johnr Posted February 21, 2012 Share Posted February 21, 2012 the engin just started ruuning really bad like its not getting enough gas. and it has no power can almost not get it moving and once i do it will not go over 35 mpg. this happend pretty much all at once. left the house stopped of at a freinds house and on the way home it all went to hell. any ideas what to look at first? Link to comment Share on other sites More sharing options...
jimoshel Posted February 21, 2012 Share Posted February 21, 2012 Clogged, dirty fuel filter. Fuel pump going bad, Rubber hose connecting filter to pump disintegrating. Link to comment Share on other sites More sharing options...
airspeed Posted February 21, 2012 Share Posted February 21, 2012 Will the engine idle properly? Has the fuel filter been changed recently? I had two spark plug wires short together and the truck would idle with a little bit of a miss but you couldn't get the truck to do over 30 mph. This happened out of the blue, it was fine until I parked it for 30 minutes, came out to go and it wouldn't. Once those wires burn through they will continue to arch. When you get two cylinders out of four cross firing, you have a severe loss of power. Separate them with some insulators and see if it goes away. It could be carbon tracks inside the cap? I'm just throwing some ideas out here... Link to comment Share on other sites More sharing options...
johnr Posted February 21, 2012 Author Share Posted February 21, 2012 all great things to look for thanks. i can tell you that filter only has about 2000 miles on it and the rubber lines are new. i dose not idle as it should . it used to idle around 800 or so its now down around 300 or 400. ill check the plug wires tomorrow but they have just as many miles as the filter. this just aint fair i was coming home from getting my new wheels mounted and then this. maybe shes having withdraws. Link to comment Share on other sites More sharing options...
pitbull4x4 Posted February 21, 2012 Share Posted February 21, 2012 My 89 2.5 ran like s#$%. It took $40 in gas to go 80 miles. I looked and could not find anything. Took it to a MOM and DAD shop that does work that I can not handle at home. Come to find out it was the hose going to the map sensor. Link to comment Share on other sites More sharing options...
airspeed Posted February 21, 2012 Share Posted February 21, 2012 EGR valve? You can do a quick check by pushing up on the diaphragm from the bottom side of the valve while the engine is running. Don't burn yourself! Link to comment Share on other sites More sharing options...
johnr Posted February 22, 2012 Author Share Posted February 22, 2012 anyone know what the fuel pressure is suppose to be on this its TBI. Link to comment Share on other sites More sharing options...
airspeed Posted February 22, 2012 Share Posted February 22, 2012 ~14-17psi Link to comment Share on other sites More sharing options...
cruiser54 Posted February 22, 2012 Share Posted February 22, 2012 What about those 3 or so vacuum lines at the throttle body that always crack and split? Good point above about making sure the MAP sensor line is perfect, no splits, cracks, not melted, you can blow through it? Link to comment Share on other sites More sharing options...
johnr Posted February 22, 2012 Author Share Posted February 22, 2012 can some one direct me to a diagram of where the MAP is located I'm sure theres one on here somewhere Link to comment Share on other sites More sharing options...
cruiser54 Posted February 22, 2012 Share Posted February 22, 2012 can some one direct me to a diagram of where the MAP is located I'm sure theres one on here somewhere Should be mounted on the center of the firewall behind the engine. A 3 wire plug and a vacuum hose going to it. Link to comment Share on other sites More sharing options...
johnr Posted February 23, 2012 Author Share Posted February 23, 2012 well I'm not seeing any of the obvouis things and i was planing on replacing sensors anyhow just due to age. i will start with the TBS mostly because i had some of the same problems on my XJ and that was it. although I'm not quite clear on how to adjust it once its on the motor. there is no room to to work plus just how do you get the muti meter probs into the plug. as i was looking around i was trying to see if i could get any codes to come up when i relized i don't think my check engin light even works. it dose not flash when i turn the key not sure if thats a realy bad sign or not. anyone? Link to comment Share on other sites More sharing options...
cruiser54 Posted February 23, 2012 Share Posted February 23, 2012 First off, no check engine light on Renix Jeeps. Secondly, you probe the connectors from the back side of the plug. Link to comment Share on other sites More sharing options...
johnr Posted February 26, 2012 Author Share Posted February 26, 2012 Clogged, dirty fuel filter. Fuel pump going bad, Rubber hose connecting filter to pump disintegrating. :doh: 4" of rubber hose. the only hose i did not replace because i did not know it was even there. it conects the pump to the outside tube ports on the sending unit. seems i was only running at about 7 psi due to the fact that this pice of hose was more like a siv Link to comment Share on other sites More sharing options...
airspeed Posted February 26, 2012 Share Posted February 26, 2012 Help me understand which hose we are talking about... Is this inside the fuel tank? Link to comment Share on other sites More sharing options...
cruiser54 Posted February 26, 2012 Share Posted February 26, 2012 Help me understand which hose we are talking about... Is this inside the fuel tank? Yes, it is. Link to comment Share on other sites More sharing options...
johnr Posted February 27, 2012 Author Share Posted February 27, 2012 yes its in the tank. and although i was able to get the sending unit out with the tank in place i was not as lucky at getting it back in. the return tube slips into a rubber bushing inside the tank. I'm guessing to keep the sending unit stable. in order for me to see where it went i needed to take the tank out. anyhow i got it all put back together and its as good as new. since i was in there i put in a new pump. i still need to check the adjustment on the TPS i installed the other day though. anyhow I'm happy all is good and my truck is working again :banana: Link to comment Share on other sites More sharing options...
johnr Posted March 1, 2012 Author Share Posted March 1, 2012 well i just got back from the test drive after making the adjustment to the TPS. i must admit the i realy did not think it was worth the time consitering i could not figure out how to get the muti meter probes inside the back of the plug with out taking the TB off the intake. but then i found two 2" long sewing needles the my wife won't miss :clapping: . i stuck them in the back side of the plug and was able clamp on these to get readings. the coarse adustment did not change no mater what i did. but i was able to make the adjustment on the fine adj. i was able to dial it in right in the middle. i got it tightened down and reconeted the fuel line. ( oh yeah i needed to disconect both of the fuel lines to access the back side of the TB & don't forget to pull the fuel pump relay) anyhow its worth it, it seems to be a 10% to 12% increas in throttle responce over just slaping it on. plus for an old timer it makes you feel good to be able to adjust something :cheers: . below are a few picks of the bad fuel line in the tank and the sewing needles stuck in the plug Link to comment Share on other sites More sharing options...
njcomanche1227 Posted March 3, 2012 Share Posted March 3, 2012 ive actually just fixed a similar problem like this in my 87 2.5l, check your distributor cap and rotor what happened with mine was the cap was letting in moisture and rusted my rotor so the spark was jumping between the plugs and it ran like $#!&. just a suggestion Link to comment Share on other sites More sharing options...
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