Help my idle PLEASE!!

[Sparkplug]

I recently swapped an 83 engine into my 81, and when I went to get the engine, I heard it run, and did all the necessary tests. It passed fine, got it for 350. I put it into my truck, and now I have some strange symptoms.

Sometimes I go to start it cold, and it fires right up, in 1 or 2 strokes, and will idle high forever, miss real bad, and not kick down. Sometimes it will just crank, and crank, and crank. When it does this, I get my squirt bottle, and spray 1 or 2 sprays of gas in the carb, then it starts, chugs like its flooded for a few strokes, then idles at about 1200, and misses. If I rev it up to about 2k it smooths out, and sounds fine. Sometimes it will be stuck at its 2 k, and then Ill come to a stop with the clutch in, and it sounds like it wants to die, only till I come to a complete stop, once Im at a stop, the idle kicks back up, but still misses a lil around 1000-15000rpm.

Now, sometimes, it fires right up, and doesnt give me any misses, nothing, just will stay at 2k rpm, My idle screw is screwed all the way in, but it doesnt hit the spring at all, so it doesnt really do anything. I cant tune my idle down, I can get it to about 1200 rpm at a warm speed, but any lower, and it falls on its face and dies. I have treid numerous combos of vacuum lines, as they were very different, to no avail. I have had this prob for sometime now, and want it fixed b4 my aussie gets here. I have read, and understand that you only need the egr, distributor advance, brake vacuum, and ? Is there something that might not be right? Maybe we messed sumthin up when we pulled it? I will be taking it to the shop to be smogged this friday, so worst case scenario, I have to pay them to fix this prob. But I really dont want to fork out some cash for my truck, that could be better spent elsewhere. Please help me!!!

[jimbo74]

sounds like a vacuum leak.... have you done any kind of tuning to it?

[skipnrocks]

My truck used to do that before I switched it to FI.  It was something wronge with the auto choke, no backfiring but it would idle at 2000+rpm.  I dont know if you have auto choke but its another idea!!

[boggerunner]

get efi, cure all your probs

[skipnrocks]

get efi, cure all your probs

LOL that should cure it!

[Sparkplug]

I know its either the carb, or vacuum lines. Im 90% sure its not the carb, as I heard the engine run before I pulled it. I just cant seem to find what I have backwards. I was hopin someone would have an idea, but I understand that it could be any number of things. I like the carb motors myself, problems like these are the only ones you have, it still runs, if somethin goes wrong on efi, it typically wont run, or REALLY crappy.

[boggerunner]

nahh, i gutted every vacume line off my efi and it runs fine, i also gutted all the egr crap and the water lines that run to the throttlebody, there are way too many usless hoses on this motor

[844x4]

I would check for vacuum leaks by spraying a little carb cleaner around the base of the carb and near any hoses.  If the idle changes when you spray somewhere, check it out.  Also grab a good manual with hose diagrams for your truck.  Is there any smoke or any unusual smells coming out the exhaust?

[79coyotefrg]

nahh, i gutted every vacume line off my efi and it runs fine, i also gutted all the egr crap and the water lines that run to the throttlebody, there are way too many usless hoses on this motor

yea but he's in Cali,   if he guts the vaccuum lines  they will throw him in

[79coyotefrg]

I would check for vacuum leaks by spraying a little carb cleaner around the base of the carb and near any hoses.  If the idle changes when you spray somewhere, check it out.  Also grab a good manual with hose diagrams for your truck.  Is there any smoke or any unusual smells coming out the exhaust?

good advice

did you swap carbs ?? 

[Sparkplug]

No there is NO smoke whatsoever, maybe a lil rich smellin, but I got a lot of exhaust leaks, maybe thats the smell. I didnt swap carbs, becaus one on my old engine was pretty much shot. Wont ne carb engine work, I grabbed the whole emissions harness too. Also, what temp and oil sensors will wire to my 81 harness? Thanks

[Sparkplug]

I shouyd mention, that t akes forever for my choke to open, at least 5 times as long as my freinds 84, but he has no thermostat, is this normal, mine takes at least 10 min.

[79coyotefrg]

I shouyd mention, that t akes forever for my choke to open, at least 5 times as long as my freinds 84, but he has no thermostat, is this normal, mine takes at least 10 min.

NO  thats not normal,  i would take the chock electric part off the old engines carb  and swap it on

for  oil and temp,  i  really  like  manual guages  (aftermarket)

[Sparkplug]

Il think ill try this, what exaclty do I need to swap? Just the cords, the whole piece off the back of the carb? What?

[844x4]

A carb can be hard to diagnose, but its not impossible.  It may be something small.  On my 84 a small diaphram caused the truck to idle rough and run so rich it smoked.  That $15 dollar problem got the previous owner thinking it was a bad motor so I got the truck for next to nothing!

Point is.  take your time and eliminate one thing at a time.

[kneedownnate]

I also have an efi setup for sale too