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1987 MA71 R154 Pearl White, Blue Velour
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Discussion Starter · #1 · (Edited)
So it seems one of my VSVs, the OBS, broke off a nipple and gave me a vacuum leak. The diagram here is really deceiving when it comes to where it physically is. I was SURE I didn't have that particular VSV (in BLUE) until I finally figured out how far up under the intake they actually put it. :rolleyes: (right between the Alternator and the front knock sensor)

I was able to find a replacement online, but then discovered that the second VSV (in green) for the EGR fails the electrical test. The unit I found on the car is part number 90910-12043, which is NOT what the diagram calls for.

Any suggestions for an alternate part number for this VSV?

Also, not related, but does anyone know the proper adjustment for the screw on the throttle body? (green arrow) I know everyone says don't mess with it, but I messed with it 25 years ago so that's that. I didn't remove the cap though so someone had adjusted it before me.

Both VSV plugs are red.

Anyhow, any help is appreciated.

Map World Organism Font Slope
 

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Premium Member
1987 MA71 R154 Pearl White, Blue Velour
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1,200 Posts
Discussion Starter · #3 ·
Ok so an update on this.

My new OBS VSV arrived today. Its the blue line above. That's the one that was sheared off and was a vacuum leak, assuming it has been working.

Oh man, this might be the winner for lifetime hardest bolt to get to/WTF were they thinking contest.

The unit is held on by a 12mm bolt. No big deal...except where it is. Its right by the front knock sensor, right up snug against the bottom of the intake manifold. To get to it required removing the alternator, the hose from the head to the block and even THEN. Every socket extension ran into something making it useless.

The final fix was to use a 12mm open wrench to pop it, but its a long bolt and a tiny bit of wrench travel space. I had no u-joints but i did have a 3/8 flexible extension. Honestly it was the first time I ever found a use for it, but it worked.

I got the poor old unit, out , cleaned the harness connector, clipped it in, new vacuum lines and managed to .... by using the force and imagination, get the bolt back on by feel.

Thankfully everything else went back together without much of an issue.

The VSV for the EGR (in green) arrives tomorrow. Right now I just have a vacuum line covering the gap.

The test drive was amazing....AND... my mysterious Code 52 knock sensor error did NOT show up. Recall I've been having this issue even after the yotaconnectors rewire kit. I'll drive it some more to make that official.

Anyhow after the initial stress it was a joy to drive around the block. :D (y)
 

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Oh, Crickey - can't believe I missed your post. I became an expert on the 3 VSVs about a month ago. Glad it solved something for you. I must have gotten all the vacuum lines to their proper components because I have no codes on startup after 22 years of sitting. The Green one in your diagram is a lot easier to install. If you need vacuum line, NAPA's windshield washer hose is much cheaper, same heat resistant construction, softer and more compliant for bends and grips on the slip fits better.
 

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1987 MA71 R154 Pearl White, Blue Velour
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1,200 Posts
Discussion Starter · #5 ·
Actually my 52 is back even after checking and re-fixing the sensor wires.

I ordered 2 new sensors. I overheated my engine many times in the late 90s and a few more times over the decades before I finally figured it out. Runs very cool now. I might have fried them back then though.

However, I did see an old article about a guy that tried everything to fix his 52, and finally gave up and bought sensors.....and that fixed it :rolleyes:

I replaced my EGR with the same part number that was on there, but even though it looks like the original in diagram, it wasn't the same part number.

I found a 25860-46010, which is a Lexus switch, but my car actually started to run like shit with it, so I switched it back.

Once I get the knock sensors installed this weekend, I'll see where I'm at. (y)
 

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Hmm. I hope it's not going to turn out to be something you have to live with. Both of my 80 series Cruisers have CE lights on for insufficient EGR flow and so do about 50% of them on the forum. It's turned out to be a knotty issue where some have even tried soldering in resisters to fool the system out of desperation, etc.

Anyhow, hope you get it resolved.
 

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1987 MA71 R154 Pearl White, Blue Velour
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1,200 Posts
Discussion Starter · #7 ·
Ouch. Well I will work backwards now. I have the yotaconnectors rewire kit I got last year so fingers crossed that it passed QA. (looks very well made)

The next thing is I spliced into the OEM cables at the ECU end as to not have to make new ends. (and I didn't have new ends. That is a potential weak link.

Lastly, 34 year old knock sensors on known BHG (1997) engine.

By the way, where did you run your wires? Currently mine come out and follow the harness, but then I swept them under the intake, passing right by that green line VSV. I was going to try to route them across the intake as OEM but haven't found where they drop through yet. That in itself might be an issue right if wind gets to the wires. :unsure:
 

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Premium Member
1987 MA71 R154 Pearl White, Blue Velour
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1,200 Posts
Discussion Starter · #8 ·
Interesting. I put in the new front knock sensor just now. I still get the 52 code, BUT, if FEELS like its out of limp mode now (y) :oops::cool:

I think I'll have to get the other one from the bottom. I really hope I don't have to remove my starter.
 
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