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General Forums => The Mess Hall => Topic started by: Backroads on November 09, 2010, 03:44:03 PM
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I posted a while back that I was replacing the engine in my jeep YJ. Its a 90 Wrangler TBI 2.5L. I swapped in a 94 engine but just converted it to TBI. So its still Vbelt, and has all the original accessories etc from the 90 on it.
Now the problem. Aside from some exhaust leaks and a failing power steering pump :confused: it starts and drives great.
So far its been a pretty random and intermittent problem but it just shuts off. As in the engine stops turning and stops running, accessories still work and steering enough for me to coast to the side of the road and restart.
There really hasnt been a pattern to it other than its usually after or during a turn. I was goofing around in the parking lot and if I would stomp on it hard and turn a little, it would die (did that twice intentionally)
Its quite possible I have vacuum lines messed up, but other than that I dont really know where to start! I'm hoping you guys can help me out some!
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check if you have fuel pressure when it stops. also see if the tacho indicates the rpm while in gear (so the engine is spinning) when dies, if is not showing the rpm (needle at zero) it means there's something with the spark or crank sensor or something electrical cutting off the spark, if it shows the rpm then most likely fuel related.
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Its at the point now where I can start it, it will run for a minute or so, but once the idle starts to drop down to where it should be (after cold start) it just keeps falling and sputters out.
I backed it up and down my driveway some to see how it acted and same thing, it will go but then instantly shut off.
As far as the needle showing rpm, I'd have to try it and see if i can get it to move enough to tell.
On a side note are there any good diagrams on this website or elsewhere of vacuum routing for a 2.5L from a 90 with TBI?
The haynes manual sucks, and all the diagrams i'm finding online are basically copies of that and it doesnt even really cross reference to whats on my engine.
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vacuum leak would generally make the idel higher, not make it die. unless you messed up the one to the map sensor or plugged the egr valve into the wrong line possible (wont run at normal idle)...
best vacuum diagrams i have been able to find are at http://jeepgarage.free.fr/ownersmanual.html.. don't have time to figure out which one actually has the vacuum diagrams atm... actually i think this is the one you want: http://jeepgarage.free.fr/OWN/2.5l%20cec%20system.pdf
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TPS maybe?
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I've had a bad TPS in my XJ before and it would run, it just would act really strange with not shifting etc (its an auto) I guess its possible, just doesnt really seems not related to throttle position, it dies if I'm off the throttle, or mashing the throttle trying to get another 10 feet to swerve off the road!!!
Now EGR valve could very well be it. As I said the vacuum lines are a nightmare, I just wanna find a good diagram and know where everything is supposed to be so i can redo the lines. Gonna check the link above right now and see what i can find.
Thanks for the help so far guys.
edit: so I get the diagram in the second link above but why is the EGR valve T'd off into the MAP sensor line?? I dont think thats how mine is, but I'm wondering whats the purpose there?
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edit: so I get the diagram in the second link above but why is the EGR valve T'd off into the MAP sensor line?? I dont think thats how mine is, but I'm wondering whats the purpose there?
its not. it T-s into the EGR/Evap solenoid. look where the arrow points to for the MAP.. its a little misleading if you look at it to fast now that i think of it. maybe ill edit it in paint and color code it if you want.. lol
(http://i164.photobucket.com/albums/u25/chardrc/jeep/vacumediagramcolo.png)
i realize this diagram is misleading since in reality all the vacuum line go through those metal lines to the back of the motor then ever rap around or go out toward the air cleaner box... and it doesn't show the 2 (or is it 3) lines that go through the fire wall to work the heating and venting stuff (one comes form the drivers side of the motor and the other form the passenger line above the evap canister. they are kinda easy to spot because they are the only ones with check valves and they become hard plastic lines to go through the fire wall)
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:beers: my friend... That is me buying you a beer!!! Thats exactly what i was looking for. And your right with all the lines going everywhere its hard to follow them on paper then retrace them through that hardline combo around the back of the engine. I will get on putting everything together right and report back! Thanks!
One more thing... On the rear of the plastic cover over the throttle body there are 2 ports and kind of a double plug of vacuum lines that goes into it... Where do those two lines go to? Is that the heater control vacuum lines?
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ya that thing on the elbow that attaches to the top of the tb is a valve for the vacuum that opens when the temperature is low enough (its for the hot air intake thing as you said) there is another one of those in the back of the airbox as well. as to where the lines specifically go. one goes to the back of the air box (on the smaller orifice (i think into the other thermo valve), not the big orifice that is for the positive pressure line for PCV system) the other one goes to a hard line near the back of the motor. i think its the hard line that is hidden under the big hard line that has the hose that goes to the airbox for the positive pressure PCV(it took me a while to get that one right last time i had the motor out). ill see if i have any pics of my jeep i can hack up to make it more clear.
edit: looked though my pics and realized i still don't have any good engine bay pics that show vacuum lines in a way i could make useful.
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Ok so one goes to the ports on the box the other goes to a hardline (is that hardline part of the group of 4 that are all connected?)
If it does, what does the other end of that hardline go to? Whats it pulling vacuum from?
heres a pic of said thing for future searches
(http://i413.photobucket.com/albums/pp218/BackroadsXJ/2ad3caf6.jpg)
I also have these 2 ports on the intake manifold itself that I'm unsure what goes there.
One is a pretty big opening, the other (might be bent?) is a small bent inlet (smaller than the one you can see)
heres a pic of those 2 holes (one has a hose going to it which is not going to the right spot im sure lol)
(http://i413.photobucket.com/albums/pp218/BackroadsXJ/4f4d500d.jpg)
and lastly heres my EGR valve (after your diagram last night im positive I have everything hooked up right as far as EGR and MAP and the PCV lines etc) I just have 3 lines coming from the EGR and the diagram only shows 2 lines. pic here (the small plastic line is the one in questions)
(http://i413.photobucket.com/albums/pp218/BackroadsXJ/637a041c.jpg)
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ok did allot of paint picture editing (lol) hope this helps. those hard lines get their vacuum form the lower part of the tb on the motor side (there is a rubber coupler to it (4 hard lines get vacuum form there) (1 of them gets vacuum form the 90 degree elbow you need per one of the fallowing pictures (your second picture).
some of the info i had to take from memory so not 100% sure (and put jeep in storage yesterday so can't check today) but i did find some pics form my jeep that may help.
i tried to stay with the same color coding as the original diagram made
(http://i164.photobucket.com/albums/u25/chardrc/jeep/vacumecolor1.png)
(http://i164.photobucket.com/albums/u25/chardrc/jeep/vacumecolor2.png)
(http://i164.photobucket.com/albums/u25/chardrc/jeep/vacumesolinoidcolor.png)
(http://i164.photobucket.com/albums/u25/chardrc/jeep/vacuemcolor.png)
(http://i164.photobucket.com/albums/u25/chardrc/jeep/vacumecolor4.png)
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@chadrc - awesome job man :thumb:
@Backroads - hope you get your rig working ( if you do make use of that applaud button for chadrc :clap: )
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Well its really starting to come clear how screwed up the whole thing is! no wonder it doesnt run right!!! I think I'm following ya there on all those traces. Gonna go back in and troubleshoot my mess tomorrow hopefully.
Again, I really thank you for taking the time to do that. Couldnt be a bigger help!
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All that is hooked up and good. Only issue is that line that you circled in purple, where those lines are supposed to be connected by an elbow...well I've got that BUT on the other end of the hardline (very bottom line on the joined 4 lines that cross the back of the head) what does that side (passenger) plug into?
There are also 2 vacuum lines coming from the transmission area in that loom of wires. One is a blue hardline the other is clear, although they may not be original color codes for that stuff.
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so now with everything hooked up right (I found another line on the pass side that SHOULD be the right spot for that bottom hardline hose thats going to the open port on the intake manifold.
but now it wont start. I'm guessing it was running before from all the open air vacuum it was sucking up~! so now I'm wondering TPS or the ICS (i think its called? the plunger the throttle hits when its closed?) are bad sensors.
gonna try and test the TPS now.
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the 2 hard plastic vacuum lines coming from the transmission area come from the trasfer-case and are used to engage and disengage the central Axle disconnect on the front axle. those lines are long gone on my jeep (previous owner went with a cable actuator) I found a diagram of the system (see below) it should be the same for all yj's so if those liens come from the transfer-case and that diagram doesn't help someone else can chim in that is more familiar with the CAD vacuum system (from the diagram i can't tell where it gets the vacuum unless the t-case creates vacuum somehow)
(http://i164.photobucket.com/albums/u25/chardrc/jeep/cadvacumediagram.png)
as for what connects into that purple hard line, its either the red #1 line going the the vacuum solenoid, or the blue line that T's into the evap canister (im leaning towards the blue line). i don't remember which but as long as the tube size matches it shouldn't matter (as long as what needs vacuum gets it).. are there 2 or 3 hard lines that go behind the motor (im having a hard time remembering)
edit for your new post: test your tps and iac as you mentioned... when you turn the jeep off the iac motor should fully extend so that the jeep has extra air to start. (have you tired to start it while holding the throttle partially open to give it some air to test your lake of air due to no vacuum leak theory)
also make sure you plugged in the egr vacuum solenoid (it wasn't in your pic, it would make it idle like crap since i think if its not pluged in it lets vacuum go through which engages the egr but shouldn't stop it form starting would just make it run rough)
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(from the diagram i can't tell where it gets the vacuum unless the t-case creates vacuum somehow)
looking at it again i would guess that it probably gets vacuum form the line that ends with a check valve, which i have no idea where it goes to.
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The evap purge line is there with the second fittig Td into it as well. That goes to a thicker hardline and into the TB. Thats all right and like the diagram shows.
As for the Xfer case and 4wd, I plan to do away with that anyways so I will just leave those go for now, unless I should cap them or something else?
There is a check valve in the engine bay, under the battery area that doesnt have anything plugged into it. I didnt know if that purple circled line should go to that? Theres really nothing else over there I'm seeing that it should go to. Its a pretty large line so it looks like it should go to something that needs a descent amount of vacuum.
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As for the Xfer case and 4wd, I plan to do away with that anyways so I will just leave those go for now, unless I should cap them or something else?
mine where just cut off after that multiple hardline connector near the evap can. would probably be a good idea to cap them off but i haven't
There is a check valve in the engine bay, under the battery area that doesnt have anything plugged into it. I didnt know if that purple circled line should go to that? Theres really nothing else over there I'm seeing that it should go to. Its a pretty large line so it looks like it should go to something that needs a descent amount of vacuum.
only check valve on the passenger side i remember is the one circled in my pic with the "4?" which i think should be connected to the 4? from your vacuum solenoid. but the other end could go to that hard-line (which makes sense... im kind of at the point where i don't remember any more details (and studying for 2 midterms this weekend has my brain working overtime)
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Everything aside from a crappy exhaust is finally kosher.
Thanks chadrc for all the help, I really had everything screwed up!
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no problem.. gotta keep the tbi's running we are vastly outnumbered :pirate:. lol.. just curious, what ended up being the more recent problem with not starting, was it a sensor or more vacuum lines.. :beers:
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as ashamed to admit it...I now know all about the YJ gas tank recall :brick:
My guage was reading over 1/4 tank of gas, so I assumed it had gas!! Well it wasnt running, and randomly shutting off because.....I HAD NO GAS!
It all makes perfect sense now, so my next object issue is to drop the tank and replace the gasket and whatever else is leaking under there as well as the sending float.
Only issue I'm having now as far as vacuum is that I only have heat on defrost, no matter what position the operating lever is in...I gotta recheck all that and see whats going on there..
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Strange since the vacuum control should be independent to the Defrost/Heat/Vent control. You should be able to manually set the heat by switching the vacuum lines. The manifold is right above the ashtray behind the dash.
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someone had found that there is a difference between the yj and xj vacuum systems and i figured id put the answer here to keep the tbi vacuum stuff in 1 area.. thanks to my recent find of a 1990fsm i found a diagram for the xj system. basically the xj uses ccv system where yj uses pcv. and some things plug into the manifold rather than the tb. i didn't take the time to color code it but its basically the same as the ones on the last page.
(http://i164.photobucket.com/albums/u25/chardrc/xjvrsyjvacum.png)
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This thread is what helped me find this board. I need some additional info to get everything just right on my 1989 YJ 2.5L
In this picture where does the hardline connect?
http://img829.imageshack.us/i/vacuumlines1.png/
On my 4 banger the line is part of the group that goes behind the head to a block of lines one the passenger side. I guess the port on the intake and vacuum line isn't shown in the emissions diagram because the small port goes inside to the dash and the bigger line goes to the axle disconnect? That is the only place I can figure it would go because my Jeep doesn't have the vacuum disconnect and this line is plugged.
Next, is the blue thing circled in this pic the 4wd indicator light?
http://img576.imageshack.us/i/vacuumlines2.png/
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the blue thing is the 4wd light sensor (part of the vacuum axle disconnect stuff)... found another vacuum diagram in the parts catalog that actual shows the true routing of the hard lines. i color coded it to match my previous images (with a few differences for clarity) hope it helps. the hard line circled in purple in the photo you quoted needs to have a 90 degree elbow connecting it to that orifice in the manifold. the other end goes around the back of the motor and then goes to the front axle vacuum disconnect stuff or it goes into a small plastic line with a check valve that goes through the fire wall. i forget which...
(http://i164.photobucket.com/albums/u25/chardrc/vacumediagramcolor.png)
edit: image was re sized in this post, if you double click and view image form photobucket you can enlarge to 100% to see it better
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split it in two for better viewing:
(http://i57.photobucket.com/albums/g222/sharpxmen/Misc/vacumediagramcolor_1.png)
(http://i57.photobucket.com/albums/g222/sharpxmen/Misc/vacumediagramcolor_2.png)
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That is a great picture of the vacuum hoses! It's so hard to look at the regular diagram and follow how the lines are supposed to run.
Now the other question I had was about the vacuum switch, part 19 on that diagram. Mine has 1 port on top and two ports on the bottom. I haven't found anything that shows where the 3rd port connects to.
Thanks for the help!
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only one of the bottom 2 ports is used. the other is one has a cap over it.
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Awesome diagram, that actually looks like what you see under the hood instead of those haynes manual diagrams!