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sprinkles08
sprinkles08, ASE Certified Technician
Category: Honda
Satisfied Customers: 22369
Experience:  ASE Master and Advanced level certified. Factory trained with 15 years dealership experience
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I have a 2005 honda civic GX ( ngv) with 235k miles, i just

Customer Question

I have a 2005 honda civic GX ( ngv) with 235k miles, i just purchased it, had head gasket issues that was fixed, the problem on this vehicle is that it runs, the about 30 seconds later it dies down, i have to crank it about 20-30 secs to restart if it
will restart but running after 5 min it would start again, andfor 30 seconds, and do the same thing, has no check engine light nor pending light
Submitted: 1 year ago.
Category: Honda
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

You may be losing spark, fuel or both. The symptoms are often caused by a failing fuel pump.

The first step in diagnosing the problem is to see if any fault codes are setting. Anything causing a loss of spark should set a code and that will give a starting point for testing. Have you checked for codes?

Have you tested fuel pressure at the time it won't start?

Customer: replied 1 year ago.
No codes has no fuel pump, its clean natural gas, has 3600 psi tank , and hAS 2 pressure regulator,it does not have terminal to check the pressure, although it does have a sensor at the end of the fuel rail
Expert:  sprinkles08 replied 1 year ago.

I wasn't aware that it was a CNG vehicle.

How did you determine there were no fault codes?

Customer: replied 1 year ago.
I have 2 scanners, no pending or actual codes
Expert:  sprinkles08 replied 1 year ago.

You have an actual scan tool?

Customer: replied 1 year ago.
i have 2 scanners
Expert:  sprinkles08 replied 1 year ago.

Is communication possible with the ECM at the time it won't start?

Customer: replied 1 year ago.
I have not check on tHat, how should i check on that?
Expert:  sprinkles08 replied 1 year ago.

You would use the scan tool to see if you're able to get in and still look at data.

Customer: replied 1 year ago.
I will do and come back to you
Expert:  sprinkles08 replied 1 year ago.

Ok.

Customer: replied 1 year ago.
i am not loosing connection with the computer still giving me some live data
Expert:  sprinkles08 replied 1 year ago.

Are the cam and crank sensor signals present and in sync?

Customer: replied 1 year ago.
My scanner is a common one i dont think it has the option to receive and record those impulse, though the injector wires were tested with noids and they had lights, one thing more i can test is the sparks on each coil , this is an indirect testing of the cam and crank sensor right?
Expert:  sprinkles08 replied 1 year ago.

What is the brand and model of what you're using?

Customer: replied 1 year ago.
Autel maxdiag the european model
Expert:  sprinkles08 replied 1 year ago.

Are you able to see engine RPM at least?

Customer: replied 1 year ago.
when it is running
Expert:  sprinkles08 replied 1 year ago.

At the time it cranks and doesn't start see if it shows RPM.

Customer: replied 1 year ago.
The rpm on the tachometer or the scanner
Expert:  sprinkles08 replied 1 year ago.

The scan tool.

Customer: replied 1 year ago.
i will try tonight and let you know, are you thinking the problem is the ecm?
Expert:  sprinkles08 replied 1 year ago.

It's possible but not likely.

Customer: replied 1 year ago.
the scanner is reading the RPM WHEN IS RUNNING
Expert:  sprinkles08 replied 1 year ago.

Yes, certainly. You're concerned with what it does when the engine does not start.

Customer: replied 1 year ago.
It still read when crancking without runing too reading about 160 to 180 rpm
Expert:  sprinkles08 replied 1 year ago.

Have you tested for spark at the time the engine isn't starting?

Customer: replied 1 year ago.
that would be my next step today
Expert:  sprinkles08 replied 1 year ago.

Ok.

Customer: replied 1 year ago.
All sparks are ok, i also checked the fuel pressure at the rail and it was about 40 but there was some gas leak on the gauge hose
Expert:  sprinkles08 replied 1 year ago.

Can you check injector pulse?

Customer: replied 1 year ago.
i did check with noid , the light was pulsating
by the way , it is not running that first 15-20 seconds run, it is cranking though
Expert:  sprinkles08 replied 1 year ago.

Have you taken a fuel sample to check for contamination?

Customer: replied 1 year ago.
Where can i check a clean natural gas and in what container that can hold 3600 psi pressure
Customer: replied 1 year ago.
The car is at the dealer, they could not fogure out
Expert:  sprinkles08 replied 1 year ago.

I had forgotten that it was CNG when I asked about the fuel sample.

Is it at a Honda dealer?

What parts were used for the CNG conversion?

Customer: replied 1 year ago.
It is factory cng . Not convrted from gasoline
Expert:  sprinkles08 replied 1 year ago.

Is it at a Honda dealer?

Customer: replied 1 year ago.
took it on monday and they domt know what is going on
Expert:  sprinkles08 replied 1 year ago.

Do you know what has been done?

Customer: replied 1 year ago.
Head job, including valves, timing belt, 30k ago low pressure and hi pressure cng filter, compression is above 150, no codes ,all coils have sparks, and the injectors has electricity, the cng pressure on the rail. Was about 42 psi. And now is not even running the initial 15 seconds
Expert:  sprinkles08 replied 1 year ago.

Has it been checked for an exhaust restriction?

Customer: replied 1 year ago.
No i did not try thay, i will remove the exhaust manifold and try it tomorrow
Expert:  sprinkles08 replied 1 year ago.

You'd want to remove the pipe from the manifold, you can leave the manifold in place.

Customer: replied 1 year ago.
But the cat converter is before The pipe, its one body with the exhaust manifold, and mostly the restrictions are in the cat converter.
Expert:  sprinkles08 replied 1 year ago.

If the converter is part of the manifold then the manifold would have to be disconnected if you were going to attempt to run it and check it that way.

The correct way to check for an exhaust restriction would be to use a backpressure gauge at the upstream oxygen sensor bung.

Customer: replied 1 year ago.
i should do it tomorrow
Expert:  sprinkles08 replied 1 year ago.

Ok.