Re: '89 CRX HF + D15Z1 troubleshooting...
 

I unplugged the IACV on my 87 Integra with 1.6l because of the surging issue. I just left it in place. I made my own adjustable throttle stop and I did get a stable idle but it would nearly kill the engine when I ran the AC.

I had to plug a $1 radio shack resistor of the same ohm value as the IACV into the harness side of the IACV connector so the ECU would still think it was there- before I did that, I was getting a CEL for it.

I was happy with the overall result.

That car would get 37 mpg at 65mph- even turning at 3500 rpms...

Re: '89 CRX HF + D15Z1 troubleshooting...
 

that's funny as hell.. Even after putting in the radioshack resistor, did turning on the A/C almost kill the engine? If so, that would explain the purpose of the IACV, that it's suppose to help regulate the idle by means other than the throttle for accessories such as the A/C or headlights.

Re: '89 CRX HF + D15Z1 troubleshooting...
 

Yes Poor college students sometimes have to figure out a cheap method to "fix" their car.

Re: '89 CRX HF + D15Z1 troubleshooting...
 

Well I would say cleaning the IACV is a "cheap" method to fix your car and it's actually effective.

Re: '89 CRX HF + D15Z1 troubleshooting...
 

I re-inspected the IACV to be sure, it was soo clean even the mesh was shiny. I unplugged it & reset the idle according to HELMS, I didn't have a diagnostic tach so I went with the dash tach (inaccurate I know but all I had) and turned the idle screw 1/3 turn (counterclockwise to raise idle a hair). It's more of an experiment than fixing it, I won't know anything until I drive it around some this weekend. Again, my TB was deep cleaned before I installed it, I don't need to retread there. What's the next easiest way to check for vac. leaks besides the spray-carb-cleaner-everywhere-and-listen-to-the-idle way? Thanks, Mak

Re: '89 CRX HF + D15Z1 troubleshooting...
 

I agree that cleaning the IACV was cheap- but it didn't work for me (apparently not for Mak either)- and that's why I moved on to "plan B".



Mak- a vac gauge might help you see if you have any moderate leaks.

I have read that some repair shops use some sort of a smoke machine to find vac leaks- the fill the intake with smoke and look for puffs around hoses etc.

Any chance that your EGR valve is stuck open a little bit?

Re: '89 CRX HF + D15Z1 troubleshooting...
 

You say the IACV was clean... did you try to actuate it to see if it actually moved with ease? My IACV was completely stuck and I hate to break it free before I cleaned it.

That's also a good point.. the EGR valve and control box is likely dirty and so needs servicing either by a good thorough cleaning. EGR would definitely be a potential factor.

Re: '89 CRX HF + D15Z1 troubleshooting...
 

I'll try and activate the IACV this weekend. The EGR might be a tad harder to clean considering the bolts are severely rounded off already (even when I used a brake line flare nut wrench) so removing it will be a hassle. I have a Vac gauge already hooked up to both my Hondas and I may try and take some video of it when I'm out and about next time under load, decel, idle, & comment when the issue creeps in. Is there any other way to clean the EGR w/o removing the solenoid itself just in case I'm unable to get the bolts off?

Re: '89 CRX HF + D15Z1 troubleshooting...
 

Might want to try to hammer the bolts, use a blow torch or something of the sort. I'd normally recommend CLR to remove the rust but because of the proximity to aluminum and the fear that CLR is actually muriatic acid, that could result in an explosion.. I like CLR (Calcium Lime Rust) because if you put it on rusted steel, scrub with a tooth brush, it ONLY removes the rust, leaving the rest of the metal intact. I used this stuff when I was restoring my electric stove which had rusted with time.

Re: '89 CRX HF + D15Z1 troubleshooting...
 

Yeah, most rust removers are acid based.