[jmart]

Hey guys/gals,

I just finished swapping my d16a6 from my unfortunately wrecked 91 Si, into my *new* 89 Dx. I swapped *everything* over. I didn't want to be splicing wires and such so I stripped the interior of the car and pulled all the harnesses and carpet and dash and seats and blah blah blah from the Si. Took about three full afternnons of work to pull everything over. I've still got to swap the rear disks and suspension, but I'll leave that alone for a few weeks.

Right now my question is about the idle. In my old car the idle would sometimes dip down a bit lower than 500 rpm (stock tach) and be a little rough. Just a little. But most of the time it was fine.I put all the fluids in and started it up now that its in the new car and the idle seems a little more rough than it was. Granted it now has good motor mounts in it, so I'm trying to take that into account. At first it idled around 1,000 rpm til it warmed a bit, then dropped down to 500-800 rpm zone. But as i drove it around a bit i noticed once it wanted to idle high around like 1,200 rpm for a couple minutes, then someimtes it would dip low again.
The power at mid and open throttle is great as usual. This engine is very tight and strong. So what gives? I thought vaccuum line, but they all appear to be connected properly.

Suggestions?

P.S. sorry for the long post

 

[downest]

Did you bleed the coolant?

 

[baker_jeff]

Either coolant or the IACV?

 

[dohcya]

check and make sure the throttle cable isnt to tight where it could be opening up some... just enough to make the car "idle" higher than norm

 

[Slicktop]

I think it could be a coolent problem also. I had the same problem and it was the T stat. Watch your temp gauge, from a cold engine it should go up to 180' (just to the left of the center of the gauge) and stay there. If it does not go up and stabilize as described replace your T stat. My T stat was adjustable and I adjusted it with the screw on the end of it to fully close when cold. Mine was cracked open even when cold and that allowed some water to flow thru causing a very slow warmup and erratic coolent temp. The EACV uses coolent temp to set the idle and if the coolent temp is eratic so will be the idle.

 

[dohcya]

ahhh that makes some sense.... =P

 

[jmart]

My temperature seems to be fine, although I did not bleed the air out in the manner described in the manual. Now that I've read it, I'll go out and do it, but I'm unconvinced that it'll make much difference. I'd be happy if I was wrong though! As is the car heats up to 180 about as fast as I ever remember it doing before an it seems to stay there. Hmmmm, we'll see.
Any other suggested things to check?

 

[bobski]

check and make sure the throttle cable isnt to tight where it could be opening up some... just enough to make the car "idle" higher than norm

X2 - Make sure there's enough slack on the throttle cable to wiggle the long run by the throttle body up and down about 1/8" with the throttle fully closed (pull the little dashpot thing). Heating the cable makes it expand or contract or something - The DX cable in particular because it's so long.

 

[dohcya]

good call

 

[jmart]

Well, this DX is basically an Si now. Its not the throttle cable, and its not the coolant. I just checked and double checked everything I could.
Also, it doesn't idle high anymore. It just consistently seems like it wants to idle at like 800 rpm or whatever that first harshmark below the 1k mark is, but it dips down around the next mark at something like 400 rpm maybe, and feels a little rough.
Hrm, maybe I need to check out this IACV or whatever.

Also, when i did the coolant bleeding procedure I vented through the bleeder, but I couldn't get the fan to kick on. I let the car sit there idling/reving it by hand at the throttle body for about 10 minutes and it wouldn't get hot enough to kick the fans on. I'm just a little worried that maybe the fan doesn't work, but th temp never even tried to creep above 180. Hrm.

**lots of head scratching**

 

[vteckillenzc]

Either coolant or the IACV?

i agree with this guy, try letting your motor warm up and pull off the iacv plug try setting your idil to 800 to 900,if it dont stay u may also have a vac. leak