88mjgilley Posted February 23, 2013 Author Share Posted February 23, 2013 Cruiser i really don't know what else to do lol i normally can fix a 4.0 just by hearing it, but with this i can't figure it out at all if the O2 sensor doesn't fix it I'm going to swap computers with a buddie. if its still the same it will be getting a head gasket and possibly a new head Link to comment Share on other sites More sharing options...
88mjgilley Posted February 23, 2013 Author Share Posted February 23, 2013 and i will check the wires but i have been under the dash quite a few times and never noticed anything Link to comment Share on other sites More sharing options...
mountainman Posted February 24, 2013 Share Posted February 24, 2013 Well hell, head gasket and new head won't fix this. Unless your leak down test shows severe leakdown on any one cyl, then MAYBE. But I'm going with all thats been said, its something simple and likely electrical. Patience and you will find it. But i wouldnt buy another part till you do. As you have already proven to yourself, none of the parts you put on were needed. keep all your old ones for trail spares. Link to comment Share on other sites More sharing options...
mountainman Posted February 24, 2013 Share Posted February 24, 2013 Looked back at original post. It sounds like a lean issue. I would put a fuel pressure gauge on it and run it to the windshield. Now drive and when it acts up, watch the gauge. That is what i would do if I were starting out at square one with your truck. If it helps, ive been a master ASE technician since about 1995, specializing in driveability and diagnosis. I still do this as my business daily. I don't put on a single part till i know which one is causing the problem. Again, not tooting my horn at all just letting you know I'm not some forum newb whos 16 and had one vehicle, trying to give you advice. ;) There are some very seasoned techs on here and most of them have been with this truck for YEARS. so i just agree with them as i have only had my manch ONE year. The amount of REAL knowledge on here is far higher than on most standard car forums. Link to comment Share on other sites More sharing options...
88mjgilley Posted February 24, 2013 Author Share Posted February 24, 2013 ok well i made a fuel gage long enough to reach to the wipers and took it for a drive. Before it starts running like crap the pressure is perfect. Once it starts it drops like crazy it starts running terriable around 27psi. and if i keep my foot in it long enough it will drop to 7-8psi. After i let off it will slowly return to the mid 30s. So now to figure out whats going on. Also it has been shut off for around 20-30 minutes and its still at 38psi. so its not leaking down. New fuel pump, strainer, and the filter only has around 1500 miles on it. Link to comment Share on other sites More sharing options...
mountainman Posted February 24, 2013 Share Posted February 24, 2013 Issues with voltage to the pump?. May have to hook a multimeter up to the pump connection and drive with someone watching that. See if voltage begins to drop coinciding with the pressure drop. And verify the ground is perfect. Youre gettin close! Link to comment Share on other sites More sharing options...
88mjgilley Posted February 24, 2013 Author Share Posted February 24, 2013 i grounded the pump within a foot of the plug and also ran a hot wire to a switch and then to the pum directly to eliminate that right off the bat today Link to comment Share on other sites More sharing options...
mountainman Posted February 24, 2013 Share Posted February 24, 2013 hmmmm. And the fuel filter is new? may be collapsing inside, that would explain some of the odd stuff going on. Link to comment Share on other sites More sharing options...
cruiser54 Posted February 24, 2013 Share Posted February 24, 2013 Airtex pump? Hoses inside the tank to the pump get replaced with the pump? Link to comment Share on other sites More sharing options...
ComancheKid45 Posted February 24, 2013 Share Posted February 24, 2013 Even if the hoses were replaced between the pump and the sending unit, both clamps need to be fairly tight.....if you do end up pulling the assembly back out of the tank, make sure to check the connections. ;) Link to comment Share on other sites More sharing options...
Jaime Posted February 24, 2013 Share Posted February 24, 2013 About a year ago I had a similar problem and replaced a lot of parts unnecessarily. It ended up being the rubber hose at the fuel filter. When cold it ran fine but once the day warmed up the road, the hose would collapse and make the truck run like crap. The odd thing about it was that the hose was solid except for one spot that was against the frame. I don't know if this is your problem but worth a try. Also check the hose that goes from steel pipe to the fuel rail. Link to comment Share on other sites More sharing options...
88mjgilley Posted February 25, 2013 Author Share Posted February 25, 2013 figured it out rust in the dang fuel tank Link to comment Share on other sites More sharing options...
cruiser54 Posted February 25, 2013 Share Posted February 25, 2013 Thanks for reporting back. Whaddya gonna do? Link to comment Share on other sites More sharing options...
88mjgilley Posted February 25, 2013 Author Share Posted February 25, 2013 power washed it, dried it, and used a shopvac to get the rest of the junk out. Also went and bought a bosch pump and filter. She is back on the road again Link to comment Share on other sites More sharing options...
cruiser54 Posted February 25, 2013 Share Posted February 25, 2013 Cool. Was the original replacement pump an Airtex? Link to comment Share on other sites More sharing options...
mountainman Posted February 25, 2013 Share Posted February 25, 2013 yay! Link to comment Share on other sites More sharing options...
Exgrayxj Posted February 25, 2013 Share Posted February 25, 2013 Cool. Was the original replacement pump an Airtex? Just curious, why does the airtex pump seem to get no love here? I needed a sender/pump assembly, and airtex was what I found. So far (couple thousand miles) all seems well ... although I do have this 100-150 rpm idle gallop ... Link to comment Share on other sites More sharing options...
cruiser54 Posted February 25, 2013 Share Posted February 25, 2013 Airtex sucks. Period. Link to comment Share on other sites More sharing options...
88mjgilley Posted February 25, 2013 Author Share Posted February 25, 2013 the quality of the Bosch is worth the money. The one i originally put in it was a el cheapo from rockauto. 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