Honda Concerto 1990 starting problem

adilnisargeo (Adil) 2018-09-09 12:42:55 +0500 #1

I have Honda Concerto 1990 model, Efi car,Automatic transmission,Mostly
drives on Cng,i am facing starting problem specially at morning,car
takes long self,after 2 or 3 long self,car starts.sometimes starts after
misfire/backfire.throttle has changed,plug cables and spark plugs have
changed as well,injectors tuning is done but problem is still there.No
any check engine light coming,can anybody help me on this irritating
starting problem?

omersiddiqui5482 (omersiddiqui5482) 2018-09-09 13:40:03 +0500 #2

Have you changed the engine... Coz concerto has either carburetor or a multi point injection...

Do you start the car on petrol... ? Try driving it a couple of hours on petrol and then check...

adilnisargeo (Adil) 2018-09-09 13:44:50 +0500 #3

yes the engine is changed, its PGM-FI 1600 cc Engine.its not carburator, it has Injectors.Car starts on patrol and then automatically switch to cng, but driving on cng.

omersiddiqui5482 (omersiddiqui5482) 2018-09-09 13:48:08 +0500 #4

That's what I am asking is doesn't have it's own engine... Sir get it checked from a cng specialist. If you are in Karachi there are plenty of such available... The engine is a B16A I guess with a PGM throttle body..

adilnisargeo (Adil) 2018-09-09 13:53:51 +0500 #5

u mean its all because of CNG usage? ok i will go to cng specialist soon but 1st let me drive on patrol for couple of days then will see if car has still start problem or not,one more thing, when cng has last point,car cannot cross 200 RPM and remains at 40 Speed,after refueling its fine...Thank you

adilnisargeo (Adil) 2018-09-09 15:00:39 +0500 #6

yesterday i went to mechanic for OBD, he said this car is not compatible with computer even it has ECU,he said this car requires manual checkup due to hard start,i didnt check IACV or vacuum leakage..

omersiddiqui5482 (omersiddiqui5482) 2018-09-09 16:35:23 +0500 #7

Mechanics lame excuses... Drive it petrol for some time Bhai if the problem persist.. it might be some ecu fault or throttle body issues. Else go and see a cng Wala he will help. I guess on low gas the pressure regulator for the cng kit is there it should not drop rpm...
Usually modern efi car including your B16A has to first start on petrol and then it converts automatically to cng without you even noticing there is just a slight jerk.. all is managed by the ECU and the CNG kit.

adilnisargeo (Adil) 2018-09-09 16:36:40 +0500 #8

Thank you bro

omersiddiqui5482 (omersiddiqui5482) 2018-09-09 16:40:32 +0500 #9

Also if IACV is dirty it will not idle correctly and engine will vibrate. Does this occur?

adilnisargeo (Adil) 2018-09-09 16:43:59 +0500 #10

yes Exactly, when shift from N to D or R, rpm drops and car vibrates.on Neutral or parking, its fine

omersiddiqui5482 (omersiddiqui5482) 2018-09-09 18:06:22 +0500 #11

If it is fine on N and P then IACV is ohk.. you just need to get it cleaned... That's all.