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Discussion Starter #1
bentley publishing still aint got no cd-roms for our cars so i need some help.
my coupe is hunting and running rich,it also needs to pass emissions.the work i've done so far is cap,rotor,034 ign wires,bosch coppers,oil cap,dipstick seal (o-ring gasket),no oil leaks on valve cover(or the complete motor),new o2 sensor(oem bosch),new high flow cat.
the isv works as when i unplug it,the idle surges so it must work,also still need to replace all the vacuum hoses and swap in a new 034 crankcase vent hose.
the question is this,if i connect a vacuum guage off one of the tees at the manifold,what hg should it be at?at what engine temp should i check?at what rpm?
also,will a new hg/boost guage,say from vdo,be good enough to give me an accurate reading to see if i have the the right manifold pressure,or should i go buy an actual,fancy,proper one.
 

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Re: manifold pressure on 7a? (littlegreek)

TPS/Idle switch on the TB your car is 91 so you likely have the two in one bosch TPS/idle switch. I have a TB with the switch for sale or you spend the money and get a new one.
 

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Re: manifold pressure on 7a? (littlegreek)

On an NA motor you have manifold vacuum, not pressure. The vac will be different at elevations and motor action (accel and decel). I'm not sure you can say what is a proper vac level under various conditions.
 

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Re: manifold pressure on 7a? (littlegreek)

sorry guys,i crawled under the car today and noticed a huge leak in the fuel line,right by the cat
i think i should fix that before i worry about the manifold vacuum(said it right this time).low fuel pressure might be the cause of the idle to be wacky,right?
i will start a new post for my new issue
 

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Re: manifold pressure on 7a? (littlegreek)

Yep, those lines are known to rot out pretty badly. Some have just cut out sections and replaced with rubber lines. Others have replaced all 3 with braided lines. Depends on the effort you want to put in.
 
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