FJ60 ABV Repair or replace? (2 Viewers)

[DirkDougler]

Hi All, long time first time. Trying to get my 86 FJ60 smogged in CA. Ya I know. I'm blowing high HC and CO, which suggests an AI problem (after failure of the easier-to-deal-with components has been ruled out). I've got many hours invested into the emissions manual so far. I had the carb rebuilt about 2K miles ago and replaced VSV1 as it also failed. Still blowing high HC/CO tho. I've narrowed the next problem down to a bad ABV. Specifically when I apply suction to the top vac tube on the ABV it won't hold any, and I'm blowing exhaust thru to the EGR inappropriately, which I conclude is likely due to a busted diaphragm in the ABV.

My question is whether there is a way to repair that diaphragm in the ABV, or do I need to buy another with a working diaphragm? The ABV housing does not appear to disassemble, so I'm thinking I most likely need to buy a replacement if I can't access that diaphragm to replace it. In reading up on this issue I understand that the ACV in general can gunk up and cause problems, but I can't think of any reason why the top ABV vac tube would be unable to hold suction and close without there being a bad diaphragm involved.

Also if anyone has one that works that they want to part with, please let me know.
Thanks!

 

[Spike Strip]

No way that I know of to repair the ABV, but anything is possible. You've got nothing to lose if it is bad (I've never seen one fail) trying to take it apart. But probably far easier to get a good used. They're often listed in classified and eBay. You'll get a better deal from MUD, though. Ebay is hella sketchy, these days.

The bad ABV is definitely a problem, but you say, "I'm blowing exhaust thru to the EGR inappropriately, which I conclude is likely due to a busted diaphragm in the ABV". The ABV just directs the ACV to either send Air to the Cylinder head or out the tail pipe or back into the intake, depending on various parameters. Has nothing to do with Exhaust and EGR. That is the Vacuum modulator, EGR valve and assorted bits.

The ACV can be taken apart and cleaned, and should be.

good luck

 

[OSS]

The 2F Air Injection system has a few doo dads associated with it (sub assemblies) to allow the system to divert air flow depending on engine conditions. The emissions computer provides a few If/Then solutions for it to change its operation.

But... to just get air into the exhaust pipe during a smog test, the ACV can be tricked with a single vacuum hose swap to blow air into the exhaust pipe all the time, bypassing just about everything. Guys have passed their smog test with this hack (direct air to exhaust pipe instead of through the ai manifold and regular system).

I don't remember which vacuum hose gets swapped for this hack, but I do recall that studying the emissions manual schematic revealed its location.
So the answer is there - you've just got to dig deeper to find it.