High Idling SVX

jcimos · #1 06-11-2011, 12:48 PM

Hi everyone! Thank for all your input with the Q&A about the issues i had with my car. Now i have a new problem. I just swapped my engine out of my wrecked 94 SVX into my new 92 SVX. Ever since the swap the engine has been idling high a little over 2k. The swap was okay, but for some reason the the engine runs rough on take off and the the idling is high. There is no check engine light but, a friend of mine said that the intake could have been cracked during the accident.

Does anyone have any ideas what i can do to fit this problem.

Cam · #2 06-11-2011, 03:09 PM

You could have a vacuum leak. If you have a vacuum gauge you can plug it into the intake manifold to read your vacuum at idle. If you do not have a gauge, then you can spray carb cleaner around the intake and underneath the intake to look for a leak. If you have changes in idle while spraying the carb cleaner, then there is a leak.

If you have a leak, you can track it down using the same method but a more localized area, to try to determine specifically where the leak is.

svxfiles · #3 06-11-2011, 04:37 PM

OR, you might have the throttle cable too tight.
There should be some slack in both the throttle and cruise control cables.

msvx95 · #4 06-11-2011, 08:04 PM

Tom, or anyone else, how tight is too tight? I thought between the spool and the bracket with the nut it was supposed to be "almost no slack". I have a higher idle at 1000 rpm right now and when I put into park it idles at 1500.

svxfiles · #5 06-12-2011, 04:51 AM

Quote:

Originally Posted by msvx95

Tom, or anyone else, how tight is too tight? I thought between the spool and the bracket with the nut it was supposed to be "almost no slack". I have a higher idle at 1000 rpm right now and when I put into park it idles at 1500.

Loosen the cable(s) untill the throttle plate is completely shut,
and you can move the cable side to side at least 1/8".

jcimos · #6 06-12-2011, 11:09 AM

So if my intake is leaking wouldn't that throw a check engine light?

icingdeath88 · #7 06-12-2011, 11:11 AM

I don't think it would. Remember, the ECU has to have an electrical connection to something for it to pick up that something is wrong. A vacuum hose that's not connected isn't exactly electrical.

jcimos · #8 06-13-2011, 12:06 PM

Well i checked all over the intake and no sign of any leak. any other ideas? She is driving like a dump truck. I need help please

.

Cam · #9 06-13-2011, 01:23 PM

I may be mistaken, but if it is rough during partial and open throttle, you can rule out the aacv and iacv. Can you check manifold vacuum with a gauge?

icingdeath88 · #10 06-13-2011, 01:56 PM

In your mods list in your profile it says you have an N62 MAF. What's the deal with that?

msvx95 · #11 06-13-2011, 02:58 PM

Quote:

Originally Posted by Cam

I may be mistaken, but if it is rough during partial and open throttle, you can rule out the aacv and iacv. Can you check manifold vacuum with a gauge?

I think it's the opposite...rough idle cold and warm would tell me it's the aacv or iacv.
Case in point I have a current code 24 iacv and it gets rough idle at warm temp.

msvx95 · #12 06-13-2011, 02:59 PM

Quote:

Originally Posted by svxfiles

Loosen the cable(s) untill the throttle plate is completely shut,
and you can move the cable side to side at least 1/8".

Ok so I loosened everything ....plate is shut and the idle won't drop below 1000...what does that tell you? + I have a code 24 that's intermittent.

Cam · #13 06-13-2011, 05:16 PM

You misunderstood me. I was saying that if it is only at idle then it could possibly be one of those things. I thought you meant it was always rough, so those would not be the culprit.

BUT, if it is only rough when warm, and only at idle, I would say the code 24 is spot on. Sounds like a possible iacv issue.

The car will idle higher when cold obviously, so maybe your iacv is dirty and will not close enough and the engine is compensating by using more fuel and raising idle.

Time for seafoam? Or remove and use some sort of cleaner directly on it.

jcimos · #14 06-13-2011, 09:12 PM

Thanks guys for the input. I checked the intake and found on leaks but i did find a busted fuel line hoses that goes to the fuel regulator. I replaced it but it still running the same. I am at my wits-end with it. The N62 MAF is the same MAF you can get out of a 90+ 300zx or a J30 (aka Z32 MAF). If there is a exhaust leak could that cause the car to run rough or could it be something else?

icingdeath88 · #15 06-13-2011, 10:28 PM

Why on earth do you have a 300zx maf in your SVX? Do you have the ECUtune stage 2 and injectors too? Because if not, I don't think the MAF will work right. Where did you get the idea that it would?

What all else is not stock about your car exactly?

As for a possible vac leak, check under the intake manifold as best you can. Old/brittle vacuum lines could have been damaged in the transplant.

Another possibility is a stuck open (even partially) IACV or AACV.

Is the idle high all the time or only certain times?