egr tube blowout turns ugly & related idle issues (1 Viewer)

[Infinity00]

I have 85 FJ60 2F engine running great, mainly operated at an altitude of 5800-6500ft. While traveling at 60 mph the EGR tube blew out of the cooler. For a couple of months prior I smelled small amount of exhaust in the cab so it was probably leaking before it blew. We didn't know how catastrophic it could be when it failed or would have looked into it sooner. When the hot exhaust filled the engine compartment at 60mph, the brakes failed, they went to the floor, luckily no one was injured. Still not sure why they failed but assumed the brake fluid boiled, also the brake booster line was damaged, wires fried and coolant tube all in the back of the engine bay where the fumes would collect and heat everything. The coolant leaked but engine didn't appear to overheat according to the temp gauge. Quickly used the e-brake and pulled off the highway. After getting a tow for 20 miles, and a couple hours later the brakes worked again (when just rolling the truck without starting it and applying the brakes, stopped no problem). Had a friend perform repairs, repairs included
removed EGR, EGR modulator EGR cooler and tube because the tube will no longer thread into the cooler everything was removed.
·A plate was bolted where the egr tube feeds from the exhaust.
·Replaced black temperature sensing gauge wire for carb fan, a green wire that goes to maybe the coolant gauge next to the valve cover
·replaced brake booster tube and accordion part that fits into intake manifold (ac something or other?)
·flushed master brake cylinder and bleeding all brake lines
·replaced choke cable
·replaced intake and exhaust manifold gasket and sealing it with orange gasket sealer (looked like it may have had a little exhaust leak past the old gasket at some point in its life)
·the carb was removed to replace the manifold gasket but nothing was done to it.
·BVSV (violet one) was broken during repairs and vacuum tube looped to bypass was added.
·Coolant tube in back replaced
At this point I'm not sure what else was done to get it to run, but I believe the timing was advanced from 7 degrees BTDC to 14 degrees BTDC and the mixture screw was turned out to 5.25 turns, and vacuum lines re-routed to possibly account for missing EGR and EGR modulator. It idled great and drove great for about 10 miles. Then it started to die when giving gas going up a slight hill, but it idled fine. I thought I could hear a sucking sound and the gas in the carb window looked low. Nursed it back to flatter area and let it sit a day. The next day it was drivable downhill. Drove the next day without too much problem, seemed okay. The friend who repaired it opened the top of the carb and found gasket material in the float needle and bowl. He removed it and it ran okay for another day or two. Then idling problems occurred. I removed the carb and tore it down. I found gasket material in the slow primary jet and cleaned the gasket material off the carb base that my friend had applied when fitting everything back together previously. I replaced everything I could from a hygrade rebuild kit (Thanks Pinhead for the youtube!). The heat shield was broken and where the metal tube for the evap system at the base of the carb insulator was cracked where it’s epoxied in place (maybe from heat, maybe from age). The infamous 4 hoses on the valve side of the carb were cracked through as well (possibly the sucking sound). I replaced the heat shield insulator combo with a Cdan Toyota one with the bonded gaskets. Before putting it on, I looked for the manifold crack so many people talk about but didn't see anything and I put the rebuilt carb back on and replaced all the vacuum lines and routed the lines correctly according to FSM and fender sticker. I capped the hard line that fed the modulator and vacuum solenoid switch that fed the egr/egr modulator (I don't remember where it led to)

Results:
The truck fired right up but will only start with the choke pulled completely out and pumping the gas pedal twice to set the choke. Once it is started, I can push the choke in but then I can only keep it idling using the throttle, or pulling the choke 1/8”, just enough to lift the accelerator but not enough to close the plate. After it starts, if the choke is pulled out all the way the engine revs to 2000-2500 rpms. When pushing the accelerator it responds immediately and sounds great. I've tried a number of things to get it to idle, adjusted the carb using the lean drop method (not very successfully), tightened carb base, and adjusted the timing. Rechecked vacuum routing, HAC right and left were wrong so I fixed those without any luck. First I put the vacuum gauge on the brake booster line hoping to remove the booster from the vacuum circuit in case it was bad and the reading was really low at 5 or so inHg. Then put the brake booster line back on and put vacuum gauge between smaller vacuum line on the manifold at accordion and one of the solenoid vacuum switch ports. The reading started at around 11-12 inHg oscillating up to 15 or so. If I gunned it and quickly let up on the accelerator it went low and then high (around 22-25 inHg) like it is supposed to do.

From reading many posts, I'm suspecting a vacuum leak somewhere but the possibility it’s just a mis-tuned carb occurred to me as well since it did run fine before the gasket material got sucked up into the jet. Or the bonded gaskets on the carb insulator don't work well, which might be why I found gasket sealer on them along with doubled-up gaskets. Maybe I need to add paper gaskets there, or send the carb off to JimC to see if he sees anything messed up or otherwise qualify it as good or bad. Right now I'm at a loss besides pulling the carb again. Oh, the fuel cut solenoid clicks, and the gas is in the middle of the carb window (but sometimes goes a hair higher than middle if I've revved it a lot). I've read other peoples post on won't idle less than 1000 rpms but there usually isn't a conclusion post identifying what the person ultimately fixed it with. Does anyone know if I can isolate the brake booster in case it was damaged and leaking vacuum? Any input/help appreciated!

 

[Spike Strip]

Musta been the evil twin that used black txt on black background .....

 

[2mbb]

reposted for you...

I have 85 FJ60 2F engine running great, mainly operated at an altitude of 5800-6500ft. While traveling at 60 mph the EGR tube blew out of the cooler. For a couple of months prior I smelled small amount of exhaust in the cab so it was probably leaking before it blew. We didn't know how catastrophic it could be when it failed or would have looked into it sooner. When the hot exhaust filled the engine compartment at 60mph, the brakes failed, they went to the floor, luckily no one was injured. Still not sure why they failed but assumed the brake fluid boiled, also the brake booster line was damaged, wires fried and coolant tube all in the back of the engine bay where the fumes would collect and heat everything. The coolant leaked but engine didn't appear to overheat according to the temp gauge. Quickly used the e-brake and pulled off the highway. After getting a tow for 20 miles, and a couple hours later the brakes worked again (when just rolling the truck without starting it and applying the brakes, stopped no problem). Had a friend perform repairs, repairs included
removed EGR, EGR modulator EGR cooler and tube because the tube will no longer thread into the cooler everything was removed.
·A plate was bolted where the egr tube feeds from the exhaust.
·Replaced black temperature sensing gauge wire for carb fan, a green wire that goes to maybe the coolant gauge next to the valve cover
·replaced brake booster tube and accordion part that fits into intake manifold (ac something or other?)
·flushed master brake cylinder and bleeding all brake lines
·replaced choke cable
·replaced intake and exhaust manifold gasket and sealing it with orange gasket sealer (looked like it may have had a little exhaust leak past the old gasket at some point in its life)
·the carb was removed to replace the manifold gasket but nothing was done to it.
·BVSV (violet one) was broken during repairs and vacuum tube looped to bypass was added.
·Coolant tube in back replaced
At this point I'm not sure what else was done to get it to run, but I believe the timing was advanced from 7 degrees BTDC to 14 degrees BTDC and the mixture screw was turned out to 5.25 turns, and vacuum lines re-routed to possibly account for missing EGR and EGR modulator. It idled great and drove great for about 10 miles. Then it started to die when giving gas going up a slight hill, but it idled fine. I thought I could hear a sucking sound and the gas in the carb window looked low. Nursed it back to flatter area and let it sit a day. The next day it was drivable downhill. Drove the next day without too much problem, seemed okay. The friend who repaired it opened the top of the carb and found gasket material in the float needle and bowl. He removed it and it ran okay for another day or two. Then idling problems occurred. I removed the carb and tore it down. I found gasket material in the slow primary jet and cleaned the gasket material off the carb base that my friend had applied when fitting everything back together previously. I replaced everything I could from a hygrade rebuild kit (Thanks Pinhead for the youtube!). The heat shield was broken and where the metal tube for the evap system at the base of the carb insulator was cracked where it’s epoxied in place (maybe from heat, maybe from age). The infamous 4 hoses on the valve side of the carb were cracked through as well (possibly the sucking sound). I replaced the heat shield insulator combo with a Cdan Toyota one with the bonded gaskets. Before putting it on, I looked for the manifold crack so many people talk about but didn't see anything and I put the rebuilt carb back on and replaced all the vacuum lines and routed the lines correctly according to FSM and fender sticker. I capped the hard line that fed the modulator and vacuum solenoid switch that fed the egr/egr modulator (I don't remember where it led to)

Results:
The truck fired right up but will only start with the choke pulled completely out and pumping the gas pedal twice to set the choke. Once it is started, I can push the choke in but then I can only keep it idling using the throttle, or pulling the choke 1/8”, just enough to lift the accelerator but not enough to close the plate. After it starts, if the choke is pulled out all the way the engine revs to 2000-2500 rpms. When pushing the accelerator it responds immediately and sounds great. I've tried a number of things to get it to idle, adjusted the carb using the lean drop method (not very successfully), tightened carb base, and adjusted the timing. Rechecked vacuum routing, HAC right and left were wrong so I fixed those without any luck. First I put the vacuum gauge on the brake booster line hoping to remove the booster from the vacuum circuit in case it was bad and the reading was really low at 5 or so inHg. Then put the brake booster line back on and put vacuum gauge between smaller vacuum line on the manifold at accordion and one of the solenoid vacuum switch ports. The reading started at around 11-12 inHg oscillating up to 15 or so. If I gunned it and quickly let up on the accelerator it went low and then high (around 22-25 inHg) like it is supposed to do.

From reading many posts, I'm suspecting a vacuum leak somewhere but the possibility it’s just a mis-tuned carb occurred to me as well since it did run fine before the gasket material got sucked up into the jet. Or the bonded gaskets on the carb insulator don't work well, which might be why I found gasket sealer on them along with doubled-up gaskets. Maybe I need to add paper gaskets there, or send the carb off to JimC to see if he sees anything messed up or otherwise qualify it as good or bad. Right now I'm at a loss besides pulling the carb again. Oh, the fuel cut solenoid clicks, and the gas is in the middle of the carb window (but sometimes goes a hair higher than middle if I've revved it a lot). I've read other peoples post on won't idle less than 1000 rpms but there usually isn't a conclusion post identifying what the person ultimately fixed it with. Does anyone know if I can isolate the brake booster in case it was damaged and leaking vacuum? Any input/help appreciated!

 

[Infinity00]

thanks, I didn't know...

 

[Infinity00]

update:
without using the choke, I got it to idle at 1000 rpm and holding vacuum at 15 to 16 in Hg, with a blip every once in a while down to 11 or so. Don't know what's causing that yet.

If I pump the brakes the vacuum drops 1-2 inHg with every pump, then jumps back up to 15-16 when I let it off. Is that normal?

 

[Slow Left]

Might want to give your fuses a quick check, especially the 'engine' fuse, just to knock that off the list if you haven't already.

Sounds like a vac leak, right? Setting the idle mix and idle speed screws or using the choke to compensate for a vac leak.

Other thing, which is one of those last resort kinda things where you have already put so much work in it and don't feel like going back to double check everything just yet, but something you can cross off the list of possibles is the Emissions Computer. Not really a computer, but rather a bread board. Located behind the kick panel to the left of your left foot if you are sitting in the driver's seat.
If you take it out and look for solders that have run into each other, that might be an indicator. Or if you are electrically inclined and know how to probe test it, then it is easy to open it up and access it. If you buy a used one, assuming they are cheap, somehow you've got to be convinced that the used one is good.
But you mentioned all that heat, so maybe it found its way back to the Emissions Computer, too.

 

[Slow Left]

Just wondering, what do you think caused the egr pipe to blow out like that in the first place?

Just wondering if that is a symptom of a clogged cat or muffler.

 

[Slow Left]

Wait a second, so right now the EGR valve and EGR valve regulator and EGR cooler have been removed and a plate is covering the EGR inlet on the exhaust manifold?

What you need to know from someone on this site who knows about desmog is whether or not you can expect the truck to run normally having done just this and not committed to a full desmog and distributor recurve.

Also, you might want to keep the intake/exhaust manifold leak on your radar still, because I'm not sure that using the orange sealer is the best way to go. I think I've seen people use it or at least mention using it on some threads, did they say it worked for them?
What manifold gasket did you use?

 

[Slow Left]

Or the bonded gaskets on the carb insulator don't work well, which might be why I found gasket sealer on them along with doubled-up gaskets. Maybe I need to add paper gaskets there

You replaced the old insulator/heat shield plate that goes between the intake manifold and carb with a new one from cdan, right? That should be good then, without adding paper gaskets or sealer as long as the faces on the intake manifold and carb were clean and the bonded surfaces on either side of the new insulator/heat shield plate assembly were clean and without any major scratches. You can check for leaks here again though, using the old carb spray method.

Just a suggestion when putting that insulator/heat shield on and tightening down the carb on top of it. I find it helps to leave the two bolts that hold down the aluminum 'wings' on the shield until last, after I have tightened down the four nuts right underneath the carb that thread onto the four studs. That way you know that when you tighten those four down, they are going flat. Take turns tightening down the four nuts on the studs under the carb, the same you would torquing head bolts; instead of tightening on down all the way, then the second, etc. Once you have the four nuts down tight, then you can snug up the two bolts on the alum wings. Those two bolts don't need to be very tight and remember you are tightening into aluminum, so go easy on them.

 

[Slow Left]

Does anyone know if I can isolate the brake booster in case it was damaged and leaking vacuum? Any input/help appreciated!

With the engine off, if you unplug the brake booster hose at the manifold and apply vacuum (~15-20 inHg) with your handheld vacuum gauge, does the vacuum diaphragm inside the break booster hold a vacuum (for minutes, not seconds)?

 

[Slow Left]

First I put the vacuum gauge on the brake booster line hoping to remove the booster from the vacuum circuit in case it was bad and the reading was really low at 5 or so inHg. Then put the brake booster line back on and put vacuum gauge between smaller vacuum line on the manifold at accordion and one of the solenoid vacuum switch ports. The reading started at around 11-12 inHg oscillating up to 15 or so. If I gunned it and quickly let up on the accelerator it went low and then high (around 22-25 inHg) like it is supposed to do.

So when you checked the manifold vac off the break booster line, you first removed the line on the break booster side, then attached your handheld vac gauge to the line and it gave you a reading of ~5 inHg?
There should be a smaller port that t's off the brake booster port on the manifold itself. The smaller port traces to the A/C idle up solenoid. Did you measure vac there, too? Did it read the same as the brake booster?

Then you checked manifold vac from a smaller port, the 'accordion'. Which one is that? But you got a higher vac reading there.
Strange.

 

[Infinity00]

Slow left thank you for your input-
So I did notice the black box dangling around my left foot with a rats nest of wires, this must be the emissions computer you are talking about. I'll check it out, will the schematics be in the emissions FSM?

 

[Slow Left]

Nah, shouldn't look like a rat's nest of wires. It looks like this (see picture); its a proper box. It is located behind the kickpanel on the left wall down there. You must unscrew 2 screws in order to remove the panel, and then unbolt the module and uplug it from the wall.
Once you've got it out, gently pull back the tabs holding the cover and you'll see the bread board. Problem is, there is no procedure outlined in the FSM to test it. Unless you know electronics and know which circuits go where, the only thing you can do (like me) is look to see if any of the solders have bled together, shorting the circuit.
Maybe someone else has experience probe testing these things, but I have a feeling most folks toss em when they do a complete desmog.

 

[Slow Left]

oops forgot to attach image. here it is.

 

[Slow Left]

Have you searched the site to see if your original problem has been identified/logged before? I still think it would be helpful to try and figure out why that j-pipe came off in the first place. The reason why, is because the original problem may still persist and be partially or fully responsible for why the rig is running the way it is now.

Was it rusted all the way through?

I still keep wondering is a clogged cat or muffler would build up enough back pressure to make that thing pop off, if it was the weakest link. The vac readings you posted kind of indicate that a clogged exhaust might fit the symptoms (see chart, lower right #16).

Also, the vac leak still fits (with the way you have to compensate by either setting carb screws or choke). Keep that on the table. Recheck manifold, base carb insulator for vac leaks. Did you test the brake booster? Try pulling the vac hose on the brake booster side, plugging it good, and measure manifold vac from the other side of the manifold (wherever that accordion thing is) - obviously while the truck is in neutral and parked with the brake on, not driving. Compare original vac reading you posted above when the brake booster line was attached with the new reading with the line plugged and see if vac improves.

 

[Infinity00]

okay I'll look for that box. As for the 'engine' fuse, what does this fuse do?

That's a good question regarding why the tube blew out in the first place, I'll have to investigate that more. Also the flapper/deflector wasn't working so maybe all of it was overheated and then blew, just writing as I'm thinking. Even after all the 'fixes' I can smell exhaust in the engine and was trying to determine where it was coming from. Thought it was the hose used to plug the tube wasn't sealed well (no clamp) or the plate that was bolted on the exhaust but maybe there's more to it than that.

I don't know what gasket was used but generally parts supplied from Kurt I think...

I did a lot of searching on what needs to change when the egr is removed and like you alluded to, most posts are regarding a fully desmogged unit. I believe at the very least the timing will have to be advanced and also because I'm at altitude (but I never had it advanced before this and it ran fine).

 

[Infinity00]

You replaced the old insulator/heat shield plate that goes between the intake manifold and carb with a new one from cdan, right? That should be good then, without adding paper gaskets or sealer as long as the faces on the intake manifold and carb were clean and the bonded surfaces on either side of the new insulator/heat shield plate assembly were clean and without any major scratches. You can check for leaks here again though, using the old carb spray method.

Just a suggestion when putting that insulator/heat shield on and tightening down the carb on top of it. I find it helps to leave the two bolts that hold down the aluminum 'wings' on the shield until last, after I have tightened down the four nuts right underneath the carb that thread onto the four studs. That way you know that when you tighten those four down, they are going flat. Take turns tightening down the four nuts on the studs under the carb, the same you would torquing head bolts; instead of tightening on down all the way, then the second, etc. Once you have the four nuts down tight, then you can snug up the two bolts on the alum wings. Those two bolts don't need to be very tight and remember you are tightening into aluminum, so go easy on them.

Yep, no major scratches, clean surfaces, tightened them correctly, tightened each one slowly in a crisscross pattern, without tightening one all the way first. I inadvertantly didn't tighten the wings until the end but didn't think about that issue. I may go back and start over since I did another snug down of the bolts after I thought there might be a vacuum leak there and those could have impacted that last snug down. hmmm

 

[Slow Left]

By the way, I recently was concerned that I might have fried my cat (stinky exhaust while I was diagnosing a carb problem), so when I had my down pipe off to replace the check valve, I removed the cat from the muffler. I shined my flashlight through it and saw light peaking through, so I figured it must be ok. When I got everything back together and got the truck running again, the vac gauge indicated that I was ok. And no more stinky exhaust.

If you are going to check for clogged cat, Man a Free sells a straight pipe that will fit in there:

http://www.man-a-fre.com/pa6/fj60catalyticconvertortestpipekit.htm

but its like $76. And it's not going to tell you if you have a clogged muffler.

If you decide to take the cat off, make sure you have six new bolts and nuts and 2 donut gaskets to reinstall (and use the copper anti-sieze on the threads of the bolts, you be glad the next time you have to pull them).

 

[Infinity00]

I'll check the brake booster vacuum more and record the results better. Maybe I can get to that later today I hope.

 

[Slow Left]

Yep, no major scratches, clean surfaces, tightened them correctly, tightened each one slowly in a crisscross pattern, without tightening one all the way first. I inadvertantly didn't tighten the wings until the end but didn't think about that issue. I may go back and start over since I did another snug down of the bolts after I thought there might be a vacuum leak there and those could have impacted that last snug down. hmmm

Sounds like you put that thing on right, not rocket science just deliberate steps. But rechecking for vac leaks is high up there for you because of the manifold vac readings you posted.

Remember, when you are spraying around with carb cleaner to check for vac leaks, if the carb cleaner is the highly flammable type, you will hear a rev in the idle; and the opposite is true for other types of carb cleaner. Can check by spray a LITTLE directly in the the throat of the carb and see what it does.