bigodub93

This issue seems to be all over the net but I can't seem to resolve it. I spent all last night looking thru these forums so I can fix this issue but it hAs not worked. So now I'm looking for help for my specific problem.
Facts: 94 civic sedan , just swapped in b20 with b16 trans. Ls obd1 intake manifold.chipped Ecu running stock euro ls map. No cel no other problems. But the car not running so I don't know if this was a issue before.

Problem:
I start the car up it idles normal right around 800 rpm
After about 30-60 sec. The idle goes upto 1800-2000. It doesn't idle hunt or surge just stays there. If I turn car off then back on it will just idle at 1800-2000.

What I've tried:
Bleed the coolant 2x
Cleaned the ivac
Cleaned the fast idle valve
Replaced the ect sensor with a known good one
Adjusted the throttle cable


What could be the problem. After all I read yesterday these things should have fixed it. Please help

94_civic_dx

sounds like u have a vacuum leak some were

bigodub93

Idk I thought a vac leak would cause the idle to hunt and also the rpm should shoot up right away right???

BryanM.

iTrader: (1)

* Check that the throttle plate closes all the way

* Check TPS calibration

bigodub93

I will get out and try the throttle plate.

Former User

Related to Bryan's point, check whether the throttle cable is adjusted too tightly or whether the throttle body is dirty.

If you cover the top of the throttle body with your palm while the engine is idling, can you kill the engine?

What CEL codes are thrown?

bigodub93

Ok throttle body had been cleaned and it does close all the way. Also I put my hand half way over the throttle body while car was running and it did not kill the motor or affect the idle.

bigodub93

I made a video that might help in solving the problem please check it out.

Former User

If you completely cover/block the entire top of the TB, does the engine die?

Also, the throttle cable looks too tight to me.

tony_2018

I second this. If you cover the throttle body and it dies than no leak. If its still running you have leak. If you just replace the intake manifold than double check that you tighten it down and those nipples in the back of the manifold are not left open.

bigodub93

So just completely cover the throttle body and see if it dies? Then loosen up the throttle cable a little bit and see if that makes a difference? And I'll double check to see if any nipples are open.

BryanM.

iTrader: (1)

It does seem like a vacuum leak.

What happens when you try to shut the throttle plate? What I mean is, when it's closed, grab were the cable connects and try to close it more.

What work have you done to it lately?

bigodub93

The throttle does not move any more when I press it. It is completely shut the way the cable is right now. But I will loosen it a little more. I bought the car with a thrown rod and replace the whole block but kept the intake manifold. So I removed the old intake gasket and put a new one on there. The guy I bought the car from said it worked fine befit eit broke. But can't rely on his info

tony_2018

Did you clean off the old gasket completely, like bare aluminum good?

bigodub93

Yes took a abrasive disc and got thy puppy clean.

bigodub93

Ok I completely covered the tv and car cuts off

Former User

Was this^ done when the engine was high idling? If so, use your fingers to cover both the IACV and FITV holes in the throttle body to see if the idle speed drops.

bigodub93

Left the house for the rest of the day but I will get on that tomorrow and let you know what happens.

CivicInUse22

I'm having the SAME exact issue with my b20b. I replaced the map sensor and tps and also cleaned out the IACV. Gonna try covering my hand over the throttle body at high idle and see if she dies. I'll keep you posted on any findings, we may have the same issue

bigodub93

Please do. We will get this taken care of

bigodub93

Ok got back on the car today. I accidentally started the car with "D" plug disconnected. I walked away for about 8 min. Came back car was warm and idling at 800rpm. Which is perfect right. Bit I did have a cel. So when I went to read the code that's when I found out the plug was disconnected. So after ibolugged it back up a started the car idle was right back at the problem spot. So this time with the car warm I plugged the upper opening before the throttle plate and there was no suction. And the lower hole still has big suction.

tony_2018

So no suction on iacv? have you tried to tighten the FITV as well?

Former User

Check for swapped sensor connectors.

If you unplug the IACV, does the idle speed drop or change?

Former User

Is air pulling from the IACV or FITV hole in the TB?

bigodub93

When it was cold air was pulling from both holes. When the car warmed up only the bottom hole which I think is the fitv hole still sucks air.