Its back...Code71 (1 Viewer)

[landtoy80]

After 2mo and cleaning out the intake chamber the #@%&* CE light is on, code 71. At this point I would love to plug the EGR and get a AU 94 1fz-fi computer and desmog the smallmouthturd. If they were cheap and could get one, what else is different about the US and nonUS or AU computer? I know they don't have cat (I don't like cats) and EGR. What about the air pump looking thing off the air cleaner? Do they have the same head, pistons, block,etc?
kurt

 

[landtoy80]

Its off now. I found a vac hose that was disconnected
kurt

 

[landtoy80]

The hose that was off was not for the EGR. The light came back on. I pulled the VSV and it tested 140 K(then symble that looks like a horse shoe) the manual calls for 30 to 34 (horse shoe). I guess it needs to be replaced??

What is the Horse Shoe symbol called and what would the K before the Horse Shoe stand for?
kurt

 

[Guest]

that symbol stands for ohms(resistance)



doug

 

[landtank]

Most coils are around 30 Ohms. Check your meter by touching the leads together and reading near 0 Ohms to be sure the meter is ok. Also make sure you have a good contact on the VSV connections as any dirt or tarnish on the connector will add to the Ohm reading as well as interupt the functioning of the part.

 

[Beowulf]

Kurt,
(Assuming your values are correct and your looking at the right page in the FSM)

This is the same problem that I had back in December with the P0401 code (same as your 71.) The fix was to replace the VSV for EGR. My values were similar to yours; I'll have to go back through the archives to get the values that mine had.

The K stands for "thousands." Technically "K" = 1,024 but that's not important. Basically, your reading is over 4,000 ohms times what the acceptable values should be.

Replace the VSV for EGR.

-B-

 

[landtoy80]

I tested it 2 mo ago and it was in spec. At least I can now remove the VSV without removing the intake chamber.When I had the chamber off, the little screws for VSV were very hard to remove, I used vice grip to remove them so not to damage the head of screw.
The part # in the VSV is 90910-12097. I hope I copied it right, I didn't remove the VSV from the hoses so it was hard to see.
kurt

 

[Beowulf]

Kurt,

>> The part # in the VSV is 90910-12097 <<

90910-12079 Valve, Vacuum Switch
This is the correct part for the VSV for EGR for a 97 1FZ-FE. You'll have to check w/C-Dan for yours.

-B-

 

[Gumby]

Kurt,
(Assuming your values are correct and your looking at the right page in the FSM)


The K stands for "thousands."  Technically "K" = 1,024 but that's not important.  Basically, your reading is over 4,000 ohms times what the acceptable values should be.  


-B-

Well, K in computer bytes is 1,024, but in the rest of the world it stands for Kilo or 1,000. As in 1,000 grams, 1,000 meters etc.
I'm pretty sure the value of the VSV is supposed to be in the K-ohm range. I think somebody else made this mistake a while back and posted it on the 80s list. I got all excited because mine was high, then it turned out it wasn't.

 

[ParadiseCruiser]

Gumby -

>> I'm pretty sure the value of the VSV is supposed to be in the K-ohm range. I think somebody else made this mistake a while back and posted it on the 80s list. I got all excited because mine was high, then it turned out it wasn't.

That "somebody else" may have been me... but the discussion (in my case) had to do with the EGR temp sensor, not the VSV.

Here's what the FSM has to say about acceptable resistance values (for a '97):

VSV for EGR : 30-34 ohms (@ 68 deg F)
:: Do not confuse with VSV for fuel (different part) ::

EGR temp sensor: 64K-97K ohms (@ 122 deg F)

Cheers, R -

 

[Beowulf]

Todd,

>> Well, K in computer bytes is 1,024, but in the rest of the world it stands for Kilo or 1,000 <<

You are correct. Computer bytes is my world so I tend to think everything revolves around computers. &nbspisk drive makers use your numbering scheme and continue to short-change us on available storage.

-B-

 

[Gumby]

Gumby -


  That "somebody else" may have been me... but the discussion (in my case) had to do with the EGR temp sensor, not the VSV.

  Here's what the FSM has to say about acceptable resistance values (for a '97):

  VSV for EGR : 30-34 ohms (@ 68 deg F)
        :: Do not confuse with VSV for fuel (different part) ::

  EGR temp sensor: 64K-97K ohms (@ 122 deg F)

 Cheers, R -

You are correct, sir. That was about the temp sensor. That makes more sense. A temp sesor should measure in K-Ohms, a solinoid ought to be much less.

My mistake.

 

[landtoy80]

I wish there was a way to desmog the 80, like I did on the fj60 and get ride of the EGR.
kurt

 

[Gumby]

Did most of my major maintenance today after only about a year of procrastinating. On the list was replace all the hoses, major tune, new flexy and sexy antenna and fix the Low Flow code.

I pulled the intake upper plenum. The chamber was almost plugged solid from the EGR to the t-body. I also pulled the VSV and that's where it gets interesting. I put an ohm meter on it and got 30KOhms, way too high. I checked it again and it was 60 ohms, still high, not too bad though. I noticed that when I held the meter on the terminals the resitance got higher. Could be a bad meter. I need to bring my Fluke in tomorrow. Could also be the windings are getting flaky when power goes through them. I suspect I need to replace the VSV. I reassembled it for easy removal. After I button it up tomorrow, we'll see if I can drive for the first time in almost two years with the check engine light off.

The PHH was BAD! I'll post pics, but I'm sure glad I didn't drive it on the 10 hr. road trip this weekend. It was also not near as bad a job as I was lead to believe. 2-3 hours at the most, but I couldn't have done it nearly that fast without reading all about others having done it. If you pull the trans dipstick tube you've got a ton of room. The ones at the heater core were more of a pain because my fat ass couldn't reach over that loooong engine.

 

[landtoy80]

"The chamber was almost plugged solid from the EGR to the t-body"

Dito for me.


I guess there would be no problem me driving it this weekend as I don't have the new VSV??? Sounds like others have had no EGR for some time.

What damage woulld happen if I never fixed it? Other than to the planet.

kurt

 

[Beowulf]

Kurt,
According to the experts, including Toyota, the EGR system is designed to reduce detonation among other things.

>> What damage woulld happen if I never fixed it?  <<

I'm pretty sure you have asked this question 3 or 4 times here, on 80sCool, and on SOR. You seem to be looking for another answer. Several of us (me, Gumby, Junk, & others) have driven for many months and many thousands of miles with the EGR system not working according to the ECU. I think (or at least I hope) it will not do permanent damage if you're not hearing it ping or knock. The knock sensor should retard the timing; though your mileage will suffer when this happens.

As I have told you before, you'll be much happier after you replace the VSV and reset the MIL. You will know your EGR system is working and you will quit worrying if the MIL is masking another problem.

Yes Kurt, I know the OZ vehicles don't have EGR systems and I know you desmogged your 60. You have a US spec 80 series now. The ECU expects to have a working EGR system. Period.

Cheers and Happy 4th of July.  

-B-

 

[Gumby]

Light came on after three trips. Obviously was not the EGR passage, although it couldn't have been working well. I suspect the VSV and I will probably replace it at some point. I would NOT reccomend anybody pulling the intake upper plenum to clean the passage or to assist in the PHH. The cleaning can be done by pulling the EGR and the throttle body. It did not help the PHH in the least.

 

[landtoy80]

You would have to remove the intake manifold to help with the PHH.
My CE light turned off again. It was off all day then turned on again. I talked to guy and told him I had 140K ohms. He haid that there might be build up on the switch. The higher the ohms the less current that can flow.

Not knowing how the VSV works, this is my threoy: The VSV might be spring loaded as that the shaft that opens the switch so vacuum can flow through. A spring might push the shaft close, stopping the vacuum from flowing.A bump might seat the switch
Or voltage might jump across the connection and work untill there is enough build up so that voltage can't jump.

He also explained what could happen with knock/ping. Not knowing what knock/ping was, this is why I kept asking.
He said that knock/ping was hard on the rings and over time thay could/would brake. Then the motor would start using oil. If I hear ping. I should retard the timing to stop the ping.

kurt

Yes I had I fine 4 of July. I hope uall did toooo.

 

[landtank]

A friend of mine had some knock and ping on his Chevy Comaro. Eventually blew a hole straight through the top of the piston. His father never changed plugs just sand blasted them and re-gapped. Warned him constantly prior to the failure, but I was a "foolish young man".

 

[Beowulf]

Kurt,

>> I should retard the timing to stop the ping. <<

Retarding the timing is what the knock sensor + ECU does.

When the knock sensor detects the engine is pinging (knocking) then it sends a signal to the ECU to retard the timing. The ECU retards the timing in large increments since it thinks something is wrong and the main purpose is to avoid damage to the engine.  Retarding the timing, via the built-in mechanisms or by changing the initial timing with a timing light, will dramatically affect performance and economy.

Adding a little (+3 degrees or so) initial timing can improve economy and performace a little; at the risk of increasing the possibility of pinging. YMMV.

From my inspection the VSV is a sealed unit and there is no way to service it. If it doesn't work then you will have to replace it with a new one. I didn't try to take it apart but if you want to experiment then I will sell you my old one cheap.

-B-