Jumping idle
 

Hey guys, pretty new the the rotary engine, so theres still alot i need to learn. I have a 88 vert n/a, and this afternoon my idle starting acting weird at start up. It jumps from about 1100 to 1300 rpm while its warm. It didnt do it this morning, so i dont know what happened. It normally idles at about 7 or 800 rpm. I checked the tps, and the volts read just like it should 1ohm, and a pinch less the 5ohms at wot. Dont know what else it could be, and any help would be greatly appreciated

Is the AC compressor on? Clicking on and off?

i dont think so. The ac doesnt even work on it. Its another thing i need to try and fix. The button works, and says is on when i push it, but no cold air

Ok, I know im supposed to check vac lines too, but am i supposed to check every single one? Or r there only a few lines associated with this problem? Ive looked around the engine, and didnt notice anything not connected. The problem is very annoying

I know this thing has been asked a lot, cause im obviously not getting any replies. But ive searched a lot about the problem. Some people saying it could be the tps, and to try disconnecting it while warm to see if its the problem. I tried that, and it stops the jumping idle, but idles even higher just below 2k rpm. I dont understand what that means really, cause i tested the tps, and the ohms read fine. Any help?

to me it sounds like a vaccum leak.

yep, sounds like a vacuum leak... get yourself a can of brake clean and start spraying... when the idel changes, you found your leak

yea i searched for a diagram for the vac lines, but it was a little confusing. Just wondering if there is a good way to test for one

Like he said above, get something flammable (carb cleaner, brake cleaner, propane) and spray it around. When the idle goes up, that is where your vac leak is. Check all of the lines/gaskets in that area.

ok, guess ill run over to auto zone and pick up a can right now. Im just annoyed cause im in the process of getting the tII manifolds, and turbo to throw on my n/a block, and i dont want any problems before that happens

Hmm i'd like to know also, since my idle jumps from 400-1000rpm instead of 1000rpm+ But when I pull a vacuum line it idles perfect at 900rpm. I checked timing, and leaks also the tps. Hopefully you can figure this out because i'd like to know also.

well you should check your vaccum lines also then. ha

his busted vaccum line might be different from yours.

ok, tried the brake clean, and nothin happened. Still idled the same, and i sprayed the whole engine bay trying to get in everywhere. I dont know if there is anywhere i missed, and not sure if there r lines under the car. So im guessing its not a vacc line. So im wondering if there r any specific lines i should be checking instead of just spraying and praying. Also i read somewhere about a thermowax maybe being the issue. Cant find the thread anymore, but could that be a cause?

have you sprayed the vaccum line from teh transmission?

to tell u the truth, i dont know. Would i have to get it from under the car? How many vac lines does this thing have?

There are vacuum lines from the transmission?? When I did my engine swap I never found any.

Have you leaned into the engine bay to see if you can hear any "ssssss" sound anywhere? Thats how I found 1 leak. But I capped it, it started to surge. No vacuum lines off anywhere, no cracks... nothing.. So if you find it before I do let me know :D If I find it before you do i'll let you know.

cool, sounds good. the sooner the better. Its only been 2 days, and im already sick of it

my car was doing this when i first got it too.. i had a stock 88 n/a vert.. the problem fixed it self.. it hasn't done this since i took the emissions bullshit off though..

do u ever have to get it smogged? how do u pass?

the vaccum line im takling about is if your car is an automatic. i just remeber that sorry.

no smog test in ny for any car that is 1995 or older

anybody else have ideas? ive sprayed the hell out of the engine bay with brake clean yesterday and today, and nothing happened? any other suggestions of what it could be? Also, let me add exactly how it started. I had driven it in the morning, and a few hours later i drove it again to get some food, but i pushed it a little hard while it was still cold, and maybe minutes later at a stop light it started the jumpy idle and it was above 1k. So something happened during that time

Hmmm I found out that the trailing plug had a slight crack on it. Also both trailing had "blow by" since there was a black ring around the porsolin {sp?} I dont know if that fixed it or not but i'm not surging anymore... (replaced spark plugs trailing only)

Also I messed with the idle screw and cleaned the bac, reset timing at 900rpm. I dont know which one of those would of fixed it. But no vacuum leaks. (-.-) I'm stumped since my idle is abouve 1k and when I lower the idle it will surge again >_<

So frank check the plugs :P

yea, i sprayed again in hopes of finding a leak, but no luck. Im gonna try cleaning my bac also, and see if its a fix. I also heard it could be the acv, which can also get stuck i guess. I heard if u remove it, block it off with a flat piece of metal, then start it up to see if it fixes the problem. If it works fine after that, then i guess the acv needs to be fixed or replaced. Kinda a pain in the ass i guess, but so is the high surging idle. Ill also take a look at my spark plugs, and see if that does anything

Oh man. I just found that the missing hose to the nipple was off and when I capped it, I just realized that it was for the pressure sensor. I reconnected it and now the high idle and surging is now gone. (Of course I did timing and adjusted the screw and plugs)

I don't know which one it was that fixed it but. hmm who knows. Let me know when you figure out yours, since mine was my pressure sensor wasn't hooked up. I idle like a champ now :D 850rpm