TOPIC: 1994 Honda Civic Ex VTEC 1.6L

I've grooved my 1994 Honda Civic Ex VTEC 1.6L and it has yet to perform in mpg as it should and it just doesn't want to idling after it has driven a bit. The idle goes up and down from .5 to 1.1.
I've capped the PCV and installed a new oxygen sensor and have widened the spark plug gap 3 times 20% from .045 to .072 for a grand total of a 60% increase. After I fill up anther tank, I'm going to increase them another 20% and see what happens.
And I did redirect the air pump line at ruffly 1/8 in.
I forgot to smell the tale pipe before I grooved, but it still doesn't smell the way it should.
Does anyone have any suggestions?

On a great note: the car can now go 60mph at 2rpm, 65mph at 2.2rpm, and 70mph at 2.5rpm! Thank you Ron

Before the rpm's were 60mph at 2.3rpm, 65mph at 2.6rpm, and 70mph at 2.9rpm or 3rpm.

God Bless,

Joseph

sounds like a vacuum leak

Joseph Welcome to the forum!

I agree w/ Dan--check for vac. leaks. Did you check your Groove for breakthrough's?

Sounds like you tried to pay attention to details. I'd hold off on plug gapping, go back and re-check your work use all available techniques hunt for pesky vac. leaks. Easy to miss 'em. Are all hoses orig. if so I'd be etra suspicious. Idle RPM "hunting" is a big indicator.

any pics of this one?

Again, welcome to the Gadgetman clan!!

Tracy G

Hello you all
Sorry for not getting back right away
I wanted to solve this Honda Ex Vtec single cam 1.6L mystery but I just can't seem to

So I went back and checked for vacuum leaks using carb cleaner & propane (I squeezed the trigger just enough before the flame would come) and it did not effect the idle.

Note: When staring the car the idle is 70% fine and 30% it will bounce from 1.5 to 1.1 twice or so and fine the idle .8 (often depending on how long I let the car warm up)or so . After I drive it for a time (some miles) it cannot fine the idle when coming to a stop (red light/stop sign) 70% of the time.

I cleaned out the IAC valve on three separate occasion (each time clearing the ECU for more than 20 min.) which did help it for a very brief space of time before it went back to its 70% to 30%.

I bought a new IAC valve (cleared the ECU) and it works the same as the old one (bouncing up and down between .5 & 1.1) when coming to the stop light etc.

Note: After driving it a few miles I drove into a parking lot and opened the hood and as the idle was doing its normal bounce I poled the electrical connection of the new IAC valve and the Idle balanced out at 1 (check engine light came on). I then reconnected it and the engine light stayed on and the car drove as if I had not reconnected it (not a smooth drive; you step on the peddle you would be jerky; not so bad after getting to 5th gear), but the idle did not bounce at all at the lights.

The funny thing was that the car only realized that I had reconnected the IAC valve when I turned it off and turned it back on again. And of course the 70% 30% idle issue came right back



On a totally separate note which made no difference on the idle: I realized that I cut the groove as if I had a electronic throttle body (but I don't) using the business card. So I re-cut the groove without filling in the old one. I thought I would use this opportunity to see what a one and an half to 1.3 wider groove could do. I also cut a new gasket for the throttle body just to leave no stone un-turned.

All in all I have seen little mpg gain with little mpg loss; so I am contemplating disconnecting the electrical MAP censer that is on top of my throttle body to see if that has been thwarting the increase of the mpg.

All comments and recommendations are greatly appreciated!

God Bless,

Joseph

some foreign models may have to go to dealer to reset the idle with factory scanner, I ran into this about 3 years ago. Most will learn but some need to be reprogrammed.

Thank you so much Dan.

I just checked with the Honda dealer and unfortunately they charge $115 but if it must be gone, it must be done. The dealer wanted to run the diagnostics test on it first to identify the problem (which is $115). I just don't think the diagnostics test is necessary.

Question: What make & model was the case that you ran into three years ago?

God Bless,

Joseph

Joseph your car should have two IAC valves which one did you replace . If you have any air pockets in your coolint it wiil act like your car.

Fast Idle Air Valve is the one that you need to look at it is under your throttle body

Thank you so much for the advice
I will look to see if I can find the second IAC valve.
The one that is clearly seen in the back of my throttle body, I already took care of with CRC Mass Air Flow sensor cleaner.
As soon as I get a chance I will look for the second one underneath the throttle body.

God Bless,

Joseph

P. S. I trust that everyone has been keeping Ron in their prayers as well as giving what they can to help him out in his hour of great need.

Here are the pictures of my RPM's after the groove

God Bless,

Joseph

Hi Joseph. Seems like you have gained power from the Groove. Thats great.

So is your main problem with idle RPM?

If so, would you check your coolant situation as per 4WD Bill. Honda's often have a bleeder screw that's opened during refilling of the system to bleed out air pockets, otherwise air is trapped in system. Perhaps a temp. sensor is getting false readings...Or a thermo-vacuum valve isn't being actuated right., or something that's operated/controlled by coolant temp...?

IF that checks out, let's go back to before you Grooved it. Were there any issues re: idle quality or otherwise?

Re: vac. leaks--experience shows that the Groove, 'cause it amplifies the man. vacuum,--will ALSO amplify any man. vac. leaks. Some engines a small unnoticed leak suddenly jumps up in significance. You need to be Fanatical on this. Study a vac. hose diagram of the engine closely. A Mityvac type hand pump vac. tester is connected to any closed end vac. operated device, like fuel press. reg, dist. vac. advance, power brake boost. anything w/ a man. vac. source where the vacuunm dead ends there. Vac. leaks are like rust, always trying to creep in w/ age.

Ron has told me repeatedly to Groove and cap/re-route PCV, then STOP. Check for leaks in Grooved TB, re-install w/ new or good. cond. gasket. Do the re-Learn procedure incl. drive part. IF exhaust cleans up and power is increased, likely is a sucessful job.

You did a beautiful job on the IAC restrict./re-route!

I suggest ya try opening up the IAC airflow, maybe a small trench in your JB dam. but only after checking the coolant and a Thourough--I mean Thourough--hunt for vac. leaks. I can't pound the drum loud enuf about vac. leaks, the bane of our Gadgetman existence!

Need to find/isolate the source of the issue.

I would leave the Ignition alone for now. Didnt see a dist. in you great pics, but check vac. advance pot and twist/release the rotor to ensure the advance mech. is smooth if you have a dist.

Don't try too many advanced mods at once, since a problem will leave ya wondering WHICH boogey-man is haunting you! (ask why I know! )

But I think you have a winner here once idle is sorted out, I like the power boost ya got!

Thanks Joseph for your write-ups and the great pics, we LOVE pics!

And remember Ron has said before that some Honda's can take a long time to fully sort themself out.

Keep at it buddy!

Tracy G

Hi Joseph go ahead and give me a call .now is a good time 971-533-6599 to talk about your honda