Honda Civic / Del Sol (1992 - 2000) EG/EH/EJ/EK/EM1 Discussion

Civic 2000 (D15Z6) Fuel Issues

 
Old 07-08-2019, 12:12 PM
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Default Civic 2000 (D15Z6) Fuel Issues

So recently I ran into an issue. I usually drive my car on CNG but because of a problem in the cng kit, I have to drive it on petrol after a very long time. Fuel gauge needle was on red without the low fuel indicator. I top up the car with around 9 litres of Petrol.
Astonishingly car only drove 40 Kms and then it starts to stop. Still no low fuel light

There are 2 issues.
Firstly the car is doing 4.44 km/litres which should be around 9 to 10 km / litres.
Secondly I want to know that does the fuel gauge needle goes below the red line or not as on my other car it goes beyond it. Secondly what about the low fuel indicator, may be the bulb is burnt? Or I was also thinking that the whole fuel in the fuel tank is not being used by the car. Is this can be possibility as it will also solve Extremely low averarage.
I have also notice high rpm on idle around 1200 to 1500 rpm without ac

The engine was swapped from Stock D16y8 to D15Z6 and after swap it has run around 25k Kilometers.
Overall car has crossed 300k Kilometers

Last edited by Hasan Khurshid; 07-08-2019 at 12:49 PM.
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Old 07-08-2019, 12:17 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

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Old 07-08-2019, 04:31 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

If you started with the tank completely dry, there will be a few liters that the pump can't reach.

Is your car actually fitted with a low fuel indicator? Very few of the USDM ones were. They may have an icon in the cluster for one, but there was no bulb, wiring, or sensor behind it. Other possibilities are that driving a long time with no petrol in the tank could have burned the bulb out, or that part of the LPG conversion is to disable the indicator.

Anything below the E line should be considered empty. The gauge isn't intended to be extremely precise.
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Old 07-08-2019, 06:06 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by mk378 View Post
If you started with the tank completely dry, there will be a few liters that the pump can't reach.

Is your car actually fitted with a low fuel indicator? Very few of the USDM ones were. They may have an icon in the cluster for one, but there was no bulb, wiring, or sensor behind it. Other possibilities are that driving a long time with no petrol in the tank could have burned the bulb out, or that part of the LPG conversion is to disable the indicator.

Anything below the E line should be considered empty. The gauge isn't intended to be extremely precise.
Thanks for your reply

I want to clarify that even on cng, the car first starts on petrol and then shifts to cng means that I always need some fuel in the tank to start the car even if I use cng regularly.
Secondly I have seen many times before the low fuel light as I am the first owner of the car from 2000. But lately it didn't light up and lastly I remember it was very Dim, difficult to see it in day.

But I don't understand that low fuel average as there are no visible signs of anything bad means it gives me a good driving experience.
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Old 07-08-2019, 08:19 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

For gasoline 6th generation Civics, it's very common for the low fuel light to fail but the fuel gauge to work fine. The cause is generally a bad fuel sending unit in the gas tank.

Just curious, does the CNG conversion kit have a separate CNG pressure gauge and low CNG pressure warning light?
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Old 07-09-2019, 08:14 AM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by muellersfan View Post
For gasoline 6th generation Civics, it's very common for the low fuel light to fail but the fuel gauge to work fine. The cause is generally a bad fuel sending unit in the gas tank.

Just curious, does the CNG conversion kit have a separate CNG pressure gauge and low CNG pressure warning light?
CNG have different 4 level light and a pressure gauge in the engine bay.

I have checked the low fuel bulb and it's not blown.
Can a bad iac valve and dirty throttle body can cause extremely low fuel average?

I also have cleaned my cluster and checked the bulbs
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Old 07-09-2019, 08:31 AM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

The problem is almost surely a bad sending unit. To verify, turn key to ON(II) and then ground the low fuel light wire of the sending unit to the chassis. Does the light turn on?
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Old 07-09-2019, 08:34 AM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by muellersfan View Post
The problem is almost surely a bad sending unit. To verify, turn key to ON(II) and then ground the low fuel light wire of the sending unit to the chassis. Does the light turn on?
I cannot access the wire of sending unit as I don't know how to remove the rear seats

But there is a 2nd problem which I also want to discuss, should I make a 2nd thread for low fuel economy?
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Old 07-09-2019, 08:37 AM
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Default Re: Civic 2000 (D15Z6) Fuel Issues



To check fuel light bulb I also got chancw to clean my cluster
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Old 07-09-2019, 09:10 AM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by Hasan Khurshid View Post
I cannot access the wire of sending unit as I don't know how to remove the rear seats
Coupe, sedan, or hatchback?
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Old 07-09-2019, 09:12 AM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by Hasan Khurshid View Post

But there is a 2nd problem which I also want to discuss, should I make a 2nd thread for low fuel economy?
My guess is that the lower fuel economy on petrol than CNG is due to the fact that conversion kit is optimized for running on CNG not petrol.
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Old 07-09-2019, 06:38 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

There was the Civic GX-- factory CNG. They're never seen in the USA other than that the model exists in parts catalogs. If you could find a parts GX and convert your car it would probably get better mileage on gas.
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Old 07-09-2019, 10:34 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by muellersfan View Post
Coupe, sedan, or hatchback?
Sedan
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Old 07-09-2019, 10:37 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by muellersfan View Post
My guess is that the lower fuel economy on petrol than CNG is due to the fact that conversion kit is optimized for running on CNG not petrol.
The car is not changed for anything else
On petrol nothing is changed. Only there is air blockage from air filter box around 50%
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Old 07-09-2019, 10:39 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by mk378 View Post
There was the Civic GX-- factory CNG. They're never seen in the USA other than that the model exists in parts catalogs. If you could find a parts GX and convert your car it would probably get better mileage on gas.
Here in Pakistan we cannot get any GX parts
Secondly sometimes cng is not available for one day so we have to have 2 options
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Old 07-10-2019, 06:19 AM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by Hasan Khurshid View Post
The car is not changed for anything else
On petrol nothing is changed.
What exactly does the CNG conversion kit include? A different ECU?

Is the conversion kit specific to the D15Z6?

Are you running the D15Z6 engine on the P2P ECU used for the stock D16Y8 engine?





Last edited by muellersfan; 07-10-2019 at 06:39 AM.
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Old 07-10-2019, 05:02 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by muellersfan View Post
What exactly does the CNG conversion kit include? A different ECU?

Is the conversion kit specific to the D15Z6?

Are you running the D15Z6 engine on the P2P ECU used for the stock D16Y8 engine?
Here in Pakistan we have general cng kits for any efi car. Kit name is landi renzo.
Nothing is changed but some device are installed to stop fuel injectors and send some false readings to ecu
Air box has 50% blockage using electrical tape
But everything else is unchanged for petrol.

Most probably my ecu would be stock one
I would check it and confirm it
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Old 07-10-2019, 05:19 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

so that means you'll have to look at your cng kit since its tricking the ecu into thinking its getting fuel. Also how did you connect the crank position sensor
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Old 07-10-2019, 05:24 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by tony_2018 View Post
so that means you'll have to look at your cng kit since its tricking the ecu into thinking its getting fuel. Also how did you connect the crank position sensor
But when I select petrol ecu should work as normal

And I didn't know about cps how is it connected
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Old 07-10-2019, 07:23 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by tony_2018 View Post
so that means you'll have to look at your cng kit since its tricking the ecu into thinking its getting fuel. Also how did you connect the crank position sensor


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Old 07-10-2019, 07:29 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by muellersfan View Post
What exactly does the CNG conversion kit include? A different ECU?

Is the conversion kit specific to the D15Z6?

Are you running the D15Z6 engine on the P2P ECU used for the stock D16Y8 engine?


I couldn't find ecu label
Wjich side it should be?
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Old 07-10-2019, 07:39 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

The low fuel light doesn't illuminate at the same fuel level every time. The one in my sedan has come on anywhere between 1/8th and any place lower, including not illuminating while showing no fuel.
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Old 07-10-2019, 07:55 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by Hasan Khurshid View Post


I couldn't find ecu label
Wjich side it should be?

The ECU code is usually present on an adhesive label on the sides of the ECU. It's also possible that the label is on the rear side of the ECU. Therefore, remove the ECU from the car to look for the label.
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Old 07-10-2019, 08:23 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by muellersfan View Post
The ECU code is usually present on an adhesive label on the sides of the ECU. It's also possible that the label is on the rear side of the ECU. Therefore, remove the ECU from the car to look for the label.
I only need to remove one bolt seen in the picture?

One more thing about low fuel light yesterday it does light up and I was on CNG and it was very dim but after I turn off the engine and restart it, it was not there.

I have never seen it full bright low fuel light previously also
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Old 07-10-2019, 08:51 PM
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Default Re: Civic 2000 (D15Z6) Fuel Issues

Originally Posted by Hasan Khurshid View Post
I only need to remove one bolt seen in the picture?
I see only one, but there may be others on the right side, which is not visible in the picture.

One more thing about low fuel light yesterday it does light up and I was on CNG and it was very dim but after I turn off the engine and restart it, it was not there.

I have never seen it full bright low fuel light previously also
Have you already installed a new bulb? It's also possible that the fuel level was not low enough to produce a bright light, or the sending unit is not functioning properly.

Ground the warning light wire at the sending unit. Grounding it should produce a bright warning light.
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