vacuume lines are all messed up.. need help

Stock FSJ Tech Area

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

vacuume lines are all messed up.. need help

Post by candymancan »

edit : Since i got 0 replies ill simplify my question.

I cant find a 90 or 91 vacuum diagram.. Only an 89.. According to the 89 i should have a non linear valve rounted together in the mess of the SPARK CTO and HDC CTO.. However.. i dont have one. and the SPARK CTO has a plug on the first nipple instead of a line going to the linear valve with an r delay. both CTO are routed weirdly and nothing like the vacuum diagram says..

I also have a weird red neck job on a metal line on the intake manifold below the carb passenger side.. As you can see in the pic.. one line has a rotten vacuum line which i replaced the other is metal and siliconed on it seems and goes to the back of the carb on the top..

Another thing is my egr doesnt work.. I have to unplug a vacuum line coming from the metalic egr and going into some big round plastic thing which actually has tons of vacuum lines all routed into the air hat and stuff. I have to plug that line otherwise if i keep it connected to the egr it stalls the engine. Another thing is my air pump works.. but one of my manifolds the air injection tubes are gone and welded.. broke off from rust i imagine. The other is there.. Can i just remove this air pump block the tube on the cat ( i have a magnaflow cat brand new) and either pinch the tubes on the last manifold or weld them shut as well ?

I dont see much point in having an EGR and Air pump if my EGR doesnt work and only 1 manifold has the injection tubs. Am i right ?


https://imgur.com/a/sB2ge
Last edited by candymancan on Sat Nov 18, 2017 1:56 am, edited 2 times in total.
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: vacuume lines are all messed up.. need help

Post by candymancan »

well i fixed two vacuum lines. the two that were disconnected the one on the carb goes to the bacl of the carb on the intake on some hex nut with two openeings.

The other with a screw on a cto with 5 ends is where the purge valve actually goes.

Can i eliminate the HDC CTO ?? I heard i can and just keep the Spark CTO. Should free up 3 more vacuum lines. I found some guide saying i can remove the HDC CTO and plug it with a pipe plug. or just plug the 3 ends. But the routjng for the spark cto i need a R.DELAY in the line. Even the original vacuum line on the spaek has an RDELAY going to the non linear valve but i have no rdelay but i have no linear valve..

What is an rdelay exactly ?
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
User avatar

nograin
Posts: 26
Joined: Thu Nov 09, 2017 7:37 am
Location: Phila. Pa
Contact:

Re: vacuume lines are all messed up.. need help

Post by nograin »

The most accurate diagram for your jeep is (or was) the sticker under the hood.
Best collection of vacuum diagrams is:
http://oljeep.com/gw/vac/GW_vacuum.html
There's a '90

Those diagrams do not include the vacuum operated accessories. Tom has some of those posted as well - they come from crevices in the factory service manuals. Accessories such as 4WD switch, heater/defrost motors, brake booster, cruise control.
User avatar

nograin
Posts: 26
Joined: Thu Nov 09, 2017 7:37 am
Location: Phila. Pa
Contact:

Re: vacuume lines are all messed up.. need help

Post by nograin »

Heh. Just looked at your link. You're new to this. :)
Here's the two pictures I saw in your link.
This one is the heat tubes for the choke. There is a exhaust cross over in the intake manifold that helps warm up. Hot air from the crossover is brought to the choke's bimetal coil so it opens quicker.
On the back of the choke assembly is a vacuum operated pull-off. The hose to it should be manifold vacuum. As soon as the engine fires up, the manifold vacuum pulls on the diagphram and that opens the choke to the running position.
choke_tubeKuAxyO1.jpg
Here on the front of your 2150, the bottom nipple is the power valve housing. That should be connected to a manifold vacuum source in an intake runner. When the engine is running, the vacuum holds the power valve closed, except under full load (wide open throttle). At full load, the fuel mixture needs to be richer than part throttle. So this is an enrichment valve. If its open or leaking under other conditions, the engine will be running rich all the time, which is bad for cylinder walls and spark plugs.
2150-front-1Gjn0Jc.jpg
The top hose is for the carburetor's fuel bowls to vent when the engine is shut off - hence the electric valve in that line. Engine running, the bowls vent inside the aircleaner.
Another thing is my egr doesnt work
Are sure? This is hard to test. EGR is only used under normal running conditions. Later EGR valves are very hard to test..
.. I have to unplug a vacuum line coming from the metalic egr and going into some big round plastic thing which actually has tons of vacuum lines all routed into the air hat and stuff. I have to plug that line otherwise if i keep it connected to the egr it stalls the engine.
See - here that makes me think the EGR valve itself is working. It just may be working when it shouldn't. The thing with many lines in it is a multi-use coolant temperature actuated switch.
Another thing is my air pump works.. but one of my manifolds the air injection tubes are gone and welded.. broke off from rust i imagine. The other is there.. Can i just remove this air pump block the tube on the cat ( i have a magnaflow cat brand new) and either pinch the tubes on the last manifold or weld them shut as well ?
All depends on what you want to do. Airtubes are easy to buy. Removing the hollow banjo bolts can be a pain. I've had the easiest time removing them with an impact wrench with the exhaust manifolds off of the engine. Anyway..
The airpump arrangements changed over the years. I'm going to assume yours has (or had) a vacuum actuated diverter valve after the pump. IIRC, Engine cold - air is injected into the exhaust manifolds. Coolant temperature warmed up, air is injected into the cat. There should be check valves on each of the injection tube assemblies. I wouldn't blame you if you wanted to ditch the manifold injection...
I dont see much point in having an EGR and Air pump if my EGR doesnt work and only 1 manifold has the injection tubs. Am i right ?
They don't directly relate. Injection helps the 2way and 3 way cats. EGR, when working, will work best with the stock engine and timing. IF you ditch the EGR, at minimum you'll want to cut back on light and moderate throttle timing. If done right, its probably a wash in terms of fuel milage.
well i fixed two vacuum lines. the two that were disconnected the one on the carb goes to the bacl of the carb on the intake on some hex nut with two openeings.
The hex nut with two nips is a manifold vacuum source. One probably controls the air cleaner vacuum motors via some temperature switches in the aircleaner housing.
The other with a screw on a cto with 5 ends is where the purge valve actually goes.
?
Can i eliminate the HDC CTO ?? I heard i can and just keep the Spark CTO. Should free up 3 more vacuum lines. I found some guide saying i can remove the HDC CTO and plug it with a pipe plug. or just plug the 3 ends. But the routjng for the spark cto i need a R.DELAY in the line. Even the original vacuum line on the spaek has an RDELAY going to the non linear valve but i have no rdelay but i have no linear valve..
I'd say since you're not familair with the operations and effects, if you want to simplify, follow a factory arrangement from the late 70s when catalytic converters were first installed for all US sales.
You do not have the required permissions to view the files attached to this post.
Last edited by nograin on Sun Nov 19, 2017 6:54 am, edited 1 time in total.
User avatar

Stuka
Site Admin
Posts: 11789
Joined: Thu May 12, 2011 5:53 pm
Location: CA
Contact:

Re: vacuume lines are all messed up.. need help

Post by Stuka »

I agree that if the engine almost dies the EGR is working, but it should not be opening up at idle. Need to retrace the vacuum lines going to it.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: vacuume lines are all messed up.. need help

Post by candymancan »

Yea im fairly new to vacuum lines lol but im learning.. at first these diagrams were like.. wtf am i looking at.. but now i can follow then fairly easily at least lol.. Aparently i had the wrong vacuum diagram.. the 90 diagram shows all my dtuff is hooked up correctly

Engine doesnt just almost die. It litterally dies and sometimes wont start.. and when it does start and drives, it sputters and barely drives when the upper line on the egr from the transducer is back in. So the only way i can keep that from happeneing is remove the line from the transducer that goes to the upper part of the egr and plug it, then the engine runs fine. When i first got the Jeep i replaced all the rotten vacuum lines. and that specific line was plugged with a half rusted in peices nipple on the egr.. When i put a new line on it thats when the stalling started.. So thats why i just plug it with a wcrew ( like it was plugged with rusted metal before).

Sorry i hope im not being confusing.. I dont know much about egrs but i figured it means my egr isnt working.. Ive read on google when a egr goes bad it causes engine stalling and other ppl had this issue and a new egr fixed it



the only line that isnt connected right according to the 90 diagram is the purge vacuum line. There is one vacuum line on the duel cto that is plugged with a screw and the charcoal canister has a missing nipple for the purge signal.

On the 90 diagram looking at tje placements of the lines on the duel cto in the back, that plugged line is the purge signal line. I do habe a new cap for the canister so i could hook up the purge signal lile it should. I dunno if that will do anything to the EGR though.

Also i just bought a open air cleaner from edlebrock.. Based on what was linked in the cold air intake thread.. and i kinda want to get rid of this mess of vacuum lines.

If i put this air hat on it will automaticly eliminate like 6 vavuum lines.. All of which eventually connect to the EGR through the transducer.

Soo if i do this shouldnt i just disconnect the egr then ?

Also found a simplifying routing for the two ctos in the front of the intake.. One cto is the egr cto but it was called the spark cto prior.. I could eliminate the HDC CTO which would get rid of 3 or 4 more vacuum lines and route the disttibutor and the purge signal to the spark cto instead.

I also dont really wanna ness with buying new injection tubing.. Is it REALLY nessesary ? I want to simplify all these lines and the injection tubing and bulky hoses and solenoids for the air injection is a mess.

If i did all this would i kill my gas mileage or hurt the engine ? Another thing is my stock air hat the front flap doesnt close when engine is hot been driven and if i take the air tube off, the flap is closed still... When i removed the vacuum line to it it finally opens and i felt a increase in throttle response.

So im wondering if the VAC temp sensor thing is even working in the air hat.
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
User avatar

nograin
Posts: 26
Joined: Thu Nov 09, 2017 7:37 am
Location: Phila. Pa
Contact:

Re: vacuume lines are all messed up.. need help

Post by nograin »

You can answer most of those questions about things working by pulling the hose off while its running. A vac gage and/or pump can be handy too. Golf tees are useful for plugging hose.

On my '85, the EGR has three controls. I suspect yours is similar. A CTO which opens when the coolant hits 155 F and the TAC in the air cleaner which opens when the air temperature in the air cleaner is 55 F or above. As Stuka wrote, the EGR gets no signal at idle regardless of temperature. It supposted be connected to ported vacuum (E) on the carb. Thats the third control. SO. If the engine dies when you connect it, either there is a hole, or its not hooked up correct. Or the carb throttle is above idle position.

If your PV is leaking, or not hooked up properly to manifold vacuum, then the carb is running rich and that might cause someone to set the idle position more open than it should be.

Your air cleaner should have a cold air snorkel that connects to the front. An open element will not get cold air. If you watched the video, this was in reference to an engine running over 6000 rpm. At the end the point out how much Hp they estimate each air cleaner & filter would support. Our jeeps are nowhere in that league of air consumption. We rarely turn them to 3500 rpm.

One flap in your snorkel is for mixing in warm air - this is for consistant carburetation and quicker warmup. Max power efforts are different animal - racers are willing to make changes at the track to compensate for conditions - that's the price for another tenth or even hundreth of a second.
The other flap should always be open when the engine is running. Its there to trap fuel vapor. It helps keep your jeep smelling like gasoline when you park it.
User avatar

nograin
Posts: 26
Joined: Thu Nov 09, 2017 7:37 am
Location: Phila. Pa
Contact:

Re: vacuume lines are all messed up.. need help

Post by nograin »

I just looked at the '90 diagram. Simpler than the mid 80s. So yours has a dedicated EGR CTO, the air tem. switch and some sort of 'transducer' on the EGR itself. The '90 FSM probably explains the transducer. Operationally, the rest is the same as we described above.

R/Delay valves are Reverse Delay. They trap the vacuum in the vacuum motors when the vacuum source is low. Lets say you floor it getting on the highway. Manifold vacuum drops from 16" to 1 or 2". Without the reverse delay, the air intake flapper would shut immediately. Instead it stays open for 10-20 seconds or whatever it is.

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: vacuume lines are all messed up.. need help

Post by candymancan »

The other flap is always open when running, and closed when off. but the first flap is always closed no matter how warm the engine is.

My EGR has some kind of transducer on it i dunno what it does. Its different then the 89 and under.

So your saying the door is suppose to open when im on the freeway ?
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

ferrum
Posts: 131
Joined: Sun Jun 19, 2016 1:49 pm

Re: vacuume lines are all messed up.. need help

Post by ferrum »

My jeep is 1976. Air cleaner damper control is simple. There is only one to operate and it is connected to temperature activated vacuum switch inside air cleaner and then to TAC port behind throttle body.
When engine is cold, it send full vacuum to the damper motor to pull air from exhaust manifold heat riser. If engine is warmed up, full vacuum no longer makes to damper motor thus not pulling air from exhaust manifold. If you stomp on the skinny pedal, you would drop vacuum thus pulling in cold air.
I’m not sure if you have vacuum motor or thermal mechanical. If you do have vacuum operated motor, test is simple. Get a hand vacuum pump and test to see if motor operates.
'76 Cherokee Chief

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: vacuume lines are all messed up.. need help

Post by candymancan »

The motor works.. Im saying the door ss closed when engine is on which opens it to that lower hole for the heat riser.. But once my engine is hot and been driven even for an hour.. if i open the hood to check the door it is still closed.. I even put a camera there and stepped on the gas pedal in park and it stayed closed. I dunno.

So my ultimate question is this.

Am i harming anything by removing the air pump the only air injection tubes left on the passenger side and all those big tubes. And then removing the stock air hat and the 6 or 7 vacuum lines to it, removing the transducer and plugging the egr. Then rerouting the egr CTO and make it into a spark cto like it is on the older wagoneers to the distributor ect.. thus eliminating the HDC CTO and also route the purge signal to the spark cto like it is on older wagoneers. In essence the only vacuum lines ill have are the 3 spark cto. the charcoal canister stuff. and the brake booster. And the 2 or 3 on the carb

If i do this i remove like 20 vacuum lines. and all the bulky air pump equipment.

Or am i being stupid ?
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

ferrum
Posts: 131
Joined: Sun Jun 19, 2016 1:49 pm

Re: vacuume lines are all messed up.. need help

Post by ferrum »

My thermal sensor(I may be calling it wrong) in the air cleaner is bad being source of vacuum leak. I also live in Alaska.
In the beginning, I just disconnected vacuum motor from TAC sensor. At this point, it always pulled in cold air. This was fine until outside air temperature dropped to -20 deg F. During warmup, my throttle plate iced up. This is when I learned importance of TAC.
Now I have two modes of operation. During summer mode, I have vacuum motor disconnected from TAC. This allows cold air always. During winter mode, vacuum is connected to TAC port which would pull warm air from exhaust manifold at high vacuum and pull in cold air when vacuum is low at high idle.
I would like to replace my thermal sensor but I can’t find it. Thus the work around.
I may not be explaining well. Go a head download 76 TSM and read about TAC.
'76 Cherokee Chief

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: vacuume lines are all messed up.. need help

Post by candymancan »

NO i understand what youre saying.
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
User avatar

nograin
Posts: 26
Joined: Thu Nov 09, 2017 7:37 am
Location: Phila. Pa
Contact:

Re: vacuume lines are all messed up.. need help

Post by nograin »

Ferrum has covered the warm air mixing.

"So your saying the door is suppose to open when im on the freeway ?" This I suppose is still a question. No - its the oterh way around.. The doors are not supposed to close when accelerating at full throttle.
If you're familiar with EFI, Manifold Vacuum is the opposite of MAP. When the throttles are restricted (closed) the pistons drawing air create a vacuum below the throttle blades. The vacuum created depends mostly on the rpm and throttle position. Idle and cruising the vacuum is fairly high, under acceleration, vacuum is lower, at full throttle it is close to 0.
In the standard system we frequently refer to vacuum in inches of mercury instead of psig or fractions of atmosphere. Its all the same, the numbers just run the opposite direction. With Vacuum, zero always equals atmospheric pressure, which is somewhere around 14.7 psia depending on the weather and location.

What you remove is an individual decision. I'm just trying to answer your questions about what each thing does. That way you figure out if its working and better understand the effect will be if eliminated.
The nice part about your '90 is that the circuits are fairly well seperated.
I think your making this harder than it needs to be. The drawing can be a little confusing - On the drawing, remove or mark in color the air intake items and the rest becomes clearer. If you look at my '85's hood sticker (on Tom's website) they did a better job showing the air intake vacuum controls.

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: vacuume lines are all messed up.. need help

Post by candymancan »

No i understand now which goes where. Youre right it is simplier on the 90 where as older ones the hdc and spark cto are all cross crossed. I tjink thats where i got cinfused looking at older diagrams


Im just going to remove the stuff. I jist spent the last 2 hrs trying to get the egr to work but it isnt working. I followed the vacuum lines to a TEE and they are all in place. but the minute i hook the egr back to the transducer the engine stalls or drives but bogs down badly.. And i aint paying 100$ to replace it lol.

I just tried to get a bolt off the injection tubing and they wont budge either.. used a 2 foot long pipe and still nothing.. heated bolt red holt.. nothing.. I think they are pretty welded into the cast manifolds. I couldnt get any of the 7 off.. So even if i wanted to replace the drivers side ones which are missing and welded i dont think i could.

So ima just cut the last 4 off and weld them.. But before i do are the bolts steel ? they arent cast like the manifolds right ? Jw before i come accross issues welding the holes on the bolts.

Im also going to remove the air hat and just go with the open air filter. I like the way it looks better.. And it sounds better too lol.

I just need to figure out what to do with the purge signal line and the egr cto... That cto is the spark cto im pretty sure they arent different.. If thats the case i can route the vacuum lines to the distributor and purge signal to it like on older wagoneers and eliminate the hdc cto.
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
User avatar

Stuka
Site Admin
Posts: 11789
Joined: Thu May 12, 2011 5:53 pm
Location: CA
Contact:

Re: vacuume lines are all messed up.. need help

Post by Stuka »

Just as a note, when people say the engine runs poorly with a failed EGR, thats typically because the diaphragm tears causing a larger vacuum leak, but the leak only happens when the EGR would be opened.

Sounds like nograin has you on the right path.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: vacuume lines are all messed up.. need help

Post by candymancan »

Question maybe i havent gotten this 90 diagram down yet after all im very confused on a few thinhs... The picture of the transducer the line that goes from it to the EGR TVS which is the thing on the stock air hat.. The 2nd lin3 on the egr tvs.. where does it go too ? on the doagram it jist squiggles around and stops on nothing.. Also the bottom line on the EGR CTO it goes all the way to the back.. and says to vacuum reservoir... What reservoir ??

the only reservoir i see back there is a ball and one line is connected to the duel cto and the outlet split into the vacuum for the transfercase and so forth.

Same with the 3rd bottom line on the duel cto.. you see and F which is a plug and the last line on it splots to the reservoir and then to double vacuum hex lile nut next to the egr.

Where is this vacuum reservoir ? Am i missing something here ? because if im reading this right.. then everything on mine 90 is hooked up weird and i dont have this reservoir ? The only reservoirs i have are two plastic bubbles.. one near the washer fluid bottles and one on the fire wall.


Omg i hate these old engines and these vacuum lines geesh
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: vacuume lines are all messed up.. need help

Post by candymancan »

Okay i finally blew a head gasket called my friend over.. He knows a lot about this.. He found the problem and showed me The lines on the Jeep were in wrong spots for the EGR CTO and one other line..

Hooked uo my egr and the engine started right up.. But as soon as i step on the gas it sputters and jerks like its dying then it takes off.. And drives fine. ai can go wot fine cruising fine.. but as soon as i slow down or let off the gas and step on it again at low speeds or from a stop it lunges foward stops acts like it died.. then moves fine.


I dunno man this guy is in his 50s and has 2 carbureted vehicles and we fixed my vacuum lines and the damn egr still causes the engine to bog down.. This egr has to be bad !!!
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: vacuume lines are all messed up.. need help

Post by candymancan »

well i removed the air hat got rid of all related vacuum line and the tranducer to egr.. plugged egr.. Remove air pump and the tube to the cat. I didnt cut off the air injection tubes. what i did was get a 3/8 pipe plug and put it with some silicone on the main port to them.

Man my air pump was noisy. engine is quieter now.. Spin it by hand and it wobbles like mad and bearings sound dry.

Im happy. engine bay is much neater now.
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
User avatar

Stuka
Site Admin
Posts: 11789
Joined: Thu May 12, 2011 5:53 pm
Location: CA
Contact:

Re: vacuume lines are all messed up.. need help

Post by Stuka »

Yeah the air pumps sound terrible. They are loud new too, just their design.

Bummer you could not get it all working, but if you don’t have emissions testing, it should be fine. Your carb may be set a bit lean now without it, but probably no enough to worry about.
2017 JKU Rubicon
Pevious Jeeps: 1981 J10, 1975 Cherokee, 2008 JK, 2005 KJ, 1989 XJ
Post Reply