dirty, fuel filter...etc enjoy the car.

 

[IHeartMyHonda]

sounds like its performing like a stock t25 car. and get yourself a good boost gauge. the stock one only "estimates" boost.

 

[zack4g63s]

+1^^

 

[airmail96]

I agree the stock t25 promises so much hope when you first get on it, but it def. wont throw you to the back of your seat all the way to red line.

 

[Tanro]

I have a stock 2g and the T-25 drops off after about 5k. I think this is the way it was supposed to work.

 

[zack4g63s]

Same with my 95 gst

 

[kingcoyote]

Thanks for all the info, guys. I got a shop manual so this weekend will probably consist entirely of checkin out various components. There are a couple unplugged connectors in the engine bay as well. I'll take some pics when I get a chance.

So what I'm planning to do throughout the week but mostly this weekend is:

1.Replace air filter
2.Pull fan (yes its the drivers side one)
3.Seafoam in gas, seafoam into the throttle body.
4.Oil change
6.Replace fuel filter
7.Build boost leak tester (unless theres an easier way that I dont know about) and check for boost leaks.
8.Figure out how to check out o2,maf, etc sensors
9.Check out those sensors and replace as necessary

Any other suggestions on what to look at, particularly to track down the fuel mileage issue ? I've had a turbocharged car before and I know high fuel consumption under boost is normal but I haven't been driving the heck out of the car and its still getting 6 or 7 mpg by my estimates.

I just ordered an o2 sensor, hopefully itll arrive by the weekend and help improve the gas mileage.

I filled the overflow tank (about 3/4) but the light still hasn't gone off. As the sensor is supposed to be at the bottom I thought that'd be fine. Should I fill it all the way up or would time be better spent looking for unhooked connectors ? Does this light also indicate a problem with the coolant temp sensor or no ?

The melted fan should be on your drives side right? Had the same thing happen to mine, just took it out. It's for the a/c and should'nt effect anything unless you run the a/c(mine didnt worked pulled it out to). Im guessing its bc you have no heat shields.

Also invest in aftermarket boost gauge. Its hard to get a good reading with the stock one.

And yeah, you're correct that there are no heat shields. Im inclined to get one to prevent such problems, I just don't know if the stock ones will fit over the headers currently on the car.

 

[zack4g63s]

Thanks for all the info, guys. I got a shop manual so this weekend will probably consist entirely of checkin out various components. There are a couple unplugged connectors in the engine bay as well. I'll take some pics when I get a chance.

So what I'm planning to do throughout the week but mostly this weekend is:

1.Replace air filter
2.Pull fan (yes its the drivers side one)
3.Seafoam in gas, seafoam into the throttle body.
4.Oil change
6.Replace fuel filter
7.Build boost leak tester (unless theres an easier way that I dont know about) and check for boost leaks.
8.Figure out how to check out o2,maf, etc sensors
9.Check out those sensors and replace as necessary

Any other suggestions on what to look at, particularly to track down the fuel mileage issue ? I've had a turbocharged car before and I know high fuel consumption under boost is normal but I haven't been driving the heck out of the car and its still getting 6 or 7 mpg by my estimates.

I just ordered an o2 sensor, hopefully itll arrive by the weekend and help improve the gas mileage.

I filled the overflow tank (about 3/4) but the light still hasn't gone off. As the sensor is supposed to be at the bottom I thought that'd be fine. Should I fill it all the way up or would time be better spent looking for unhooked connectors ? Does this light also indicate a problem with the coolant temp sensor or no ?



And yeah, you're correct that there are no heat shields. Im inclined to get one to prevent such problems, I just don't know if the stock ones will fit over the headers currently on the car.

If the you unplug the sensor on the botton of the overflow tank the light will go out. As far as the heat shields go I'm not sure. If it has the spots for the bolts then I dont see why not.

 

[kingcoyote]

Changed out the o2 sensor, the old one was black and the holes in it were completely covered in carbon deposits. Cars running a bit better and gas mileage has improved.

Haven't had time to test for boost leaks, but thats next on the list. Changed out the air filter. How can I test the MAF without switching it out for another one ?

The owner said he just changed the plugs and wires but when I get home I'll pull the plugs and check em out.

 

[TSiTalonawd96]

Changed out the o2 sensor, the old one was black and the holes in it were completely covered in carbon deposits. Cars running a bit better and gas mileage has improved.

Haven't had time to test for boost leaks, but thats next on the list. Changed out the air filter. How can I test the MAF without switching it out for another one ?

The owner said he just changed the plugs and wires but when I get home I'll pull the plugs and check em out.

When the car is running, tap on the top of the MAF sensor with the handle of a screwdriver and listen to see if your RPM's go up or down. If no effect, you can check the resistance. Not sure which ones but you can probably find it on VFAQ.com. That site is awesome.

 

[kingcoyote]

In case anyone with similar symptoms sees this post I have the following information:

I took the car to a DSM specialist who ran the codes and found what appeared to be a stuck open injector(later a bad circuit code for the injector) and a bad crank position sensor. After alot of diagnostics he decided it was the ECU and swapped one in. The trouble codes dissapeared and its running great now with alot more power and much better mileage.