cruiser54 Posted February 10, 2015 Share Posted February 10, 2015 Normal. Link to comment Share on other sites More sharing options...
88whitemanche Posted April 13, 2015 Author Share Posted April 13, 2015 Ok fellas... I really haven't been driving often like I liked to... But this weekend I did an hour drive to one of my buddy's place to do my axle seals.... Shut off on me twice....it's literally like a light switch! Off and on almost instantly .this was the morning and in the afternoon...drove flawless with no problems... This was Saturday. At first since I was low on fuel so I instantly thought the fuel pump could be going out... So I filled the tank up full And kept driving it...the next day sunday(today) I'm driving about 20mins In the morning no problems... I shut it off and do some stuff then drove it another 20mins to a park and it shut off on me and it didn't backfire on me because I ddint have my foot pressed down on the pedal ...I let off the throttle rolled about 10ft and boom cut on again...so I instantly knew it wasn't the pump because I had a full tank of gas.... I know it has to be an electrical problem or something... Any ideas? New- icm, coil, tps, cps, plugs, wires, cap, rotor, pump(3 years ago) , map sensor.... Have done all of cruisers renix tips, upgraded grounds and added.... I'm really just getting tired of this... I hate that it's sitting like an actual lawn ornament... Link to comment Share on other sites More sharing options...
cruiser54 Posted April 13, 2015 Share Posted April 13, 2015 Have you done Tip 27? What's your CPS output? Link to comment Share on other sites More sharing options...
88whitemanche Posted April 13, 2015 Author Share Posted April 13, 2015 Yes tip 27 has been done.... Will give you more info tuesday when I get back to the truck.... Link to comment Share on other sites More sharing options...
cruiser54 Posted April 13, 2015 Share Posted April 13, 2015 10-4 Link to comment Share on other sites More sharing options...
Eagle Posted April 13, 2015 Share Posted April 13, 2015 I suspect the oxygen sensor. The clue that jumps out at me is that the backfire occurs after you've had your foot down, and then let off the accelerator. The ECU is supposed to "see" that and reduce the fuel flow to the injectors accordingly, based on the change in oxygen ratio in the exhaust, as reported by the oxygen sensor. When O2 sensors start to get weak, the response time tends to lag. So if you have your foot down (running rich for power) and suddenly let off, the O2 sensor doesn't report the change instantly, so the injectors keep dumping gas into the cylinders. The engine can't burn it all, so some of it goes right out the exhaust. ==> Backfire. Link to comment Share on other sites More sharing options...
gogmorgo Posted April 13, 2015 Share Posted April 13, 2015 Correct me if I'm mistaken, but wouldn't the ECU be informed by the TPS when you back off the throttle? You'd get a much faster result than waiting for even a good O2 sensor to catch up, and it's what happens when you open up the throttle. Link to comment Share on other sites More sharing options...
88whitemanche Posted April 13, 2015 Author Share Posted April 13, 2015 Eagle- Tha backfiring only happens when it cuts back on and my foot is the on the pedal because I barely have time to do what my instincts tell me to do and that's to avoid an accident and get off the hwy to the side of the road.... It seems to only happen at wide open throttle on the hwy which is most of my daily driving... Link to comment Share on other sites More sharing options...
Jaime Posted April 13, 2015 Share Posted April 13, 2015 Last year I was having the same problem with my 88, only at about 35-45 mph. It ended being the ICM. I got one from the junk yard simply because I had no way of testing it and the cost was high without knowing if the old one was bad. I got it for about 3 bucks and is still working. Link to comment Share on other sites More sharing options...
88whitemanche Posted April 13, 2015 Author Share Posted April 13, 2015 Icm was replaced same time as the coil... Link to comment Share on other sites More sharing options...
88whitemanche Posted April 13, 2015 Author Share Posted April 13, 2015 Cps- .33 ac volts.... So cps needs to be replaced.... Will order one from Napa... Could this cause my light switch? Link to comment Share on other sites More sharing options...
cruiser54 Posted April 13, 2015 Share Posted April 13, 2015 Cps- .33 ac volts.... So cps needs to be replaced.... Will order one from Napa... Could this cause my light switch? Nope. Sorry. Drill the cPS mount per Tip 7 Link to comment Share on other sites More sharing options...
88whitemanche Posted April 14, 2015 Author Share Posted April 14, 2015 Ok.... So I have a question...what does the starter relay power up? Earlier today I turned the key and nothing(no click or crank nothing just dead silent) Usually when this happens I just tap the relay and it cranks up the trucks after.... Link to comment Share on other sites More sharing options...
cruiser54 Posted April 14, 2015 Share Posted April 14, 2015 Ok.... So I have a question...what does the starter relay power up? Earlier today I turned the key and nothing(no click or crank nothing just dead silent) Usually when this happens I just tap the relay and it cranks up the trucks after.... Tons of stuff!! If I were smart enough to post photos up here, I could show ya. Try scanning through my photos link below. Link to comment Share on other sites More sharing options...
88whitemanche Posted April 14, 2015 Author Share Posted April 14, 2015 Also do these 2.5s have 2 coolant temp sensors? I've replaced the one in the back of the head for the gauges and never replaced the one in the intake manifold....(if that's the other one) Does the one in the intake manifold cause problems with how the engine runs? Link to comment Share on other sites More sharing options...
cruiser54 Posted April 14, 2015 Share Posted April 14, 2015 Also do these 2.5s have 2 coolant temp sensors? I've replaced the one in the back of the head for the gauges and never replaced the one in the intake manifold....(if that's the other one) Does the one in the intake manifold cause problems with how the engine runs? The one in the intake manifold is likely an Intake air temp Sensor. Link to comment Share on other sites More sharing options...
ento45 Posted April 14, 2015 Share Posted April 14, 2015 happen to me and check coil conection on modulo Link to comment Share on other sites More sharing options...
88whitemanche Posted April 15, 2015 Author Share Posted April 15, 2015 I know about the MAT sensor because I've removed it and cleaned it.... And it's the one on top of the intake.... This one I think as per another site...says its the CTS and its in the side of the intake.... This website....idk how accurate this could be... http://m.4wdmechanix.com/?url=http%3A%2F%2Fwww.4wdmechanix.com%2FTuning-and-Troubleshooting-the-2.5L-Jeep-TBI-Four.html#2723 Link to comment Share on other sites More sharing options...
cruiser54 Posted April 15, 2015 Share Posted April 15, 2015 Could be. Link to comment Share on other sites More sharing options...
88whitemanche Posted April 25, 2015 Author Share Posted April 25, 2015 Well I did the cps mod...replace the starter relay and It gave back that old spiffy power the 2.5 has...then I Drove it this morning for over the first 30mins no Pblms After 45mins it shut off and came back on but with normal street driving this time...doing maybe 15mph(traffic/construction).... I picked up my pops to take him to the store to do groceries and halfway there it shutoff completely and didn't want to start.... I cranked and cranked then pulled out my multimeter and checked the cps- 0 ohms.... I was able to let it cool off for 20mins and it started up and now it's running flawless.... I'm going to buy a new cps from Napa and wait till it comes In because they don't have it in stock... Link to comment Share on other sites More sharing options...
88whitemanche Posted May 8, 2015 Author Share Posted May 8, 2015 So changed out the cps and its runs FLAWLESS! Wow!.....but Aslong as this problem has been happening it has to be running past 45mins.... So I let it run and run and run until it past the 45min mark and nothing happened...as soon as I shut it off and put the key in the on position so I can hear the fuel pump prime....it didn't until I turned the key the 2 Nd time....starts up perfect.... Tried it again....turn key and didn't hear the fuel pump prime...turn over to crank and it struggles to stay on like if it's missing some power to the pump.... I'm going to remove the pump and check the wiring or if not I'll order a Bosch pump.... Link to comment Share on other sites More sharing options...
88whitemanche Posted May 9, 2015 Author Share Posted May 9, 2015 Checked the wiring to the pump and everything was nice and snug.... I guess when it's starts getting hot it will fail and cool down just enough to keep running until it heats up again and fail again.... New Pump ordered...hopefully within the week I'll be installing it....if not then the following week.... Link to comment Share on other sites More sharing options...
88whitemanche Posted May 27, 2015 Author Share Posted May 27, 2015 Welp replaced the pump and it still happens... I'm at a loss fellas...idk what to do Link to comment Share on other sites More sharing options...
cruiser54 Posted May 27, 2015 Share Posted May 27, 2015 What's the spray pattern out of the injector look like? Link to comment Share on other sites More sharing options...
88whitemanche Posted May 28, 2015 Author Share Posted May 28, 2015 Will check that out Friday when I get back to the tRuck.... Link to comment Share on other sites More sharing options...
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