89comanchePeggy Posted May 11, 2019 Share Posted May 11, 2019 (edited) Hey everyone. So i have An 89 Jeep Comanche. 4.0 manual trans. 239,000kms. Rwd long box. I got it back from the shop shop after having my rear diff overhauled and it seems to have a lag of power when accelerating after shifting into anything but 1st and reverse. It’s like UncleBen was saying. I replaced the plugs and the wire, distributor cap and rotor, fuel filter, air filter, cleaned the idle air sensor, cleaned the ignition coil, serpentine belt, oil change, seafoamed the engine and tank and finally replaced the fuel pump. I visually Checked the relays and they look okay... its running a hell of a lot better now but I am still experiencing this lag when shifting into gears. Before it went to the shop about 1.5 months ago it was like foot to the pedal and it was pulling me. Peppy as hell and now not so much. Any ideas on what else it could be? Edited May 13, 2019 by 89comanchePeggy action correction Link to comment Share on other sites More sharing options...
benjy_26 Posted May 11, 2019 Share Posted May 11, 2019 Check your O2 sensor. Mine was acting funky on and off. I pulled mine and it was completely trashed. I threw on a used one I had kicking around and it runs like a champ now. Link to comment Share on other sites More sharing options...
Eagle Posted May 11, 2019 Share Posted May 11, 2019 Tacking this question onto a five-year old thread is confusing. I split this new question out. Link to comment Share on other sites More sharing options...
Drahcir495 Posted May 12, 2019 Share Posted May 12, 2019 I have the same issue but with the automatic. I will try replacing the O2 sensor as it needs it anyways. Link to comment Share on other sites More sharing options...
JMO413 Posted May 12, 2019 Share Posted May 12, 2019 The bell crank that runs from the throttle cable to throttle body on mine was crusty. Lubed all the pivot point and it was much better. Link to comment Share on other sites More sharing options...
89comanchePeggy Posted May 13, 2019 Author Share Posted May 13, 2019 I forgot to say that I have also replaced the O2 sensor. I will certainly check the bell crank. Today I will try rotating my relays and throwing a new one in there to see if this makes any changes. It also appear that I have the brake fluid leak that is hitting my fuse panel. I have been having my fuses just get cooked, the plastic not the actual fuses (mostly the blower motor fuse, but others have been affected minorly). Could this have something to do with this lack of power? I also am wondering if it could be the fuel pressure regulator? Link to comment Share on other sites More sharing options...
Manche757 Posted May 13, 2019 Share Posted May 13, 2019 Quick loss of power for my MJ happened when the inside of a rusted muffler collasped and blocked exhaust flow. The muffler had not been making sounds indicating it was rusted out. Link to comment Share on other sites More sharing options...
89comanchePeggy Posted May 13, 2019 Author Share Posted May 13, 2019 I know parts of my muffler are wearing out so I will certainly take a look at that! Link to comment Share on other sites More sharing options...
89comanchePeggy Posted May 13, 2019 Author Share Posted May 13, 2019 Replacing the fuel pump relay didn't seem to make a difference. I also lubed up the bell crank, again no change. Link to comment Share on other sites More sharing options...
Ωhm Posted May 13, 2019 Share Posted May 13, 2019 Check vacuum hose from intake manifold to MAP sensor for cracked, leaky conditions. O2, MAP and TPS are primary sensors used for fuel delivery. Link to comment Share on other sites More sharing options...
yxmj Posted May 14, 2019 Share Posted May 14, 2019 Check and see if you have a clogged cat..... Link to comment Share on other sites More sharing options...
89comanchePeggy Posted May 14, 2019 Author Share Posted May 14, 2019 Great, thank you! I will check the MAP to Throttle body hose today. After that I will check the cat. Will keep you posted Link to comment Share on other sites More sharing options...
89comanchePeggy Posted May 15, 2019 Author Share Posted May 15, 2019 I checked my map to throttle hose yesterday, I had snapped the line when I replaced my last fuel injector (forgot to read the part where you unplug it first...and by forgot, I just didn't) I replaced it using a section of hose and two hose corners. It doesn't seem to be leaking but I am going to a scrap yard today to grab some other parts and will see if I can find one of those as well. Checking cat today. Also is there one or two o2 sensors on the 89 4.0 comanches? I have only found one but have read/ seen pictures that imply two... After reading all about the FRAM oil filters I will be replacing the one I put in recently today as well. Link to comment Share on other sites More sharing options...
Ωhm Posted May 15, 2019 Share Posted May 15, 2019 One (1) only O2S. Link to comment Share on other sites More sharing options...
omega_rugal Posted May 15, 2019 Share Posted May 15, 2019 On 5/11/2019 at 12:59 PM, 89comanchePeggy said: Hey everyone. So i have An 89 Jeep Comanche. 4.0 manual trans. 239,000kms. Rwd long box. I got it back from the shop shop after having my rear diff overhauled and it seems to have a lag of power when accelerating after shifting into anything but 1st and reverse. It’s like UncleBen was saying. I replaced the plugs and the wire, distributor cap and rotor, fuel filter, air filter, cleaned the idle air sensor, cleaned the ignition coil, serpentine belt, oil change, seafoamed the engine and tank and finally replaced the fuel pump. I visually Checked the relays and they look okay... its running a hell of a lot better now but I am still experiencing this lag when shifting into gears. Before it went to the shop about 1.5 months ago it was like foot to the pedal and it was pulling me. Peppy as hell and now not so much. Any ideas on what else it could be? Map sensor, Tps sensor... the O2 is ignored during acceleration, the Ecu only uses it with the engine hot, during idle and cruising, at WOT it reverts to open loop Link to comment Share on other sites More sharing options...
89comanchePeggy Posted May 17, 2019 Author Share Posted May 17, 2019 I have ordered a new TPS, it will be here next week. I also cleaned my EGR yesterday, it was absolutely CAKED in carbon deposits. Also my MAP to throttle body hose definitely has a leak so I will be performing Cruiser54's hose replacement. Link to comment Share on other sites More sharing options...
Ωhm Posted May 17, 2019 Share Posted May 17, 2019 Clean the EGR and repair MAP hose then see if your back to normal. Maybe no need for a new TPS. Link to comment Share on other sites More sharing options...
89comanchePeggy Posted May 18, 2019 Author Share Posted May 18, 2019 On 5/17/2019 at 9:51 AM, Ωhm said: Clean the EGR and repair MAP hose then see if your back to normal. Maybe no need for a new TPS. Cleaned the EGR and fixed the map to throttle hose using RTV sealant. Turned out the rubber bit that went into the throttle body was lose and causing a leak. Anyway. Still didn’t fix it. With the leak cleared up it seems to have worsened. I believe it’s the tps. As when i push on the throttle rod it bogs down and almost shuts off the truck. Link to comment Share on other sites More sharing options...
DirtyComanche Posted May 18, 2019 Share Posted May 18, 2019 You can test the TPS with a multimeter. Link to comment Share on other sites More sharing options...
89comanchePeggy Posted June 28, 2019 Author Share Posted June 28, 2019 Sorry for the delayed update on this just got back from vacation. Received my new TPS. I had tried previously to remove the tps but the torx head was so stripped I wasn't able to. This time I ended up using needle nose vice pliers and removed it. As soon as I started to pull it out I noticed that the lever on it wasn't in the right position. So turns out someone had removed it and reinstalled it incorrectly which ultimately was the problem the whole time! So now I have an incredibly tuned up truck and the power is back! Thanks for all the help everyone Link to comment Share on other sites More sharing options...
Ωhm Posted June 28, 2019 Share Posted June 28, 2019 Now you're going to need to keep an eye out for traffic cops. Link to comment Share on other sites More sharing options...
Pete M Posted June 28, 2019 Share Posted June 28, 2019 yay! Link to comment Share on other sites More sharing options...
omega_rugal Posted June 29, 2019 Share Posted June 29, 2019 9 hours ago, 89comanchePeggy said: So turns out someone had removed it and reinstalled it incorrectly which ultimately was the problem the whole time! makes you want to go and kick that someone´s @$$... Link to comment Share on other sites More sharing options...
89comanchePeggy Posted August 19, 2019 Author Share Posted August 19, 2019 You are right! But now I have a spare TPS that I paid next to nothing for! Link to comment Share on other sites More sharing options...
Pete M Posted August 20, 2019 Share Posted August 20, 2019 18 hours ago, 89comanchePeggy said: You are right! But now I have a spare TPS that I paid next to nothing for! spares are never a bad thing. Link to comment Share on other sites More sharing options...
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