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loosing boost after about 45 min


holeshot
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I have been having this problem for a while.it boost fine until After driving for about 45 min or so I loose boosting ability. And its a gradual thing it will lose it a few psi at a time until I have to feather the throtle to get it to go. When it does it, it jumps and bucks when it boost...its a 87 with no major mods..any sugestions or thoughts on why it would be doing this?
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You have loud exhaust? Cracked exhaust manifolds?

 

You looked at your spark plugs? Leaky injectors, plugs get wet and misfire. Plug dry overnight then fire again and repeat after they get wet.

 

Pull the pipe off that leads to the throttlebody, use a flashlight or reflect sunlight using a mirror (best, free, no heat, very bright) they crank the motor for a second then watch to see that neither drip.

 

Also sign of a cracked head. Coolant heats up, cracks open and coolant drips in, then sprays in and car runs like crap. Let it cool off and the crack has closed. This is the beginning of a crack that will leak all the time. You have white exhaust or are losing coolant?

 

CTS connector pluged into the temp. gauge unit by mistake. Car heats up, CTS circuit gets no reading because its on a dead leg since its a switch that closes after coolant is hot (for overdrive and hvac) then it grounds out the wire to the ECU and the resistance is whack and runs like crap.

 

http://www.b2600turbo.com/images/ECICTS.jpg

 

 

Edited by Indiana
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i have an 87, it had the exact same symptoms, basically i eliminated everythig and fixed it, check your injectors, check your filters including on frame, my problem ended up being the lemon shaped o-ring in the throttle body, basically it was holding boost after sitting until it got hot because of quagulated fuel that had leaked...as soon as it returns to liquid state...gues what youve got a huge boost leak, rebuild your throttle body, it takes about 15 mins to do and its just one more thing to check of the list until you find the problem

 

-Curt

Edited by scooterdude92
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