MWLW20

I recently swapped a D15B into a 95 Del Sol and got only one code which is the IACV (code 14).

Things I have done:
-Searched and read plenty of threads
-Cleaned the IACV
-Tried another working IACV to check to make sure the sensor wasn't bad.
-Measured the voltage to see if it was the wire but got 12.2v which is good.
-Tried the old ECU to test if the ECU isn't bad
.....problem remains.

The engine idles fine but around ~1,500-1,700rpms it gettings bouncy and throttle seems delayed and makes the car jerky. This seems to happen a lot after the car has been driven ~15 min. Is there anything I'm missing or could test? Thanks in advanced.

Former User

If you unplug the IACV connector with the engine idling , does the idle speed drop?

Did you check for a short or open in the Grn/Wht wire running from the IACV plug to terminal A9 of ECU connector A?

MWLW20

just doubled checked and no open or short and with the connector out the idle remains a steady 800rpm

Former User

Are you saying the idle speed drops from 1.5-1.7Krpm to almost normal after unplugging the IACV?

With the engine warm, if you block the throttle body port leading to the FITV with your finger, does the idle speed drop further? No air should be pulled through this port when the engine is warm.

Also make sure the idle speed is adjusted properly:

MWLW20

Sorry for the confusion, I meant ~1,500-1,700rpm under driving conditions and a constant 800rpm before and after pulling the connector.

Former User

The failure of the idle speed to drop after unplugging the IACV indicates that the IACV is not working. This could mean that it is not receiving power, is broken, or is not getting a ground signal from the ECU at terminal A9. Have you carefully inspected the IACV and connector terminals for damage or corrosion?

MWLW20

Everything looks good and I cleaned the IACV again tonight. I was suprised at how clean the plate is where the coolant lines connect and the overall condition. Do you think it is time to purchase a new IACV?

Former User

I thought you already tried swapping the IACV with a known good one? If so, I'd concentrate on the wiring.

MWLW20

Yea I did try a known good one but I was thinking maybe a brand new one? What wiring should I focus on at this point if there is no short or open wires and A9 terminal is fine?

Former User

I'd recheck the power wire and carefully inspect the respective terminals in the IACV and ECU connectors for damage and corrosion. The problem must be the wires, connectors/terminals, IACV, or ECU. You swapped in a known good IACV and ECU so the problem must lie with the wires, terminals, or connectors.

MWLW20

I'll take a closer look at everything again....hopefully I can get this taken care of soon. Thanks for all of your help.

MWLW20

Everything looks fine...at this point I have no idea...would this be a issue to take to honda? Only problem with that is I don't have hundreds to throw at them....any help would be great

Former User

The service manual diagrams below show how to troubleshoot code 14.

You also might want to try the other items mentioned in post #4.

MWLW20

Ron so if I tape off the whole and then put the intake on and start the car if the idle drops then it is the IACV? I haven't tighten the white screw in the FITV could that be a potential problem to? Like since there is no sensor there that that could be the source of the problem and the only code it knows is 14?

MWLW20

bump

Former User

Are you saying that the FITV has been removed and that the FITV port in the throttle body is blocked off? The sole function of the FITV is to raise the idle speed when the engine is cold, so when you start your engine, is the idle speed very low and the engine sometimes dies?

After the engine is fully warm, the FITV completely closes and no longer bypasses air to the intake manifold. Therefore, if your idle is abnormally high after the engine is fully warm and the FITV port is completely blocked off, then the high idle has to be caused by the IACV, a vacuum/intake air leak, or a misadjusted idle screw. My guess is that the PO removed the FITV because it was a pain in the *** and, to compensate for the loss of this cold-engine idle control, he up adjusted the idle adjust screw so that the cold engine wouldn't stall. But after the engine is warmed up, you pay for this alteration by having a high idle. In my opinion, you should consider reinstalling the FITV and properly adjusting the idle speed, and then go from there.

slow96lude

could he have it plugged into the wrong connector. isnt the iat the same plug

Former User

It's possible, but I assume that the OP would have noticed whether the wires for the IACV connector do not match those in the diagram.

Sambo_Eddo

possibly just bleed the coolant system? I wouldn't think it would throw a code but it's definitely given me idle issues in the past. I suppose if there was air right at the IACV it could possibly.

MWLW20

No the FITV is on the throttle body I was asking if this is how you would preform the test. I had some something like that described on a different thread.

slow96lude

I wasnt refering to the the fitv I was refering to the Intake air temp sensor located relativly close to the IACV

Former User

No, just use your finger to block the throttle body port leading to the FITV when the engine is warm and idling. If you feel air being pulled through the port when the engine is warm and the idle speed decreases, then the FITV is faulty and needs to be adjusted or cleaned.

Also adjust the idle speed as shown in the diagram.

MWLW20

I know its been a few days but here is an update. I order a new TPS sensor and throttle body gasket to try the original throttle body that was on the engine. In the process of sliding the engine under the car the tps sensor was broken.

When I took the throttle body off tonight I noticed a like a knick in the intake manifold. This makes sense now because that is where the leak is coming from. My question now is...what do I do? Is there a way to repair the manifold or do I order a new one? I have until Saturday before I go back to school.

MWLW20

bump for RonJ@HT

Former User

I wonder whether a silicone-based gasket sealant used in conjunction with a new throttle body gasket might do the trick. Just make sure to torque the bolts to spec and to give the sealant time to fully dry.