there seems to be enough people in here now with enough knowhow- think i`ll throw out the bone, see if anyones heard of this...
and yes, I have one just like it.
On the renix or earlier chrysler jeeps-usually pre 95, we all develop vac leaks. Almost all can be traced to either the hardline leaking at the battery, or the brake booster. We lose vacuum going uphill, or trying to meld the go pedal to the floorboard. Said action automaticly causes *0* vacuum, or a pressure build-where there should be none, causeing the MAP sensor to get all hissy and try to throw more fuel down the pipe. More fuel, more power, more vacuum...or so the story go`s......Been there , done that-it aint the case.
Why is it then, that the vacuum problem gets worse the warmer it gets?(not to be confused with the voltage dropping when tempetures rise- solved that)
think about this- several people have this same problem , and as far as I know, its never been solved on any of the forums for the years Ive been tracking it.
example- I have NO vacuum leak- its tested, it holds. Useing a vac guage in the driveway(HA!-) I have steady vacuum, no pips or dips-from idle to 6000rpm(no strain/all in nutreal),- In cold weather I do have a minor vac leak at the booster-when pressed-common.
Road test- at 70degrees ambient temp- I can get halfway up a hill (testhill)
before the defrost kicks in, which means no vacuum-starting pressure.
At 80+ degrees ambiant, I can get 1/4 up the hill.
Anything over 90 and the defrost kicks in at the bottom part, soon as the engine senses strain.....at 100, I have no vacuum as soon as the engine senses any strain-- the kicker?- downshifting causes an immediate vacuum return, followed by slow lose again.
One could therorize that the ambient temp would cause a vac line thats leaking to open more with higher temps. BUT, all the hoses are underhood at a constant temp-the engine bays stays around 130 to 150 reguadless.
ponderance: would a semi clogged cat convertor cause a buildup of exhaust that backflows into the intake where the vacuum begins? If so, why would heat be a factor?
solve it, and your "Da MAN"