Poor idle your thoughts? injector?

[Juiced240]

Alright so i know theres a million of these and ive spent 3 days reading through them all. Heres my situation, my 91 coupe w/ DOHC KA has been sitting sense about january of this year with a bad radiator(had a hole in it) lol. I have 3 other cars that are turbo and great fun so i didnt bother with this until last week. When it was sitting i took my distributor out and tested it on a buddys car sense he was having some problems. I redid my timing at top dead center and prop adjusted the distributor and all was well.

Started the car and it warms up ok but not great sounds like a bit of a miss. Once it reaches hot idle it stinks like raw gas out the back more than normal lol (catless 3" exhaust) and it lopes like i have cams and stumbles and shakes. When i drive it though it drives completly fine and WOT pulls have what feel to be full power nothing holding it back. It sounds normal while doing anything except for idling.

What i ended up doing was a compression test which came out great and all cyl were within 2-3psi. i replaced the spark plugs and rechecked timing 3 more times just to be sure. While it is idling like crap i can pull the injector harness plug off the #1 injector and it has no effect when all the others will make it die. I can also pull the #1 plug wire and it will not effect anything.

So i swapped around my plug wires to see if it followed and it did not. So i assumed it was the #1 injector sense it has new plugs and all thats the only thing left in that cyl that could be a problem.

The thing of it is i still have yet to fill my tank with fresh gas so its been sitting in there for about 9-10 months. Im wondering if that could have anything to do with it? But then i would assume it would run rough overall not just in that one cyl. Maybe thinking to throw a bottle of injector cleaner in and fill the tank with some fresh premium to see if anything clears up?

Any ideas at this point would be great so i dont waste money on new injector(s).

[jeff420]

id say its the injector or the o ring

[Juiced240]

forgot to mention theres no check engine lights.

[KoopaTroopa]

I had a bad injector on my ka, instead of a bad idle it was more of a wobbly engine at idle, higher rpm's seemed to smooth it out tho.

If you've got a multimeter read the resistance across the 2 prongs on the injector. The reading should be 11 ohms, mine was like 34 on the bad one.

The Orings like to crack too tho.

[Juiced240]

Yea i think im going to go over to harbor freight here in a bit and grab one. Many uses for those that i never have done because i didnt have one. After i get that Ill post the results of the test.

[Juiced240]

Forgot to update this yesterday, all the injectors tested out between 11.8 - 12.0 so there all pretty much normal & matching. Today im going to put two bottles of injector cleaner in, and fill the tank for the first time sense it sat. Cruise on the highway and see how it turns out after running that through.

[Juiced240]

Put the cleaner in and filled the tank on premium. Ran it on the highway full bore on the on ramp and nice cruise for 10 miles then stop and go in the city for 10 more miles.

It still wont idle for $hit! Heres what i see, anything above 2K rpm it runs normal and fine. Less than 2K, #1 cyl will not fire for whatever reason. I was at walmart and pulled the wire again and held it neer the valve cover to ground it out and it was not firing at all that i could see :/.

So i still have not cleaned the IAC or whatever on the firewall side of the intake mani. Would this be a symptom of a sticking/clogged IACV?

Also note the plug wires look like the original ones but like i said if i swap the wires around theres no change. So maybe the distributor?
Modified by Juiced240 at 7:29 PM 10/15/2009

[ghx407]

Check the #1 injector's o-rings; if they're broken you found your problem.

If the o-rings look fine, swap the #1 cylinder's plug wire, spark plug, and injector around to see if the problem follows any of the parts to another cylinder. That should help you narrow down the problem. Remember to lubricate the injector o-rings when installing them.

[Juiced240]

good ideas, ill check those o rings out tomorrow. I actually have a set of 4 brand new ones ive been sitting on doing nothing. Ill just replace them all when testing.

[Juiced240]

Replaced all the o rings and it still did it... So i was spraying carb cleaner and i found the leak! On the intake manifold right at the front of the motor next to the #1 runner i sprayed and vroom it idled itself right back up. So i turned it off and coated i with some RTV lol letting it dry now for a few hours and seeing if that did it. I also went to advance auto and ordered a new intake manifold gasket to replace it.

Also of course in the process of tigheting the intake manifold i dropped my best 12mm socket into hell and cant find it lol.

[NismoRacer34]

I know you checked your wires already but i had this same problem. The end of my dist. rotor was really burnt so I replaced the cap, rotor, and wires and they have seemed to fix the problem.

[Juiced240]

I guess that will be the next step. I tried to start it again after the RTV dried and it still runs like complete trash until 2K rpm. When i spray carb cleaner around the area that it made a diff in last time it does not do anything at all.

I took the maf off and cleaned that out good with some cleaner. Im done for the day the thing is really ticking me off.

Im positive local parts stores wont have the cap and rotor i need so that wont be happening tomorrow i bet. (sorry in a poor mood now)

[Juiced240]

Actually im in luck just found a new cap and rotor for $14 at orielly's

[Juiced240]

Just to update those didnt work either..

I tested the coolant temp sensor and it read completly wrong (.7 when it should have been between .25-.30 so i went and got a new one at advanceauto. Tested it fresh out of the package at .30 perfect. Hooked it up and no change lol.

So im positive i found the problem, the intake manifold gasket seems to be bad for sure. I noticed there is now coolant leaking right where the intake mani meets the head. While chugging at idle i spray carbcleaner from below at the intake mani and the idle clears right up .

I just really dont feel like replacing this thing lol. Has to be done, bout to go place an order for the gasket sense no one has it in stock around here.

Anything and everything else that would cause these problems has been ruled out. I will update the thread after the new gasket has been put in for anyone thats searching for an answer to thier idle issues.

why it is the gasket/vacuum leak-nothing else is wrong (coolant temp sensor, maf, injectors, pump, distributor, coil, cap, rotor, hoses cracked, ohm/volt tested everything else that would effect idle)- the issue is only while under vacuum loads aka when WOT it pulls like normal and doesnt run like crap