chevyboy07 91

had my car running pretty good for a while now until just recently. Today, i noticed the car had a hard time starting. it took a while longer then ususal to fire, but still no big deal. However, the idle would jump up to like 2500 for approx 10 seconds then come back down to normal and run fine. it only did it on start=ups (hot or cold).

Well, on my way out tonight, it did it again except it jumped to 4K+ rpm and STAYED there....no matter what i did, it wouldnt come down AT ALL!

TPS is set at .57 and i replaced the IAC right there in the parking lot. I checked all the general vaccum hoses and lines I could think of. Under TB, FP regulator, EGR, etc but nothing was wrong.

What the heck is the problem here!?!?! I'm so damn sick of the trouvle this thing has been giving me. Between tuning and all that stuff, its getting old QUICK

pasky

Wow, I have a pretty bad idle problem myself, its hit 3000 and still does at start up, but never up to 4000. You might wanna check your coolant sensor, maybe your car is stuck in open loop (or is it closed?). Sorry, wish I could help you more. My first thing to check would be the vacuum hoses, intake gaskets and TPS/IAC, but it seems you already did, sorry man =/.

chevyboy07 91

thanks pasky....this looks like a tough one

TTT

leirch

Have you checked your throttle blades to see if they are stuck open?

Checked the brake booster to make sure its hooked up?

You must have a stuck pedal/throttle blade problem or a massive vaccumm leak, there is no way that the IAC could bring the RPMS up that high.

chevyboy07 91

hey guys,

throttle blade is OK, booster line im 99% sure is on, but ill check again tomm afternoon..

here's something for ya tho....I got some carb cleaner out and started spraying around, here and there...hoses, vac lines, etc All that checked out OK.

So, next i start to spray around the manifold. Driver side of the motor checked out ok....the car was idling like crap(still) and when I sprayed it didnt change its crappy attitude one bit. So i moved on to the pass. side and when i sprayed the thing revved up to like 5K LOL and came down to 4K again. SO i sprayed and sprayed all around that side, and it was singing all sorts of different tunes. So, it seems thats the problem.....CRAP!!!!!!!!

Well, what im going to try and do is check out as many manifold bolts as possible WITHOUT pulling the runners, etc. I custom formed my runners with new welds, huge bore openings, etc etc (long story) so they are a SERIOUS pain to work with. I will also pull the valve covers and run a nice bead of RTVV around the manifold to head junction. I really dont see why it wouldn't work. There isnt constant fluid in contact, etc....i think it'll hold like that.

opinions/comments/LOL@me's????

Morley

You may have an injector with an o ring that is gone (maybe more than one). Try directing the spray of carb cleaner right at the base of the injectors on that side.

chevyboy07 91

i'll tell you what, i now have a few frigin o-rings loose in my damn head!!!! This stuff, pisses me off so bad, i just don't know what to do anymore man. I torqued the manifold back down to 30 ft.lbs and ran a bead of RTV all the way around the sides just to be sure.

Well, I have the SDPC base and the ARP bolts that come with it are good except for in 2 locations. Directly under the front passenger runner and under the driver rear runner. The bolt heads are too tall (i noticed this during initial install). So, i replaced them with regular shallow head bolts. Anyway, I had to take the #2 cylinder intake and exhaust rocker arms off in order to slip a wrench under there and try and crank that bolt down. So, no torque reading on that one, but it's good and snug. Also, I had to take the #6 cylinder intake rocker off for the same reason.

Bottom line, its still doing the same thing. Maybee the leak is from the "inside" of the manifold....theoretically, i only RTV's 1/4 of the possible sides. could be pulling from the lifer valley.......argh!

Morley

I would think you'd be seeing a lot of smoke from your exhaust if this were the case.

leirch

I'm with Morley on this one. Assuming your Plenum and Runners are sealing properly(Always check about 6 times more than you have to).

I am leaning towards o-ring problems. But something tells me its a problem with the runners.

Ed Maher

You should be able to pinpoint exactly where the leak is using carb cleaner and the straw.

I see you talking about 'custom welded' runners. I'll be so bold as to venture that a seam cracked.

A 4000rpm vacuum leak is a seriously big vacuum leak. I once completely fubarred a lower runner gasket on my car such that 1/2 of the gasket was actually pressed into the port and completely not sealing. Even like that i could idle at 1000rpms. A disconnected brake booster isn't much worse than 1500-2000rpms either. So you're looking for a hole almost 2x the size of the brake booster hole

chevyboy07 91

whelp, i totally i agree with what you guys are saying...and i wish i had the guaranteed answer :/

ya know, even when i spray round the injector o-rings the car changes its attitude. When i spray around some runner gaskets the car changes attitude. There is like 5 different places of my concern. One is definetly the manifold also. The thing is. Minor, tiny little vaccum leaks are actually normal. There is no such as a perfect seal and i think MAYBEE??? its all adding up?

Something went terribly wrong, and i belive its in the induction, therefore i will replace it all and just be done with the guess work. Another very MINOR possibility is a popped head gasket towards the atmoshphere...not the rest of the motor....i dunno guys, I'm stumped.

*edit*: the car was running great, and this probem gradually occured. On the night it started acting weird, it was only at 2500 for approx 10 seconds then it went down and ran fine....then it went to 4K, etc and here we are

Ed Maher

Thats why i'd lean towards you busted a weld. Sounds like a small crack opened, which raised the idle speed until the IAC backed off 10 seconds later. Now the crack is wide open and you're at 4k.

I know small leaks are 'normal', but like i said, even a wide open brake booster won't idle at 4k. You have a HUGE leak or a stuck throttle

chevyboy07 91

hrmmm, Ed you may be on to something bud! thanks to all for putting your thoughts/comments to this. I appreciate it.

chevyboy07 91

well, got some more info for you guys.

I pulled the plenum and runners tonight. Ed, you were right on man. There is some cracking on each of the runners where the welds were made. Actually, i wanted the runner ports to have a specific port entry size and while i was marking my lines to cut, i realized there wouldnt bee sufficient material for the gaskets to seat on, so i had a friend (bad *** welder) fill in some material around MOST of the ports of my SLP's. Then i ground them down flush on a belt machine and began to port the rest of the runners. Well, it all looked great and they seemed to be ok. One of our concerns was the runners warping due to the welding. SO, we were going to fill them with water and weld them like that, but it was ruled against b/c he said we could "shock" the ends were there was no water and ruin the piece. So he welded them on the lowest heat possible (cast aluminum sucks anyway) and we ran them like that.

It's kind of interesting, the only areas where they cracked are where the bolts come through the manifold FIRST.....then to the runners(self tapped). There is one bolt on each runner that does that (on the bottom) Seems, like the runners got tweaked?? Man, i have a hard time beliveing that this just happened. I was having very minor idle issues since day 1 with the car, and got it to idle decent up until recently. Again, both runners are cracked in that area as described above.

Finally, these are SLP runners which i love (looks). I hate the tube looking runners. They are polished very nicely along with the plenum and i would like to repair them. They both look repairable, but on one of them, the crack propogated to and THOUGH the bolt hole. SO, that will be an interseting (to say the least) fix.

What do you think guys....BIG MOUTH runners or try and repair these???? Pretty much, i dont wanna have to do this again, but if i have odds saying they may work, then ill go that route
Also......... should i rule out the manifold now?? I need a way to be sure if the manifold is ok or if those gaskets need replacing!?!?
opinions...comments...

12 Sec GTA

Dump the intake and go HSR.

Don't look back.

ski_dwn_it

I did not read the entire post. But HOLY bean! 4k idle!

Its not a sensor causing the problem, you need bunches of air to make it rev that high.

Throttle blades sticking?

Huge vac leak, like one side of the runner fell off?

Something is allowing air to get into your engine that should otherwise not be present at idle.

Hope you find it!

Oppps nevermind I see that you got it! Good, sorry for the crack problem though.

chevyboy07 91

HSR huh? Man, its just too pricey for me at the moment.

Still wondering if i should pull the intake and replace those gaskets though. it's so easy, i think i'm going to do it anyway.

12 Sec GTA

$600 is CHEAP!

But I know that everyone's monetary situations are different, so I'll leave it at that...


Fix the gaskets. Get your car on the road. Make $600 in one night.



I know not ALL of you SFFBA boys are pansies.. some of you guys actually race

chevyboy07 91

yeah, i here ya. Actually, i used to make quite a bit on the road.....slowed down a bunch tho. Too strict on the laws these days.

Plus the whole tri-county area knows about this car already....cant get a race for my life anymore.

12 Sec GTA

Yup. News went north too.


I've heard about your car a few diff. times..




You have any pics of your custom runner setup you can throw online? I'm interested in seeing what you did.

Verviticas

holy geez, 4k idle....thats full blown race car idle. Indy style. Too bad its a problem and not the point.

Therogamare

Hi,

i had same problem on Mitsubishi lancer Es 2004, after I changed IAC sensor(I thought it’s bad, but it was lose cable of throttle) my car started to putting idle to 4k and when i put old back car back to normal.

turns that sensor they sell now don’t match exactly like factory one.

hope that this will help 😀