Sudden Lack of Power

[FutureFireMan530]

Hi guys, I have an 89' Jeep Cherokee Pioneer running the 4.0 litre engine with the stock 5 speed set up. It has the peugot tranny and part time transfer case for four wheel drive.

In the last week I have noticed a sudden lack of power, for example there is a lot less acceleration, more hesitation, it has a harder time makeing it up steep hills and so on. It almost feels like something is binding or its choking, or I am constantly towing something but with no odd noises that I have noticed. I suspected blocked exhaust, so I pulled the assembly and ran it without the muffler and cat, but no luck. It is doing the same thing. Like I said, I haven't noticed any odd noises from the engine. Any ideas?

Thanks,
Shane

[90xj06]

doesn't sound like your fuel mixture is right check o2.

[FutureFireMan530]

Thanks for the reply, but I just replaced the O2 sensor 2 months ago to pass DEQ. I will still go take a look at it and check the connections, but if there are any other ideas or possibilities I would like to hear those too. Thanks agian,
Shane

[90xj06]

fuel pressure? and tps?

[langer1]

Weak spark.

[FutureFireMan530]

Thanks guys. I did the cap, rotor, plugs and wires at the same time I was trying to pass DEQ, those were my first options, but I have not done anything with the TPS, and how do I check for fuel pressure?

[90xj06]

there is a little tire like spout on the fuel rail.

[FutureFireMan530]

i assume i have to go get a special gauge for that. its a tid bit larger than air pressure lol. in the meantime my tps seemed alright, but that is just with a visual and a not very detailed volt reader. it gives whole numbers, i cannot find my good one. i am going to dig a little into my cap and rotor and plugs and what not and try to diagnose a little farther. thanks for all the help so far.

[90xj06]

you can probably rent the gage at you local autostore.

[langer1]

You can buy a nice pressure test set at Harbor freight for $15.00

[FutureFireMan530]

The fuel pressure is fine... As is the fuel filter. I checked the fuel filter the only way i know how by pulling it off and blowing trough it. not clogged, any other ideas? I also forgot to mension it is havving slightly longer starts than normal, but not by much.

[langer1]

The fuel pressure is fine... As is the fuel filter. I checked the fuel filter the only way i know how by pulling it off and blowing trough it. not clogged, any other ideas? I also forgot to mension it is havving slightly longer starts than normal, but not by much.

Is still stand on weak spark, it should be blue and easy jump an inch.

[FutureFireMan530]

Alright, for the weak spark how do I diagnose what the problem is. I mean plugs? wires? cap and rotor?

[langer1]

Test it coming from the coil, if it's weak there it's the coil.

[Dr. Dyno]

Since you've already replaced other ignition components and you're still getting harder starting with a lack of power, I'm inclined to agree with the diagnosis of a bad coil. The MSD 8228 is a good stock replacement.

[FutureFireMan530]

thanks everybody. I'll be checking that now.

[FutureFireMan530]

I am having difficulties. How might I go about this... the manual is twisting my brain.

[carnuck]

Dude! Mine did the same thing on my way to work. The old cat barfed chunks into the muffler! That made a quickie cork and dropped my power/speed like a rock! I had to unscrew the O2 sensor in order to get to work (left my claw hammer at work the day before)

[FutureFireMan530]

Hahah, I already knew I needed a muffler, but My cat is fine. it wasn't clogged, so that wasnt the proble, i just had a broken baffle so it rattles, but problem solved, for that anyways.

As for the lack of power I am still trouble shooting. The coil seems fine, so i chatted with my uncle who has had an 88 since new. He is thinking It a possible EGR valve, so as soon as I get the exhaust back together that's where i'm looking. Again, thanks to everyone. Hopefully i get it fixed soon. I HATE driving a Hundai. or however its spelled.

[MadMrJake]

Hey i had this same prob... as funny as it may sound i pulled my fule pump and found that there is a rubber hose that was all gummy. i replaced it and cleaned the choke, the dam thing runs better then when i took it to a shop and spent over 1200 buck to get it to run right.
like i said its a long shot, but it worked for me.

[FutureFireMan530]

Isn't the fuel pump inside the tank? that sounds like a fun job... but if the EGR valve doesn't solve it then thats where i'll head next.

[MadMrJake]

Yeah it is; but it wasn’t that hard to get to. I did not have to drop the tank to do it took all of an hour. It was a trip, I did not think that it would be it but it was. I was having a hard time starting due to loss of pressure in the fuel lines. I replaced all the o-rings on the injectors thinking that would be it, but it was not. I read a lot of post on here and thought of checking out the fuel pump. When I took, it off I was very surprised to find that the rubber hose was all gummy and cracked; and as I was taking it out of the tank it split in two. I replaced it and now it holds the pressure and start right away. I worked for me and only cost me 10 bucks, 6 bucks for 3 bucks for the hose.. The rest was tax. Hope this works for you.

[langer1]

You said your fuel pressure was fine, what was it? Should be 31#

[FutureFireMan530]

I went and baught a new gauge, i didn't my buddy's wasn't constant but it was close and usually around 29. My new gauge is 20 constant, so now I am zeroed in on the fuel pump. Also, after blocking off the EGR valve the started up and shut off a lot easier, no more diesleing. I'll get started on that tomorrow and replace the EGR valve, hopefully problem solved. I'm getting ready to go to a rodeo, so it's gonna have to wait. Yee-haw.

[langer1]

No Rodeo for me but A Antique steam power show. I got to get my 47 Oliver ready.

http://img.photobucket.com/albums/v11/langer1/77oliver.jpg

[carnuck]

I've had people bring "other" fuel filter brands in that were clogged due to crappy gas. (they were less than a week old too!)

[FutureFireMan530]

Well the Rodeo turned out to be awesome. George Straight was there whatching his sun Bubba ride in the rodeo. And I completly forgot that i am driving up into seatle tomorrow to do some Fire Department training, it's an overnighter so my fuel pump is gonna have to wait a couple more days. :( that just bummed me out.

[langer1]

Don't forget it can also be the fuel pressure regulator.

[carnuck]

Could be the reg sticking open (drops pressure) I'd put a can of 44K in and see if the $20 miracle cure works for you! I get 307 miles on a 15.25 gallon fill (average over 5 tanks now) in a 230,000 mile Comanche with 4.0L, BA 10/5, 3.73 gears (D30 front and D35 rear) on 33" tires (no tcase yet as the 4x4 conversion ain't quite done yet)

[FutureFireMan530]

Thanks guys I'll take a look at both, I am hedding out right now.

[FutureFireMan530]

Here is the scoop. I pulled the fuel pump. As is was comming out, the rubber hose that connects two metal tubes pops off of the upper half. The metal clamp holding it wasn't tight enough, so I am thinking... maybe that could be the cause of lack of pressure? what do you think... it would save me buying a new pump.

[langer1]

Sure worth a try, that thing puts out 39 psi when you first turn the key on.
It has to be high pressure fuel hose and tight.

Oh and get a new hose, that one is shot, make sure it says fuel injection hose on it.

[FutureFireMan530]

Poblem Solved! It was the loose connection causing a leak in the fuel line that I couldn't see. Thanks again to everyone for all their help, keep up the good work.

Shane

[MadMrJake]

LOL... i had the same problem. didnt think it was that but it was!

[FutureFireMan530]

I know how that goes... but she is runnin' like a champ now. New EGR valve and she will be rockin and good for another 200,000. :)