brunson67

Hello, newbie here to both Yota Tech, and owning a 2nd Gen 4Runner. Two weeks ago I purchased a 1992 4Runner 4 wheel drive, V6, 5 speed. My wife had mentioned numerous times it was her dream vehicle back in the 90's, so I found this one a couple blocks from my work. Story is a couple bought it brand new in 1992, he passed away about a year ago and it sat in the garage until recently. She decided to have it towed to a local repair shop, the battery was dead. Once it was there she decided she didn't want it in the garage anymore, as it reminded her of her husband. The mechanic made her an offer and he bought. He has been driving it for the last three month with plans to give it to his son, but his son is messing up in school, so his wife said sell it. He didn't get any service records on it from the lady, but she said here husband always made sure it had service done and repairs done. The mechanic I bought from said all he did was charge the battery and flush the EGR valve, as the check engine light was on. He said the heads had obviously been done not to long ago, but had no records. he said they look brand new, not even the smallest amount of grease or oil, and you can see new RTV sealant here and there he said, which I looked and agree. It has 180,000 miles on it. It runs great with exception to a few thing -
1. Oil pressure gauge reads extremely low at idle, but doesn't smoke, doesn't overheat
2. The check engine light just came back on. Since he just cleaned the EGR valve, is it safe to assume I should replace it?
3. It has the slightest surge at steady RPM. Is this related to the EGR valve being bad?

Overall this thing is extremely clean, everything works, and the interior is immaculate. I'll post pictures soon. I just got done detailing it and removing the original graphics, removing the running boards and mud flaps, and installed a Kenwood deck in it, which by the way this forum solved issues I had with that too. I'm sure I'll be asking a lot of questions as I progress with this cool 4Runner, plans are to eliminate the crossover and put a good exhaust system on it, and put some good All Terrain tires on it, 31x10.50-15 Falcon AT's most likely.

Thanks!

Rob

grousehunter 61

don't take anything I say as fact, but I just removed the EGR valve and the reed valve from my motor, blocked the EGR port and blocked the vacuum lines, running great so far, but I am watching for problems, I have maybe 50 miles on it without the valves. Look and see what they do and see if you can do without, as I said, don't do it without talking to a lot of people, I may be wrong, but it sure makes changing the spark plugs easy.....A lot of this is dependent on where you live, here in my part of Idaho, we don't have smog checks, I don't think you can get by with that in kalifornia......

Co_94_PU

iTrader: (-1)

Don't guess test!

You need to put an oil gauge that reads the actual PSI if you're concerned. Low on the stock gauge doesn't mean much unless it never moves of the key on position.

No, you need to pull the stored trouble code(s), it only needs a jumper wire and a minute to-do.

A stuck open EGR valve can cause the engine to not run at idle speed, a stuck closed one will.have no effect on idle quality.

brunson67

Co_94_PU

iTrader: (-1)

You check the oil pressure with an oil pressure gauge, available from the local auto parts franchise or harbor freight, by changing the electrical sending unit for the fitting included in the guage kit.

There are procedures listed in the service manual for egr testing, someone else will maybe link to it for you, from memory you warm up the engine apply vacuum to the EGR valves vacuum port with the engine at idle and the engine will try and stall out. There is a second bit that has you maintain a speed in the 50-55 mph range in two short trips of about 3 miles that verifies the EGR gas temp sensor..

Personally if I apply vacuum to the valve and get a good solid THUNK when I release it I know the valves not sticking. Is it 100%, or by the book, no of course not.

welcome to Yotatech
Check for stored codes
http://www.4crawler.com/4x4/CheapTricks/TroubleCodes/

​

brunson67

scope103

There's nothing wrong with this advice, except ...

Once you get your gauge, how do you hook it up? Turns out there's about 9-10 commonly used thread size and pitch for oil pressure connectors. Which one do you use? Well, Toyota uses 1/8" BSPT (British Standard Pipe Tapered -- go figure). Is a 1/8" NPT close enough? They sure look the same! Well, no. Those two are close, but they have a different number of threads per inch. You might be able to screw the 1/8" NPT in, but it would distort the thread in the block, and you'll never get it to stop leaking. The good news: The Harbor Freight set has the 1/8" BSPT fitting.

Okay, you shop at HF, and you measure the oil pressure. Say you get 50 psi at 3000 rpm, but only 5psi at idle! Barely lifts the needle. Is that bad? You need to know the specs. http://web.archive.org/web/201003261...16oilpress.pdf And that very low oil pressure at idle is WITHIN spec.

snippits

I can tell you one thing no flush is going to get out the carbon that I cleaned out of my EGR valve on a 92 22RE with 184,000 miles. It was at least half way clogged with hard carbon. I use carb cleaner to soak it multiple times, and chip away at it with a flat head screw driver. Took a while, but I finally got it cleaned good enough.

brunson67

Scope103 and Snippits, thanks for the heads up on both accounts! Looks like I'm heading to get a new EGR today and a Haynes Manual, as well as Harbor Freight! LOL

scope103

Wait, what? You're buying a new EGR setup because that was something that was fixed before?

First, read the codes (fer cryin' out loud!) You're talking many hundreds of dollars to replace the EGR valve, Modulator, VSV, Temp sensor. And you have no idea if your problems have ANYTHING to do with the EGR! Here's the procedure for checking the codes: http://web.archive.org/web/201211190...85diagnosi.pdf (There really is an SST for that, but everyone here uses a paperclip. Or Co_94_PU, a "jumper wire.")

brunson67

I'll check it first, but I have a feeling its bad based on the previous owner saying that's what the code said, and he flushed it, reinstalled, and the check engine light went away, it then passed smog. I buy it and with in a few weeks the check engine light comes on. Purely speculation here, but I will need to check to see what the code says. Also, if it ends up being EGR, is it recommended to replace the Modulator, VSV, and Temp Sensor?

brunson67

Okay, Got code 71, EGR. Thanks for the link scope103! Now the question, is it truly EGR, or is it the modulator, VCV, or Temp Sensor?

Co_94_PU

iTrader: (-1)

Four, and maybe a little bit of number one.. But those are just guesses so on with the testing!

Apply vacuum to the EGR with the engine at idle, a good test result is the engine stalling. Apply vacuum with the engine off then release the vacuum, a good result is a solid thunk sound of the valve closing.

Trace the vacuum lines backwards from the modulator, with this line disconnected at both ends you should be able to pass air thru it about the same as a twizzler (yes that's totally a legiy technical test, OK I made it up apur of the moment but it's valid.

​​​​​Check for no flow thru the thermal vsv with the engine cold, verify flow with the engine at operating temperature. If you don't get flow with a warm engine pull the bvsv (bimetal vacuum switch valve) off the front of the intake and give it a good descaling then retest (they scale up over time, the scale increases the time it takes for the valve to open and needs done atleast once every thirty years or so... Might as well do your ect sensor at the same time while you've got the coolant system open)..

​​​​​​intake in line is the EGR temp sensor. Check the temperature of the pipe feeding the back of the intake after a five mile highway speed trip, it should be well over 100°, if I recall its actually something like 200°C.

There should be something for the modulator but I don't recall..

All/most of this is in the same place scope linked above. On the way back machine.

scope103

Here's the FSM on testing the EGR Valve, VSV, and Modulator. http://web.archive.org/web/201204061...77exhaustg.pdf (I think Co_94_PU is more familiar with the 22re, no?)

You can also test the temp sensor, though that is less likely to fail. http://web.archive.org/web/201003261...00egrgaste.pdf

And don't get overly tied up on individual parts; your truck is not some sort of giant LEGO. For instance, if the temp sensor is disconnected it will throw a code. If the vacuum lines are disconnected (or mixed up, or blocked, or cracked) the EGR won't work.

brunson67

Update - Drove it to Pep Boys to get a new antenna mast, then came back to our shop and pulled it in the bay, so engine is warm/hot during these tests, I started the engine, pulled a vacuum from the EGR and it died. I then left engine off, pulled a vacuum from the EGR and didn't here a thunk sound. As I was looking into testing the Modulator I heard a clunk sound, I then retested the EGR with engine off, pulled a vacuum and released vacuum and got the thunk. The thunk I heard I realized I heard a few times before while I had the hood up right after driving. Is there such a thing as a sticky EGR valve? Sometimes this thing feels really strong and responsive when I start it up ands drive, then I start up again and it doesn't feel as good. This plus the guy/mechanic I got it from saying all he did was flush the EGR valve, just made me think is it sticky,. thoughts?

I then tested the Modulator, or at least I think I did it correct, but I did get air through the lines about like a "twizzler". I blew air through Q and P I believe. Still need to check the thermal vsv and the EGR temp sensor, I'm assuming I can just use a thermal gun to check the temp at the location?

Thanks,
Rob

Co_94_PU

iTrader: (-1)

Isn't there an electronic vsv in this era also on the EGR lines, could be plugged up here on the atmosphere/release port..

Assuming you did the same on the first attempt as you did on the second, pull vacuum then release to receive a clunk of the valve closing, and were connected directly to the EGR it maybe sticking.

I don't recall how many pipes and gaskets you need to pull to get at the EGR in the v6, but it might be time to get a few gaskets and have a look.

brunson67

scope103

The temp sensor is what directly triggers the CEL. "Flushing" the EGR valve (whatever that means) won't repair a broken wire. (Though, to be fair, it could have been broken any time.) There's nothing fancy about the signal, so if you have enough wire you can do a careful splice. If not, RockAuto has them for $123 ($189 at an online dealer.)

brunson67

grousehunter 61

Just a follow up. I have a bout 250 miles on the 93 toy with out the reed valve and egr valve, running great, seems to be a lot quieter, gas mileage is about the same thing the power.........