Looking for some help before I give up on my 88'
05-17-2014, 01:51 AM
#106
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Year: 90,84
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Engine: 4.0,2.5
Gottcha'. You might make double sure it's clear, not restricted. It's a very small tube. (and very important). The MAP is boss for fuel supply. The 02, temp, IAT, all those are to fine tune what the MAP does.
Last edited by DFlintstone; 10-16-2014 at 05:23 PM. Reason: tune
05-17-2014, 03:33 AM
#107
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Yeah that's what I've been reading. I had a weird thing happen today to that i just remembered, when I was warming it up and it started to stutter, I opened the throttle up pretty quickly and the rubber hose going from the air box to the throttle body clasped like something was blocking it. It was weird. I opened up the air box and made sure the filter was in place and everything looked fine. Might have been a fluke or something
05-17-2014, 04:47 AM
#108
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Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
What injectors you running ? Mine had a slight stumble it never really bothered me. It went away once I upgraded . JM2CW .....
05-17-2014, 06:17 AM
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05-17-2014, 04:08 PM
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OKAY, back with some numbers... The CPS AV test came back with a reading around 320 mV when I was cranking it over. And I tested all of the injectors while I was out, not sure of what range they needed to be in, but all were in the vicinity of 2.6 - 3.8 V.
So funny thing that happened today while I was out there trying to see if I could get it to make the issue happen again.
I was letting it idle and warm up, so I was kinda standing around and twiddling my thumbs, and I notice that there was a slight increase in the idle. Nothing to major but it went up, so I figured it was warm, and sure enough as soon as I slightly pressed the throttle it acted in the same manner by almost dying. It didn't, so I released it and the idle came back up. I did this same thing as soon as I slowly pressed the throttle. So I sat back a bit by the front bumpper to let it idle and I noticed an air leaky sound. So naturally I thought I must have knocked out a vacuum line(since it sounded like it was coming from that cluster connection in the front) but I couldn't find one fast enough before the sound just went away. Yeah, just stopped! But here's the crazy part, as soon as it stopped, the idle went slightly back down. And guess what, it was running just fine(still, the missing was still being felt in the block) and I could press the throttle without it cutting out! I'm going to try and reoccur the same thing tomorrow because now it wants to run all fine and dandy.
I think this jeep is trying to mess with me
So funny thing that happened today while I was out there trying to see if I could get it to make the issue happen again.
I was letting it idle and warm up, so I was kinda standing around and twiddling my thumbs, and I notice that there was a slight increase in the idle. Nothing to major but it went up, so I figured it was warm, and sure enough as soon as I slightly pressed the throttle it acted in the same manner by almost dying. It didn't, so I released it and the idle came back up. I did this same thing as soon as I slowly pressed the throttle. So I sat back a bit by the front bumpper to let it idle and I noticed an air leaky sound. So naturally I thought I must have knocked out a vacuum line(since it sounded like it was coming from that cluster connection in the front) but I couldn't find one fast enough before the sound just went away. Yeah, just stopped! But here's the crazy part, as soon as it stopped, the idle went slightly back down. And guess what, it was running just fine(still, the missing was still being felt in the block) and I could press the throttle without it cutting out! I'm going to try and reoccur the same thing tomorrow because now it wants to run all fine and dandy.
I think this jeep is trying to mess with me
Last edited by bdcontraplayr; 05-17-2014 at 04:12 PM.
05-17-2014, 04:33 PM
#111
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You completed checking/cleaning grounds and have 1 ohm from B on the TPS to battery negative. OK, it's time to check/adjust the TPS is my call. I hope you double checked that map tube. Around here bugs like to get into little things like that and plug them up. Being it came from a JY I'd be darn sure its clear. (a restriction would cause exactly what is happening). Also, here's a thing I have "canned" on vacuum leaks>>
Vacuum leaks suck. I go around with short little shots of starting fluid, if you hit one the sound of the engine will change. Small little shots! You don't want that stuff to accumulate. It's a fire hazard, but It evaporates right away. Also with a tube, or a section of hose you can listen for it. Don't forget the lower O rings on the injectors need to seal as well. (uppers would leak fuel).
The manifold bolts have a habit of loosening, especially that rear one. On anything like that you never want to tighten only one. It can warp/bend, even crack things. If I found that any that where easy to reach where loose, I'd pull the air cleaner and tighten them all, starting in the middle and working out towards the ends. I go over about three times. It's a bear of a spot to get a torque wrench on them all. Just don't ape on it. If its firm and not turning, no point in going on to break it, a REAL *****. The rearmost bolt underneath takes a little doing, but it can be done with the right extension. For that very back one by the firewall I use way long extensions (18"), with a swivel at the socket. Anyway, that's a good thing to check on any old Jeep. ALSO, there is a large line coming off the intake, rear of the TB that goes back to the firewall, across, then forward down to the vacuum ball behind your right front bumper. You can pinch that off or unplug it and cap the nipple to test if you have a leak there.
Vacuum leaks suck. I go around with short little shots of starting fluid, if you hit one the sound of the engine will change. Small little shots! You don't want that stuff to accumulate. It's a fire hazard, but It evaporates right away. Also with a tube, or a section of hose you can listen for it. Don't forget the lower O rings on the injectors need to seal as well. (uppers would leak fuel).
The manifold bolts have a habit of loosening, especially that rear one. On anything like that you never want to tighten only one. It can warp/bend, even crack things. If I found that any that where easy to reach where loose, I'd pull the air cleaner and tighten them all, starting in the middle and working out towards the ends. I go over about three times. It's a bear of a spot to get a torque wrench on them all. Just don't ape on it. If its firm and not turning, no point in going on to break it, a REAL *****. The rearmost bolt underneath takes a little doing, but it can be done with the right extension. For that very back one by the firewall I use way long extensions (18"), with a swivel at the socket. Anyway, that's a good thing to check on any old Jeep. ALSO, there is a large line coming off the intake, rear of the TB that goes back to the firewall, across, then forward down to the vacuum ball behind your right front bumper. You can pinch that off or unplug it and cap the nipple to test if you have a leak there.
Last edited by DFlintstone; 05-17-2014 at 05:44 PM.
05-17-2014, 11:17 PM
#112
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???? Well Cool! (I guess I was still writing while you were editing). Maybe the map tube burped! In any case you may still want to check/adjust the TPS.
05-18-2014, 04:47 AM
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05-18-2014, 04:06 PM
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OK, can someone explain to me on how to check the tps? I've read over cruiser's way of doing it, but its like reading Chinese. Is it on the AC volts or the DC volts? The meter I have from my brother has an automatic setting for the range and I don't know what the hell I'm looking at.
05-18-2014, 09:35 PM
#115
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The only one single thing on the Jeep that uses AC volts is the CPS test. Everything else is either resistance in ohms, or DV voltage within a 20 volt range.
It seems overwhelming, but it's not when you take it one little step at a time. (that applies to allot of wiring issues) . You can double check that one ohm on the ground at B. Now check the "reference", the voltage at "A", that is coming from the ECU. (I had 4.8 or 9).
Now you have your input voltage to the TPS, "backprobing" at A. Multiply that by .17, and that is the number you want to see at C. You can change that # at C by rotating the TPS. (that's the actual adjustment).
OK? One thing. You will find the the thing changes a tad as you tighten the screws. I get it snug, then tap it with a screwdriver, then tighten more.
So give it a shot let us know what you get!
The three wires in the connector are clearly embossed with the letters A, B, and C. Wire "A" is positive. Wire "B" is ground. DO NOT UNPLUG THE CONNECTORS !! Key ON, measure voltage from "A" positive to "B" ground by back-probing the connectors. Note the voltage reading--this is your REFERENCE voltage. Key ON, back-probe the connector at wires "B" and "C". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For example: 4.82 volts X .17=.82 volts. Loosen both T-20 Torx screws attaching the TPS to the throttle body and rotate the TPS until you
have achieved your desired output voltage. Tighten the screws carefully while watching to see that your output voltage remains where it is supposed to be. If you can't achieve the correct output voltage, replace the TPS and start over.
It seems overwhelming, but it's not when you take it one little step at a time. (that applies to allot of wiring issues) . You can double check that one ohm on the ground at B. Now check the "reference", the voltage at "A", that is coming from the ECU. (I had 4.8 or 9).
Now you have your input voltage to the TPS, "backprobing" at A. Multiply that by .17, and that is the number you want to see at C. You can change that # at C by rotating the TPS. (that's the actual adjustment).
OK? One thing. You will find the the thing changes a tad as you tighten the screws. I get it snug, then tap it with a screwdriver, then tighten more.
So give it a shot let us know what you get!
The three wires in the connector are clearly embossed with the letters A, B, and C. Wire "A" is positive. Wire "B" is ground. DO NOT UNPLUG THE CONNECTORS !! Key ON, measure voltage from "A" positive to "B" ground by back-probing the connectors. Note the voltage reading--this is your REFERENCE voltage. Key ON, back-probe the connector at wires "B" and "C". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For example: 4.82 volts X .17=.82 volts. Loosen both T-20 Torx screws attaching the TPS to the throttle body and rotate the TPS until you
have achieved your desired output voltage. Tighten the screws carefully while watching to see that your output voltage remains where it is supposed to be. If you can't achieve the correct output voltage, replace the TPS and start over.
05-19-2014, 04:46 PM
#116
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The only one single thing on the Jeep that uses AC volts is the CPS test. Everything else is either resistance in ohms, or DV voltage within a 20 volt range.
It seems overwhelming, but it's not when you take it one little step at a time. (that applies to allot of wiring issues) . You can double check that one ohm on the ground at B. Now check the "reference", the voltage at "A", that is coming from the ECU. (I had 4.8 or 9).
Now you have your input voltage to the TPS, "backprobing" at A. Multiply that by .17, and that is the number you want to see at C. You can change that # at C by rotating the TPS. (that's the actual adjustment).
OK? One thing. You will find the the thing changes a tad as you tighten the screws. I get it snug, then tap it with a screwdriver, then tighten more.
So give it a shot let us know what you get!
The three wires in the connector are clearly embossed with the letters A, B, and C. Wire "A" is positive. Wire "B" is ground. DO NOT UNPLUG THE CONNECTORS !! Key ON, measure voltage from "A" positive to "B" ground by back-probing the connectors. Note the voltage reading--this is your REFERENCE voltage. Key ON, back-probe the connector at wires "B" and "C". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For example: 4.82 volts X .17=.82 volts. Loosen both T-20 Torx screws attaching the TPS to the throttle body and rotate the TPS until you
have achieved your desired output voltage. Tighten the screws carefully while watching to see that your output voltage remains where it is supposed to be. If you can't achieve the correct output voltage, replace the TPS and start over.
It seems overwhelming, but it's not when you take it one little step at a time. (that applies to allot of wiring issues) . You can double check that one ohm on the ground at B. Now check the "reference", the voltage at "A", that is coming from the ECU. (I had 4.8 or 9).
Now you have your input voltage to the TPS, "backprobing" at A. Multiply that by .17, and that is the number you want to see at C. You can change that # at C by rotating the TPS. (that's the actual adjustment).
OK? One thing. You will find the the thing changes a tad as you tighten the screws. I get it snug, then tap it with a screwdriver, then tighten more.
So give it a shot let us know what you get!
The three wires in the connector are clearly embossed with the letters A, B, and C. Wire "A" is positive. Wire "B" is ground. DO NOT UNPLUG THE CONNECTORS !! Key ON, measure voltage from "A" positive to "B" ground by back-probing the connectors. Note the voltage reading--this is your REFERENCE voltage. Key ON, back-probe the connector at wires "B" and "C". Measure the voltage. This is your OUTPUT voltage. Your OUTPUT voltage needs to be seventeen percent of your REFERENCE voltage. For example: 4.82 volts X .17=.82 volts. Loosen both T-20 Torx screws attaching the TPS to the throttle body and rotate the TPS until you
have achieved your desired output voltage. Tighten the screws carefully while watching to see that your output voltage remains where it is supposed to be. If you can't achieve the correct output voltage, replace the TPS and start over.
So I did it, adjusted it and paid attention while tightening it so its right were it needs to be. My base reading was a 4.9 and I set it at .833.
Not the tps, still the same thing is happening. I wonder if I have a shotty throttle body, or maybe I should take the intakemanifold off and give it a good cleaning
05-19-2014, 05:04 PM
#117
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Did you check a few easy to reach manifold bolts and see if they were loose?
05-19-2014, 08:41 PM
#118
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Year: 1990
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It ain't a dirty intake manifold for sure.
05-20-2014, 06:27 AM
#119
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DF-Can you tighten the manifold bolts after only removing the air box? I've got to do mine and was dreading taking out all my injectors etc to get at it.
As for the OP, have we eliminated the fuel pressure / fuel pump from the equation? If it's dying on throttle application, but idles ok, do we have adequate fuel supply? I've got an annoying stumble with my '87 but I'm living with it until I upgrade the injectors. It only happens on hard acceleration and then seems to level out ok after.
When a running engine dies, I usually think loss of spark, loss of fuel or loss of air. So, ignition coil seated electrically, CPS good, grounds good, fuel pump good, all wires zip-tied and off of hot parts of engine etc.
A tough one for sure.
As for the OP, have we eliminated the fuel pressure / fuel pump from the equation? If it's dying on throttle application, but idles ok, do we have adequate fuel supply? I've got an annoying stumble with my '87 but I'm living with it until I upgrade the injectors. It only happens on hard acceleration and then seems to level out ok after.
When a running engine dies, I usually think loss of spark, loss of fuel or loss of air. So, ignition coil seated electrically, CPS good, grounds good, fuel pump good, all wires zip-tied and off of hot parts of engine etc.
A tough one for sure.
05-20-2014, 08:02 AM
#120
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Year: 1990
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DF-Can you tighten the manifold bolts after only removing the air box? I've got to do mine and was dreading taking out all my injectors etc to get at it.
As for the OP, have we eliminated the fuel pressure / fuel pump from the equation? If it's dying on throttle application, but idles ok, do we have adequate fuel supply? I've got an annoying stumble with my '87 but I'm living with it until I upgrade the injectors. It only happens on hard acceleration and then seems to level out ok after.
When a running engine dies, I usually think loss of spark, loss of fuel or loss of air. So, ignition coil seated electrically, CPS good, grounds good, fuel pump good, all wires zip-tied and off of hot parts of engine etc.
A tough one for sure.
As for the OP, have we eliminated the fuel pressure / fuel pump from the equation? If it's dying on throttle application, but idles ok, do we have adequate fuel supply? I've got an annoying stumble with my '87 but I'm living with it until I upgrade the injectors. It only happens on hard acceleration and then seems to level out ok after.
When a running engine dies, I usually think loss of spark, loss of fuel or loss of air. So, ignition coil seated electrically, CPS good, grounds good, fuel pump good, all wires zip-tied and off of hot parts of engine etc.
A tough one for sure.