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Discussion Starter · #1 ·
Ok guys, here's the story. I never have been able to make W.O.T. with my car. I thought it might be a fuel delivery issue. I have changed the fuel filter, installed a 307 fuel pump and 50# MSD injectors. I had a buddy burn 2 chips, one for street 93 octane and the other for strip 105 octane.

Here is the problem, when I try to make WOT, my rpm and boost gage goes up and down like mad. It's almost like some one is moving the throttle up and down real fast. When I just ease into the throttle, everything seems just fine.

I don't know if this is a related problem, but I have never gotten good gas milage, 12 mpg, and my plugs have always burned rich.

Thanks again guys. :cheers:
 

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does your scantool show timing retard when this is going on?

Are you taking egts?

What is the fuel pressure at wot and how much boost are you running?
 

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What fuel are you using? Last time in Kansas 91oct was the best I can find. I see you have 93 chips. That will cause issues with boost over 12lbs.
 

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Aftermarket or stock gauges?
Boost up down sounds like a split IC hose or a hole in the IC.
 

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Discussion Starter · #5 ·
I don't have a scan tool, no gauges either. I have to get out of the throttle at 1/2 to 3/4 throttle. My car hops and jerks so bad, I'm afraid something will break. My tps is set where it should be. I have a set of heavy duty IC hoses from john's performance. Having a pin hole in the IC could be possible. The new chip I had burned is set up for 91 octane. I have my waste gate set up for 16 lbs boost.

Even before I changed injectors I had problems. When I ease into the throttle, everything runs fine. But at WOT, it just seem to lose power. Now with the 50# injectors, I cant get but 1/2 throttle and 8 or 10 lbs boost.

:confused: :confused: :confused:
 

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ICT87GN said:
I don't have a scan tool, no gauges either. I have to get out of the throttle at 1/2 to 3/4 throttle. My car hops and jerks so bad, I'm afraid something will break. My tps is set where it should be. I have a set of heavy duty IC hoses from john's performance. Having a pin hole in the IC could be possible. The new chip I had burned is set up for 91 octane. I have my waste gate set up for 16 lbs boost.

Even before I changed injectors I had problems. When I ease into the throttle, everything runs fine. But at WOT, it just seem to lose power. Now with the 50# injectors, I cant get but 1/2 throttle and 8 or 10 lbs boost.

:confused: :confused: :confused:

A good radiator shop should be able to do a pressure test on that I/C.
 

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Without an after market boost gauge it will be hard to tell what your boost is because the stock guages tend to be inaccurate.
The car maybe having major knock and timing is being pulled.
I would also do the tap test on the maf.
You really need to give us some scantool readings.
You can check the IC with an old tire tube.
Cut some circle patches with one being at the valve stem.
Cover one end and add air at the valve stem end.
 

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Without a scan tool or real boost gauge (not the stock LED pos) you'll be on your way to getting very proficient at changing head gaskets and pulling the motor out for frequent rebuilds. That may sound a little harsh but it's true. You can not run these car without a scan tool! If you try it will eventually blow up! You state your car is jerking doesn't accelerate smoothly. This most likely is the ECM trying to retard the timing to save itself before it blows. Or it could be a fuel delivery problem, either of which is really bad.
 

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Discussion Starter · #9 ·
OK, I been busy checking every thing out. No leaks in the IC. Set fuel pressure to 42-43 lbs. Checked the cam sensor, vaccum, cylinder compression, TPS. Did some test runs with turbo link hooked up. No knock retard. only thing it showed was rich fuel mix above 850. I switched the MAF next and it ran 85% better. fuel pressure goes up smoothly with boost.

Now the problem I'm having is when I lighly put my foot on the throttle, it spits and sputters as if i'm running out of gas. It seems to get worse when the car get hot. What should I check out next?

:dunno: :dunno:
 

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Is TPS output linear/uniformly increase with accelerator input? Chkg this with a Scanmaster (SM) is cake (you better hurry up & get one NOW!).

W/O a SM, go to gnttype.org for procedure using voltmeter.
 

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Discussion Starter · #12 ·
yes the tsp check good. i even tried a new tsp and had the same results
 

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50# injectors seem to big ,are you running to rich? sounds like there to much gas (50#) not enough air, might be flooding out when you go WOT
 

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gmaltese said:
50# injectors seem to big ,are you running to rich? sounds like there to much gas (50#) not enough air, might be flooding out when you go WOT
50# injectors are hardly too big if the chip's cut right for them.
 

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ICT87GN said:
yes the tsp check good. i even tried a new tsp and had the same results

As long as you have turbolink to use, what is the IAC value at idle when the engine's warmed up??
 

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he said it gets worse when it gets hot....i had the same problem before I switched to a lt1/translator and got rid of that crappy oe maf sensor.

Ed may be on to something with the chips....change those out if you can.

50# inj seem ok with a 49 turbo.
 

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The heat could be pointing to coilpak or Ignition module or both. Any access to know good ones?
 

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Discussion Starter · #19 ·
I swapped the coil pack, but had the same result. I have a newer coil pack that was put on by the previous owner. maybe the problem is in the ignition module. does make sense. who sells them? does gm still carry them?

I do agree on going with the maf and translator. i been looking into it

I need more pics of dead presidents!!
 

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ICT87GN said:
I swapped the coil pack, but had the same result. I have a newer coil pack that was put on by the previous owner. maybe the problem is in the ignition module. does make sense. who sells them? does gm still carry them?

I do agree on going with the maf and translator. i been looking into it

I need more pics of dead presidents!!

Don't we all! (presidents)

Yes it certainly could be the Ignition module. They are available new, but expensive.

Give John a yell. Check this thread of his. Maybe he will (probably will) sell you just the module.

http://www.turbobuicks.com/forums/showthread.php?t=49269

Much cheaper than new, and works as well.
 
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