DelSol_SD

Hello everybody, I'm a new user here- although I have lurked on this forum before and found useful info for fixing a few things on the crx I had. I'm not a mechanic though, anything I've done myself I consider very basic (brake pads, oil change, main relay fix)

Anyway... I now have a 1994 Del Sol Si.. engine is a D16 Vtec I believe (I'll double check after work... d16z6 i think)

Last month I replaced the head gasket and timing belt (at a shop) and the car had been running fine since then.

This month the car developed a new problem where the idle will occasionally surge between 1000-1500 with a solid check engine light, or it will be around 1500 but still sound like it's pulsing and have the CEL. Seems like a random problem because sometimes it runs fine and sometimes it gives me the CEL and idles like I described...

So far what I've seen regarding other people's similar problems is to look for vacuum leaks, clean/replace IACV, or clean /replace FITV.. I'm currently trying to dig as much info as possible but I am in uncharted territory a bit here as I only have experience cleaning the IACV on the crx.

I know I should find out what the code for the light is... but any insight into this problem would be greatly appreciated!! and sorry if I missed a thread that already perfectly addresses this issue

you should be able to hear the idle surging in the video

92ehatch

No amount of advice will help without the code.

DelSol_SD

Hey thanks for responding.. I looked up how to pull error codes and I got 14 which is IACV

I guess I'll try cleaning that out tomorrow

Former User

Diagnose rather than replace.

Use your finger to cover the hole leading to the IACV or FITV in the TB. Does covering one of these holes stop the surging?

DelSol_SD

I'll have to try plugging the holes tomorrow when there is some light out

DelSol_SD

Here's an update

I suspected the fitv was the real culprit since the issue was only happening after its warmed up.

Today I took the entire throttle body off, and cleaned it with throttle body cleaner. I also sprayed inside the fitv since I couldn't remove the plastic thing inside to really clean it thoroughly. Let it dry for like 6 hours and it seems to be running just fine now.

DelSol_SD

Hmm the problem came back. Perhaps I didn't clean the fitv thoroughly enough. I've seen people block fitv off completely, I wouldn't miss it being in SoCal.

Can I remove the throttle body and put something between the TB and FITV? Is there anything else I'd need to do to 'delete' the fitv?

92ehatch

To block the fitv you just loop the coolant line to connect to the iacv and block the vacuum ports off with gasket material