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.

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

https://en.wikipedia.org/wiki/Calcium_Lime_Rust
Mostly harmless...I bet it's fine for aluminum.

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

Well I'd definitely not call it "mostly harmless" since it is capable of seriously hurting you if you don't wear gloves while using it.

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

Eh, the EGR's bolts are destroyed...they won't budge & nothing will grip them beyond an infant's strength to turn them. I PB Blastered them overnight but they are too far gone. In other news the IACV clicks fine w/ supplied 12v & back when disconnected. My thought would be to drill/grind the nuts off if I have to but the one closer to the fuel rail is a tight space for sure. I'd have to drill the bolts out completely and use a hex bolt/new nut combo to tighten her back down. Never used CLR for car-related stuff.....

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

As a last resort, I sometimes use a hammer and long thin chisel on rounded off nuts to spin them loose.

The chisel needs only to be moderately sharp and you need to angle the chisel as much as possible to get it to rotate but not so much that you end up carving off chunks of the nut.

If you have a welder and enough clearance, you can sometimes place a large nut over the rounded nut and weld the two together.

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

I'll try the chisel method, I don't have a welder handy, it would come in handy on days like today.

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

***update***

Never got the EGR off and the nuts are now officially mutilated. Once I reset the idle w/ a bias towards high (we're talking 50-75 RPM max) she cleared up most of her gremlins that are idle related, still have noticeable rev in neutral overrun. I have to focus on house related crap now so I may lay off smoothing her out til I get some extended top hats to lessen the Eibach Sportline thunk. Thanks everyone, Mak

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

Lots of info- thanks a lot all! :)

BTW "The PCV valve is new, and with the straight-through VX design I don't see how it can fail, it's just a hollow elbow."

Maybe important for some - the elbow is not the PCV. The PCV is located under intake manifold (hard to reach but possible when you put your whole arm between firewall and intake manifold).

Cheers!

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

one of these days I'll get a video of the "fickle Shift light". Below 2k and usually in 3rd gear up a decent hill, the shift light will flicker like an old fluorescent bulb until it builds enough RPM's and decides to stay on solid green. Still has neutral rev overrun, but the original cruise/buck issue is much smaller at the moment.

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

I should have done this one post #1...better late than...

This is "cruise/buck".
https://youtu.be/rLj6wmSDDRc

This is "fickle shift light".
https://youtu.be/EJCU98uB-ik

I believe these problems are related. Any suggestions?

Thanks,
Mak

P.S. Is there a way to embed these videos?

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

I've created a new thread just for videos, as this thread is too long for some attention spans...:)