Nasty accelleration! Whats wrong?

[hopwoodp]

Okay..... I have a 95gsx with some simple bolts ons( evo3 turbo, cat back, greddy front mount i/c and pipes, mbc, 190 lph pump etc).

The problem is that lately when I take off in 1st gear my car starts to stutter at 3,000 rpm to 5,000 rpm and it seems to be getting worse and worse. I also noticed this problem on the freeway as well.

The vaccuum hoses are connected correctly. The boost pressure is at 8psi(Stock injectors and no fuel controller). The big question is, can the mas affect this or the o2 sensors or both. Also, the car idle ranges from high 1,300rpm to 700 rpm at sertain times. I have had these mods for a year and this hasn't occured until now. Please let me know what you think maybe affecting this. Semper Fi

 

[92awddsm]

I think you should check compression and do a boost leak test to see if that is causing the proble. Quick tip, everyone is going to tell you the same thing so go ahead and do it.

 

[kazzam]

before you do what that guy said, or even while u are doing what he said, check your plugs and make sure they are clean. CLean them if necessary and check the gap. if its over .028 then thats the culprit. I did that and gapped my plugs at .026 and no hesitation or sputter..
hope it works

 

[Forces32psi]

and then after you do your compression test if its crappy, and if the car starts to overheat check your head gasket.. my car would studder like that around 5000 rpms and i changed EVERYTHING and then found out that it was a blown headgasket.. steven

 

[hopwoodp]

I checked the spark plugs and they all looked okay but, they did have a red powdery coat on them. They are the denso irridium spark plugs and they are the coldest I could get from auto zone.

Also, My gas mileages sucks. 200 miles = 15 gals. That is not right. The other day my friend was driving behind me and he said he could really smell the fuel. I'll try the compression test and see if it checks out and I'll let you guys know. But, new spark plugs would probably be a good idea. Thanks for the info.

 

[IllEagl]

Do yourself a favor and get NGKs...

 

[90AWDTalon]

I checked the spark plugs and they all looked okay but, they did have a red powdery coat on them. They are the denso irridium spark plugs and they are the coldest I could get from auto zone.

Also, My gas mileages sucks. 200 miles = 15 gals. That is not right. The other day my friend was driving behind me and he said he could really smell the fuel. I'll try the compression test and see if it checks out and I'll let you guys know. But, new spark plugs would probably be a good idea. Thanks for the info.

How cold is "they are the coldest I could get from auto zone" ? You don't want to go too cold. Also check the whole ignition system, not just the plugs.

 

[CanadianTSi]

Do a boost leak test and get some stock NGK Plugs.

 

[spyderturbo007]

Do you have a way to check your O2 voltage. Most of the time if you're getting shitty gas mileage your O2 is shot or on it's way out. Do you have a CEL?

 

[hopwoodp]

Do you have a way to check your O2 voltage. Most of the time if you're getting shitty gas mileage your O2 is shot or on it's way out. Do you have a CEL?

I do in fact have a check engine light.... I know when I check it, it will pretty much tell me my o2's are messed up and maybe some other stuff. I plan to shoot the system when I return from vacation next week.

I have a feeling that my mas is totally screwed but, can't say that for sure yet...

 

[spyderturbo007]

You will probably get a P0140 CEL. Fuel trim (bank 1).

If your O2 is bad the ECU will max out the trims at 12 and 17%. If the trims stay that way you will get the FT CEL.

Good luck.

By the way, I just picked up an O2 sensor from the dealer yesterday $139 with tax.

 

[Forces32psi]

you can pick up a O2 sensor from autozone or oriely's for $60. and yo ucan order them fromt tallahasse mitsubishi for $80..this is for a 1st gen though, im not sure if prices would be different then either of the 2g O2 sensors. and get some NGK bpr7es plugs..steven

 

[hopwoodp]

Yeah, I figured the o2 sensors were kinda jacked so, I went to auto zone to get one but, all the had was the bosch universal but, I didn't care, I got it anyway. So, now I just need to get the rear o2 sensor and hopefully things will go good from there. I also just got some new spark plugs as well. I am going to try to take care of this stuff sometime in the beginning of next week.

On base we have an auto hobby shop that has all kinds of cool stuff there that we can use for really cheap. They only charge $2 an hour plus, they give you help will problems you have with the car. I am pretty sure they got scan tools there as well. So, I will defenatly hit it up and see what come up. Thanks for the help guys

 

[kazzam]

I checked the spark plugs and they all looked okay but, they did have a red powdery coat on them. They are the denso irridium spark plugs and they are the coldest I could get from auto zone.

Did you check the gap in the spark plugs? it should not exceed .028. If its more then that then the high flow of air will blow them out... u'll have a hesitation feeling when you are at wot. Normal driving, however, will still feel ok.

 

[spyderturbo007]

So, now I just need to get the rear o2 sensor and hopefully things will go good from there.

Just some FYI....the rear O2 will not effect they way your car runs. It's only there to verify the catalyst efficiency. Just in case you wanted to save yourself some money. It will, however, most likely trip the CEL.

 

[hopwoodp]

This weekend I changed out my front o2 sensor and after installing it I noticed a small difference. The a/f gauge was showing that it is trying to correct the fuel curve over to the leaner side. It wasn't doing that before. I'm guessing that o2 sensor was in the car for several years and was pretty jacked.

I am waiting for some new spark plugs to come in from ongreenperforance. I figured that while i'm at it I should order a new mas because, I think that was the problem. I am thinking that the mas got wet while I was cleaning the intake filter(don't ask how), and maybe something got shorted out or messed up. My idle is still fluctiating every so ofter and once in awhile there isn't too much hesitation. I am still consuming alot of gas and I only drive maybe 3 to 5 miles a day around the base. Hopefully I will get that other stuff in shortly.

 

[kazzam]

I am waiting for some new spark plugs to come in from ongreenperforance. I figured that while i'm at it I should order a new mas because, I think that was the problem. I am thinking that the mas got wet while I was cleaning the intake filter(don't ask how), and maybe something got shorted out or messed up. My idle is still fluctiating every so ofter and once in awhile there isn't too much hesitation. I am still consuming alot of gas and I only drive maybe 3 to 5 miles a day around the base. Hopefully I will get that other stuff in shortly.

I suggest that before going crazy and spending tons of money on new mas and sensors and whatever else u think is broken, go to the dealership and have then check your ecu mulfunction codes. that will tell you what really is broken or needs fixing. It will cost you like $80 or so. Or, if you are lucky, there is an open safety recall for our cars(95-96 turbo). They will hook the car up the computer and if you nice to them, they'll tell you what is wrong for free -i just go that done today and all is well. give that a try. call em up and give them your vin number. They'll look it up for you

 

[spyderturbo007]

go to the dealership and have then check your ecu mulfunction codes. that will tell you what really is broken or needs fixing. It will cost you like $80 or so.

Autozone and Advanced Auto will pull the codes for free.

 

[FyxxterZC]

Also get new plug wires as well as plugs. I had a bad hesitation in my 95 gst from bad plug wires. It doesn't take long for them to go. Considering even the guys running magnacores can shoot spark out of the plug boots. Make sure it's not either the plugs or plug wires before you buy a new mas. I've never heard of anyone replacing a mas or it being faulty. First time for everything though......Good luck!

ps. If you get a new o2 sensor look into a new fuel filter as well.

 

[hopwoodp]

Also get new plug wires as well as plugs. I had a bad hesitation in my 95 gst from bad plug wires. It doesn't take long for them to go. Considering even the guys running magnacores can shoot spark out of the plug boots. Make sure it's not either the plugs or plug wires before you buy a new mas. I've never heard of anyone replacing a mas or it being faulty. First time for everything though......Good luck!

ps. If you get a new o2 sensor look into a new fuel filter as well.

I just replaced the fuel filter last month and it seemed to improve alittle.

 

[hopwoodp]

Ok, I just got in my new mas and spark plugs today from ongreenperformance and installed them today after work. I took it out for a test drive and man, I haven't had that car operate to smooth. So, yes the mas was pretty screwed up and no check engine light so far. The car idles perfectly and there is nother else wrong with the car....

So, now I get to go smog the car and begin phase two. Which is finish the exhaust, most likely a rnr 3" o2 eliminator downpipe with a hfcc since the are only 10 mile away from me and maybe a sbr exhaust manifold.

Let me know what you guys think.

 

[oldman]

Did you hack the old mas (removing the honeycomb)?

 

[hopwoodp]

Did you hack the old mas (removing the honeycomb)?

No, I didn't. I am not too sure if that is a really good idea. I haven't really heard that much feed back from many people about it.

 

[hopwoodp]

I went to autozone to get my codes pulled by my friend that works there. THe only code I got was p0505_ something to do with idle. I don't know what is malfuntioning. THis is the 1st time I have heard of the problem . If anyone had had this before please let me know. Thanks

 

[hopwoodp]

I also just ordered the new Slowboyracing exhaust manifold + porting. It seems like it will be awhile before it comes in but, I can't wait to see what it looks like and how much more it will change my performance.