No start this morning

jeepurnaz said:
http://www.naxja.org/forum/showthread.php?t=65558&highlight=bad+battery
Click to expand...

jeepurnaz...I'm not discounting your suggestion. I also have a 2001 that I actually pulled the battery out of and tried that. No difference. The connections are tight and the posts are free of any muck. Mine is definitely drained now though b/c of all the attempts at starting it. Thanks for your input. I need all the help I can get. I'll keep you all posted on what happens. I'm going to pull the TB off tonight and remove the IAC and clean it. If that deosn't make a difference, I may go down to the Springs and see about getting a TPS, MAP, maybe even a coil. Wish I had a buddy with another one that I could swap sensors. The 01 is different. At least the MAP was, I'll check the rest.
 
have you mentioned if you checked for error codes? I didn't think of it when I suggested the MAP, but Matthew's post reminded me I DID get an error code for my MAP when I had the bad sensor and similar symptoms.
 
Update:
No codes were able to be pulled. I've had this Jeep for 2 years now and so I decided to do tune up stuff b/c it's going to need it soon anyway. I did cap, rotor, plugs, wires. No change in the symptoms. I can still get it to start if I get in the throttle. Bad smell of gas when it does run. Runs smooth, no misses. Dies as soon as I let off the throttle. Pulled the plugs and they are wet with gas. I just don't think this is fuel pressure related. The spark was no world class. It was yellowish and not blue, perhaps weak. I'm wondering if coil would be a good idea to try. It's 30 bones. I might try that in the morning. If that doesn't do it then I hate to say it but I may take it somewhere. I don't want to blow 111 on a MAP, 40 on TPS just for kicks. It'd be flippin' sweet to get this sourced before Monday. We're supposed to get a good bit of snow and I'd rather not ride the moto in that sheat. Thanks for the continued interest fellows. I'll keep you posted tomorrow.

Hey Buzzard...how the heck did you diagnose faulty MAP with no code. That and TPS should throw code I'd think. That sucks. Did you just guess/throw sensors at it. I might throw something else at it.
 
I used a friends Mitchel on Demand and the iATN network. When we watched the data stream the MAP readings seemed sluggish. We disconnected the battery, smoked a cig, hooked the battery back up. We did this so the computer would reset. Got it restarted and watched the data stream. MAP readings still off and sluggish. I don't remember the exact readings but they didn't equal up to what they should have been. I wish I had captured the old readings and the new ones for comparision purposes.

I think there is a write up on testing the sensor. I have it in .doc format if you want ii.

110 for a MAP? I got mine at NAPA for about $40.00
 
When testing the MAP with the ignition ON, there is supposed to be between 4.5 and 5 volts. I show nothing. Why isn't this throwing a code? The sensor IS 110. There was a mid year change in 96. The one that mounts on the firewall is 40 bucks. I'm trying to decide whether I should throw 100 bucks into a MAP sensor or just take it somewhere? Any thoughts?
 
Well it seems from your additional observations that the engine is definitely running rich. If when giving it throttle the engine runs smooth, but rich, I would say your ignition system is fine.
I would say not to spend money on a TPS or coil.


One possibility is that the ECU/PCM thinks that the engine is running lean so it made the mixture rich. This could be caused by a bad MAP sensor or a very bad vacuum leak. Are there any vacuum hoses that have fallen off or are cracked? Are there any breaks in the hose that is connected to the MAP sensor? Check all vacuum hoses including the hose connected to your brake booster. Can you hear any hissing when the engine is on?


The other possibility is that your fuel pressure regulator has failed and is letting a much higher pressure get to the injectors. In order to eliminate this possibility you need to check the fuel pressure.

MAP
 
You are not the first person to talk about a hose coming off the MAP sensor. There was a mid year change and my sensor mounts directly to the throttle body. There is only one small elbow that connects the MAP to the TB. Everything else going to the intake looks fine. No hissing.

I actually did buy a pressure testing kit. I hooked it up to the test port on the fuel rail and when I turned the ignition on, I got a reading of 48 psi. The Haynes manual sucks b/c it does not tell me what the specs are on fuel pressure. It seems like I need to know if that initial pressure is ok before moving on. I almost ordered a MAP from NAPA today but now I'm debating taking it to a shop. I did check the pressure regulator is indeed in the tank with the pump. It's not like this on all 96 models though I don't believe.
 
On my 99 XJ the pressure is supposed to be at 49.2 PSI +/- 5 PSI according the the factory service manual.

Check the pressure with the engine running. If the pressure is within those specs, I'd suspect the MAP sensor or some elusive vacuum leak.
 
Would a faulty MAP cause it too put out some smoke and odor from the exhaust? It smells rich.

Thanks for those #'s too. That'll be easy to check in the a.m.
 
The job of the M.A.P.(manifold air pressure) sensor is to monitor the air pressure/vacuum of the intake manifold.

At idle or during acceleration, the vacuum is high and the ECU realizes that the engine needs little fuel. At open throttle or higher, the vacuum decreases so the ECU realizes that more fuel is needed.

If this part is not reading properly it will send the wrong message to the ECU and the ECU will provide the wrong amount of fuel.

In your case the MAP is reading a lower vacuum reading and this will cause the ECU to make the engine run rich.

Is the smoke from the exhaust black? If so it's definitely running very rich.

The Cherokee is supposed to have a vacuum canister in the front bumper on the passenger side. You might want to check that connection.

MAP
 
Well the fuel pressure on ignition and while running is 48-50. Definitely within the range you gave. The disadvantage of living in a small town is that the auto stores aren't open and neither of them had the right MAP. 2 stores I checked in the Springs had to order it. Everyone has the MAP that mounts in a different location. There's a guy with a mid to late 90's XJ that lives the down the street from me.. He rolled it and is trying to sell it. Maybe I'll go down and see if he'd let me borrow his sensor to try before I decide to buy one or take the Jeep to a shop. Thanks again MAP.
 
Old Man...you win the prize of a cold beer of your choice. It was indeed the TPS. I decided to go with a new one on a whim. Getting the old one out was a chore. The bolts were seized. Finally got it off and the new one installed. Then the battery was so drained I couldn't get it started to see the reults. Had to shovel the driveway of the snow and then push mine out far enough so I could maneuver my wifes to jump start it. It started up and idled like normal. Thank you all for your help/input. Now that I am out in CO I really hope to attend some drives and meet you. Guess not til the Spring though. Well next is my RE SYE and driveshaft and then the Surco roof rack.

-Chris.
 
Hate to bring this one back from the dead but...

same thing happened this afternoon after work. Starts if you're all in the throttle. I got it home and tried to start it a handful more times with the same reults. Then...it started and would run if I let off the throttle totally but idled really bad. Turned it off and no start at all...just turn over.

I unplugged the TPS and checked the connections. They look good. I pulled a plug and it had some carbon on it and smelled rich, which it should have. I replaced all plugs and instead of gapping at .035, I gapped at .040, hoping that the bigger gap might produce a better spark. No change.

Both days it's done this have been very moist (either rain, mist or snow) and colder temps. I'm wondering if there is a wire somewhere that is shorted. Maybe ground to TPS is bad? I'm taking it to someone on Tuesday. I'll ride the moto til then. I'll let you all know.

-Chris
 
If intalling the new TPS solved the problem and it did this again, maybe the connector that plugs into the TPS is the issue?

There could be corrosion on the connector contacts. You should try cleaning the connector end with some kind of contact cleaner. Clean with alcohol and let air dry, coat things with dielectric grease and re-install.

Or you could just replace the connector altogether.
Just throwing ideas out there.

MAP
 
MAP, you and anyone else can take your ideas and throw them directly my way. I'm jaded and bitter at my Jeep right now. I did unplug the connector and checked things. The sensor is what has the actual pins (3 of them). The connector is female. It's pretty small but maybe I can get in there with some Q-Tips or a rag over one of the terminals on my volt meter. I'll stop on the way home and get some contact cleaner and some di-electric grease.
I change the plugs again only b/c I worried whether a set of plugs that had been flooded with fuel acts the same afterwards? It appears to make no difference. Thanks for the thoughts.
 
You may want to check the connections at the PCM. I don't think there's any chance of wear there that would just affect one circuit, but it's always worth a shot.

Also, did you throw any codes this time?

And, try disconnecting the battery for 30 seconds and seeing if that helps.
 
I didn't get any codes this time either. I did the battery thing last time but didn't give it a shot yet...I will. I haven't tried cleaning the connector on the TPS yet either. I went and drank margaritas tonight. I'll try all this jazz tomorrow afternoon.
 
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