Pete-87-22r

I'm sure this has been posted several times before but I didn't find much that applied to me when I googled it. My truck is an 87 Xtracab, 22r carb, 4x4, completely stock, manual transmission and I recently put on a cab high shell. When I first bought my truck I was getting about 22MPG, It had a rough idle, and idled at around 800rpm. I was expecting to get a little better mileage once I smoothed out the idle and got it down to 700rpm. I recently went through and got the timing back to 0* (it was retarded about 5* before), the idle down to 700 and replaced my #4 plug wire because the contact was a little corroded for some reason. Now im getting 16mpg. I still got 20mpg after I put on the shell, all I can think of is maybe the AAP diaphram or something, maybe the valves need to be adjusted? Also I'm in Southern California and my truck was brought down from Colorado within the last year and its got the HAC valve, pretty sure it's not doing anything now but this is my first truck and I'm driving 40 miles a day for school, so 16mpg aint good.
Thanks, Pete

xXbrutalXcoreXx

Check to see if the diaphragm on the acceleration pump is still good. I just replaced mine after finding out that every time I gave it gas, fuel was leaking out past the diaphragm. Check this link for some useful info: http://www.bluebassdesign.com/boonin/carb_faq/

Gamefreakgc

Wrong engine

snobdds

A 22r is a lot different than a 22re. This^^ does not apply to a 22r.

Gamefreakgc

Ahh, my bad. I missed that part!

Pete-87-22r

Dug into the vacuum lines today after school and found the AAP is dry but there was quite a bit of gas in the top hoses of the HAC. Checked my idle speed again and it was back to 850rpm??? Corrected that, gonna see how it does now. Think maybe I forgot to reajust it after doing the timing. Would the idle speed affect the mileage all that much?

oldblue

what kind of plugs did you use? sounds stupid, but it can make a difference

Pete-87-22r

Spark plugs or the vacuum plugs? I dont know about the spark plugs but they're the same as when I got it and they're fine. For vacuum plugs I used an earplug for the big line from the air cleaner and im using nails wrapped in electrical tape for the little 1/8" ones. I guess thats not ideal but I figured it pluged em pretty good.

stock87

Did you unplug the vacuum advance when you set the timing? Base timing is supposed to be 0° with the lines unplugged and capped. It's supposed to advance to 12° when you plug it back in. If you set it without unplugging the lines...

Pete-87-22r

I did the timing right. Been adjustin the valves today and ran into a bit of a headache. The #4 cylinder had low compression (120 while the rest were 145), the valves were clicking on the same cylinder but not bad, found out they were a little tight, so I adjusted them to spec (.008 intake .012 exaust). Started the engine up again and they started clicking really loud, adjusted them again, same thing. Tightened them back to where they were before, and now theyre not as loud but still noticable. The engine was warmed up every time before I adjusted them. My engine only has 111000 miles so I'm lost.