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General Forums => The Mess Hall => Topic started by: pioneer4x4 on February 27, 2010, 01:56:25 PM
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i have an 86 2.5 auto xj, and have been having an intermittent hesitation problem, some days it will do it and go for a while not doing it. i thought i fixed it when i noticed one of my egr bolts stripped out not sealing properly to intake, but now it returned yesterday. so i went out and bought a mityvac vacuum gauge and at idle i get a very rapid 19"-21", slow acceleration it decreases then slowly increases and steadies to about 22". when i rapidly open and close throttle its 0"-25", all this seems somewhat ok, except i would figure more than just 1" increase when i slowly rev up but manual says anything above idle indicates clear exhaust, was seeing what yall thought? kinda suspect clogged exhaust from not much noticeable increase in "hg. also manual states that lower than normal and rapid fluctuations in a range of 3" and as engine speed increases needle will steady indicates worn valve guides. but doesn't seem low to me, just very rapid and i just had a head job about a year ago. but I'm new to this vacuum testing scene. also Ive got some lifter clack going on, not real loud, but at idle its noticeable, and for jeeps this isn't anything too un-ordinary, would this have any effect on my rapid needle movements? any suggestions would be greatly appreciated. thanks in advance.
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no imput on that question, well how about this one...when i got my 86 2.5 xj, there was not emissions vapor canister, so i pulled this one out of a Comanche and a buddy of mine hooked up all the vac lines. my question is does it matter to interchange them like this? will it work? and also my diagram says i should have a egr canister solenoid, but i dont, is it essential to have one? also i am questioning his ability to hook this thing up properly, can yall tell what lines should go where? i know the pics are kinda hard to tell, but from left to right i have one opening on far left, then in middle i have another which is capped off and the one under it has a perminant plastic cap, and directly up on top where the circle/cap is another (one yellow hose is going to), then further right is another opening. im pretty sure the circular cap is the purge and that should go to egr t'd into the solenoid i dont have. but not sure on the rest. just seeing if yall have a similar one to this one and could tell me how yalls is hooked up. thanks
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i have an 86 2.5 auto xj, and have been having an intermittent hesitation problem, some days it will do it and go for a while not doing it. i thought i fixed it when i noticed one of my egr bolts stripped out not sealing properly to intake, but now it returned yesterday. so i went out and bought a mityvac vacuum gauge and at idle i get a very rapid 19"-21", slow acceleration it decreases then slowly increases and steadies to about 22". when i rapidly open and close throttle its 0"-25", all this seems somewhat ok, except i would figure more than just 1" increase when i slowly rev up but manual says anything above idle indicates clear exhaust, was seeing what yall thought? kinda suspect clogged exhaust from not much noticeable increase in "hg. also manual states that lower than normal and rapid fluctuations in a range of 3" and as engine speed increases needle will steady indicates worn valve guides. but doesn't seem low to me, just very rapid and i just had a head job about a year ago. but I'm new to this vacuum testing scene. also Ive got some lifter clack going on, not real loud, but at idle its noticeable, and for jeeps this isn't anything too un-ordinary, would this have any effect on my rapid needle movements? any suggestions would be greatly appreciated. thanks in advance.
i read this about 3 times to understand what you're asking - if i get it correctly your question is this: "is it normal for the vac to fluctuate between 19 and 21?"
i am not sure if the egr comes in play here, my Jeep does not have one - all i can tell you is that my vac is steady at idle.
the other behavior is normal (0-25 when open closing the throttle). same with opening the throttle a little, the vac would go up and then once the rpm increases it will go back down.
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yea thats pretty much the jist, i know most of the results are ok, but my main concern war the rapindness of the needle at idle.
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yea thats pretty much the jist, i know most of the results are ok, but my main concern war the rapindness of the needle at idle.
maybe you can block the egr for a test at idle and see if that changes the needle bouncing (i have no clue how the egr works). Or you can take a compression test to see if you have a bad intake valve.
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86 means that tis a tbi jeep so it has an egr.. the first page of this pdf has the entire vacuum diagram of the emissions stuff which should be helpful maybe.
http://jeepgarage.free.fr/OWN/2.5l%20cec%20system.pdf
the purge/egr solenoid can be seen in this pic to the right of that battery not the best picture but should give you an idea of what to look for.. although this is a yj so the placement will probably be different for your xj.
(http://i164.photobucket.com/albums/u25/chardrc/jeep/IMG_2607.jpg)
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maybe you can block the egr for a test at idle and see if that changes the needle bouncing (i have no clue how the egr works). Or you can take a compression test to see if you have a bad intake valve.
if the egr is activated at idle it will not idle / it would run very ruff. egr should only operate when jeep is warmed up and at partial throttle (assuming its functioning properly which would be doubtful if you don't have the vacuum solenoid but my guess is that egr is currently always off or your idle would be messed up).
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thanks for the photo, i dont have that anywhere. i put vacuum on the egr and it does not hold any, so im thinking the diaphram is gone in it, but would that cause a leak into the system? kinda dont think so since the egr would always be closed if it rips. ill see if i can find a block off plate to see if any changes occur during vacuum test. thanks
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ok so i went to the pick and pull and got a different canister and a solinoid. hooked up all vac lines properly. but as soon as i start it up the egr opens up all the way and idles like crap. if the solinoid goes out could it cause unrestricted vacume? is there a way to test it?
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the solenoid should block vacuum from getting to the egr when it is energized. so see if when your motor is cold / at idle see if it is getting power or not and go from there.
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so check the connector when its unplugged or probe thru backside when plugged in?
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would probably be easyest to unplug it and either put test light between the 2 terminals or use a volt meter. with the motor on ideling. should have power at idle
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well i just checked it and am getting 7.8 volts on the connector, but then when i kept the + prob on the connector and put the - probe on negative batt. terminal it showed 12 volts. why would that be different?
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computer must (edit might)be limiting voltage somewhere going to it.. or it has resistance somewhere that's not supposed to be there... im not shure what the voltage is suppose to be (ill have to try look it up tomorrow)
this may have an answer http://jeepgarage.free.fr/OWN/2.5l%20cec%20system.pdf
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just a thought but keep in mind that i am not familiar with the TBI so could be wrong: is the ECU giving ground or +12v on this? a bad ground can cause what he describes (less voltage)
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it started raining on me when i was testing it earlier, so i didnt have time to see what the resistance was from the ground wire to the battery, but im thinking its excessive since i got two different readings from ground at connector and ground on batt. hopefully its not raining in the morning. but if you could find out what volt is suppose to be there id appreciate it, ive researched it but have come up with nothing. thanks for all yalls input.
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well i checked the ground wire on that connector and it was 0.003-0.004 ohms, im pretty sure it should only be like 0.001-0.002 ohms right? looks like those wires goes into cab probably to computer. i checked ground for computer and its 0.001 ohms. also this is the same canister i got from the junkyard, the far right one says carb bowl on it, should i block it off or T it like the link chardrc posted? right now i T'd it to the second most left port, going to pcv because thats what all my diagrams show. ill try to clearly state where i have vac lines going. starting far left circular deal goes to egr T'd in with solinoid, 2nd over goes to pcv t'd to 4th port. 3rd port goes to gas tank.
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are there solenoid operated charcoal canisters and non-solenoid operated charcoal canisters? cause i was thinkin maybe i have a canister thats not intended to work with a solinoid? not sure what a cto is but i have read alot of threads mentioning a cto is what operates theirs. just a thought.
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did some pdf reading.. didn't find any voltage calling for the solenoid but form diagrams looks like it should be 12 volts. you can check the resistance from the solenoid ground at the diagnostic controller to the solenoid end and then to battery ground to try to help pinpoint where the extra resistance is from (but that's about my only idea for that). to answer sharpxman ecu supplies ground.
my reading hinted that there can be 2 kinds of canisters (one for and one not for solenoids) but it said all Chrysler use the kind for a solenoid but that's just for that year... anyways its important that the canister is hooked up correctly. i would have the jeep running and unconnected the vacuum hose to the solenoid (from the canister / egr side of the solenoid not the manifold side) if there is vacuum on the canister side there is something else wrong aka vacuum where their shouldn't be. i would hook up the canister like the diagram shows.. but i think the main important thing is that the egr / purge solenoid line goes to the inlet that comes out of the valve. (im no expert on how they system works and im just going off of what i read and my interpretation of diagrams. ) what did the canister come out of?
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sorry for the late reply just got off work, i didnt even think about checking at the diagnostic connector, good point ill check that tomorrow. i have two canisters the one i have in there now im not sure what it came out of, got it from nacho at amc 4x4 in arizona, just told him my make and model and he sent it to me. the other one i got out of a comanche, im pretty sure it was a 2.5L its been a while though. right now i have it hooked up like the diagrams, but currently have the egr line plugged, because thats the only way it will idle smoothly till i find the culprit. gonna mess with it more tomorrow. also ill post more pictures of the two canisters tomorrow and anything else i come up with. thanks for all your help.
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ok so i had it running (cold) and i unhooked the egr vac line off the solenoid like stated previously and there was vacuum from the solenoid nipple and from the vac line. so i guess its not hooked up right (or wrong canister) and the solenoid isn't blocking vac as well. as far as my resistance test went from solenoid (-) connector to D1 connector (-) there was 3.5 ohms and from solenoid connector (-) to D2 connector (-) was 3.2 ohms. and from solenoid connector (-) to batt (-) was 3.2 ohms. and from batt to D1 it was 0.8 ohms and batt to D2 was 0.4 ohms. so im thinking there is excessive resistance somewhere resulting in my low voltage problem. here is a shot of each of my canisters, the one in the jeep right now has labels where each vac line should go (dist vac, PVC, tank, carb bowl) but the other one doesn't. i put this one in because it looks most like how the diagram shows it to be and also i have no idea about where the vac lines should go on the other one. does either one of these look like yalls? Ive been trying to find out about the one that doesn't have labels so i can try putting that one in and seeing if anything changes. as far as the electrical stuff i think i may have to take it to the shop for that one, im not very good at chasing wires and such.
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The bottom one looks like a MPFI YJ Evap. canister.
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yea i found someone selling this same one a little while ago on ebay from a 92 yj, do you know of any differences between the egr functions on tbi and mpfi, are mpri electronically controlled or vacuum operated like the tbi? im pretty sure they are vacuum as well but idk. i have researched there are solenoids/canisters normally open and normally closed and id figure the mpfi and tbi would be more similar in function as opposed to carburetor which may be diff. i found an 89 shop manual that i have been looking at but didn't say much as which ones were normally open or closed, and not much of anything on emissions but i need to look through more thoroughly again. thanks for your help
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yea i found someone selling this same one a little while ago on ebay from a 92 yj, do you know of any differences between the egr functions on tbi and mpfi, are mpri electronically controlled or vacuum operated like the tbi? im pretty sure they are vacuum as well but idk. i have researched there are solenoids/canisters normally open and normally closed and id figure the mpfi and tbi would be more similar in function as opposed to carburetor which may be diff. i found an 89 shop manual that i have been looking at but didn't say much as which ones were normally open or closed, and not much of anything on emissions but i need to look through more thoroughly again. thanks for your help
my '95 YJ doesn't have egr - i don't think any of the 91-95 had one
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the canister in the first picture looks alot like the canister in my tbi jeep.. so i would stick with that one of the 2 you have. but since you are having vacume from the canister at all times tio the egr the canister that would elad me to think the canister isn't working correctly. i would cross refrence with mine but it is in storage :brick:
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i don't think the vacuum canister you have will work. the outlet you are using is labeled distributor vac which needs vacuum all the time so its always giving vacuum which is why your egr is always on (can test this theory buy turning on jeep unplugging that line and seeing if there is vacuum there or not from the canister but from what you said before that is the only place where that vacuum would come from)). basically that canister is from a carbed jeep which is controlled differently. the other canister may work.. biggest thing that you need is to have one port that only gets vacuum applied to it and wont make vacuum itself from the other inputs to the canister. the carbed one looks correct but with the labels and what is actually happening it doesn't seem like it will work unfortunately.
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yea i was thinking the same thing about the carbed one, i went and put my vacuum gauge to the other canister and all the ports hold vacuum except the one on the far left, so im guessing thats the tank vent. the little port on top im thinking would be the one for egr and one underneath would be pcv. how ever im not sure if i use the one on the far right because its so small to put a hose on and it has a cross in it for some reason. and i couldn't blow through any of them except for the one on far left. do you think this can is plugged since i cant blow through it?
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id look at a vacuum diagram for the vehicle its from to see what that one goes to for what it is supposed to do...
looked at a diagram for 92 yj (what it came form right?) anyways the middle one goes to manifold (vacuum source) the one to the left goes to the fuel tank(fuel tank vent) and the one to the right goes the the air-box venturei.. so id try with the center outlet going to purge solenoid / egr (test to see if you get vacuum into that opening or it its one way out like you need) then have gas vent to the left and pvc to the right.. it may work that way but not entirely sure especially since the stock one has the pcv split into t2 for some reason.
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what would be the downside of blocking the egr completely and use a 91-95 vap canister that is vacuum actuated (at least that's what i think it is)?
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im pretty sure re-circulating the exhaust gas back through the system lowers the cylinder head temperatures. but if anyone can chime in if that is correct or incorrect. id love to block it and be done if it wont have any problems.