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acts like iut has a rev limiter at 4000 rpm
Posted: October 7th, 2011, 1:30 pm
by dewjeep
i built a 4.6l stroker in the spring ran great till about a month ago.. it is acting like it has a rev limiter at 4,000 rpms will drop to 3,000 rpms and then back up to 4 but only des it driving or if i take it up slow in neutral. i have changed computer with a spare stock one, tps new, map new, o2 new, temp senser new, and crank senser is new.. lost on what else it can be... i am running a custom ground 440 lift rv cam, 30 over pistons, its a short rod stroker, 24lbs venom injectors, dynomax header and exhaust, excel coil, 8mm msd wires, and bosh platnium plus plugs... if you have any thoughts please let me know thanks..
p.s motor has tons of power till 4000 rpms till it acts like it has a low rev limiter.....
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 7th, 2011, 1:35 pm
by Missourian
It may be in your muffler or exhaust system... something may have changed resulting in increased back pressure.
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 7th, 2011, 1:35 pm
by dwg86
Distributor indexing?
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 7th, 2011, 3:29 pm
by herbiehind
fuel starvation?
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 7th, 2011, 3:51 pm
by SilverXJ
Have you checked your fuel pressure? Last two times I had a symptom like this the pump was failing. Hit 3500 RPM and it was like it had a limiter. You may have to check it while driving as well because it didn't do it stationary when I had the problem.
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 7th, 2011, 9:16 pm
by dewjeep
i have just replaced the fuel pump because it died forgot to write that on the list of things replaced and did a new fuel filter at the same time
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 8th, 2011, 4:30 am
by SilverXJ
What is your fuel pressure like? You will have to check it while driving.
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 8th, 2011, 12:42 pm
by cameraman7d
could be a cam going bad mine started doing that then would die... when it idled down.... good luck... ended up mine ate the #2 exhaust lifter...
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 8th, 2011, 1:33 pm
by dewjeep
i would hope the cam isnt bad motor is just broke in only has 4000 miles on it so far
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 8th, 2011, 1:35 pm
by dewjeep
will have to check fuel pressure yet dont have a fuel pressure tester and only get a couple days at a time home
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 13th, 2011, 4:08 am
by cameraman7d
cameraman7d wrote:could be a cam going bad mine started doing that then would die... when it idled down.... good luck... ended up mine ate the #2 exhaust lifter...
also by the time this happened i had just hit 5500 miles on my motor... was a crane cam...
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 13th, 2011, 11:07 pm
by dewjeep
fuel preasure is staying at 41 p.s.i. from idle till it hits 4000 rpm
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 14th, 2011, 1:42 am
by gradon
What year and what Jeep?
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 17th, 2011, 2:53 pm
by dewjeep
1991 jeep cherokee sport 2dr 5 speed
Re: acts like iut has a rev limiter at 4000 rpm
Posted: October 17th, 2011, 11:20 pm
by Missourian
Do you still have a catalytic converter on your XJ?
