sup guys
my car has been acting funny for the last while and I cant figure it out, hopefully someone can give me some advise on what to check or what to fix. let me explain.

a while back, I noticed my car not making full boost, it always made 15psi according to the gauge, it use to hit it and hold it nicely.
lately, its been hitting 12 psi and dropping off to 10psi.
it always makes atleast 10psi, always holds atleats 10psi, but like i said, sometimes it will hit and hold 12, others it will hit 13 and drop off to 10.
and sometimes, the gauges reads 10-12psi but the car barley moves.
everything sounds normal, but the car wont pull, its showing its making the boost, and you can hear the "spool" but the hesitation is ridiculous, its as if something was holding it back.
sometimes when it gets really bad, I let completly off the gas and go back on it and the car seems to work better, it still only makes the 10 or 12psi, but it doesn't lag and sit there as much. its hard to explain.

so far i've changed, plugs, wires and downpipe.
still getting the same results, I also took the inlet pipe off the turbo and checked it out, no visible signs or damage there, no play.
i've checked for leaks and breaks in any piping. only thing I did not test that I could get at was the intercooler, I plan to test that out this weekend.

theres no funny noises, no vibrations, no nothing, the car seems to be the same way it was, with the exception of the not enough boost.
I don't know how big a difference 3-5psi makes but to me the car is "gutless", it doesn't seem to have near the pull it used to.

what can I check ? what could cause this ? anyone have a similar problem before ?

Could be a bad knock sensor, or really bad lifter tick or exhaust leak causing phantom knock.

When the ECU reads knock from the knock sensor, it will pull the timing and you'll feel hesitation. You could spool boost but go nowhere because of the retarded timing.

It could also be an intake leak.

A couple links that could help:

http://www.vfaq.com (some instructions here for intake leak test)
http://1000q.dsm.org

Check your PCV valve.

Is your clutch slipping? It sounds like it to me. Watch your tach, does it continue to move on up faster than you are accelerating?

for not making enough boost, yeah, rob's probably right about the intake leak (from what I've learned here anyhow...)

so, maybe two problems - slipping clutch and intake leak.

Check the intercooler. I dont know about the 2G but on the 1G's the outlet can have a lot of holes almost a buckshot effect.

Also check for knock as Rob indicated. Wastegate and blowoff.

Also a clogged cat would strangle the car and especially at higher speeds. The back pressure is harmful so figure this out before pounding on your car anymore

ok, heres an update.
checked for leaks in piping, intercooler, intake mani and exhaust mani, nothing, all is good there.
Had some exhaust work done after this started to happen, Got a new flex pipe and I removed my Converter.
Its been about 2 weeks sence I got the exhaust fixed.
Still not working right, made about 12psi then dropped off to 10, not near the power/boost it use to make.
So, last night im driving, 3rd hear rpms at about 3000 and Bang, Check engine light pops on.
I figured it because of the missing cat.
So I figure the talon would be like most other cars and by "unhooking" the battery you can reset the ECU and clear the codes, so this is what I did, let it sit for about 10 minutes before attaching the batter cable again.
So I fire the car up, check engine light is gone, thats one bonus, and hasnt come back on sence.
even more odd to me, according to my boost gauge im Making and holding 13psi.
I tried a few times and it hit and held it with no probs, engine sounds nicer while under boost and seems to have a lil more pull, to me its still Not the same as when I first got the car, but more then what I had non the less.

How and Why can resetting my ECU make me gain and hold 3 psi more then before ? it makes no sence to me ?

something messed up ? just a wild fluke ?

I also checked for shaft play back when I was in test mode, theres was minor side to side, no in and out.
I dont think its enough to hurt anything bacuse it seemed like a tiny amount of play to me.

thats my update. any ideas ? suggestions ?


ok, update #2
My problem came back, now worse then ever, it will not pass 10psi on the gauge, car feels slow, not near the pull, no matter the rpm it wont pass 10psi.
So, I was bored today and decided to vent to the asmophere for a few minutes by removing that recirc pipe, now, with doing this I decided to give the car a little run on the highway, by doing this I hit 13 psi, now at this point im stumped, so I took the car home, re attached the recirc pipe and "un vented" and the car is back to 10psi.

I must add that when I was venting it hit 10psi like it always did for the last while, then as I got up in the rpm's it jumped over to 13psi in a hurry and there was a noticable differnce in pickup, best I can discribe is it hit 10psi and held it, then as the rev's got higher, Im thinking around 4500-5000 the gauge moved itself from 10 to 13 in a hurry, it was a very fast change on the gauge from 10-13psi, faster then ive seen the gauge move before, its was as if I went from 3 cylinders to 4 (expression), it was an instant jump on the boost gauge and an instant jump in the pull of the car. very noticable. it pulled better and even sounded better.
I was focusing watching the boost gauge so im not to sure about where the revs were, from a quick glance I seen a little under 5000rpm.


now, I must point out that even when the car hit 13psi it still didnt feel right, still nothing near the pull the car used to have or it should have in my opinion.

The last comment I got from a mechanic was I might have a dead injector and or its not spraying the way it should be, thoughts on that ?
thoughts on the psi jump while venting ?

This problem is really starting to bother me

"So, last night im driving, 3rd hear rpms at about 3000 and Bang, Check engine light pops on."

Sounds like you blew your intercooler pipes (again)

DSMs don't like to have the BOV vented. (I assume you did block off the BOV return on the intake bacause if you hadn't it would run real lean and u'd blow your engine)

Before you destroy your car, maybe you would like to have an experienced DSM driver troubleshoot the car for you. Sounds like you are in over your head.

There are too many things that can be wrong. You said you tested your car for intake leaks..how? What did you do exactly? You also need a datalogger to help see what trips the CEL and check if all other sensors are working right.

Sounds a lot like what my car is doing(see Can't feel kick in... thread in General Technical Discussions), only I don't have the spike, mine just holds stock boost at 10-11psi. The spike is probably because of boost creep since you removed the cat. Another member on here said he was spiking to as much as 16-17psi with a complete A'Pexi exhaust system with no cat and no boost controller to control boost levels.

Anyone want to offer to trouble shoot my car? I'll bring the 12x341x5%

Do you still have the boost control solenoid hooked up?

I'm currently experiencing the exact same thing in my Eclipse. It's driving me nuts. Sometimes the car pulls like the good old days, and other times (most of the time it seems) the car just spools up and goes no where? Everything sounds normal except the car doesn't go.

Keep me posted on your findings. I'm going to do a intake leak test this weekend and pull / check my plugs. I see what I find.

I also have a post "2G hesitating/bucking when accelerating??"

Anyone in Markham area wanna lend me a logger or help me log some pulls?

Mark

Mark

Add me to the list of this problem. I also have a centerforce stage 3 so It might be slipping....but I doubt it. No vacuum leaks...no boost leaks. Whats that leave yea?
Its time for a compression test. Hey guys with the problem..does your car pull lie a mother****er when its cold but lays down when warm? Mine does.
Any answers welcome.

Ha ha, wow... I remember the first time I posted this problem there was nobody who shared the same problem and I actually felt pretty stupid. Kind of lame, inept, retarded... like Christy Brwon must have felt. Now it seems that there are more by the day. Not that that's a good thing, I just don't feel left out anymore

It seems to be intermittent for everyone, so I don't see it being anything big/obvious. That's probably why everyone is having a hard time finding out what the problem is. I know I've checked all the big things, thats why I'm all out of ideas and would really appreciate someone else taking a look.

Lee, my car pulls better in the cold, but I still have the problem even in the cold. That's why it makes absolutely no sense to me, any of it. I doubt its the clutch, because if it's anything like mine, it wouldn't accelerate fine from a stand still. And it's not like the revs "jump" a lot/fast like they would if the clutch was slipping, they just "stumble" and are "choppy".

Stupid question, but how man k's your cars have on them? Mine has 250,000, and I'm thinking maybe it's just getting tired. Even though the compression is fine, the pistons and rings were change about 80,000 ago, and the head has been done twice on it, last time being 20,000km ago. So I don't see it being anything to do with that. But like I said, I don't know what to think anymore or what to check

I experience this and am 99% sure it's just my exhaust leak at the manifold when hot, and my lifters when cold.

I'll post back when I fix the exhaust leak (hopefully today).

I thought that could be a problem too, but then I remembered its always been a problem for me, even with the old turbo on there and the bolts tightened and no leaks.

Hopefully the bolts don't break on you like they did on me

45,000 km on rebuild. Iam actually confident its the rusted wastegate actuator. I dont really care cuz Iam getting a SCM34 soon but If it still happens its probobly one of the vacuum lines AFTER the boost guage one.

I'm pretty confident it's not the wastegate actuator, ha ha, sorry...
I'm only saying that because I put on an all new turbo set up and still have the same problem as with my old turbo. With which, by the way, I believed it was the same thing causing the problem.
Then again I'm not saying the cause its going to be the same for everyone, or who knows, it might be, I'm just thinking it's too intermittent to be something like that. I still like Rob's idea of something pulling back the timing, I just wish I knew what it was
Good Luck.

OK
Results are in.

There is now no exhaust leak against the head and my phantom knock seems to be GONE!

Even with a tapping sound still (due to the new exhaust leak I've created - I'll explain in another thread ) -- since there is no leak between the head and the exhaust manifold, the knock sensor doesn't seem to be picking it up anymore.

Here's my update from testing over the weekend..... 72000 miles on my Eclipse. 7ES's plugs are being used and they where check and re-gapped.

I made an intake leak tester - $3.00 worth of home depo parts and one free valve steam from a service guy at crappy tire .... I found two minor leaks. One from the lower FMIC pipe to the turbo pipe and the second from the Brode UIC Pipe. I adjusted some hose clamps, added and extra one and the car seems to be back to normal. However, I only drove it for about 1 hr in rush hour traffic, so couldn't really boost a lot ..... keeping my fingers crossed ....

MM