1997 Dx HAtch D16y5 swap vtec always on

413joe

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I recently purchased a 97 dx hatch on Craigslist. This model civic is supposed to come with a d16y7. At the time i had no idea and have only recently found that it is in fact a d16y5 engine in the hatchback. So i assume someone who owned it before me had swapped engines. It appears that the wiring harness for the engine and im assuming the ecu are still that of a dx. The Vtec is wired to a switch and can be toggled on and off. This engine comes with a variant of vtec called vtec-e. This variant of vtec is normally activated at at around 3,000 rpm. It opens up all 16 valve instead of the 12 that are in use without vtec. THis is supposed to help with better mpg. My question is will running vtec-e all the time hurt my vehicle in any way. Obviously my mpg would suffer but would having all 16 valves working all the time do any damage. The car has no idle problems or CEL

EDIT:
Somes pictures
http://imgur.com/a/mpKXi
 
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Wreckless Hype

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You're running an HX motor, designed for fuel efficiency, in a DX where someone wired up an on/off switch for vtec-e.

Even in the stage before all intake valves open together, the intake valves are still opening. 4 of them are not closed, they are opened only a small bit to create a better charging of the intake air to lean out the mixture for better fuel economy.

This sounds incredibly dumb, because if vtec is not engaging when it needs the other valve open to supply a proper mix, it won't be happening and yea, that's going to cause issues. Running vtec all the time is going to kill your mpg obviously. This sounds like a really bad idea.

I'd buy the correct ECU and get it wired correctly. Engaging the cam to work the way they are supposed to under heavy load is not going to help you any.
 


413joe

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You're running an HX motor, designed for fuel efficiency, in a DX where someone wired up an on/off switch for vtec-e.

Even in the stage before all intake valves open together, the intake valves are still opening. 4 of them are not closed, they are opened only a small bit to create a better charging of the intake air to lean out the mixture for better fuel economy.

This sounds incredibly dumb, because if vtec is not engaging when it needs the other valve open to supply a proper mix, it won't be happening and yea, that's going to cause issues. Running vtec all the time is going to kill your mpg obviously. This sounds like a really bad idea.
what would you suggest for a fix. there is no wiring for the the vtec solenoid. The car runs better with the switch on but would turning it off be better for the engine?
 

Wreckless Hype

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what would you suggest for a fix. there is no wiring for the the vtec solenoid. The car runs better with the switch on but would turning it off be better for the engine?
I think leaving it on until it's fixed would be the lesser of two evils. Turning it off is going to leave it in the fuel saver, leaner mixture mode and when load increases, it needs more than can be provided and I think you're going to see some serious issues there.

I'd look into the proper ECU for it and wiring harness, or a D16Y7 for the car. Probably the same price when you see prices of the Y7...
 


xxBLOOD88SHOTxx

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I doubt your car is always in "vtec"

unless you have two switches to activate both pins (the first to fully open all the valves and the second to switch over to the VTEC lobe) then the engine isn't doing what it is suppose to.

Your switch may just be allowing it to run both intake valves on the mild lobe, which isn't vtec. If your car was running on the vtec lobe constantly, you would know it.
 

413joe

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I doubt your car is always in "vtec"

unless you have two switches to activate both pins (the first to fully open all the valves and the second to switch over to the VTEC lobe) then the engine isn't doing what it is suppose to.

Your switch may just be allowing it to run both intake valves on the mild lobe, which isn't vtec. If your car was running on the vtec lobe constantly, you would know it.
well the switch followed back to the vtec solenoid so i just assumed it activated it.but you are probably right. i guess ill just leave it on for now
 

xxBLOOD88SHOTxx

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Does the car actually run any different if you flip that switch?

My next question would be are you sure the CEL light works?
 

413joe

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Does the car actually run any different if you flip that switch?

My next question would be are you sure the CEL light works?
im not sure how i could test if the CEL light works the dash doesn't appear to be tampered with. Its not a very noticeable change honestly just seems like better throttle response and sounds a bit better not so bogged down.
 

413joe

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When you first start the car does the CEL light come on?
no it does not. ive been looking into vtec-e more and this type of vtec can already be activated as low as 2,500rpm stock (depending on how aggresive you are with the gas pedal. So this form of vtec is meant to run for longer amounts of time. it also had different lobes that a d16y8. it has only two that lock together during vtec e here is a picture http://imgur.com/eQgklfp
 

Wreckless Hype

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im having my buddy come over with a code checker if it runs any codes should i just pull the cluster out and check for the LED?
Regular bulb. Definitely scan for any codes and you need to fix the bulb issue regardless. When you turn the key to the on position, it should come on for a few seconds at least and then turn off. That's how it works on pretty much every car ever. So if yours isn't doing that, investigate that issue.
 

413joe

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Regular bulb. Definitely scan for any codes and you need to fix the bulb issue regardless. When you turn the key to the on position, it should come on for a few seconds at least and then turn off. That's how it works on pretty much every car ever. So if yours isn't doing that, investigate that issue.
i was thinking about putting an ex cluster in it anyways since it doesnt have a tach on the dx models. i think this would fix my possibly tampered with CEL light

after some investigating i found that the bulb had indeed been broken and after replacing this bulb the CEL now remains on. The car is not registered or insured yet so i can not bring the code to get checked. my buddy just ordered one online so now i wait for more details. Anyone have any idea what maybe throwing the code. It looks like a d16y5 with a d16y7 wiring harness and im assuming d16y7 ecu. will that in itself cause CEL?
 

XpL0d3r

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Not irrelevant to the tech issue, but I'm from the 413 as well. Pittsfield...

You can jump the service connector near the ECU. Use thin wire or a paper clip. Turn the key, and if you have a CEL, it will start flashing. It's giving you a number. Long flashes are 10, short are 1's. Sooo for example, long-long-long-short-short would give you code 32. If there's more than one code, there will be a brief pause before flashing the next one.

Also, you can usually borrow CEL code readers from Advance Auto and stuff. I actually persuaded them to let me take it home to use. You could give that a try.
 

413joe

New Member
Not irrelevant to the tech issue, but I'm from the 413 as well. Pittsfield...

You can jump the service connector near the ECU. Use thin wire or a paper clip. Turn the key, and if you have a CEL, it will start flashing. It's giving you a number. Long flashes are 10, short are 1's. Sooo for example, long-long-long-short-short would give you code 32. If there's more than one code, there will be a brief pause before flashing the next one.

Also, you can usually borrow CEL code readers from Advance Auto and stuff. I actually persuaded them to let me take it home to use. You could give that a try.
i tried using the paper clip trick but i didnt seem to work im not sure if it works with cars newer than 96. The light does blink once though when the car is turned to on mode on the ignition. the code for 1 blink is either low or high voltage for the primary o2 sensor. i remember reading that the hx had a primary 5 wire o2 sensor could this be throwing the code since both o2 sensors are 4 wire
 

413joe

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i tried using the paper clip trick but i didnt seem to work im not sure if it works with cars newer than 96. The light does blink once though when the car is turned to on mode on the ignition. the code for 1 blink is either low or high voltage for the primary o2 sensor. i remember reading that the hx had a primary 5 wire o2 sensor could this be throwing the code since both o2 sensors are 4 wire
Will changing the wiring harness and ecu fix my problems .what kind of problems would I run into with o2 sensors. I'm open to suggestions. I just want to know the cheapest course of action to get this car road leagal and VTEC working properly would be nice too
 

HeX

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You're approaching your issues the totally wrong way. You cant expect to fix a problem when you dont even know what the problem is yet. Guessing is not how you fix a car. Read the codes then post them here, then ask for suggestions to those specific error codes. Otherwise, the only other option to consider is swapping in a D16Y5 ECU to match the motor.
 

413joe

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You're approaching your issues the totally wrong way. You cant expect to fix a problem when you dont even know what the problem is yet. Guessing is not how you fix a car. Read the codes then post them here, then ask for suggestions to those specific error codes. Otherwise, the only other option to consider is swapping in a D16Y5 ECU to match the motor.
ok i will update when i have acces to a CEL checker along with codes. i still think ill need the ecu and proper wiring harness if i ever want this engine to run properly though
 

HeX

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ok i will update when i have acces to a CEL checker along with codes. i still think ill need the ecu and proper wiring harness if i ever want this engine to run properly though
Installing the proper ECU is probably the only thing you should do, if nothing else.
 


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