bdub

Hope someone can help me with this. A few days ago i tried to start the engine, and nothing. I charged the battery overnight (battery bought back in April this year), and put it on the jeep and it ran fine for a few days, but the voltage gauge steadily dropped, finally again, it the engine wouldn't turn over. So, this sounded like the symptoms of a bad alternator. Last night i took the alternator off, had it tested, and sure enough it came up bad. I put the new alternator back on today, buttoned it up, and the engine turns over but will not start at all. Almost seems like a computer fault or something? I don't know...

One clue i have, which i'm not sure, but i took the filter box off to loosen the serpentine belt. By doing that i may have bumped something? I know when i buttoned up the filter box there was one thin line, maybe vacuum line, that hooks into the back top half of the filter box that isn't hooked to anything. Anyone know what this line is? i think it was hooked to something before but got bumped off, wonder if that would make it not start? HELP!

bdub

bump. Any ideas? computer fried? sensor fried?

dennis461

Post pic of the line for a better chance at answering.
Do you have a battery charger?
Charge up the battery fully, it should start without an alternator output.

Buy starting fluid, spray into intake while cranking and see if it helps.

Get a timing light hooked up to the ignitino coil wire and check for spark.

bdub

Sorry, its the thin line going into the back of the filter box with an elbow.

As far as the other stuff, I really think its a computer or sensor issue, it turns over pretty healthy, the battery is fully charged. its just when i stuck this alternator on it i tried to start it up and it will not start.

bdub

This all just strikes me as being really weird. I hook up a new alternator and now the engine just won't start? Even before i replaced the alternator it still started okay if the battery was charged enough... I'm really at a loss here... I don't know if by putting the alternator on it back-fried something else, which is what i'm thinking, but i'd rather not have it towed to a dealership and pay hundreds and hundreds of dollars to fix. So far no help on thread/forum searches that would even minimize the odds

kojoff

I know youre not getting much in the way of answers here, but, is there a possibility that you missed hooking up a wire or may have broken a wire on the alternator? Kind of weird that it was starting but now wont. That line youre asking about is a vacuum line, hard to see where it went or what it is by the pic, but if you look hard enough, you may see a open nipple somewhere. I had hell with finding the missing one on mine, but all it did was cause the engine to rev.

bdub

Just to eliminate some possibilities... could it be the crankshaft position sensor? Would that cause the engine to turn over okay but not fire?

kojoff

Well, yeah. But I would look over the rest too... hopefully you just missed something. But, if its turning over strong, got good fuel pressure, that could be a possibilty. Stupid CPS...

Jeep, Ride XJ

yes it could cause it to turn over and not start...if none of ur gages work it would be ur Cranks position sensor. the best way to test it is to unplug it and turn or igniton on , and if ur gages now work. then replace the Crank position sensor

Rock Toy

If I'm trying to get a rig started that will turn over the first thing I do is check for spark and fuel. Pull a plug wire off the plug and leave it close enough to the plug so that it will arc and turn the engine over if it has spark start looking somewhere else.
I always do the easy stuff first.

bdub

Thanks guys... The gauges are working fine when i try to start it, so I'm hoping its not the CPS. I'll check for spark next. Also, this may be a really rookie question, but where is the ignition coil on this thing located? I saw a pic that showed it next to distributor housing, but I'm not seeing it there... any pics or drawings showing location would be appreciated!

bdub

Nevermind... found the problem. MAP sensor. unplugged it and plugged it back in, started it and runs great... Weirdest thing. Thanks for all your all's help.

brycen62

I know that this was a while ago, but I just wanted to say thanks. My jeep did the exact same thing, I tried what you said, unplug and plug in the MAP sensor and she is working once again.

SairsyFairy

Sorry to did up an old thread but our jeep refused to start this morning and I found this thread and unplugged the MAP sensor and re plugged and she started!!

Thanks

cruiser54

That doesn't work on the Renix Jeeps. The CPS can be tested with a voltmeter though.