North American Turbocoupe Organization



I'm loosing boost
k_liff's88 Offline
Member
#1
When I get on it in 1st or 2nd gear my boost gauge is shooting up to red and then it just feels like I lose all my power. Is this my waste gate opening up ?
Bone stock except for CAI, Hurst Shifter and a Walbro 255 fuel pump. Gillis 2 stage on the way !
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grey88smokin Offline
Posting Freak
#2
Do you mean the boost drops when you shift ? Mabye the air is getting too hot from overboosting.
84 SVO 1C
08 MKZ
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Spooler87 Offline
Posting Freak
#3
It very well could be that you are overboosting. What kind of shape is the BCS and vac lines in?
All hail Project "Marauder" !
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grey88smokin Offline
Posting Freak
#4
What year TC and what turbo do you have ? The wastegate opens to divert exhaust from spinning the turbine, that limits the ammount of boost you will make. The Waste gate actuator should open the waste gate in a fluid motion, meaning that if it is set at 10 psi, the turbo should not make 12 psi and drop to 10. It should just climb to 10 psi and hold.

To me it sounds like the boost control selonoid(BCS) is letting you overboost in 1st and second. If your using the stock BCS I would strongly reccomend using a Gillis or at worst case senario making one. The BCS is very prone to falling apart or leaking, that could be the problem.

Do not let that needle go to the red, w/o an aftermarked fuel pump upgrade, and depending on your intercooler, if any, your at great risk of poping your head gasget, or a piston. Expecialy if you running an IHI turbo, they heat the air up after 18 psi.
84 SVO 1C
08 MKZ
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k_liff's88 Offline
Member
#5
Quote:Originally posted by grey88smokin:
Do you mean the boost drops when you shift ? Mabye the air is getting too hot from overboosting.
No, it's not dropping. It stays in the red.
Bone stock except for CAI, Hurst Shifter and a Walbro 255 fuel pump. Gillis 2 stage on the way !
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k_liff's88 Offline
Member
#6
Quote:Originally posted by grey88smokin:
What year TC and what turbo do you have ? The wastegate opens to divert exhaust from spinning the turbine, that limits the ammount of boost you will make. The Waste gate actuator should open the waste gate in a fluid motion, meaning that if it is set at 10 psi, the turbo should not make 12 psi and drop to 10. It should just climb to 10 psi and hold.

To me it sounds like the boost control selonoid(BCS) is letting you overboost in 1st and second. If your using the stock BCS I would strongly reccomend using a Gillis or at worst case senario making one. The BCS is very prone to falling apart or leaking, that could be the problem.

Do not let that needle go to the red, w/o an aftermarked fuel pump upgrade, and depending on your intercooler, if any, your at great risk of poping your head gasget, or a piston. Expecialy if you running an IHI turbo, they heat the air up after 18 psi.
It's an 88 with the stock IHI turbo. Also, it doesn't do it all the time, just every now and then.
Bone stock except for CAI, Hurst Shifter and a Walbro 255 fuel pump. Gillis 2 stage on the way !
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grey88smokin Offline
Posting Freak
#7
Yea, your deff overboosting from what I can tell, allmost deff running out of fuel too. I would chech the hoses to the WGA, I am thinking it could be sticking too possibly. Not too sure how you would diagnosis/test a bad WGA.
84 SVO 1C
08 MKZ
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k_liff's88 Offline
Member
#8
My dad actully has a 255 lph pump he said I could have. I guess that would be a good start. Thanks for the help.
Bone stock except for CAI, Hurst Shifter and a Walbro 255 fuel pump. Gillis 2 stage on the way !
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Robert Camp Offline
Posting Freak
#9
No, that's not exactly a good start. The fuel pump is mentioned as you are likely going lean with high boost and the current, what I assume is stock, fuel pump. It can't deliver the fuel necessary for the increased air volume. The lean condition can cause major havoc with your engine.
But that will not solve the overboost. Something else is happening to get the uncontrolled overboost and you need to figure that out first. Then with the increased fuel available due to the higher volume pump you can crank your boost up. BTW, the pump should be a high pressure version.
Robert Camp
'86 Medium Regatta Blue TC, 5-speed, original owner.
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k_liff's88 Offline
Member
#10
Quote:Originally posted by Robert Camp:
No, that's not exactly a good start. The fuel pump is mentioned as you are likely going lean with high boost and the current, what I assume is stock, fuel pump. It can't deliver the fuel necessary for the increased air volume. The lean condition can cause major havoc with your engine.
But that will not solve the overboost. Something else is happening to get the uncontrolled overboost and you need to figure that out first. Then with the increased fuel available due to the higher volume pump you can crank your boost up. BTW, the pump should be a high pressure version.
Yes, the current fuel pump is stock. But if the current fuel pump can't provide enuff fuel for the leaner conditions at high boost, wouldn't a higher volume pump solve that ? Also, I'm not that concerned about cranking my boost up, not yet anyway! There's other things I want to do first. Like a stinger 3" exhaust, ajustable fuel pressure regulator and the bigger fuel pump. I already have a CAI, although I've been told mine is not the greatest setup. Anyway, those are the first couple of things I'm planning on doing. Do them mods sound ok, am I missing anything that I should do before them ? Besides finding the overboosting problem
Bone stock except for CAI, Hurst Shifter and a Walbro 255 fuel pump. Gillis 2 stage on the way !
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