Its slow then pop! it goes fast!

[lovemym]

I did search and read all of the ones that came up but none of them had my exact same scenario. Mine as stated in other threads feels slow sometime and other times it is spinning the tires all the way to 3rd! The thing that Ive noticed that makes my problem different is that sometimes if I baby the gas just enough to start boosting ill feel a surge of power and then if I floor it, it takes off like a bat out of hell. It feels as if the blow off valve or the waste gate is shutting, therefore im getting all of my boost. I just wanted to ask to see if anyone has had this exact same problem so that I know where to start. The car is a 97 GST all stock except intake and exhaust. Thanks for any help in advance.

 

[ClevelandDSM]

Sounds like you need to do a boost leak test.

Other then that, the whole babying(?) the car then letting it rip.. it might be the clutch slipping?

 

[habitatguy187]

Do you have anything to log with? Could be that when you try to punch it w/out babying it it's dumping tons of fuel (due to a boost leak) in too early, causing it to be slow until the turbo spools up. So +1 for doing a boost leak test, that's probably what the problem is.

 

[lovemym]

I just drove it to get something to eat and this time when I punched it I felt it pop then it went faster, then around 4k or so it dropped down again, so I got back home and played with things and noticed that the blow off valve seems to be a little loose meaning I can turn it with my hand with a little pressure so im going to go tighten it up and see if that makes a difference. Ill post back and let you know what I found out if I get to drive it again today. thanks for all the help

 

[habitatguy187]

Yeah you have to tighten that screw down on the bov. I know it sounds nice but tighten it up for real, hopefully that's the only thing wrong. When you say you "felt it pop!" what exactly do you mean by that?

 

[ClevelandDSM]

Yeah the pop thing is confusing me also.

 

[lovemym]

Well its not actually a pop it just suddenly gets faster all at once. Feels kinda like vtec or lift in a toyota. It only does it sometimes its real intermitent. Sometimes it just halls butt sometimes its slow and sometimes it starts off slow then you feel a kick and it gets faster. Its almost like the waste gate is a little bit open and then slams shut if that makes any sense. I have the Lotus Exige engine in my MR2 Spyder and when it hits 6400 it lifts and an instant 40 more HP comes on and thats exactly what it feels like when it does it. Now I went out there and tightend up everything and drove it and it feels better but not great, just to let you know.

 

[bagged420a]

sounds like that instant power kick is just the boost kicking in. you should run a BLT

 

[Black94DSM]

Engine is probably knocking, causing ecu to pull timing. Then all the sudden it stops pulling timing and you get full timing back.

I say you just need a tune up and check your knock sensor to see if its bad or not.

 

[sLiCRiC911]

sounds like a boost leak somewhere along the lines of the pipes... engine might not be responding right and knocks at that rpm...

 

[98gsxtuner]

Are you sure it could be boost leak? I had massive boost leak on my car and it spooled the turbo up to 20psi (what i have it set at) but the car didn't how should i say this pull i guess, so it was spooling but i wasn't getting the power. I actually had trouble making it up hills. So if it was a boost leak wouldn't he not have the power at all?

 

[JEFFREYCASTGSX]

Does it loose power in between shifts?

 

[Dserge]

I have the same issue going on right now...

If I punch it has nothing sometimes....Then other times if I let it rip it scares the hell out of me....

I would start with new plugs and wires gapped at .028...Then the good ol boost leak test.

Sometimes it spools and everything but just feels like something is holding me back, is that what you are experiencing? Fuel filter maybe?

 

[rick_dsm90]

check your knock sensor. i had that problem and everyone said it was a boost leak but it turned out to be a knock sensor dripping this nasty black shit all over the back of my block.

 

[habitatguy187]

START with a boost leak test, it should be done as regular maintenance anyway. Then check your knock sensor for the black goo, although that doesn't always mean that they're bad. If still nothing, get something to monitor knock and see if your timing's getting pulled, but my bet is still on a boost leak.

AND LET EVERYONE KNOW WHAT YOU FIND OUT!

 

[lovemym]

Thanks guys ill set out to make me a boost leak tester tomorrow hopefully, and ill let you know what happens. Almost everything yall are saying makes since. I did put new wires on it but have not changed the plugs because they looked good still. Is the knock sensor visable from the top side? It seems like if the knock sensore was going bad it would send a code but I guess not because it was mentioned above and he didnt say anything about a cel. Well ill see what I can find out and keep yall posted.

 

[92_talon_awd]

My car used to do the exact same thing when I bought it. I had to go into boost soft and when I got there I could hammer down, if I just throttled it from the start it would pull timing like a bastard and even though I was boosting fully it felt like I was towing a trailer full of bricks. Turned out I was leaking from my J-Pipe and it was picking that up as knock, once I fixed that it was all good. You really need a datalogger so you can tell if your sensor is picking up knock.

 

[lovemym]

Well since i tightened up everything it now just feels consistantly slow, its not horrible slow but not where it was. The weather has been bad lately so I have not had much more chance to do anything with it. But when I do ill let you know what it was if I find it.