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General Forums => The Mess Hall => Topic started by: sureshot007 on October 20, 2009, 06:42:01 PM
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I have heard that the 2.5 runs lean at high rpms. What can I do to solve this? Btw - it's TBI.
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I have heard that the 2.5 runs lean at high rpms. What can I do to solve this? Btw - it's TBI.
not sure how lean that is so depending on that you can increase you fuel pressure to compensate - best is to log the AFR on one of your runs and see what you get, increase the pressure gradually until you get the desired AFR by logging multiple runs. I use innovate lc-1 and an ssi-4 to log my map, tps, rpm and afr readings.
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How do I adjust the pressure regulator? I have an LC1 I can use to check the afr - I just have much more experience with mpfi and ecu tuning.
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How do I adjust the pressure regulator? I have an LC1 I can use to check the afr - I just have much more experience with mpfi and ecu tuning.
same here (more knowledge on mpi) but the idea is the same - you'll need an adjustable regulator that goes instead of your stock one - but as far as details on your TBI i have no idea so you'll have to do some research. so what does your lc-1 show as far as AFR? what's is it from max to min (lean to rich) range?
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How do I adjust the pressure regulator? I have an LC1 I can use to check the afr - I just have much more experience with mpfi and ecu tuning.
the stock FPR is supposed to be adjustable take a look at the link... page 6 and 7
http://jeepgarage.free.fr/OWN/fuel%20injection%20system%20tbi.pdf
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the stock FPR is supposed to be adjustable take a look at the link... page 6 and 7
http://jeepgarage.free.fr/OWN/fuel%20injection%20system%20tbi.pdf
great link :clap:
sureshot, that means you're good to go, would be easy to increase your fuel w/o any mods, make sure you don't go too high though - you can in fact calculate the target pressure based on your target afr and current afr and fuel pressure (based on the pdf chadrc posted it is 14.5psi at stock setting).
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That is PERFECT! Thank you!
As for my afr, I haven't hooked it up to the chief yet. I need to do some engine work before I even bother with it. It's a winter project so it's going to be a little time before i have some updates with pics.
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hate to bust bubbles, but i too have been down that road with my 2.5 TBI and and its a headache! the regulator adjusting screw has been covered with a pressed in piece of pot metal, i had no success of getting it out, what i had to do is drill a hole straight through and tap some threads and use a bolt to make it adjustable. however even though i increased pressure i think my more noticeable gains was from swapping in a higher flow GM injector. but even then the ecu is still gonna control the amount of fuel by adjusting the pulses sent to the injector. the best thing would be to reprogram ecu, but thats not possible (as far as i could research) with this renix TBI system. but then again i was talking to the guy at clifford performance and he said there was a guy in cali that could reprogram this ecu, but id have to drive it to cali and that was just far of a trip for this jeep. u may think about relocating the intake manifold temp sensor and see how that plays out. either way this TBI system is junk!! ive heard many people just swap it to a carb and have loved the results. something else to consider.
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It would not be hard to put the MPI off a Cherokee/Wrangler 2.5 in the truck, 99% of the harness is in the engine compartment.
Dodge Dakota 2wd trucks also had the MPI as I recall.
Dave