89 cherokee camshaft sensor test (how does)
Senior Member
Joined: May 2012
Posts: 925
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From: Fort Erie, CANADA
Year: 1987
Model: Cherokee
Engine: 4.0
X2 on the plugged catalytic converter. I had an '87 Buick T-Type and it would idle nice and quiet and when you put it to the floor, almost nothing happened. Took it in to mechanic and he said the engine was just old and tired. It looked fine, didn't burn oil or anything. Took it to a muffler shop and the guy there knew right away it was a plugged converter. Put on a new one and I spun the tires on the way out! Night and day difference.
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Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
CRUISER’S VACUUM TEST FOR EXHAUST RESTRICTION
Your vacuum gauge should come with an instruction booklet outlining the procedure. Hook the vacuum gauge up to a source on the intake manifold. Start the engine and note the vacuum reading. Usually 17 to 21 inches of vacuum. Throttle the engine up to 2,000 to 2,500 RPM for 20 seconds or so and the vacuum reading should stabilize to the same reading you got at idle. Let the throttle snap shut. The vacuum reading should shoot up about 5 inches of vacuum higher for a second and then come quickly down to the original reading. If the vacuum reading stays high and comes down slowly with jerky needle movements, you have an exhaust restriction.
Your vacuum gauge should come with an instruction booklet outlining the procedure. Hook the vacuum gauge up to a source on the intake manifold. Start the engine and note the vacuum reading. Usually 17 to 21 inches of vacuum. Throttle the engine up to 2,000 to 2,500 RPM for 20 seconds or so and the vacuum reading should stabilize to the same reading you got at idle. Let the throttle snap shut. The vacuum reading should shoot up about 5 inches of vacuum higher for a second and then come quickly down to the original reading. If the vacuum reading stays high and comes down slowly with jerky needle movements, you have an exhaust restriction.
Thread Starter
Junior Member
Joined: Dec 2014
Posts: 38
Likes: 0
Model: Cherokee
Yeah sorry I do have bad Grammer. Anyways ya the line to the map sensor is a plastic one. how would I test the cat? Because today I was messing with it and it'll run and rev up to maybe 1200 and anything over that is missing and backfiring. I did get the tps adjusted properly according to an article I found on here. Also I know that the cat can't be totally blocked because I have an exhaust leak in the back just as it curves up to go over the rear axle.
Last edited by cruiser54; Jan 6, 2015 at 10:20 PM.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Yeah sorry I do have bad Grammer. Anyways ya the line to the map sensor is a plastic one. how would I test the cat? I was planning on removing that somewhere down the line anyways. Because today I was messing with it and it'll run and rev up to maybe 1200 and anything over that is missing and backfiring. It's not like I have a problem cutting off the cat but is there anything else it can be? I me I did get the tps adjust properly a cording to an article I found on here. Also I know that the cat can't be totally blocked because I have and exhaust leak in the back just as it curves up To go over the rear axle.
And, discussion of the removal/modification of emissions equipment is strictly forbidden on this forum. I have edited your post.
Last edited by cruiser54; Jan 6, 2015 at 10:20 PM.
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
X2. For instance, remove the comma from, "I helped my uncle Jack, off a horse", ...it doesn't mean the same thing.
Aren't there apps that make those dumb things smarter? Doen' this over the internet is like trying to tie your shoes with chopsticks. Now with the "smart" gadgets, English seems like a second language, and one of the chopsticks is "bendy".
(not to pick on you nuggie, it's just frustrating)
Aren't there apps that make those dumb things smarter? Doen' this over the internet is like trying to tie your shoes with chopsticks. Now with the "smart" gadgets, English seems like a second language, and one of the chopsticks is "bendy".
(not to pick on you nuggie, it's just frustrating)