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General Forums => The Mess Hall => Topic started by: JJ984x4 on October 25, 2010, 10:24:35 PM
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Working on my 98 wrangler auto trans (3 spd 30rh) replacing the TCC. Finished the trans and started to fill w fluid, went to start it and run it threw the gears and it wouldn't start. Went and tried to track down the prob and she has no fuel pressure. Come to find out for some reason the fuel pump has no power going to it...? Any ideas? I have checked - it has fuel, the fuel pump fuse is good and the fuel pump relay is good. Any thing will help... Thanks
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pinched and or cut harness?
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do you have spark? did you check the other fuses? (there should also be a main fuse for the PCM)
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Checked all fueses as far as I know, the fuse block under the hood by the batt and the fuse block behind the glove box. I have looked around where I was working on the trans and have found no pinched wires. The only thing I havnt checked is to see if when I lifted it some thing got pinched. (to lift it I drove it up a ramp until the front drivers side corner was about 2 1/2 ft off the ground) and I can't imagine that that little amount of flex would kill power to the pump. I will continue on it today and keep an eye on the forum. Thanks for your thoughts
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And yes I do have spark just no power to fuel pump and the guages quit from what I can tell ( the fuel guage and voltage don't budge when I cycle the key) the oil pressure guage does move when I spin it over but that's the only guage i have seen move
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And yes I do have spark just no power to fuel pump and the guages quit from what I can tell ( the fuel guage and voltage don't budge when I cycle the key) the oil pressure guage does move when I spin it over but that's the only guage i have seen move
just another thought - check the crank sensor and make sure it's plugged in, although you shouldn't have spark if it was unplugged or out of place
see if you have power to the relay (on both the high current side as well as the command side). You can also try to jump the relay (remove the pump relay and power the pump directly) to see if it starts or not
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Have not tried jumping the relay but have sent 12 volts direct to pump and got nothing. So I will try jumping and see if there is any power at the pump connector. but If I get no power at the pump connector what exactly is between the relay and the pump and/or between the ign. Switch and relay that could be @$€#ĄŁ up?
I've got to be overlooking some thing. Thanks so far hopefully together we can figure it out W/out your ideas and thoughts I'm just about ready to give up. Also is there anything that would kill both the pump and guages at the same time???
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Have not tried jumping the relay but have sent 12 volts direct to pump and got nothing. So I will try jumping and see if there is any power at the pump connector. but If I get no power at the pump connector what exactly is between the relay and the pump and/or between the ign. Switch and relay that could be (at) $€#ĄŁ up?
I've got to be overlooking some thing. Thanks so far hopefully together we can figure it out W/out your ideas and thoughts I'm just about ready to give up. Also is there anything that would kill both the pump and guages at the same time???
a general fuse or power would cause that, but since the engine does not start it's hard to tell - not sure if the gauges are powered when you crank the engine, they might not be.
if you say you sent 12 volts to the pump and got nothing then maybe your problem is a ground. If you have good ground then maybe the pump is dead (can't see why but that can one problem)
did you look at the crank sensor to make sure is plugged in and the sensor is in place (bolted on properly)?
EDIT: have a look at the cam sensor too (at the connector i mean)
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BOth are pluged in and un touched (cam and crank) have not tested the sensors themself but can't see them just going out (but then again I can't see the PCM or fuel pump just going out while working on the trans) I have taken the day off today (spent the last 4 days 15 hrs a day on it so I needed a break) so figured I'd spend the day on the net poking around I'll return to the banging my head on the fender tomorrow. So Any ideaS will be explored tomorrow
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Skimmed this thread but if the gauge and pump aren't working, I'd suspect something with the harness going to the tank.
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Did all trans work w it still in jp no pinched wires that I have found but I Will keep looking. Thanks
Justin
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Did all trans work w it still in jp no pinched wires that I have found but I Will keep looking. Thanks
Justin
check to see if the pump relay has 12v output when you crank it - that way you'll know if it's a problem before or after that relay and go from there.
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Yeah, you're going to have to check them with a VOM. I'm gonna guess an open-circuit someplace. If you can't find a connection to tap, you can always shove a small pin through a wire to get a reading from. Like Sharp said, start at the relay and work back.
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Ok worked on it a bit today... The fuel pump fuse blows every time I cycle the key. I checked it the other day and it was fine checked it today and it's blown. The relay is good, and when I jump across the relay the pump runs great. Got a short somewhere that will have to wait till next week sometime Me and a VOM
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i had something like this happen to me !the relay pack was bad -both relays gave up their soul and corrosion in the connections as well..........
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:biggrin: so dont know what the actual prob is other than for some reason it no run. To make a long story longer I ended up doing away with the fuel pump relay. I wired a power wire from an acc fuse to the fuel pump and ran wire (w an in line fuse) to make the necessary loop for the PCM so the PCM still thinks there is a relay in there and the pump has power only when the key is switched on. Again don't have a clue what is wrong w it but it now runs. Found do grounded wires, no pinched wires, No shorts, and no bad relays. So my conclusion is what ever was wrong w it is now rigged good enough for her to run. The wife is very happy to have her jeep back and that in turn makes me very happy!!!!! :naughty: So thanks for your help guys As soon as I get a chance I will take some pics and see if I can figure out how to post them. Thanks again. Ps if any one needs help w any wiring of a TJ I think that I have the wiring diagrams permanently burnt into my brain
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I take it back... It's not fixed I drove it today about 20 miles and it popes the #11 fuse in the fuse box ( under dash). And piped every one I put in no matter weather the fuel pump relay bypass (see earlier post) was pluged in or not. I'm chasing electrical grimlens They are there and then they are gone and then they are back on a diff. Fuse The #11 fuse is for "PDC coils" what is this and how is it related to the fuel pump relay. I'm lost and need some help and to make it even worse I loaned my jp manual out
More chasing down wires Ill keep yall posted as to what I find
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I take it back... It's not fixed I drove it today about 20 miles and it popes the #11 fuse in the fuse box ( under dash). And piped every one I put in no matter weather the fuel pump relay bypass (see earlier post) was pluged in or not. I'm chasing electrical grimlens They are there and then they are gone and then they are back on a diff. Fuse The #11 fuse is for "PDC coils" what is this and how is it related to the fuel pump relay. I'm lost and need some help and to make it even worse I loaned my jp manual out
More chasing down wires Ill keep yall posted as to what I find
you're popping that fuse 'cause you skipped the relay. PDC coils I think means the Power Distribution Center coils (for the relays) and is not meant to carry the amps for the fuel pump. If you want to jump the pump then use a wire straight from battery but this is for testing and not permanent install (and if you really need to use it as an emergency fix to get home have it wired with am appropriate fuse and corresponding wire size) - you should fix the problem and not find a temporary workaround as a permanent fix (not trying to give you a lecture but you could start a fire like this).
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yep could start a fire i watched a guy do it yesterday on the trail when he tried to use a temp fix as perm. luckly they just gave out fire extingushers as a saftey bonus at work a couple weeks ago i wonder if they offer free refills since i now need one.
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I would love to fix the actual prob. But for now it's just sittin in the drive way until I have some time and some help. You are correct A temp fix will only make more problems down the road. I do have a good fire extinguisher! Haha. Hope I never have to use it
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same thing happened to me in my 97 just the other day. i was driving and it just shut off, i could not hear the fuel pump when i turned on the key so i check the fuses under the hood and all was fine i checked behind the dash all of the ones back there said nothing about fuel or anything so i figured it was a bad fuel pump. i got it back to the house with help from a good buddy and his trailer and we replaced the pump, but it did not start. i checked all of the fuses and the pdc coil fuse was blown soi replaced it and started the jeep it ran for a few minutes and blew. i did this again and it blew as soon as i put the new fuse in. i checked every connection and every wire around the jeep for signs of a crimp or a short nothing. i did a little internet research i found that the asd {auto shut down},horn,fuelpump,ac all run off of this fuse. it supplys power to the activation coil in those relays when the key is on. the asd is the confusing part because it controls the coil ,the pre heater in the o2 sensor, the distributer, and computer so that when you turn of the key it shuts down all of those funtions to kill the jeep. i unpluged every conecttion on the jeep all of them, including the computer. i then plugged them back in making sure to get them all connected tight ,saving the computer for last, then i replaced the fuse again with a new one and started the jeep. it has been running fine for a week. i am not sure what i did to correct the problem but it worked and i hope you have the same luck as i did.
good luck let me know if you find anything else as this is still a mystery to me
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I'm in the process of working on a fuel pump issue with my 97'. Sounds like I should look into a few things before I replace the pump.
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Well I know what I'm tryin next. I'll spend some time dissconecting and conecting at all points and if
it's that easy I'm gonne have to kick my self for not trying this earlier. Thanks for the info about the PDC coils and the ASD relay I'll keep you posted thanks
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could be a bad relay coil - it could short out when getting hot, so if it happens again you could remove the relays and plug them back in 1 at a time until the fuse blows to identify which one's at fault.
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jeep wont run without the asd and fuel pump relay in but you can take out the horn and the ac to see if they are the culprit
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jeep wont run without the asd and fuel pump relay in but you can take out the horn and the ac to see if they are the culprit
yeah, you're right - not sure what was i thinking...
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any updates?
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Sent it to an auto electrical specialist this morning, waiting to here back from them. Hopefully they will figure it out in a timely manner. I will let yall know what and when they find something out
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The ECU is fried.
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Did they open it up? Depending on what's actually 'fried' it might be fixable for cheap.
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They didn't say I will be asking tomorrow. What who how and all that good stuff? I'm not to good at all the elec. Stuff obv. I sent it to a shop once it got past my exp. (over my head) I'm a great tech to a certain point Rebuilding a V12 on a Jag. No problem but messing w the internals of a computer and your talkin gibberish
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The most common problem with PCM's is the capacitors going bad. New ones are like $1.
http://www.jeepforum.com/forum/f13/lazy-pcm-capacitor-replacement-how-501574/
http://www.jeepforum.com/forum/f12/crash-course-brain-surgery-replacing-capacitors-ecu-492597/
Not sure if it will fix your problems but it's worth a check.