mj2stay Posted June 10, 2007 Share Posted June 10, 2007 86 2.5L TBI Well I broke the lines loose at the throttle body and there,s no fuel flow when the engines cranked. If I pour a little gas into the throttle body and crank it ,it runs. I can drive at all speeds fron idle to freeway speeds and and no surges or no cutting out. It runs fine untill I turn it off and try to crank it again and I,m back to square one.How do I check the fuel pump? Are there any relays to check? Link to comment Share on other sites More sharing options...
JeepcoMJ Posted June 10, 2007 Share Posted June 10, 2007 86 2.5L TBI Well I broke the lines loose at the throttle body and there,s no fuel flow when the engines cranked. If I pour a little gas into the throttle body and crank it ,it runs. I can drive at all speeds fron idle to freeway speeds and and no surges or no cutting out. It runs fine untill I turn it off and try to crank it again and I,m back to square one.How do I check the fuel pump? Are there any relays to check? that makes no sense...if you pour the gas in, it wouldn't run for long. if you're pouring the gas in and it starts and runs continuously, then the lines you broke off are probably vacuum lines and should be replaced. Link to comment Share on other sites More sharing options...
mj2stay Posted June 10, 2007 Author Share Posted June 10, 2007 Oh its the fuel lines allright metal lines,one input,one return.I broke the input loose while the motor was running and it spewed gas out.How do I go about jumping the fuel pump while it's still in the tank to see if it's in the wiring or to see if the pump is even pumping? It's as if I might be loosing the prime. Could it be that when I pour some gas in, it primes the system then it turns into a siphoning situation.I don't know! Link to comment Share on other sites More sharing options...
JeepcoMJ Posted June 11, 2007 Share Posted June 11, 2007 Oh its the fuel lines allright metal lines,one input,one return.I broke the input loose while the motor was running and it spewed gas out.How do I go about jumping the fuel pump while it's still in the tank to see if it's in the wiring or to see if the pump is even pumping? It's as if I might be loosing the prime. Could it be that when I pour some gas in, it primes the system then it turns into a siphoning situation.I don't know! re-explain the current situation in steps please. i can't decipher how you are saying this. so the input line (the bigger) for the fuel system cracked. you have replaced it yes? did you just put a clamp and rubber hose over it or actually replace the bad line? if it broke, and you didn't actually replace it, of course it's not going to work. remove your fuel line again and turn the key to the on position. the pump should turn on and build pressure. if it doesn't, then your pump is bad or the pump relay is bad. please also elaborate the driving down the road part...how are you driving it with just dumping gas down into the throttle body? that is not possible as dumping the gas down does not create enough gas to run it more than a few seconds, much less drive it. this sounds like a vacuum line problem to me...to the fuel pressure regulator. should be located near your throttle body and be a little canister with one vacuum line coming out of it. that controls the amount of current sent to the fuel pump via some other gadgets. if you half-assed the fuel line of course it isn't going to run. also, if the fuel when it was "spitting out" got on any of the throttle body sensors (in them etc.), it may cause problems too. Link to comment Share on other sites More sharing options...
mj2stay Posted June 11, 2007 Author Share Posted June 11, 2007 O.K. by "cracked" I mean that I took a wrench and loosened it while the engine was running.And, no I'm not pouring gas in the throttle body while I'm going down the road, that might make me a redneck! I swear it runs great after I pour a little gas in the throttle body just to get it to start.If I do not do the pouring gas thing, and loosen the big metal line to the throttle body and turn the key to the on position, no gas comes out. Oh yes ,I didn't allow enough gas to spew out to get everything soaked. I'll check the vacuum line and where would the fuel pump relay be located? Link to comment Share on other sites More sharing options...
offroader461 Posted June 11, 2007 Share Posted June 11, 2007 :nuts: yea I'm also way lost on whats happening?? Link to comment Share on other sites More sharing options...
mj2stay Posted June 11, 2007 Author Share Posted June 11, 2007 Well then O.K. I'm thinking fuel pump but if I could find out where the fuel pump relay is located on a 1986 2.5 litre Throttle body injection system, I could check that before I get too involved replacing the pump. Link to comment Share on other sites More sharing options...
mj2stay Posted June 11, 2007 Author Share Posted June 11, 2007 Is it just me, or is what I described that confusing? And what happened to rule #1 ? Link to comment Share on other sites More sharing options...
JeepcoMJ Posted June 11, 2007 Share Posted June 11, 2007 Well then O.K. I'm thinking fuel pump but if I could find out where the fuel pump relay is located on a 1986 2.5 litre Throttle body injection system, I could check that before I get too involved replacing the pump. if it runs after you put gas into it then it's either A. not the fuel pump, or B. the fuel pump is partially clogged and/or is putting out minimal pressure. now, I believe I am correct that the 86 had a electric fuel pump correct? the relay will be next to the fusebox or by the right front coil spring mount underneath the hood I believe. ...you could have something clogged and maybe a sensor not plugged in all the way, or something along those lines too? We ARE being friendly, but your initial statement didn't make any sense from a technical standpoint...I'm probing you for information and offering up suggestions to get you thinking of other possibilities too. tryin to help man :D Link to comment Share on other sites More sharing options...
comancheman Posted June 11, 2007 Share Posted June 11, 2007 just an idea, but maybe the fuel pump is on its way out and it doesnt make enough pressure to start the motor but is sufficient to keep it running once it has been started. Link to comment Share on other sites More sharing options...
mj2stay Posted June 11, 2007 Author Share Posted June 11, 2007 yeh,I'm thinking a bad wire connection , fuel pump relay ,or the fuel pump. I've had my Comanche since it was new in '86 and I've done just about all the repairs to it myself. Thanks for the input,I thought may be someone else may have had the same problem before.On future posts' I'll try to be more specific and detailed with my explanations and questions.Thanks again and I'll post what I find. Link to comment Share on other sites More sharing options...
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