So then, I bought this truck awhile ago as an economical alternative to my diesel F-250, Paid $500.00 for the truck and it has been a long road, I replaced the timing chain and rebuilt the top half, I left a stripped exhaust stud to be replaced later, smogged it and passed and have been driving, fixing, improving and building since March. Well this weekend I put a heli-coil in the head and replaced the bad exhaust manifold stud and gaskets. Now it is idling rough cold or warm, doesn't matter, I read in the forum that timing should be set at 5 deg. with vac. advance hoses pulled and plugged and around 10 degrees with vac. advance hoses hooked to dist. now I noticed no change with them pulled, plugged or attached, I checked all the vacuum lines and they all look good/ hooked up (I replaced the vacuum lines (one by one so not to hook 'em up wrong) last month and rebuilt the carb. on the same weekend. Sh** of it is it was running fine and as soon as I fixed the exhaust leak BLAMMO new problem! Anybody have any ideas on what to do? As I said it idles rough all the time but runs great under load or above ~1100 rpm. Losing patience and wifey is getting pissed. Sorry so long

 

Sounds like the inner vacuum advance diaphragm (the one closest to the engine) is bad which is becoming a common problem with these trucks since they're now in their mid 20's. Easiest way to check it is to remove the distributor cap and independently suck on both vacuum lines leading to the diaphragms. Both diaphragms should hold perfect vacuum indefinitely. The advance plate should move and stay in the same place until you release the vacuum.

The rough idle is a result of both a vacuum leak from the ruptured diaphragm AND the lack of timing advance, also due to the ruptured diaphragm.

 

I'll check that out tonight. Thanks for the help, any upgrade suggestions for hybrid daily driver/ weekend explorer?

 

So when I got home it started fine, idled fine, ran around town fine. Hmmm Must be another gremlin, maybe he got pushed out the exhaust pipe So I'll see if it stays good. Thanks again for the help 85sr5yoty.

 

If your timing isn't advancing/de-advancing with the inner vaccum hose connected/disconnected at idle, your vacuum advance diaphragm is shot.....end of story!! But, if you want poorer performance and worse gas mileage......keep driving it "as is."

 

carb trucks(22r) should be 0 btdc try that it will run much MUCH better

the 22RE is 5btdc

 

i thought it was 5btdc too cause i was going by my 90 pickup on my 85 so i set it there ran like crap then i noticed at 0 it purred like a kitten and could make it up this hill by my house lol and i read somewhere its supposed to be at 0

 

it varys from year to year a my 85 22r is at 0 recommended but a 84 i do believe its at 5

 

Thanks, I'll try the 0 BTDC but I did check yhe Vacuum advance and found that it was non-op I was given a spare with the truck and wouldn't you know it, it is also bad. I checked around and it's hard to find the vacuum and when I did it was more ($160.00) than a replacement distributor ($120.00) wit the vacuum diaphrams-go figure. Of course I could get either part from the dealer but vazcuum is ~$190.00 and dist is ~$450.00. Anybody know where to get just the vacuum at a less exorbent amount?

 

Did you get a part #?

I got my vacuum advance diaphragm from 1sttoyotaparts.com for $100. I do have a different diaphragm than yours, so it may be less or more $$$.