Topic: vacuum tests?

[pioneer4x4]

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.

[pioneer4x4]

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.

[pioneer4x4]

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.

[chardrc]

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?

[pioneer4x4]

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.

[pioneer4x4]

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.

[Jeffy]

The bottom one looks like a MPFI YJ Evap. canister.

[pioneer4x4]

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

[sharpxmen]

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

[chardrc]

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 

[chardrc]

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.

[pioneer4x4]

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?

[chardrc]

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. 

[sharpxmen]

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)?

[pioneer4x4]

 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.