Kingman Posted December 15, 2008 Author Share Posted December 15, 2008 My buddy had a car, and it started doing this and it turned out to be the fuel pump, and it took a week to order the part, and he needed the car, so he would lightly tap on the access door under his rear seat with a hammer. I guess for him it wore out to the point where the pump would stick. I am NOT suggesting you hit your truck with a hammer! Grandpa's JGC does the same thing when it's really cold out. Been doing it like that for years now Link to comment Share on other sites More sharing options...
Kingman Posted December 15, 2008 Author Share Posted December 15, 2008 thats exactly what minw did try disconneting your coolant tempurature sensor I have a whole thread about my experience with that stupid sensor. What this is doing is much different than what happened when my sensor went out. Link to comment Share on other sites More sharing options...
Kingman Posted December 15, 2008 Author Share Posted December 15, 2008 Drove it to school today, didn't act up. Thermostat froze shut though, overheated within a few miles. Then finally opened up and I could get to school. I forgot to replace the water I had put in the radiator when I replaced that bypass hose not too long ago. Whoops! Strangely, didn't act up at all.... Link to comment Share on other sites More sharing options...
Huck Posted December 16, 2008 Share Posted December 16, 2008 I'm pretty sure if there was something wrong with a sensor, it would spit out a code. The Pressure Regulator however, is vacuum controlled. It doesn't have anything to do with the computer. It can make the system create too much or not enough fuel pressure. It's a pain in the (insert body part here) to work on because it's on the back side of the Plenum. Here's a link to napaonline.com for the part I think you need. I think you can test your regulator with a vacuum pump. Link to comment Share on other sites More sharing options...
Kingman Posted December 16, 2008 Author Share Posted December 16, 2008 I'm pretty sure if there was something wrong with a sensor, it would spit out a code. The Pressure Regulator however, is vacuum controlled. It doesn't have anything to do with the computer. It can make the system create too much or not enough fuel pressure. It's a pain in the (insert body part here) to work on because it's on the back side of the Plenum. Here's a link to napaonline.com for the part I think you need. I think you can test your regulator with a vacuum pump. Did a lot of driving today, didn't act up once. We'll see how long it stays like this... I don't even know what the Plenum is? Link to comment Share on other sites More sharing options...
Kingman Posted December 17, 2008 Author Share Posted December 17, 2008 And still nothing today... Link to comment Share on other sites More sharing options...
91PathSE Posted December 17, 2008 Share Posted December 17, 2008 I didnt read the whole thread, to see if this was covered. But it sounds like fuel pump...which this actually just happened to me...replaced the pump and it was fine. Link to comment Share on other sites More sharing options...
Kingman Posted December 17, 2008 Author Share Posted December 17, 2008 I didnt read the whole thread, to see if this was covered. But it sounds like fuel pump...which this actually just happened to me...replaced the pump and it was fine. It does, but I couldl hear it going loud and strong when it was acting up. Could you hear yours as well? Link to comment Share on other sites More sharing options...
BowTied Posted December 17, 2008 Share Posted December 17, 2008 Hearing the pump operate does guarantee proper pressure. Link to comment Share on other sites More sharing options...
88pathoffroad Posted December 17, 2008 Share Posted December 17, 2008 True. Your fuel pressure regulator should be next to the fuel filter. (he has the VG30i, not the VG30E) To be honest, these problems sound like either an injector problem or the MAF not working right. I dunno why it works fine in park tho. Weird problem. Link to comment Share on other sites More sharing options...
Kingman Posted December 17, 2008 Author Share Posted December 17, 2008 (edited) True. Your fuel pressure regulator should be next to the fuel filter. (he has the VG30i, not the VG30E) To be honest, these problems sound like either an injector problem or the MAF not working right. I dunno why it works fine in park tho. Weird problem. I hope it's not the injectors. If it starts acting up again, I want to raise the idle from 800 in drive to 1200 and see if that changes anything, and continue raising the rpms until it stops sputtering or dieing if 1200 isn't enough (idles at 1300rpm in park). Then wouldn't it just be a matter of air supply or the amount of fuel it's getting? I think if this, because the Classic Cherokees with the 4.0 have a pretty common problem of idling like crap and very long start times after sitting due to a the fuel pump getting weak, and the fuel pressure regulator. My mom's is suffering from one of these. At low rpm's, doesn't run so hot, but when you hit the gas, the pump picks back up and supplies sufficient pressure to run the engine. Edited December 17, 2008 by kingman92010 Link to comment Share on other sites More sharing options...
Kingman Posted December 17, 2008 Author Share Posted December 17, 2008 Hearing the pump operate does guarantee proper pressure. I thought about that after I posted Link to comment Share on other sites More sharing options...
Simon Posted December 17, 2008 Share Posted December 17, 2008 idling at 1300rpms in park is WAY too high... Should be about 750rpms Link to comment Share on other sites More sharing options...
Kingman Posted December 17, 2008 Author Share Posted December 17, 2008 idling at 1300rpms in park is WAY too high... Should be about 750rpms Once again, I put it there Link to comment Share on other sites More sharing options...
Simon Posted December 17, 2008 Share Posted December 17, 2008 Once again, I put it there Right....I knew I read that, but forgot about it. There's definitely an issue if you can't have the truck running at proper idle. If it were me, I'd set it back where it should be, so I could at least start as close to "baseline" as possible. Link to comment Share on other sites More sharing options...
Kingman Posted December 17, 2008 Author Share Posted December 17, 2008 Right....I knew I read that, but forgot about it. There's definitely an issue if you can't have the truck running at proper idle. If it were me, I'd set it back where it should be, so I could at least start as close to "baseline" as possible. I've had the idle set higher for months now, in case you're thinking I just did it because it's acting up. It idles at 800 in drive, so that's pretty baseline right? The rpms themselves that is, regardless of the tranny position. It's also very hard for me to even get a solid rpm, because I think there's some sensor that's going nuts with it, when I set it to its lowest, sometimes it will idle at 400rpm, and then jump to 700rpm in drive, and then back down...I have a thread about that as well. But right now it's running fine, I'm not going to touch a single thing until it acts up again on its own. Link to comment Share on other sites More sharing options...
Simon Posted December 17, 2008 Share Posted December 17, 2008 I've had the idle set higher for months now, in case you're thinking I just did it because it's acting up. It idles at 800 in drive, so that's pretty baseline right? The rpms themselves that is, regardless of the tranny position. It's also very hard for me to even get a solid rpm, because I think there's some sensor that's going nuts with it, when I set it to its lowest, sometimes it will idle at 400rpm, and then jump to 700rpm in drive, and then back down...I have a thread about that as well. But right now it's running fine, I'm not going to touch a single thing until it acts up again on its own. The thing is, your idle shouldn't drop 500rpms just because you're in drive. Something's wrong there. Mine drops MAYBE 50rpms when I shift into D. I hear what you're saying about upping it, and it makes sense, to keep it running until you figure this out, but I think that, at least while you're trying certain fixes, you should lower it to 750. Sounds to me like the MAF sensor causing your idle issues. Link to comment Share on other sites More sharing options...
Kingman Posted December 17, 2008 Author Share Posted December 17, 2008 The thing is, your idle shouldn't drop 500rpms just because you're in drive. Something's wrong there. Mine drops MAYBE 50rpms when I shift into D. I hear what you're saying about upping it, and it makes sense, to keep it running until you figure this out, but I think that, at least while you're trying certain fixes, you should lower it to 750. Sounds to me like the MAF sensor causing your idle issues. Taking a closer look at it, it's idling at 1150 in park, not 1300. I misread the number of lines Sorry about that... Link to comment Share on other sites More sharing options...
91PathSE Posted December 17, 2008 Share Posted December 17, 2008 Yes my fuel pump only killed the motor when in gear...it wasnt getting enough fuel to keep it going...but when in park/nuetral it was fine..Not sure why...My boss and the other mechanic I work with couldnt even figure it out. Link to comment Share on other sites More sharing options...
Kingman Posted December 17, 2008 Author Share Posted December 17, 2008 Yes my fuel pump only killed the motor when in gear...it wasnt getting enough fuel to keep it going...but when in park/nuetral it was fine..Not sure why...My boss and the other mechanic I work with couldnt even figure it out. Sounds like mine... How much was the pump and where did you get it at? Link to comment Share on other sites More sharing options...
Huck Posted December 17, 2008 Share Posted December 17, 2008 How much was the pump and where did you get it at? Here's what NAPA has. In case you couldn't tell, I really like NAPA. Link to comment Share on other sites More sharing options...
91PathSE Posted December 18, 2008 Share Posted December 18, 2008 I got mine from work...It only cost me $65....I would buy from napa or parts international...thats who we deal with at my shop and they are both great. But napa is the best. Link to comment Share on other sites More sharing options...
BowTied Posted December 18, 2008 Share Posted December 18, 2008 Hearing the pump operate does guarantee proper pressure. I meant to type does NOT ... if the pump is running the pressure regulator may not necessarily be doing it's job. Now, that is what I was thinking when I mistyped. Now I see some agree with what I mistakenly typed, so likely I am now wrong (right by accident initially)....??? I have heard of a failed regulator being the problem with other vehicles and thought it fit the symptoms here a bit. Link to comment Share on other sites More sharing options...
Kingman Posted December 18, 2008 Author Share Posted December 18, 2008 I meant to type does NOT ... if the pump is running the pressure regulator may not necessarily be doing it's job. Now, that is what I was thinking when I mistyped. Now I see some agree with what I mistakenly typed, so likely I am now wrong (right by accident initially)....??? I have heard of a failed regulator being the problem with other vehicles and thought it fit the symptoms here a bit. lol, it didn't register that NOT wasn't in that sentence until you just pointed it out. Link to comment Share on other sites More sharing options...
BowTied Posted December 18, 2008 Share Posted December 18, 2008 lol, it didn't register that NOT wasn't in that sentence until you just pointed it out. So I typed it wrong and everyone read it the way I meant to type it? LOL that is funny. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now