B18B1 very high Idle at start and intermittent idle after driving??

[Sylent Nite]

Title says it all. I acquired a 1994 DB8 with a B18B1 in it. On cold start up the car Idles around 2,000 RPM. After running for a bit it will go down to around 8 to 900, but at a stop it surges sometimes between 900 to as high as 1600 or so. At first I thought it was a vacuum leak but i'm not sure at this point. Any help would be great. Thanks

[CaTcH22]

May be the IACV is starting to go bad. Any codes?

[Sylent Nite]

None that i am aware of, previous owner may have unplugged the CEL though, Ill go and plug my scanner to it and check and see if its throwing anything.

[CaTcH22]

Cycle the key and see if the cel comes on then goes off after about 1 second. And a 94 cant be scanned, you"ll have to jump the scs connector. Count the blinking lights. lol

[Sylent Nite]

Ha yea your right. My scanner only does OBD2, lol. But no the CEL doesnt cycle at all which means he had to have unplugged it. Guess in my lunch break I will go and pull the cluster and plug it back in, now I gotta see if I can remember how to do the jumper to count the flashes,. lol

[CaTcH22]

Yeah people pull the bulb to sell the cars. Hahahaha. 1 long flash is 10 and a short flash is 1. So 2 longs and 3 short would be code 23.

[Sylent Nite]

Cool, code 23 im assuming is for the IAC valve? I know thats a common issue with B series motors too. Thanks for the input so far also Catch!

[CaTcH22]

Not a problem. 23 was just an example. I think 14 is for the IACV.

[Rsporty]

Not a problem. 23 was just an example. I think 14 is for the IACV.

IACV is 14 or 15.

I'd remove the IACV and spray it out real good with some carb cleaner.
Don't forget to check the fast idle valve, on the bottom of the throttle body, too. It has a plastic "retainer" that comes unscrewed over time.
Just remove the cover plate (2 screws hold it on) and you'll see the retainer. It's a round plastic piece with a hole in the middle and a slot in each side. Use a flat head screwdriver or something similar to screw it back down, all the way, till it stops.

Unless it's a vaccuum leak, these two are usually the culprit and both are easy fixes. Takes about 15 minutes to do each.

[Sylent Nite]

Nice, I did notice a line going into the throttle body on the front side held with 2 screws, looked like it had some coolant coming out of it. Like a slow leak or something. Ill def. check those both out when I go on break. Thanks for the input guys its really appreciated.

[NOCLUE]

iac is code 10 i belive one long blink, thats what it sounds like

[jdmshytyo87]

OBD1

Code Meaning
1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
3 MAP - manifold absolute pressure sensor
4 CKP - crank position sensor
5 MAP - manifold absolute pressure sensor
6 ECT - water temperature sensor
7 TPS - throttle position sensor
8 TDC - top dead centre sensor
9 CYP - cylinder sensor
10 IAT - intake air temperature sensor
12 EGR - exhaust gas recirculation lift valve
13 BARO - atmospheric pressure sensor
14 IAC (EACV) - idle air control valve
15 Ignition output signal
16 Fuel injectors
17 VSS - speed sensor
19 Automatic transmission lockup control valve
20 Electrical load detector
21 VTEC spool solenoid valve
22 VTEC pressure valve
23 Knock sensor
30 Automatic transmission A signal
31 Automatic transmission B signal
41 Primary oxygen sensor heater
43 Fuel supply system
45 Fuel system too rich or lean
48 LAF - lean air fuel sensor
54 CKF - crank fluctuation sensor
58 TDC sensor #2
61 Primary oxygen sensor
63 Secondary oxygen sensor
65 Secondary oxygen sensor heater

[NOCLUE]

[QUOTE=jdmshytyo87;39158700]OBD1

Code Meaning
1 O2A - Oxygen sensor #1
2 O2B - Oxygen sensor #2
3 MAP - manifold absolute pressure sensor
4 CKP - crank position sensor
5 MAP - manifold absolute pressure sensor
6 ECT - water temperature sensor
7 TPS - throttle position sensor
8 TDC - top dead centre sensor
9 CYP - cylinder sensor
10 IAT - intake air temperature sensor

SCORE

[jdmshytyo87]

thought that might help out a lil bit...later...

[Sylent Nite]

Ok, so I pulled the code today, sure enough the doucher had the bulb out of the CEL light. It gives me 4 long pulses and a quick 5th pulse. Anyone know what that is?? Not seeing it on the list above. Thanks

(EDIT) It just hit me thats code 41, lol Sprry been a while since I pulled OBD1 codes so bare with me, lol. So thats being said its the 41 Primary oxygen sensor heater???? Exactly WTF i that, lol

[DarKStaR]

that shouldnt cause it to idle like that. Check your intake manifold gasket also. Get some carb spray or brake cleaner and spray along where the intake manifold meets the head, if you hear the idle change pitch then you know you need to replace the gasket.

[RBS]

you may have a possible vaacoom leak, find that leak danny san!

[Rsporty]

I don't think the O2 sensor is causing your idle problem.
Might just need that, TOO.
Did you clean the IACV and check the fast idle valve, like I said?
Also, try spraying carb/injector cleaner on the vaccuum lines and listening for idle surges.

[gsrcivic]

take some carb cleaner and spray it close to the corner of the intake manifold on the drivers side....same thing was happening to my car i replaced everything and it turned out to be a vac leak on the underside corner of the intake manifold...if it surges when u spray it replace the gasket..but to start easy make sure ur tb gaskets good

[deondre]

im 100% sure its your FITV.its under your TB. 3 10mm bolts takes it off. unscrew the 2 philips screws on the backside of the FITV and then screw the valve down inside of the FITV ( dont over tighten). plug everything back up and i guarantee it will stop your idling from beingso high on start up, and it will not surge. had to do it to 3 of my b18 motors....takes about 20 mins tops!

[Rsporty]

im 100% sure its your FITV.its under your TB. 3 10mm bolts takes it off. unscrew the 2 philips screws on the backside of the FITV and then screw the valve down inside of the FITV ( dont over tighten). plug everything back up and i guarantee it will stop your idling from beingso high on start up, and it will not surge. had to do it to 3 of my b18 motors....takes about 20 mins tops!

Hmmm.
Sound familiar?

[EJdm]

Wow I'm also having this problem n my 90 teg but rev a little higher on col n hot... Gotta try some of these stuff tomorrow...

[alieyuyang88]

Wow I'm also having this problem n my 90 teg but rev a little higher on col n hot... Gotta try some of these stuff tomorrow...

x2