EGR system is a mess

semlin

curmudgeon
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My problems sound puny besides Dan's issues, but I'll report anyway.

Bought a vacuum pump/gauge and did some tinkering with the EGR. It was in complete disaaray. I am guessing there in no emissions testing in utah because no one has touched this system in a while or maybe ever.

EGR modulator filter was so choked with carbon I couldn't get it out in one piece. It is completely blocked. The hose between modulator and egr valve crumbled at the valve end when I touched it. Part of the metal nipple on ther egr valve crumbled into many pieces inside the hose. The hose to the VSV was in similar shape. It seemed like a seam running the length of the hose had also disintegrated.

Can't get a new filter until monday at the earliers so I cleaned out the modulator as best I could with compressed air, and have the bad hoses temporarily replaced with windshield/vacuum hose for now and I put what's left of the filter back in the modulator on the theory something is better than nothing.

With the modulator filter in such rough shape I don't know what use the vacuum tests are but I did them anyway. I get no vacuum at all at cold or hot engine temperatures at 2500 rpm so I fail the FSM test. With engine off I can induce vacuum with the pump through the egr valve at the nipple that goes to the modulator, but it loses pressure quickly. Can't get any vacuum from the VSV nipple end. Not sure if you're supposed to.

Also got a nasty shock when I opened the DLC / diagnostic for the first time. All the contacts are full of white greasey stuff. Is this maybe dielectric grease or something? Anyway, the system seems to work. Jumping the E1 and TE1 yields a steady flashing check engine light so no codes. As far as I can tell from the FSM, this also indicates the DLC is working.

Anyway, as usual I have a bunch of questions if anyone knows the answers:

1. PN# for the modulator filter (dealer says it's not available separately) or is there a possible substitute if you can't get this separately?

2. are there any specifications for the small hoses in the EGR system? I notice some say #1 on the side while some say #0. Not sure if heat sensistivity is an issue. As usual my Toyota dealer had no idea and gave me a bunch of 5/32 vacuum/windshield line. Not anxious to have it melt on me if there are heat requirements.

3. Should/can you clean the modulator beyond replacing the filter? I have blown air through all the nipples using an aerosal can. Is there anything else to do? Given how bad the filter was does the modulator need replacing?

4. There appears to be enough of the nipple left on the EGR valve to preserve a vacuum with a hose over it, but why would it disintegrate like that? Every nipple on the EGR system I checked had rust where it contacts the hoses, but the hoses were really bad where they contacted the EGR valve and something had clearly eaten the rubber away down to the lining for about an inch away from the valve. The EGR feeder pipe was cold to the touch when I checked it after warming up. Could there be oil in these lines or would that just be the egr valve getting very hot after running long distances?

5 I haven't taken the EGR valve off yet as I don't see what I could do except replace it and I can't get parts until next week. Given the vacuum test result should I just do that or is it worth waiting to see if a clean moulator filter or maybe some VSV work is going to magically change everything.

6. Should I set some time aside to pull the cover and get at the VSV to test it given the vacuum result? It looks like a 3 or 4 banana job in the FSM.

Anyway, on the bright side the engine seems to sound quieter and smoother with these hoses replaced. Or at least I will keep telling myself that :cheers:
 
Joined
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Replace the modulator. If you don't you will have to keep cleaning it.
Get all the gaskets needed to pull the intake chamber. and several bottles of carb cleaner and pull it and clean it.
Take the VSV off and learn how to remove it with the chamber on. Or better yet just replace it if you have extra $$$ and save the hassel of replacing it later.

Utah uses salt and other stuff in winter that is hard on alumunuimun and steel.

While you have the intake off get all the gaskets(spark plug gaskets,valve seal etc) to remove the valve cover and check the valves.


Also pull the EGR and clean it and the temp sensor and the EGR tubes.
 

semlin

curmudgeon
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ok, thanks Kurt, the prices on these parts are shocking.

I will shorten my list of questions accordingly

1. does the vacuum test necessarily signify a problem with the VSV or are you guessing?
2. with what shall i clean the egr valve / sensor?
3. still need to know if any specifications for vacuum hose. Second Toyota dealer gave me same "don't know" answer and said they never use Toyota vacuum hose.
4. How much time am I saving by checking the valves now? I mean if I get that far I may as well do the PHH while I'm at it and make a day of it.
 
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Somewhere in the foothills...
Simon,
1. I think you have to pull the VSV for EGR and test with a meter.
2. Try carb cleaner but I had no luck at all with cleaning the EGR valve. Waste of time for me.
3. Can't help.
4. Abstain.

The EGR modulator is about $50. I have one that was removed from my truck that I would be happy to send to you. It was the easist part to replace and a new one didn't fix my problem.

As Rick will tell you, and I agree, throwing new parts at the EGR problem will eventually fix it but will empty the Cruiser fund. The temp sensor and VSV can be measured with a standard multi-meter. My problem ended up being the VSV but I removed the EGR valve twice for cleaning and a 3rd time to put a new one on.... and I put on a new EGR modulator. Wish I had taken the time for the VSV tests but that's water under the bridge.

FYI, you can remove the VSV without removing the intake. You need a long extension and you remove two bolts from below then the rest from above. I had a mechanic do it and he told me what he did.

-B-
 

semlin

curmudgeon
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B-wulf, thanks for the help. The modulator is $112 here. The egr valve is $340! I hope Dan gets back to feeding his dogs soon! He's going to get some business.

I've been reading all the backstories on the 401 / 71 code issues and the various solutions. It always seems to lead from modulator to valve to VSV. Weird that I have no code at all, yet I think my vacuum test results suggest VSV for EGR failure and my modulator filter is black and clogged. I should be reading 71. I am wondering again about that "grease" in the DLC.

Anyway, I found your old post about removing the VSV without removing the chamber and also gumby's post about cleaning the chamber without removing it. The no removal approach sounds good to me. My problem is I will likely have to do it twice or do without my daily driver for a week unless I order a new vsv in advance. If you still have the photos you originally posted for vsv removal help, it would be great if you could pm them or repost so I can assess which way to jump. I think I follow you but...

Maybe I'll use the extension bars from the jack kit for my 3' extension bar ;)
 
Joined
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Messages
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Somewhere in the foothills...
Simon,

>> I am wondering again about that "grease" in the DLC. <<

Sounds like di-electric grease to me. I wouldn't worry too much if everything seems to be working OK. Did you find it in other connectors?

>> If you still have the photos you originally posted for vsv removal help, <<

I can post pics of the VSV that was removed from my engine but I don't have any pics on the removal or anything that would help you other than getting a good idea of what it looks like.

The VSV for EGR is p/n 90910-12079

(Later....)
I updated the links in the archive post so you should be able to see the pics now. It seems like the forum conversion a few months back broke some of the links.

https://forum.ih8mud.com/index.php?board=2;action=display;threadid=1863;start=msg13177#msg13177

-B-
 

ppc

M Go Blue
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Nashville, TN
semlin,

I think that are some differences in model years and which state (CA/NY) the vehicle was originally purchased in. In my 94, purchased in CA, there is a temperature probe in the EGR where idcruiserman discovered that in his 93, which I think came from AZ, only had a plug in the wiring harness but no temp sensor fitted. That being the case the 93 models like that may not have as sophisticated of a control and malfunction detection system as later years or different states.
 

semlin

curmudgeon
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north of 49
Aha, so no EGR temp sensor = no recurring 71 code = another reason to buy the mighty 93 as long as you are not in Ca or NY. Of course your egr may be broken and you don't know so you choke everything up with carbon but what the hey... at least my dash has no flash

Thanks for the photos B-wulf. Knowing what stuff looks like helps quite a bit in this instance. The FSM sketch looks like spaghetti.

Dan's dogs must be much smaller or hungrier than the local dogs because they sure require a lot less alpo ;) I am ordering up a vsv and modulator plus gaskets. It is worth the gamble on the price of the VSV to only have to take it out once. Once I get all that in and clean the valve and chamber I will try the emissions test again.
 
Joined
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When I removed the chamber the VSV tested good. It failed at a later date. The VSV is spring and magnet that opens a valve. I think the valve gets stuck or the spring gets week or stuck so it works then it doesn't. Hit a bump and it works again.
The mod. gets a hole in it letting in carbon.
The EGR tube in the chamber was carboned up to the point that it was almost pluged.
 

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