Problem since i've gotten the car, lag?

[Luix1g]

I have a 90 gsx and I love her but ever since I got her she's had this annoying problem. Sometimes it lags so much and it's at random times. Frequently enough to be quite annoying. I go full WOT and it doesnt really go anywhere. I'm not that experienced but I try my best to keep her in tip top shape. I've been multiple boost leak tests in the past and elimanated them all except one at the TB. I don't know if that's the problem because other times I go WOT and it pulls great and really hard. If I try to do a hard turn from a stop WOT and sometimes it goes but really choked up and slow. Other times It will just sit there for a second and then finally and barely go. I don't know if the correct term is lag but it feels like it. It feels like sometimes it just gets so choked up and feels almost blocked. Rpms are not smooth throughout some pulls. My spark plugs maybe? I changed them recently though and still does it when there brand new. I'm running the stock 14b with apexi turbo back exhaust, 15 psi, fp race headers, greddy type s, walbro 255, evo 3 ported o2, 1g mas and intake with filter. My gauge shows it does not creep. I'd really appreciate any and all input. I've thought of my injectors or maybe a valve isn't sitting right but I don't know if that could cause it. Maybe my turbos going bad? Something internal, to much exhaust flow, or the TB plate doesnt open fully or something along those lines, do i need a tune? I really don't know, please any help is appreciated. If you have more questions to help me diagnose ask them. Tyvm

 

[wraoffroad]

that could be alot of things if the turbo is bad check for shaft play and make sure that is spins correctly. pull your injectors and make sure they are nice and clean.There is also the MAS if it isn't clean it might be able to do that. Pull the valve cover off to check for bent valves. also check your timing marks to make sure that they are lined up. I think you close to the source of the problem I just hope its note something serious. Maybe crankwalk? Im lucky enough that I have never seen a motor with one so I am not sure. OH and maybe the CAS it would cause the motor to not keep up with itself.

 

[sniver]

Phantom knock, and/or Dieing knock sensor sounds like culprit do to the randomness.

Have you fingered your knock sensor to see if it has the black plague leaking out of it?
Ever replace the fuel filter?

 

[Luix1g]

that could be alot of things if the turbo is bad check for shaft play and make sure that is spins correctly. pull your injectors and make sure they are nice and clean.There is also the MAS if it isn't clean it might be able to do that. Pull the valve cover off to check for bent valves. also check your timing marks to make sure that they are lined up. I think you close to the source of the problem I just hope its note something serious. Maybe crankwalk? Im lucky enough that I have never seen a motor with one so I am not sure. OH and maybe the CAS it would cause the motor to not keep up with itself.

Thanks for the input. I'll check tommorow all of these things. I doubt it's crankwalk, but let's hope it's nothing to serious. I'll post back with the results. I also forgot to mention on a cold startup the idle surges to about 1.5k rpm and back down but I think that's due to a failing isc I believe.

Phantom knock, and/or Dieing knock sensor sounds like culprit do to the randomness.

Have you fingered your knock sensor to see if it has the black plague leaking out of it?
Ever replace the fuel filter?

Thanks for the help. This is interesting. Ill check the knock sensors condition. Also about the fuel filter a few days ago I put a brand new one in along with a new walbro 255. I do not have an Afpr, but will be getting one soon. I test drove it after the install and I felt as if nothing really changed except for it running more rich. I think so because it smells a little more, gas mileage is a bit less when I step on it, and the occasional backfires when doing pulls at higher rpms. Id also like to note that when doing pull it climbs rpm abit notchy at times and slightly hesitates on occasion. Although the fuel pump did help with higher boost and it doesn't struggle for fuel like it did with the old pump which was old i'd say and the filter was poo. I'll check my spark plugs to see if their foul and properly gapped. I'll report my findings.

 

[gusu]

You should really fix that throttle body leak. For your idle surge I'd delete your EGR, make sure your ISC is working, delete unnecesary vacuum likes, and everything else others frequently mention if you search for it. A possibly reason for your boost to act up I'd if you aren't letting your car warm up before hard pulls, a cheap manual boost controller, or a bad boost selonoid. I'm not sure if it's called a boost selonoid or not since I took mine off to install my boost controller a long time ago and never needed to research them.

 

[fourgsixthree33]

I have had problems like this since the day I bought my car. It has gotten worse and worse. Bought new plugs, wires, oil change, and a few other odds and ends. Now I am leaning towards an alternator. Eventually, I have been having problems with my lights flickering. i.e. dash lights, head lights, tail lights, etc. Also, my idle "surges" up and down at about 50 RPMs and is consistant with the flickering lights. My fuel pump also makes a buzzing sound.

These problems just recently occured. Before all this, it was just the lagging, studdering, hesitation, similar to what you are describing. There is a large hill on my road. When I first bought the car, I could hit 70mph at a landmark at the top of the hill. Then it would only do about 60mph at the same spot. Now, when the car is running half way descent, it will only hit 55mph. Maybe a little less. But when the car runs like shit which it does 80% of the time, I can only go like 35mph.

It just feels like the juice is being sucked out of the battery. But like I said. Sometimes, it runs "OK"

 

[nocardick]

My car has done this same thing since I bought it too.It seems like its worse when it's real cold out too.It feels like its bogging out but if you feather the gas a little bit and then give it some throttle,it pulls hard.I know my turbo is gone and I think that is the problem.It whines pretty bad when under boost.I'm also thinking that it could be a bad knock sensor

 

[fourgsixthree33]

My car has done this same thing since I bought it too.It seems like its worse when it's real cold out too.It feels like its bogging out but if you feather the gas a little bit and then give it some throttle,it pulls hard.I know my turbo is gone and I think that is the problem.It whines pretty bad when under boost.I'm also thinking that it could be a bad knock sensor

I have noticed that too. If you feather the throttle, it pulls better. What also helps is being on and off the throttle before pulls. I do this 4 or 5 times before it begins to pull.

 

[nocardick]

I have noticed that too. If you feather the throttle, it pulls better. What also helps is being on and off the throttle before pulls. I do this 4 or 5 times before it begins to pull.

Exactly the same situation with my car.I thought it could be due to a crap ebay boost controller I had,so I removed that,but it still does it.I'm thinking its my mas,but I'm just going to hold off on it until I install the GM MAF setup I have and DSMlink.I'm leaning towards a bad turbo,bad knock sensor,or possibly a bad coolant temp sensor maybe?

 

[fourgsixthree33]

Exactly the same situation with my car.I thought it could be due to a crap ebay boost controller I had,so I removed that,but it still does it.I'm thinking its my mas,but I'm just going to hold off on it until I install the GM MAF setup I have and DSMlink.I'm leaning towards a bad turbo,bad knock sensor,or possibly a bad coolant temp sensor maybe?

How old is your alternator? Check the voltage on the battery with a voltmeter. Maybe your alternator is going bad like me. How long have you had these problems?

 

[sniver]

I know when my car used to phantom knock, it won't get out of its own way. Example; if I tried accelerating from 2600 rpm in 3rd, it just pull timing,and not go anywhere. but if I shifted into 2nd, at say 3300 rpms, and gave it 1/4 throttle, let off, and mashed it it would haul. Replaced knock sensor, fixed that about 95% of the time.

Could be spark plug blow out, over gapped plugs, or under powered coils. Turn every damn light, blower , defroster, and wiper on, make sure its over 13.x volts at like 1.5-2.5k rpm. It should be at 14 volts, but Ive never had a DSM alternator that was. Check voltage at the alternator, the battery, and the coil if you know how.

I think your more likely to have a naked hooker blowing you and secretly pulling fuses than crankwalk, like whoever said.

I also doubt its a bent valve, or a mechanical timing issue, or any mechanical issue. It would always suck if that was the case.

 

[4g63jojo]

how much gas do you normally have in the tank when this happens?

 

[Luix1g]

I know when my car used to phantom knock, it won't get out of its own way. Example; if I tried accelerating from 2600 rpm in 3rd, it just pull timing,and not go anywhere. but if I shifted into 2nd, at say 3300 rpms, and gave it 1/4 throttle, let off, and mashed it it would haul. Replaced knock sensor, fixed that about 95% of the time.

Could be spark plug blow out, over gapped plugs, or under powered coils. Turn every damn light, blower , defroster, and wiper on, make sure its over 13.x volts at like 1.5-2.5k rpm. It should be at 14 volts, but Ive never had a DSM alternator that was. Check voltage at the alternator, the battery, and the coil if you know how.

I think your more likely to have a naked hooker blowing you and secretly pulling fuses than crankwalk, like whoever said.

I also doubt its a bent valve, or a mechanical timing issue, or any mechanical issue. It would always suck if that was the case.

This is starting to sound a lot like what it could be. I have yet to 'finger' my knock sensor but I'll get to it when I can. Update-Today I gapped the spark plugs to .28. I found out all of them were random for some reason. Two were .35 and the others around .40+. Wow I know. Also I upgraded the spring for my boost controller to hold boost and now works a lot better. Now it creeps from about 11 psi to 15 psi which I think it should though normally due to my exhaust mods. I always let the car warm before driving it. I did a few pulls and it runs a lot smoother, I haven't drove it enough yet though to see if the problem continues. It happens throughout normal driving sometimes aswell not just hard driving. But so far after about half an hour of driving it did not do it. I also did a compression test and the results were 145 across the board. So I think that throws mechanical issues farther. Next I'll check the knock sensor and try and see how the voltage on everything faires out. Thank you once again.

how much gas do you normally have in the tank when this happens?

I normally have around a quarter tank. I have heard something about 1g's turning hard has the gas move away from the pump on hard lefts I believe. Maybe you can offer more input on that or if you have any more questions about it I'll answer them. Thanks

 

[Ineedboostman]

Sounds alot like the turbos hanging up. I had the same problem with my t25 had alot of sift play but still seemed to spin ok. I guess maybe under load it was just catching the compressor cover. I put on a 16g and no more problem.

 

[4g63jojo]

you original post sounds excactly like what i was experiencing thats why i asked about your gas level.. I could only put 10 or 15 bucks in my tank at a time and my house is way out in the cut and at random times on my way home my car would cruise and handle light acceleration but any more throttle than that it would lag, putter and sumtimes misfire. 1 day i put 30 bucks in it and it did not do it at all forever then when it started gettin under an 1/8....what do ya know it started again.. so i dont know im just throwing it out there thats what happended to me and yours sounds similar but i dont know

 

[nocardick]

How old is your alternator? Check the voltage on the battery with a voltmeter. Maybe your alternator is going bad like me. How long have you had these problems?

My alternator is not old at all.I replaced it maybe 10-15k miles ago,and I've had this lag problem since I've gotten the car back when I was 16,so 5 years ago.It's really sounding like the knock sensor is bad,or the turbo.And I know the turbo is shot on my car.Not blowing oil but it whines like a school girl

 

[sniver]

+1 for spark plugs gapped for my tractor. I bet thats a large portion of you problems. Drive and keep us updated. The remaining little issues could then be the knock sensor if it happens occasionally, only time will tell.

http://i134.photobucket.com/albums/q94/ApexVIII/GSX/IMG_2150.jpg heres a bad sensor, you can see it oozing. bad pic, but you get the point.


nocardick ,Ineed boost, rebuild/replace your turbo before its to late. How are you going to feel it it actually breaks a fin, and sucks it through, and ruins your motor? Besides that, the turbo on Luix's car is not the issue here, turbos don't lag hang up, eat babies, then get diarrhea, and then work. They have play,they whine,then seize/explode.

As for 4g63jojo, I'd bet either your tank baffle was screwed up, or your sender was wrong. Had this happen to me with a 4500 izuzu turbo diesel. On that, the tank baffle/gas holder was cracked, so it repetitiously and randomly lost power under half tank.

 

[dsmspickdad]

Fuel Cut?

 

[AllWheelRS]

You should really fix that throttle body leak.

+1 you may be surprised how much boost leak those seals can cause.

 

[sniver]

Dsmspick dad-Most certainly not fuel cut, if feels like you crashed into a wall.