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Please help...having big time boost problems

1660 Views 7 Replies 7 Participants Last post by  The Radius Kid
Here's the story...the car was recently in my garage for about a month getting alot of new parts. I got a new adjustable wastegate actuator arm (set at stock setting for now), new solenoid, new vacuum hoses, new pcv valve, new plugs (CR43TS), new heavy duty intercooler hoses, and all new exhaust which includes Poston's 3" DP with hi-flow CAT, and the 2.5" Hooker exhaust with the turbo mufflers...

Now here's the problem...the car slightly hesistates to get going from a stop or a light roll...when I 1/2 throttle it...the boost is fine and hits about 10 psi and no problems...when I 3/4 or try to go WOT, the boost goes all over the place and the car goes herky-jerky until I let off the gas...

Now I checked all hoses and such and they are tight and secured...I know for certain the wastegate rod is the stock length...and I know there are no exhaust leaks...and the turbo is in great shape...and no I do not have a scan tool yet which is a no-no!

So here's my conclusion to this problem...I still have the stock fuel pump and regulator (70,000 miles), and I think when I try to punch it, I am severely leaning out and can't run the full boost because there is not enough fuel...everything else on the car is pretty much stock and in good working order...but I think the pump and regulator need to go

What are your guys' thoughts about this? am I right and will changing these two things clear up the boosting problems??? Thanks for any help.


1987 Buick Grand National - 70,000 miles, Stock engine: Poston chromed MAF pipe, homemade cold air induction system w/ 9" K&N air filter behind headlights, Poston 3" Downpipe with high-flow CAT and test pipe, 2.5" Hooker cat-back exhaust system, adjustable wastegate actuator set at 15 lbs of boost on 93 octane for now until fuel pump and regulator are upgraded (coming soon), K&N breather by-pass kit, ANS Performance 93 octane street/strip chip, throttle body coolant lines blocked, 160 degree thermostat, removed 1 screen from MAF sensor and removed intercooler screen, CR43TS spark plugs, BFG P255/60/R15 all-weather rear tires... first track times next spring=(

1995 Mercury Cougar XR7 - 87,000 miles, Stock 4.6L V8 Engine: dual exhaust out the rear, modified air-box with cold air induction, modified chip, adjustable fuel pressure regulator, P245/70/R16 all-weather rear tires; 14.9 @ 92mph

"Have U Been Beat...By A Grand National Lately?" <--many have been

Note to all Ford/Chevy/Import owners: BUICK OWNZ J00;)
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This is a good example of what happens when you do several mods at once.
We all have been there...

You are diong the right thing by upgrading the fuel side, but without the a scantool, there is no really good way to tune. A scan tool is a mod, after all, you want to get the most out of your combination-Right?

If you had a knock guage, we could see if you were getting timing retard, due to knock (most likely scenario) The extra air provided by the K&N needs to be dealt with, so why not consider a thrasher chip?

The screen removal might have messed you up, especially if the MAF went in backwards. (Don't laugh,-it's happened) The arrow should point to the TB.

One suggestion, Postons has a fuel guage that can be masking taped to the windshield for checking the WOT pressure. Under $50 last I checked, and something everybody should have..
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It's my limited experience with getting help via online with these cars that NOT having a scan tool is multi-faceted problem. First of all, you can't troubleshoot your own car. Second (and more important in this case) is that nobody else can help you, either. The only thing they can do is suggest throwing money at it, with a bunch of upgrade parts and hope that you stumble upon the problemed child. A lean fuel condition is a popular suspect, but so are (though SLIGHTLY less common) MAFs, coil packs, wires, etc. The $100 for the AFPR and $100 for the FP are purchases that you will without a doubt make, but I believe it's in your best interest to use that money for a scantool, first. Once you start throwing numbers (along with the symptoms) at these guys, you'll be amazed at the precision they can home in on successful repair. I know it's not the answer you want to hear, but it's with good intentions that I give it. Good luck.
Basically if you're going to mod your car, you need a scantool to do it right.

Wouldn't it suck it find out 1000 miles later that you had been leaning out and knocking everytime you dropped the throttle? I don't think your engine would ever forgive you

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Get a scantool... Put the stock wastegate actuator back on and see if that fixes your overboost problem. Did you buy a High Boost actuator? If you did they are impossible to control boost under 18-20 lbs

87-T-TYPE, PT54,MSD50's,Crane Billet Roller,JE forged20over,P&P Heads,Manley valves,Hemco 65mm& Acu65TB,V2 FM, P.I.9.5 -7disc,Jimmys Trans, new times soon.
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Try putting the MAF screen abck in too, unless you have a chip for it. And check the fuel filter.

Does the car buck slightly around 45mph? That would be a good sign of the MAF, since the computer doesn't realize that the MAF is flowing more than it's saying. Thus, it's lean all through the throttle/RPM band.

Also, there's a link on gnttype.org to build your own audible KR buzzer, I suggest it.
looks like I need to get a scan tool before anything else! it makes sense tho...I should just not even mess with the performance parts of the car until I do get a scan tool...I need to just drive the thing normal until I get one and then figure out what the heck is going on...you guys might be right about the maf sensor/coil pack...still have the stocker maf and the coil hasn't been changed in a couple years...

btw I am back to the stock chip and put the other maf screen back in and switching the chip helped tons...but still can't boost over 10 psi...still surges...oh well

[This message has been edited by d0n_3d (edited November 20, 2001).]
Try adding about 4#'s fuel pressure.See if that helps.I've been down this road.Thta's of course assuming the ignition is all right.Can't go wrong with extra fuel,only too little.

Give em' hell!
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