Acceleration issues

ANDRE’S 87 GN

New Member
Sep 30, 2018
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I’m having issues with hesitation and popping under medium-hard acceleration stock car, with exception of turbo tweak chip an 3.5 ls1 MAF an translator any suggestions on a possible fix


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TexasT

Texas, Where are you from
Sep 10, 2002
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Meter across the coil terminals to determine the resistance, not fool proof but if way off a sign it is bad.
Gauge on the rail to determine fuel pressure and if it is rising with the boost.
Watching a voltmeter to see about the alternator and if it is putting out the needed power.
 

ANDRE’S 87 GN

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Sep 30, 2018
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TexasT can you give me more information for testing the coils car has new 225 amp Alternator not sure about fuel pressures under boost at idol 30 to 35 psi


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ANDRE’S 87 GN

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Sep 30, 2018
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Scan master readings
IAC 140
O2 CC 0
Spark Adv 71.3
Inj Pw 55.5
mv 443
Ret 0.0
LV8 0
INT 128
BLM 128
Coolant 149.0
Air Temp 71.6
RPM 0



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berserker6

Assistant to the regional manager
Oct 1, 2009
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And fuel pressure baseline should be with vacuum removed 43psi give or take. FP gauge on the rail can be and often are innacurate. You'll need a gauge where you can see the fuel pressure rises 1 for 1 with boost.
 

ANDRE’S 87 GN

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Sep 30, 2018
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Thinking I may have found my issue I’ve noticed a whistle while under boost sounds completely different than turbo spool vacuum leak somewhere


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berserker6

Assistant to the regional manager
Oct 1, 2009
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Your scanmaster readings at warm idle would have shown a vacuum leak in your INT and BLM
 

ANDRE’S 87 GN

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Sep 30, 2018
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Also I forgot to mention I’ve got the turbo tweak chip combo with 42lbs injectors with a stock fuel pump so it may be time for an upgrade any suggestions


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berserker6

Assistant to the regional manager
Oct 1, 2009
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Every car is different but 128 is where you want to be. Above and its adding fuel due to a possible vacuum leak. Some say +10 is ok but I like mine at 128
 

HouseofSpeed

Hangin' and Bangin'
May 27, 2001
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Truth be told, for what you have the Translator and MAF swap were unnecessary unless your stock MAF died. Vacuum leaks, voltage supply and grounds will kill you on drivability with these cars....super sensitive. I can work you in if you hit a wall.
 

berserker6

Assistant to the regional manager
Oct 1, 2009
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You haven't mentioned seeing knock when the car's giving you trouble. If you haven't seen any then proceed with your troubleshooting. If you have seen it then stop doing whatever it is you're doing when it happens. Then proceed with caution.
 

TexasT

Texas, Where are you from
Sep 10, 2002
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I would be hunting up this "mystery sound" that could be a vac leak. Those numbers as others have pointed out the car isn't fully warmed up with a temp of 149* unles you are running a thermostat that opens at 135-140*.
Stock fuel pump worries me. That is asking for a head gasket problem. Really need to look into the fp and what it is doing. My offer stands if you want to bring it over we can put a gauge on it and see.
When you accelerate what do the O2 numbers so. I see at the isle they are around 400. At wit they should be up in the .750 range to be safe. A lot of guys shoot for .720 as lean is mean but changing a hg is only so much fun.
As far as the ohming the coil goes, you put your meter on ohms and measure the reaistance across the coil on the stock coils. I would have to look and see where they are suppose to be but 12k ohms sticks out to me. This doesn't rule it out but as above if it is way off we can put that in the "we think there is a problem" column.
 
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