93 4.0 not reving over 2,000rpm
10-25-2018, 07:46 PM
#1
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Year: 1993
Model: Cherokee (XJ)
Engine: 4.0
93 4.0 not reving over 2,000rpm
The issues started with a crank no start that was eventually diagnosed as a cam shaft sensor, It was sitting for a few months while I tried to get it started on my own, replaced pretty much everything in the ignition system, plugs, wires, cap rotor, ignition coil, and crank shaft position sensor. I brought it to a shop down the street last week to get the new distributor put in.
When I got it back it was having an issue that I wasn’t having before, it wouldn’t rev over 1,500-2,000 rpm, even in neutral. It starts and idles fine but when I start to drive it it lurches and sputters as soon as I give it any gas. My next thought was a clogged cat or muffler so I took the cat off and the issue is still the same.
Any help would be much appreciated.
When I got it back it was having an issue that I wasn’t having before, it wouldn’t rev over 1,500-2,000 rpm, even in neutral. It starts and idles fine but when I start to drive it it lurches and sputters as soon as I give it any gas. My next thought was a clogged cat or muffler so I took the cat off and the issue is still the same.
Any help would be much appreciated.
10-25-2018, 08:24 PM
#3
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Year: 1993
Model: Cherokee (XJ)
Engine: 4.0
10-25-2018, 08:55 PM
#4
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Year: 2000 sport
Model: Cherokee (XJ)
Engine: New 4.0l from s&j engines
What is the fuel pressure showing?
Go tap on the catalytic converter see if it sounds like stuff is rattling around inside.
Go tap on the catalytic converter see if it sounds like stuff is rattling around inside.
10-25-2018, 09:30 PM
#5
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Year: 1993
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I can’t remember exactly what the fuel pressure was, but it was correct according to the forum post I looked at, the mechanic also checked it and said it was fine.
I’ll check again in the morning.
The catalytic converter is very rattly and definitely needs to be replaced. I unhooked the exhaust at the cat to make sure it wasn’t plugged and causing this issue. it’s still doing the same thing even with the exhaust straight pipped
Last edited by Roryd; 10-25-2018 at 09:34 PM.
10-26-2018, 06:52 AM
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31 psi is the fuel pressure spec for the 93. But there's more. Disconnect the vacuum line leading to the fuel pressure regulator and the pressure should jump to approximately 39 psi. If there is raw fuel in the vacuum line leading to the FPR, replace the regulator as it has a ruptured diaphragm.
Is the check engine light on? If so, you must retrieve codes for clues. You can use the simple "key on- key off technique for your 93. More on how to do this below.
---------------------------------------------------------------------------------------------------
Retrieving OBD codes on the Jeep Cherokee (XJ) OBD1 Models: 1991-1995
1) Start engine (if possible). Move transmission shift lever through all positions, ending in Park. Turn A/C switch on and then off (if equipped).
2) Turn engine off. Without starting engine again, turn ignition on, off, on, off and on within 5 seconds. Record 2-digit fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash, 4-second pause, flash, flash, flash. After a slightly longer pause,other codes stored are displayed in numerical order. When MIL begins to flash fault codes, it cannot be stopped. Start over if count is lost.
NOTE: A "5-5" will always occur to signal the end of the sequence. Some will flash the "1-2" code indicating a recent battery disconnect even if you haven't done it. Ignore these two codes, and mark down all others.
Is the check engine light on? If so, you must retrieve codes for clues. You can use the simple "key on- key off technique for your 93. More on how to do this below.
---------------------------------------------------------------------------------------------------
Retrieving OBD codes on the Jeep Cherokee (XJ) OBD1 Models: 1991-1995
1) Start engine (if possible). Move transmission shift lever through all positions, ending in Park. Turn A/C switch on and then off (if equipped).
2) Turn engine off. Without starting engine again, turn ignition on, off, on, off and on within 5 seconds. Record 2-digit fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash, 4-second pause, flash, flash, flash. After a slightly longer pause,other codes stored are displayed in numerical order. When MIL begins to flash fault codes, it cannot be stopped. Start over if count is lost.
NOTE: A "5-5" will always occur to signal the end of the sequence. Some will flash the "1-2" code indicating a recent battery disconnect even if you haven't done it. Ignore these two codes, and mark down all others.
10-26-2018, 03:37 PM
#7
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Year: 1993
Model: Cherokee (XJ)
Engine: 4.0
31 psi is the fuel pressure spec for the 93. But there's more. Disconnect the vacuum line leading to the fuel pressure regulator and the pressure should jump to approximately 39 psi. If there is raw fuel in the vacuum line leading to the FPR, replace the regulator as it has a ruptured diaphragm.
Is the check engine light on? If so, you must retrieve codes for clues. You can use the simple "key on- key off technique for your 93. More on how to do this below.
---------------------------------------------------------------------------------------------------
Retrieving OBD codes on the Jeep Cherokee (XJ) OBD1 Models: 1991-1995
1) Start engine (if possible). Move transmission shift lever through all positions, ending in Park. Turn A/C switch on and then off (if equipped).
2) Turn engine off. Without starting engine again, turn ignition on, off, on, off and on within 5 seconds. Record 2-digit fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash, 4-second pause, flash, flash, flash. After a slightly longer pause,other codes stored are displayed in numerical order. When MIL begins to flash fault codes, it cannot be stopped. Start over if count is lost.
NOTE: A "5-5" will always occur to signal the end of the sequence. Some will flash the "1-2" code indicating a recent battery disconnect even if you haven't done it. Ignore these two codes, and mark down all others.
Is the check engine light on? If so, you must retrieve codes for clues. You can use the simple "key on- key off technique for your 93. More on how to do this below.
---------------------------------------------------------------------------------------------------
Retrieving OBD codes on the Jeep Cherokee (XJ) OBD1 Models: 1991-1995
1) Start engine (if possible). Move transmission shift lever through all positions, ending in Park. Turn A/C switch on and then off (if equipped).
2) Turn engine off. Without starting engine again, turn ignition on, off, on, off and on within 5 seconds. Record 2-digit fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash, 4-second pause, flash, flash, flash. After a slightly longer pause,other codes stored are displayed in numerical order. When MIL begins to flash fault codes, it cannot be stopped. Start over if count is lost.
NOTE: A "5-5" will always occur to signal the end of the sequence. Some will flash the "1-2" code indicating a recent battery disconnect even if you haven't done it. Ignore these two codes, and mark down all others.
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10-27-2018, 01:20 PM
#8
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Year: 1993
Model: Cherokee (XJ)
Engine: 4.0
31 psi is the fuel pressure spec for the 93. But there's more. Disconnect the vacuum line leading to the fuel pressure regulator and the pressure should jump to approximately 39 psi. If there is raw fuel in the vacuum line leading to the FPR, replace the regulator as it has a ruptured diaphragm.
Is the check engine light on? If so, you must retrieve codes for clues. You can use the simple "key on- key off technique for your 93. More on how to do this below.
---------------------------------------------------------------------------------------------------
Retrieving OBD codes on the Jeep Cherokee (XJ) OBD1 Models: 1991-1995
1) Start engine (if possible). Move transmission shift lever through all positions, ending in Park. Turn A/C switch on and then off (if equipped).
2) Turn engine off. Without starting engine again, turn ignition on, off, on, off and on within 5 seconds. Record 2-digit fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash, 4-second pause, flash, flash, flash. After a slightly longer pause,other codes stored are displayed in numerical order. When MIL begins to flash fault codes, it cannot be stopped. Start over if count is lost.
NOTE: A "5-5" will always occur to signal the end of the sequence. Some will flash the "1-2" code indicating a recent battery disconnect even if you haven't done it. Ignore these two codes, and mark down all others.
Is the check engine light on? If so, you must retrieve codes for clues. You can use the simple "key on- key off technique for your 93. More on how to do this below.
---------------------------------------------------------------------------------------------------
Retrieving OBD codes on the Jeep Cherokee (XJ) OBD1 Models: 1991-1995
1) Start engine (if possible). Move transmission shift lever through all positions, ending in Park. Turn A/C switch on and then off (if equipped).
2) Turn engine off. Without starting engine again, turn ignition on, off, on, off and on within 5 seconds. Record 2-digit fault codes as displayed by flashing MIL.
3) For example, fault code 23 is displayed as flash, flash, 4-second pause, flash, flash, flash. After a slightly longer pause,other codes stored are displayed in numerical order. When MIL begins to flash fault codes, it cannot be stopped. Start over if count is lost.
NOTE: A "5-5" will always occur to signal the end of the sequence. Some will flash the "1-2" code indicating a recent battery disconnect even if you haven't done it. Ignore these two codes, and mark down all others.
ok ok all the fuel pressures are correct, 31 at idle, jumps to 39 when pulling the vaccum line from the pressure regulator. It was at 39 psi when I engaged the fuel pump but didn’t start the Jeep, slowly going down the longer i left it on. Is that normal?
what should my next step be?
could this be caused by the shop incorrectly putting in the new distributor?
10-27-2018, 05:15 PM
#9
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Year: 1999
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Keep us updated.
Last edited by tjwalker; 10-27-2018 at 05:43 PM.
11-01-2018, 03:06 PM
#10
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The shop said they are positive The distributor is in correct, I guess my next step will be to try a new computer? I don’t understand how that would have gone bad from just not being driven but I’m gonna give that a shot next.
11-01-2018, 04:50 PM
#11
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https://tomasz.korwel.net/2006/12/19...omment-page-1/
11-01-2018, 07:39 PM
#12
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um, if it started after they put the distributor in, it's the distributor. Likely a tooth off. Amateur did the work.
11-02-2018, 05:30 AM
#13
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i would also suspect the distributor. these don't get timed by the dizzy, maybe that mechanic did not know that.
other thing that comes to mind is the coil. if it's bad, it won't rev up very high.
other thing that comes to mind is the coil. if it's bad, it won't rev up very high.
11-02-2018, 10:53 AM
#14
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i replaced the coil when I was trying to trouble shoot my crank no start issue, but I used a cheap auto zone one. I’ll try putting the stock one back in. Thanks for the tip
11-02-2018, 03:27 PM
#15
Seasoned Member
I agree with the coil , I used to have a Nissan four wheeler and the guys at work used to think it was funny to short the coil , after it hit 2000 rpm it just went dead, took me a few hours to figure it out, Pay back was a ***** though. I can't tell what I done as to not incriminate myself....