Androidmj

I took off my UIM (last time i did so, and also last time i started the car, was 2 months ago)...and the gasket was wet in a bunch of places, does this indicate that I need a new gasket? the gasket is metal and has been reused a couple times, but i've been having a 3400rpm idle since i last put the manifold on, so could this be the problem?

I also previously (2 months ago when i last started it and had a 3400 rpm idle) sprayed the UIM near the gasket with carb cleaner and the rpms jumped a bit higher.

ijneb

Most likey the problem.

I thought carb cleaner was susposta make the engine die?

JONSKI

Carb cleaner isn't going to help seal and will probably loosen the rubber coating on the gasket. Take your intake elbow off and start your car in-gear (I'm assuming you have a manual transmission), and then put the car in nuetral and let it idle. One-by-one put your finger or thumb over ports A, B, and C in the diagram. How much air is being sucked through them?
A lot? (strong suction, want's to give you a hickey)
A little? (not very much suction, hardly makes a sound when I take my thumb off)
None? (no suction at all)

RX7Wishing

so the uim gasket is reusable??

JONSKI

All intake metal gasket are reuseable provided they still have their rubber coating.

Androidmj

The metal gaskets never had a rubber coating on them, and I sprayed carb cleaner where the UIM meets the LIM to see if the gasket was leaking, the rpms jumped a bit but i wasn't sure if they were gonna jump that quickly anyways sinces the idle was rising up until the point I shut the car down. (this was all 2 months ago).

Oh, also, the AWS hose (i think thats what 'C' is on your diagram) is capped because i have a greddy elbow

Also, what is that test going to show me? that I have a leak past the TB?

thanks
mike

JONSKI

If a leak was causing your engine to idle at 3400rpm, then it would have to be HUGE and you would definately hear it! Like a large chunk of your LIM gasket is missing or you forgot to connect your brake booster line. If your AWS is plugged, then it's most likely that your ECU is fully opening your ISC.

Is the electrical connector to your AWS unplugged? If so, is there a 330Ohm resistor stuck in it?

BTW, the rubber coating looks like black paint.

Androidmj

No the electrical connector is not plugged, i plugged the hose when i installed the new intercooler...also, it looks like you have a black rubber band that goes between your TB and your intercooler elbow...i don't think i have that, should that be a problem? Also, if a vacuum leak is not causing my continually rising idle, what could be it.
I mean i am going to be replacing my TB and UIM gaskets tomorrow, but you don't think this could be it?

what is the isc? and what could i look at if it doesn't end up being the gaskets or the pettit ecu(which is a long shot).

mad_7tist

i mean if you are down ther it is a bitch to do so why not put a new one in? also those layered steel gaskets are usually ok to re-use. fwiw

Androidmj

put a new what in? and also i don't know if id call the gaskets layered, they just seem like thin steel peices with a ridge down the middle of them that gets crushed to form a seal

The UIM and TB gaskets aren't a bitch to do, and thats all i have off right now, so i'm not really down anywhere...

althought i do have a profec B boost controller i need to install so i will have to remove a little more to do that, but i'm not sure of what else i can be checking.

Juan

iTrader: (28)

That "black rubber band" is a gasket. If you dont have it there, air will leak through and screw with your idle. Order a new one for it.

poss

iTrader: (5)

That gasket is before the TB, so it's not going to affect idle. Not having it in there will possibly let unfiltered air into your car and leak boost if not sealed.

JONSKI

If the electrical connector for the AWS is unplugged, then it NEEDS a resistor. Otherwise your ISC (Idle Speed Controller) will open up too much. Also, make sure that your throttle cable isn't too tight. Attach your throttle cable while the intake elbow is off and make sure that the throttle plates are completely closed. As the others have said, the rubber band thing is a gasket. It doesn't affect idle, and the cracks are too small to suck in any large dirt particles. The biggest problem this will cause is boost loss. In other words, you are undermining some of the money and effort put into performance mods, because you are missing a $10 gasket.

Here's a pic of the ISC. It's attached to the firewall side of the UIM, next to the TB. It sucks in air through port (A) as illustrated in the picture I posted earlier.


- Jon

rdavidsrx7

old topic, but....yes carb cleaner will kill the idle not make it jump.

Juan

iTrader: (28)

After posting, I realized that it wont affect idle. But it was too late to edit. Replacing that gasket is still a good idea.

Androidmj

sorry, i checked and i do have the throttle body "rubber band" gasket.

Its snowing here now pretty badly.....damn new york springs....so i'm going to be working on it next sunday instead.

So what should i be doing with the ISC...can i simply disconnect it and see if my idle drops? Also, if i swap in my old computer (stock ecu, instead of my pettit ecu) will that do any harm with the idle jumping to 3400ish rpms with all my mods? The reason i am thinking about this is because the only time this problem has happened is with the new ecu in there (its used).

heres the chronology of all my issues...i was having problems with my idle being way too low and my AWS not working and pick up was too slow, so i did a hose job, and put in a new air intake. I realized that the issue with not being able to hit 3000 on startup was likley due to my coupling from the intercooler to the turbo being loose. I started it up and the engine shook like a mother for a few minutes and idle was incredibly horrible, so then i took off the UIM to check everything out. I realized that I had the MAP Sensor hooked up to a random **** that wasn't even a hose..........so then since i had some stuff off the engine i decided to put in my DP, intercooler, and AST. Then i waited for my new computer, popped it in, and i had the idle problem where it revs up to around 3200rpm and then continuously rises to about 3600ish before i shut it down. Engine shakes were completely gone though because i attached the MAP sensor correctly...

sorry, last long paragraph was just to let u know whats been goin on so far...........

Androidmj

so what types of things can effect the idle, especially drastically, and how can i test them. Like someone mentioned the ISC, how can i test that. Also, could a broken check valve mess up my idle this much?

any realistic ideas are GREATLY appreciated

-mike

also, i plan on doin that test that JONSKI put up with the A B and C ports...should i unplug the AWS hose and check the suction on that? and also what will this test help me with, like what am i looking for?

scotty305

iTrader: (2)

Quit typing, just go perform the test. I think it's safe to say that Jonski knows more about diagnosing your problem than you do, so you should just follow his advice.

-s-

Androidmj

I did your test JONSKI, both ports in the throttle body want to give me hickeys, alot of suction....what does this mean?....oh and the gaskets didn't cure the problem

rdavidsrx7

If this were an intake leak that was bad enough to rev your idle up to 3400 you would probably be able to hear the leak. Have you sprayed carb cleaner anywhere else to check for air getting in where it shouldn't...particularly when the car does idle at 3400? If it aint external than it must be internal like the ISC like stated earlier. What ECU did you get will it allow you to remove and block off the ISC or any other partslike the ACV or anything?

Edit: when you say that both ports have suction do mean the ones circled in red (A and B). "A" should not have suction except when the car is using the AWSto get it's revs up, if this still gets suction at operating temps then the AWS is F-ed up and you should just block it off and throw in a resistor because it isn't needed.

Androidmj

yes ports A and B have a ton of suction. I have plugged the AWS. What resistance value/watts value do i need to place in the AWS plug?

JONSKI

I'm 90% sure this is your problem. Unplugging the electrical connector from the AWS will cause the ISC to go wide-open. Unless you've actually eliminated and blocked-off the AWS, you can plug it back in.

If you want to eliminate your AWS, then you will need a 330 Ohm or 360 Ohm resistor. It can be a 1/2 Watt, but if a 1 Watt is available, then get that. Also, if flame-proof is available, then get that as well. Just stick it into the connector and wrap some electrical tape around it.

Androidmj

i will go grab a resistor and do this, however, i have not unplugged the AWS from the manifold, i simply plugged the aws hose.

rdavidsrx7

AWS hose?
there is a vac line that goes to the double throttle but only an electrical connection to the aws. You should still have the double throttle hooked up as that will not increase your idle, only restrict flow if not functioning correctly.

Good luck
Bob

Androidmj

Well, i stuck a 330 ohm resistor in the aws electrical plug, and BAM the idle was at a solid 1500 rpms, i let it sit for like 2 and a half minutes and it sounded great. Then i checked the oil and coolant levels because i had just replaced both, and so i refilled them and started it again. The idle was at a solid 2100rpms, my feeling is that once it warms up it will settle down, i'm happy its below 3000 and i think the rest may be just adjusting the idle screw or something, becuase the idle is solid both times and the vac reading is a solid 19-20.

HOWEVER, I looked over the engine bay and my BRAND NEW PETTIT AST was leaking at the seam between the larger diameter cylinder and the smaller diameter cylinder where the cap goes into............so i emailed rx7trix and will be calling tomorrow to see if they will send me a new one if i return it...................so basically, regarding the idle, it seems to be a hell of a lot better now, but i haven't brought it to operating temps yet