Topic: Stttuer between 3 and 4K RPM's - HELP!

[jfrabat]

OK, guys, I need your opinion before I open anything up...  My Jeep came back to Panama from Costa Rica a week ago, and it was working just fine.  Ths week I came back to Panama, and I got a sort of lack of power some times, and a stutter other times when the revs get between 3,000 and 4,000 RPMs (sometimes is closer to 3,000, other times it happens at about 3,500 and others closer to 4,000).

My current main suspect is (as it was a couple of weeks ago), the distributor cap and the rotor.  I have a spare in my Jeep, so I can easily swap them out (other than the fact that I have to do it the cheap tools and a poor selection, but given the ease of the work, it can be done), but I wanted your opinion as to wether you agree with my diagnostics or not.  I dont want to take it to the shop because that would mean being without transportation for a while...

Felipe

[sharpxmen]

OK, guys, I need your opinion before I open anything up...  My Jeep came back to Panama from Costa Rica a week ago, and it was working just fine.  Ths week I came back to Panama, and I got a sort of lack of power some times, and a stutter other times when the revs get between 3,000 and 4,000 RPMs (sometimes is closer to 3,000, other times it happens at about 3,500 and others closer to 4,000).

My current main suspect is (as it was a couple of weeks ago), the distributor cap and the rotor.  I have a spare in my Jeep, so I can easily swap them out (other than the fact that I have to do it the cheap tools and a poor selection, but given the ease of the work, it can be done), but I wanted your opinion as to wether you agree with my diagnostics or not.  I dont want to take it to the shop because that would mean being without transportation for a while...

Felipe

shot in the dark but i remember you mentioned having the stock coil but the plug gap was left as recommended for the PD Daemon coil, just thought i'd mention it in case you didn't make the change back to stock gap yet

the other thing i can think of is the tps, but hard to tell if that is it without a code.

[jfrabat]

shot in the dark but i remember you mentioned having the stock coil but the plug gap was left as recommended for the PD Daemon coil, just thought i'd mention it in case you didn't make the change back to stock gap yet

the other thing i can think of is the tps, but hard to tell if that is it without a code.

OK, first off, I will re-reply, as I had already replied, but it seems the message got deleted (I even got a confirmation e-mail saying Art had replied, but that seems to be gone as well).

I did leave the plugs gapped at .050", but it was running fine all the way from San José to Panama (almost 600 miles).  It is also doing its thing only after it warms up (makes the coil a suspect, I would say).  But it is NOT throwing a CEL at all (have not checked codes, but I figured a Crank or Cam position sensor would throw a CEL at least - although, now that I think about it, last time my cam position sensor went out, it did not throw a code).  Before I left San José, I read the codes, and the only one I got was coolant temperature too low (engine was up to operating temp).

I took the Jeep to the shop this morning, but they said to bring it by tomorrow, as they would not be able to touch my rig until tomorrow.  Since I have plugs, coils (I got 3 of them in the Jeep!), rotor and cap (brand new), I will just ask them to swap everyting out while I am at work.  I will also take the oportunity to have them change out my oil pressure sending unit (which keeps dying on me!) and check both the KC daylighter long range lamps and slimlite fog lights (one lamp of each is acting up; the slimlights have issues with the cables on the rear, as if you move them, they come on; the daylighters I feel is a ground issue, as the sme thing happened to the same lamp last time).  I will also have them check the fuel pressure as well while they are at it, just to rule out the pump as the culprit...

[jfrabat]

Judging by the fact that my exhaust sounds like a rattle can, that the problem has now gone away, and by the fact that it happened before only when the engine got hot, I suspect I have officially killed my second cat.  In any case, I took the Jeep to the shop today, and asked them to just remove the cat and put a pre-muffler there instead (something that uses glass pack; I dont want any restrictions there).  That'll be one less thing I need to worry about from now on. 

And for the ecologists out there, keep in mind that half the year this Jeep stays in Panama and is not driven, and the other half, when it is in Costa Rica, it is not driven more than 100 miles, as it is NOT my daily driver.  Plus, we dont have any emissions inspections in Panama...  Which also helps!

I also asked them to change out the plugs (I'll keep the gapped ones as spares), change the oil, change the oil pressure sending unit (once AGAIN it died on me), and fix the lights...

Felipe

[jfrabat]

Well I just got back from the shop.  I am not 100% sure, but for SOME reason, I THINK the problem was in fact the cat...  I still got all the other stuff done (new plugs gapped at .035", swapped out the coil, and got otherminor stuff fixed like the lights, horn and oil pressure sending unit), but I also ended up taking out the cat.  Since there was not any resonators or pre-mufflers that I liked (as in no restrictions), I just went with a straight pipe.  The Jeep is now a bt lowder, but inside the cab it is not SO much noticeable (it is if you are standing outside, though).  As far as revving, it revs faster above 3,000 rpm, but just a tad.

Felipe

PS: Here is the reason I THINK it was the cat:

[sharpxmen]

Well I just got back from the shop.  I am not 100% sure, but for SOME reason, I THINK the problem was in fact the cat...  I still got all the other stuff done (new plugs gapped at .035", swapped out the coil, and got otherminor stuff fixed like the lights, horn and oil pressure sending unit), but I also ended up taking out the cat.  Since there was not any resonators or pre-mufflers that I liked (as in no restrictions), I just went with a straight pipe.  The Jeep is now a bt lowder, but inside the cab it is not SO much noticeable (it is if you are standing outside, though).  As far as revving, it revs faster above 3,000 rpm, but just a tad.

Felipe

PS: Here is the reason I THINK it was the cat:

all that missing honeycomb could have ended up in the muffler, did they check that?

[jfrabat]

It's not there...  The thing that worries me is WHY this happened.  This is the third cat on this rig.  The first one was the one that the rig came with, and I swapped it out with a regular cat, which I killed when my coil died on me (apparently, there was some gas getting to the cat, and igniting on contact; at least, that's what it sounded like).  This cat survived 3 tries with the PD coil (same situation that killed the previous cat), so it is possible that this is what killed it.  I also suspect that since the cat was not originally welded in place, some water from the trail could have gotten in and clogged it.  About a year ago, the cat came off the pipe (maybe it was already getting clogged up?) and this is when I welded it into place...  I am just happy I changed out the O2 sensor before the trip to Panama, because I would suspect it was in a similar state as the cat...