98'Jeep Cherokee XJ - Won't Start The first time, but always starts the second????
My girlfriend has a 1998 Jeep Cherokee XJ with the straight 6 engine. When it is cold, or has been sitting for a few hours after driving, we will get in it, and turn the key and the engine will be turning over, like a normal start, and everything seems to be working fine, but the engine won't start. After letting it do that for a few seconds she will stop, turn the key back, and then start the car up, and it will turn over ans start up immediately. I don't really think it could be the started, since it is turning the engine over fine, and I can't hear any noises out of the ordinary what soever (I have a 2006 wrangler with the same straight 6, even though hers has the older distributor). Is this a fuel problem? Fuel pump? something that needs tweaked? It has about 156,000 miles on it, and it otherwise is an awesome car. Any hints on what to check? what needs replaced? How to do it? I would love to get it fixed! I am replacing the evaporator/hearter core in another week, so it would be nice to just take the whole weekend and do everything. Please post/send any hints/tips, and I would especially love photos or write ups on how to solve this!!!!
lowicz95: when you say "prime the fule pump," what exactly do you mean? pushing the gas pedal a couple times? or is this a hood up test? I'm fairly good with most mechanical things, but when it comes to the engine and starting (other than replacing a starter) I'm at a loss.
GeologistFelix: I always try to understand what some of these things do, versus just do them (to gain a better understanding of everything that is going on). What would turning the key to this point and letting it stay there for a few seconds do? Is there some delay in the ignition relay? would replacing it eliminate this? I want to make it to where she won't have to remember to do that everytime. As you can imagine, she's impatient, lol.
Theres a few things that could be the problem. First have you checked the battery? It may still be turning the engine but not fast enough, I had that problem in my dakota and it was the battery. You can have that checked out at any regular parts shop for free. Next if it isnt the battery it could either be a fuel pump problem or the computer. I had a computer problem in my YJ and it wouldnt start when it was cold because the computer would not send power to the pump unit but it would start after a couple tries. As for the fuel pump try priming the engine like lowicz mentioned. Just turn the key to the accessory mode, the pump should kick on for a second, then turn it off and try starting it. If its just the pump replacing it should fix the problem as there shouldnt be a delay in the pump.
Thanks Sam24th! I thought it might be something like that. What part of the computer could be bad? Just a fuse, or the whole thing? What does that part look like? Do you have a photo or a link to show that? Thanks for all the great initial responses everyone!
i doubt it's a problem with the computer or the fuel pump specifically. there is a pressure check valve in the fuel pump that tends to go bad.
turning the key to the on position and leaving it there for a few seconds will not help the situation. you need to cycle the key between the on and off position three or four times while pausing in each position for a couple of seconds. something like this: ON..2..3..4 - OFF..2..3..4 - ON..2..3..4 - OFF..2..3..4 ON..2..3..4 - START. Each time you place the key in the ON position, the fuel pumps runs to build up pressure in the system, also called priming. if you have a faulty pressure check valve in the fuel pump, one "priming" will not build sufficient fuel pressure to allow the engine to start.
the battery could also be a culprit. it is possible that there is not sufficient voltage to start the engine. the XJ is pretty fussy when it comes to voltage and it is possible that the engine will seem to turn over normally but won't start due to low voltage.
since you say the engine starts fine on the second attempt it seems more like a fuel delivery problem to me. the only way to replace the check ball is to replace the entire fuel pump assembly. there will be no additional failure of the fuel pump because of this problem though, so as long as you're OK with turning the key a couple of times you could keep driving it like this forever.
1983 CJ7 - Built in HS, in storage
1998 ZJ - Project in the making
Thanks Danw77! That is what it is starting to look like. The battery is only 1 year old and is a pretty good one. The car just started doing this a few months ago. It's her primary car so I want to make sure its good to go (so she can save her money and not get another one, she is going to school now too so the money can be used elsewhere). I'm thinking I may just replace the whole part. Does anyone know of a good fuel pump write up with pictures?
It's not a fun job since you have to drop the tank, but it's not impossible either. It is A LOT easier if you don't have a fuel tank skid plate. I do, which is why I have been doing the key turn trick for the past two years.
Anyway, here's a write-up from the sticky I mentioned:
I'll throw this in; I was having these same issues but it went from two attempts to start to not starting at all over the course of two weeks. It ended up being the fuel pump relay. Sorry if someone already recommended this. I have a 1998 XJ 4.0 5 speed. This is the second oem relay I've had to replace.
I'd rather be judge by twelve than carried by six.
the steel can on top of the pump assy is also the fuel pressure regulator. I had that go bad on my Wrangler. you need a fuel pressure test gage. screw it on the airconditioning-LOOKING fitting on the fuel rail. Start it up let pressure stabilize. Shut off and watch for gauge to bleedoff. it should hold system pressure while not running at least 10 min; if NOT the pressure reg portion of that silver can is bad. That is also your fuel filter. the prts stores will tell you "N/A seperately" but yes they are! I get mine from Ebay the $35 ones are the exact same part as the ones listed for $100 or more. You pull them outta the box and same stampings same numbers etc....
98 XJ 4.0L, 5 speed, 140,000+ miles. Went on December snow run and was starting fine. Returned home and next time I tried to start I had to crank the starter much longer than normal. Tried the "turn on key and wait 5 seconds, turn off key, turn on key and wait 5 seconds, turn off key, turn key to start" routine and it starts right up without the long cranking. Seems to be a common problem with the fuel pump check valve that requires building up fuel line pressure again to the injectors. Shouldn't hurt anything to use this routine until warmer weather when I can change out the pump assembly.