Near Stock and hesitates at WOT.

[TA^Guy]

Ok, I guess this is kind of a no brainer but I want to lay my cards out on the table and see what you Buick Pros think.

For the past few months my car hesitates when at WOT, but runs perfect idle to about 3/4 throttle. But runs better at WOT when it's just been started and still cool or cold. It also gets worst as the motor warms up. Found no vaccum line pulled off, but noticed the stock up-pipe is rusted through. Also scanning the computer it says I'm running rich, and needs a EGR.

I currently have no gauges, and only mods are a hot wired Walbro 307, ATR Pitbull Exhaust, test pipe, V8 radiator, and TB coolant by-pass. Question is, do you feel is I repair the up-pipe (friend is going to bend me one at work), EGR, and maybe new injectors shall this solve my problem? Or do you think it sounds like something else and the problem lays deep with-in?

I really don't have the cash to go balls out on it. The body needs work, and the tranny will soon need a rebuild, I purchased a new motorcycle, and my wife and I are looking into buy our first home. So I'm pinching pennys and would like to tackle one problem at a time.

Thanks for any suggestions.

 

[HOTSIX]

I'm liking the injectors as a problem here....how old are they...when was last cleaning...what size are they...etc etc

PS: I went balls out once....dont try it.....I got arrested.

 

[WFO]

Originally posted by HOTSIX

PS: I went balls out once....dont try it.....I got arrested.

you hung around too long.you gotta do it then take off.


i'd say you should definitely repair the up-pipe.that'll improve driveability and make tuning easier.

does the car keep moving at wot,just sputtering?or does it go to a certain point then shut completely down?

later,sean

 

[TA^Guy]

Hotsix,
The injectors are stock and the car has almost 67,000 miles on it.
I'll try not to go balls out, especially this time of the year I might freeze them off. lol

WFO,
It sputters but keeps going, normally if I get to agressive with it, I just back off until it stops sputtering (around 3/4 throttle).

I plan on repairing all the above, but right now it's a matter of time and money.

 

[WFO]

it's probably a combination of things.a hole in your up-pipe will make you run rich and dirty injectors will aggrivate the situation.contact chuck leeper here on the board and he will clean/flow your stock injectors cheap.

then we'll see where you are..

later,sean

 

[HOTSIX]

How bout just getting the stokers cleaned and flow tested ?

That shouldnt cost ya too much...even if it doesn't solve the problem - your guaranteed to improve flow and operation of the injectors - remembering how old they are now.

 

[TA^Guy]

My buddy that is going to make my up-pipe has the tools to clean fuel injection systems. But from what I understand the stock injectors were never great to begin with.

I'm mechanically inclined but have never tackled a transmission rebuild. My buddy actually went to school to specialize in trannys and insists that we should do it ourself. I have a few idea's but while you guys are so great with TR's (I'm a FBody guy but learning) what rpm stall coverter do you think I should install on my near stock hotair GN?

 

[WFO]

Originally posted by TA^Guy
My buddy that is going to make my up-pipe has the tools to clean fuel injection systems. But from what I understand the stock injectors were never great to begin with.

there's nothing wrong with clean/flowed stock injectors,and they should be fine til you get to the 12's.especially on a budget!

Originally posted by TA^Guy
I'm mechanically inclined but have never tackled a transmission rebuild. My buddy actually went to school to specialize in trannys and insists that we should do it ourself. I have a few idea's but while you guys are so great with TR's (I'm a FBody guy but learning) what rpm stall coverter do you think I should install on my near stock hotair GN?

you and your buddy can do the rebuild with the assistance of bruce and co. over on the tranny forum.listen to what they tell you,use the parts they sell and remember that this is not a th350 and you will be fine.the stock convertor is a 2400 stall and works very well,but you can get re-stalled stockers that work good too if you plan on going with a larger turbo later on.i'd go with no more than a 2800 stall,that should be fine with most turbos you would be using in the futrure.

later,sean

 

[Matto]

up pipe

My car did not run well when I had a slight leak in my up pipe and I got an ATR one and tightend up my headers and crossover pipe and it ran much better, my car has the same amount of miles on it as yours and I may change the injectors as well

 

[cool 84]

Just curious, what does your boost go to at WOT?

 

[TA^Guy]

Originally posted by WFO
there's nothing wrong with clean/flowed stock injectors,and they should be fine til you get to the 12's.especially on a budget!

you and your buddy can do the rebuild with the assistance of bruce and co. over on the tranny forum.listen to what they tell you,use the parts they sell and remember that this is not a th350 and you will be fine.the stock convertor is a 2400 stall and works very well,but you can get re-stalled stockers that work good too if you plan on going with a larger turbo later on.i'd go with no more than a 2800 stall,that should be fine with most turbos you would be using in the futrure.

Seiously, thank you for all your help. I didn't have much of a clue to what the factory stall was but was considering using a 2400-2600. I'll check out what 'bruce & co' have for me.

Originally posted by cool 84
Just curious, what does your boost go to at WOT?

No clue, I have no gauges yet.

 

[Buick From Hell]

These engines are also famous for weakling valve springs...

 

[TA^Guy]

Ok, I have anothe rquestion for you guys.
What size is the stock up=pipe and should I step it up with a stock turbo, or keep it the stock size so I keep velosity up and lag minimal?

 

[FJM568]

First off...You at least need to get a boost gauge...Hook it up to where there is a pipe plug fitting on the front drivers side of the intake manifold behind the coil pack...

Second thing is...What you are probably experiencing is detonation or knock retard at WOT...Try to add in some higher octane gasoline and see if it goes away...You are running premium(at least 91 octane right now, RIGHT ??? The higher the octane, the better... Stay away from the octane boosters in the small bottles...

As for everything else...Leave it all alone and don't start upgrading or throwing parts at it before you figure out what is wrong now...Your fuel system upgrades are okay and should be done regardless of if you never do anything else to the car...

And for everyone else who replied earlier...I don't know how many times I've said it...Throwing bolt-ons at a problem won't fix the problem...Start with the basics...The first clue in this situation is that it runs better at 3/4 throttle and slows down at WOT...That is generally a detonation problem...Throw some octane at it and see if it fixes it...Then go from there...

As for the up-pipe, I think the stock pipe is 2 1/4...As long as you use mandrel bent tubing when you make the new one, you will be miles ahead of what the factory put on there...

 

[TA^Guy]

Thanks for the pipe size, I thought it was either 2.25 or 2.5"s.

I already run 91 octane fuel in it (actually 93, around here it's either 89 or 93).

And as far as I'm aware it's not denotation. I've experianced that before in other cars and this is pretty different.

I'm about 100% sure it due to the bad up-pipe. Don't know if you read it, but the stock one is rusted to hell and back. Only things bolt-ons that are going on it are those that need to be replaced, like the EGR, up-pipe (down pipe is being made while it's there too), and maybe injectors. When it falls on it's face the exhaust gets thick and smells like raw fuel.

The gauges will have to wait until the up-pipe and ERG is repaired. Once thats done I'll be purchasing a knock sensor, boost and fuel pressure gauge to start off with.

 

[FJM568]

Well, as for detonation, it may not be what you think...On these cars, when detonation starts, the ecm pulls out timing and it makes it feel like something is holding the car back...If you back off of the throttle and get to a point where the motor isn't detonating, it feels stronger...The heavier the detonation, the more timing it pulls out...It really kills the power of the motor...You most likely won't be able to hear the detonation, but it may be there...

One other thing...Check all vacuum lines carefully...Especially the ones connected between the turbo/wastegate actuator/wastegate solenoid...It may be that you are overboosting past what your boost setting should be, thus causing detonation...

Very first thing you need to buy is a boost gauge...PERIOD...You need to know where your boost is at before you start throwing parts at it...Don't worry about the up-pipe...The only thing that it is affecting is how long it takes you to get to max boost and increases lag time...You will still get there, but it just takes longer...It won't cause the problem you are experiencing...But it does need to be fixed...But first, put a boost gauge on it and let us know what you find out...

Throw some higher octane gas at it and see if the hesitation goes away...

 

[SLOW_85]

Being you say it runs better cold. Check the o2 sensor. Sounds like it may be bad or lazy. MY 02.

 

[TA^Guy]

Originally posted by SLOW_85
Being you say it runs better cold. Check the o2 sensor. Sounds like it may be bad or lazy. MY 02.

Good call, seeing as it runs rich good chance it's fouled right up.
My buddy goes back to work soon (he was in the hospital) so once he's back I'll wait a week and then tear into it.

 

[TA^Guy]

Well this week it started running really oddly and I had enough of waiting. I started by checking the fuel pressure at the rail (only about 35psi with teh car not running) then I replced the fuel filter.
Next the coil pack, plugs and wires were replaced. Problem solved. No more hesitation at full throttle.
As my friend is back to work he bent me a new up-pipe. It didn't line up perfectly so he put it back in the machine to bend it a hair more and cracked the pipe. So hours down teh drain he stripped the braid covering off the stock pipe and welded me a make shift bandage. I'll bring the car back in a few weeks for a new up and down pipe to be bent.

Glad to have my girl running strong again.