Join Date: Aug 2005
Location: , Alabama
Intermittent no start, open throttle, it starts
99 WJ limited, 4.0 2wd.
I have had this jeep for a little over two years now without a hitch. A week ago my girlfriend calls me around lunch and says it wont start. I get home that afternoon and look it over. I dont see anything under the hood that out of place. I try to crank and it wont start. So I start simple, check for fuel. I hook my test guage to the rail and I get pressure, so I'm getting fuel. I pull the coil pack and check the plugs, they smell of gas, but the gas doesnt smell all that great. I think, maybey bad gas or water in the fuel. I unhook the fuel line from the fuel rail and put it in a bottle and let it pump a little out. No water, still smells a little odd, but not real bad. So I am starting to think maybe spark. I replaced the CPS with a mopar a few months after I bought it. I replaced the trans and messed up the old sensor when I put it back in, so I had to buy new.
So I thinnk maybe the cam sensor. I have a spare, put it on and try to start. It kinda spits a little, so I figured it was flooded and opened the throttle a bit to help clear it. It starts and take a little bit of feathering the throttle for a few seconds before it would idle. I drove it around and it seems to run ok. So I figured it was that cam sensor.
It runs fine for a couple days, then the GF comes to see me at work for lunch, when se goes to leave, it wont start again. I go out, try it myself and no start. For some reason I tried opening the throttle a bit and it sputters to life and then seems to run ok. I tell her to go straight home. She gets home no problem. I hook up the fuel test guage again and start it, fuel pressure is good. I go back to suspecting the fuel again. I let it set for a couple days untill last weekend. I bring home some 5 gal buckets and drain all the fuel from the tank, change the fuel filter, added some fresh fuel from a can, get it started, go to the gas station and fill it up with fresh fuel. After I fill it up, it still doesnt want to start without opening the throttle a bit. I go back home and start thinking. I think, well, if I have to open the throttle a bit to get it to start, maybe the IAC is being slow or not working. I swap it out with a spare that I have. I try it and it fired up like new. I let it set for about half a hour, try it again, starts fine. I drive it a few places sunday and no problems. My GF drives it all this week with no problems at all starting untill today. She goes to get in it to come see me at lunch (had not been started since that time yesterday) and it wont start again. I get home this afternoon and try it. Same deal as before. Wont start unless I open the throttle a little, and have to hold it open for a few seconds before it will idle, otherwise it dies. I put my fuel pressure guage back on it, fuel pressure is still good, it holds about 53 psi. I drive it a bit and it seems to run ok, but now it seems to want to surge a tiny bit if I get on it. I am listening for anything that sounds like vaccum leaks, I spray intake and TB with carb cleaner looking for vac leaks. I find none. I swap out the MAP with a spare I have and no change. I do the key trick and check for trouble codes, there are none, check engine light does not come on when driving.
I'm starting to run out of ideas on what it could be. It has been rock solid dependable and no issues with the engine since I have had it, now all the sudden I get this. Anyone have any suggestions?
'93 YJ 4.0L, AX-15, NP-231HD/SYE, 8.8in rear, OME 2.5 lift, WJ knuckle/brake conversion, hydroboost. Warn M10000 winch. Hope to some day build a stroker for it.
'79 Cherokee Chief, 401 MPFI fuel injection, T-18/D-20 and hydroboost. Otherwise stock.
Future mods: NV4500, NP205, high pinion D60 front and smooth bottom D60 rear, e-lockers front & rear. SOA with 35X12.50's