Need help/Suggestions '89 Cherokee Limited
01-05-2010, 08:11 PM
#16
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Year: 1996
Model: Cherokee
Engine: 4.0L HO
As far as I know nobodies thrown it out there yet but I would check your Throttle position sensor (TPS) it should be a 3 wire sensor on the throttle body. Im suggesting this because from what i make out of this its more RPM related. It may be possible there is a bad spot on the inside of the TPS causing it to act a little strange when the needle tries to go past it. Hows it run under load etc?
01-05-2010, 08:27 PM
#17
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Year: 2000
Model: Cherokee
Engine: 4.0 I6
As far as I know nobodies thrown it out there yet but I would check your Throttle position sensor (TPS) it should be a 3 wire sensor on the throttle body. Im suggesting this because from what i make out of this its more RPM related. It may be possible there is a bad spot on the inside of the TPS causing it to act a little strange when the needle tries to go past it. Hows it run under load etc?
this could be your problem.. take the throttle body off and clean the hell out of it.. pull the iac and tps... pull the whole t/b off the intake to get a good cleaning.. DONT DAMAGE THE GASKET.. This issue dosnt seem like a big problem... I am going to take a wild guess AGAIN and say plug wires cap rotor and spark plugs are probally shot... check em and fill us in tomarow, glen....
01-06-2010, 01:01 PM
#19
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Year: 2000
Model: Cherokee
Engine: 4.0 I6
IAC= Idle air control..ITs on the throttle body attached with 2 torqs screws, next to the tps.. I clean a throttle body with carb cleaner...TAke the WHOLE throttle body off..There are 4 phillips screws holding it in place on each corner..dissconect the sensors plug ins and leave them on the t/b , then unbolt the sensors from the t/b when you have the t/b unbolted.. there is a gasket on the t/b and manifold.. just be carful when pulling the t/b off as much as you can..I always use a old thooth brush some towels and carb cleaner to do a t/b... let us all know whats going on and if you have any more questions, glen...
01-06-2010, 06:32 PM
#20
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Alright, here is where I am at:
Spent a while today starting with the basics. i checked the wires, plugs, cap and rotor. All seemed to be good. Checked air filter and it is nearly brand new. While I was standing back looking at it while it was running (Making sure I put everything back together right)I noticed that one of the ingectors seemed to look alot cleaner than the others but it hasn't ever been replaced. Upon closer inspection I saw that it was actually leaking a small bit of gas from it looked like where it connects to the Fuel Rail. So I took apart the rail and the injectors and pulled them out. It was number 4 I think that was leaking. I saw that there was a TON of junk built up on all of the other injectors except for this one. So I cleaned all the junk off, cleaned number 4's O rings really good and then put it back together (Broke a little itty-bitty vacuum hose that I'll have to fix/replace in the process...).
It started right up easier than ever! And then i went around and looked and number 4 is not just leaking a little bit of fuel but now its doing ALOT of fuel and it is idling slightly rough and high (about 850-900)
So my question is: Obviously I need to fix number 4 but can I just try buying new O rings for it? I've never done anything with injectors before but if thats all it needs it should be fairly simple. Also, could that leak have been my original problem? Knowledge of pressure tells me that the fuel rail should be under some pressure because it even looks as though it has a pressure release (like a bicycle tire tube). If number 4 had been leaking for an extended amount of time, it would have been "stealing" that pressure away from the others which would explain why it isn't getting the gas it needs in the other injectors which would mean that it would sputter while driving. Is all of that correct logic? Or am I missing something?
I haven't taken apart the Throttle Body at all yet. It got dark, its really cold, and I was a little upset that the injector is worse than before. Tomorrow is another day....
Thanks for any help and suggestions! you guys really have helped alot!
So to sum everything up:
1)Injector leaking alot. Can I buy new O-rings? Will this fix the problem?
2)Could this leak be the cause of my original problem?
Spent a while today starting with the basics. i checked the wires, plugs, cap and rotor. All seemed to be good. Checked air filter and it is nearly brand new. While I was standing back looking at it while it was running (Making sure I put everything back together right)I noticed that one of the ingectors seemed to look alot cleaner than the others but it hasn't ever been replaced. Upon closer inspection I saw that it was actually leaking a small bit of gas from it looked like where it connects to the Fuel Rail. So I took apart the rail and the injectors and pulled them out. It was number 4 I think that was leaking. I saw that there was a TON of junk built up on all of the other injectors except for this one. So I cleaned all the junk off, cleaned number 4's O rings really good and then put it back together (Broke a little itty-bitty vacuum hose that I'll have to fix/replace in the process...).
It started right up easier than ever! And then i went around and looked and number 4 is not just leaking a little bit of fuel but now its doing ALOT of fuel and it is idling slightly rough and high (about 850-900)
So my question is: Obviously I need to fix number 4 but can I just try buying new O rings for it? I've never done anything with injectors before but if thats all it needs it should be fairly simple. Also, could that leak have been my original problem? Knowledge of pressure tells me that the fuel rail should be under some pressure because it even looks as though it has a pressure release (like a bicycle tire tube). If number 4 had been leaking for an extended amount of time, it would have been "stealing" that pressure away from the others which would explain why it isn't getting the gas it needs in the other injectors which would mean that it would sputter while driving. Is all of that correct logic? Or am I missing something?
I haven't taken apart the Throttle Body at all yet. It got dark, its really cold, and I was a little upset that the injector is worse than before. Tomorrow is another day....
Thanks for any help and suggestions! you guys really have helped alot!
So to sum everything up:
1)Injector leaking alot. Can I buy new O-rings? Will this fix the problem?
2)Could this leak be the cause of my original problem?
01-06-2010, 07:26 PM
#21
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Year: 2000
Model: Cherokee
Engine: 4.0 I6
Alright, here is where I am at:
Spent a while today starting with the basics. i checked the wires, plugs, cap and rotor. All seemed to be good. Checked air filter and it is nearly brand new. While I was standing back looking at it while it was running (Making sure I put everything back together right)I noticed that one of the ingectors seemed to look alot cleaner than the others but it hasn't ever been replaced. Upon closer inspection I saw that it was actually leaking a small bit of gas from it looked like where it connects to the Fuel Rail. So I took apart the rail and the injectors and pulled them out. It was number 4 I think that was leaking. I saw that there was a TON of junk built up on all of the other injectors except for this one. So I cleaned all the junk off, cleaned number 4's O rings really good and then put it back together (Broke a little itty-bitty vacuum hose that I'll have to fix/replace in the process...).
It started right up easier than ever! And then i went around and looked and number 4 is not just leaking a little bit of fuel but now its doing ALOT of fuel and it is idling slightly rough and high (about 850-900)
So my question is: Obviously I need to fix number 4 but can I just try buying new O rings for it? I've never done anything with injectors before but if thats all it needs it should be fairly simple. Also, could that leak have been my original problem? Knowledge of pressure tells me that the fuel rail should be under some pressure because it even looks as though it has a pressure release (like a bicycle tire tube). If number 4 had been leaking for an extended amount of time, it would have been "stealing" that pressure away from the others which would explain why it isn't getting the gas it needs in the other injectors which would mean that it would sputter while driving. Is all of that correct logic? Or am I missing something?
I haven't taken apart the Throttle Body at all yet. It got dark, its really cold, and I was a little upset that the injector is worse than before. Tomorrow is another day....
Thanks for any help and suggestions! you guys really have helped alot!
So to sum everything up:
1)Injector leaking alot. Can I buy new O-rings? Will this fix the problem?
2)Could this leak be the cause of my original problem?
Spent a while today starting with the basics. i checked the wires, plugs, cap and rotor. All seemed to be good. Checked air filter and it is nearly brand new. While I was standing back looking at it while it was running (Making sure I put everything back together right)I noticed that one of the ingectors seemed to look alot cleaner than the others but it hasn't ever been replaced. Upon closer inspection I saw that it was actually leaking a small bit of gas from it looked like where it connects to the Fuel Rail. So I took apart the rail and the injectors and pulled them out. It was number 4 I think that was leaking. I saw that there was a TON of junk built up on all of the other injectors except for this one. So I cleaned all the junk off, cleaned number 4's O rings really good and then put it back together (Broke a little itty-bitty vacuum hose that I'll have to fix/replace in the process...).
It started right up easier than ever! And then i went around and looked and number 4 is not just leaking a little bit of fuel but now its doing ALOT of fuel and it is idling slightly rough and high (about 850-900)
So my question is: Obviously I need to fix number 4 but can I just try buying new O rings for it? I've never done anything with injectors before but if thats all it needs it should be fairly simple. Also, could that leak have been my original problem? Knowledge of pressure tells me that the fuel rail should be under some pressure because it even looks as though it has a pressure release (like a bicycle tire tube). If number 4 had been leaking for an extended amount of time, it would have been "stealing" that pressure away from the others which would explain why it isn't getting the gas it needs in the other injectors which would mean that it would sputter while driving. Is all of that correct logic? Or am I missing something?
I haven't taken apart the Throttle Body at all yet. It got dark, its really cold, and I was a little upset that the injector is worse than before. Tomorrow is another day....
Thanks for any help and suggestions! you guys really have helped alot!
So to sum everything up:
1)Injector leaking alot. Can I buy new O-rings? Will this fix the problem?
2)Could this leak be the cause of my original problem?
01-07-2010, 12:46 PM
#22
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Year: 1989
Model: Cherokee
Engine: 4.0
putting o rings on is easy, just get a little gas on them first so you dont rip them when installing. but idk if this is your daily driver or what but if you can afford the down time maybe test the injectors to see if their all working and then maybe get them flow tested. A buddy of mine lost a 400hp motor from a injector going out, just a thought though.
01-07-2010, 01:27 PM
#23
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Need help really fast. I went and bought the little kits for the o rings for the injectors and it comes with 4 pieces.
2 Brown O rings (I know what these are for)
1 Yellow harder plastic piece
1 blue-purple cap looking piece.
What are the yellow and cap looking things for?!
2 Brown O rings (I know what these are for)
1 Yellow harder plastic piece
1 blue-purple cap looking piece.
What are the yellow and cap looking things for?!
01-07-2010, 01:38 PM
#24
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got pics? sometimes you get stuff that doesnt apply to your car, like one kits fits 8 different cars and you only use what you need.
01-07-2010, 08:09 PM
#25
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Alright here it goes for today's adventures....
I figured out the O rings and how to replace them. I replaced them and it was still leaking. I assume that it was the injector. I went out and bought a new one and installed it. Now it is not leaking but because it was "stealing" all that pressure from the other ones, they are all starting to leak slightly (hopefully all just O rings).
After fixing all of that problem I tried it and my symptoms are all the same still....
So I went on to the next step of taking apart the throttle body and cleaning it all. I cleaned it all up. The IAC had a bunch of junk built up so I thought that might be it. Put it back together and still nothing... Everything is the same...
So I start thinking maybe its getting fuel but not enough. I got a new fuel filter and put it on. Nothing...same... I got a fuel line pressure gauge and tested my pressure up on the fuel rail and compared it with the pressure of a cousins. Exactly the same pressure.... Still same symptoms....
So 4 and half hours, $100 and I'm still back where I started a few days ago...
I know that the Throttle Position sensor can go bad sometimes. Could this cause my problem? How can i test it to see if it is bad?
Also someone mentioned something about a camshaft position sensor (or something like that) that they had on an old car that was running similar to how mine was. Once they replaced that, they were fine. Does the Cherokee have anything like that? Could this be the cause of my problem?
Thank you all so much for all the help this far. I really appreciate it! I don't know if I would even be this far without you guys.
I figured out the O rings and how to replace them. I replaced them and it was still leaking. I assume that it was the injector. I went out and bought a new one and installed it. Now it is not leaking but because it was "stealing" all that pressure from the other ones, they are all starting to leak slightly (hopefully all just O rings).
After fixing all of that problem I tried it and my symptoms are all the same still....
So I went on to the next step of taking apart the throttle body and cleaning it all. I cleaned it all up. The IAC had a bunch of junk built up so I thought that might be it. Put it back together and still nothing... Everything is the same...
So I start thinking maybe its getting fuel but not enough. I got a new fuel filter and put it on. Nothing...same... I got a fuel line pressure gauge and tested my pressure up on the fuel rail and compared it with the pressure of a cousins. Exactly the same pressure.... Still same symptoms....
So 4 and half hours, $100 and I'm still back where I started a few days ago...
I know that the Throttle Position sensor can go bad sometimes. Could this cause my problem? How can i test it to see if it is bad?
Also someone mentioned something about a camshaft position sensor (or something like that) that they had on an old car that was running similar to how mine was. Once they replaced that, they were fine. Does the Cherokee have anything like that? Could this be the cause of my problem?
Thank you all so much for all the help this far. I really appreciate it! I don't know if I would even be this far without you guys.
01-08-2010, 11:50 AM
#28
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Year: 1999
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Until recentley I used to repair and build standard and race fuel injected engines and have done for nearly 20 years.
Throttle position sensor would be my bet. The tps is a variable resistor of sorts. They have a wiper that moves across the surface and gives a varying resistance to the fuel injection computer (ecu).
They usually start to wear out where most of the activity occurs. Which is exactly what you said that at 1750 rpm (highway cruising revs) the problem occurs.
Where there is no wear on the tps quadrant the fuel injection gets the correct signal. So 99% of the time the vehicle will idle and accelerate briefly then run like a bag of bolts where the worn section is then as you drive through it the engine smooths out on the other side.
Sorry but tps's are not servicable. Get a new one. Check how it fits as usually they have a slight adjustment so that a new one has to be in the idle position when the throttle butterfly is fully shut. So that butterfly position matches tps setting.
Hope this helps.
Throttle position sensor would be my bet. The tps is a variable resistor of sorts. They have a wiper that moves across the surface and gives a varying resistance to the fuel injection computer (ecu).
They usually start to wear out where most of the activity occurs. Which is exactly what you said that at 1750 rpm (highway cruising revs) the problem occurs.
Where there is no wear on the tps quadrant the fuel injection gets the correct signal. So 99% of the time the vehicle will idle and accelerate briefly then run like a bag of bolts where the worn section is then as you drive through it the engine smooths out on the other side.
Sorry but tps's are not servicable. Get a new one. Check how it fits as usually they have a slight adjustment so that a new one has to be in the idle position when the throttle butterfly is fully shut. So that butterfly position matches tps setting.
Hope this helps.