Low boost/low vaccum

Jovez

Registered User
Ok, up until now I thought it was supposed to be like this but, i guess not. The vaccum on the car is at about 12in at idle, boost will only go up to about 9 lbs at WOT. The only time i have seen 20 in on vaccum is after WOT when it comes back. I checked for leaks with soapy water and found nothing. What else would cause this? Car btw is an 89 xr7 w/ CAI. Car has trouble starting, until it warms up then its ok. But the boost problem is still there.
 
Check all vacuum lines, IC tubes, SC top, inlet plenum... essentially anywhere that has air flow through it. Your also better off using something like brake cleaner and spray it onto any of the joints. If there's a leak then it will immediately smooth out for a moment for you.

Fraser
 
Ok, went over every single place that air flows through on the engine with propane and brake cleaner as mentioned. Car runs a little better now than in december, but still has the same low boost/vac problem. Any other problems cause this other than leaks?
 
Other issue

Just a thought....you said your car has trouble starting and assume keeping idle when cold. Could possibly be a coolant sensor or idler mod. That might tie into the vac. boost problem. Just a thought....I could be way off.
 
>Any other problems cause this other than leaks?

  • Worn engine... rings/pistons/cylinders etc.
  • Plugged cats
  • Damaged exhaust
 
Your also better off using something like brake cleaner and spray it onto any of the joints. If there's a leak then it will immediately smooth out for a moment for you.

Fraser

Ok first of all, I made my FMIC. Therefore theres leaks I know it haha:eek: Ive also had a vac line come off before. I think you have to be one lucky guy to get brake/carb/starter fluid or propane to work. Ive sprayed it into a purposely made leak with no change. I have never ever found a leak with it. Only thing that works for me is pressurizing the whole thing. Just thought I rant alittle because I hate when that method doesnt work because it would make life so much easier.
 
Ahh. Ok then I shall try to make a pressure tool see what I can find.

I kinda turned away from a worn engine due to the fact that it just turned 85k miles which I consider to be somewhat low. But you never know...
 
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