PGM Carb Kings - diagnosis Please

**shake** · 30-09-2012 02:27 PM

OK so my ED Dual Carb Civic needs help. OK I need help with it..
Cold start, turn key, starts fine, idles well for a few seconds. Then the idle starts to drop low and chug. If left long enough without driving off or bliping the throttle it will stall. Plus the clouds of black smoke out of the exhaust and stain on the ground behind the car can't be ignored.
Once warmed up, the smoke clears, the idle is high (2k rpm), dropping the idle back to normal with the adjustment screw is fine and you can now drive it like normal all day. But next day same same.

**shake** · 30-09-2012 04:13 PM

Rotor cap is fine, dizzy is less than 2 years old (according to previous owner), plugs and leads are new (less than 5000kms). The light on the pgm carb ecu, in the passanger foot well is not on, no flashing nothing, not even with just the ignition on. Not sure if its suppost to be on, off, flash or what not.

**EDCivic** · 04-10-2012 09:54 PM

Understand your situation. Had a similar issue with ours and was a huge pain to resolve. I did find diaphragms on the bottom of the bowls of the carbs that had deteriorated and were leaking fuel i.e. more often than not after you turn the engine off there was a strong smell of fuel in the engine bay. Replacing these from a donor carb helped a lot but I thing what clinched it was replacing the vacuum control box (mounted on the passenger side of the firewall). It plays part and parcel of the idle control system containing amongst other things 3 solenoids that manage ignition, idle boost and a power control solenoid. Though I never bought one you CAN get a carby service kit for these from Repco but at around $270. Donor carb from a low k (200k’s) was $44 from U_Pullit. Hope this helps…a bit.

**shake** · 05-10-2012 12:46 PM

I'll try swapping the VAC box and see if its better.
Thats the trouble with fault finding with second hand parts of the same age, the part I swap in could be stuffed also...

**shake** · 05-10-2012 05:36 PM

I changed the carbs and VAC box a couple of weeks ago, due to my choke assembly being damaged. But I just changed the VAC box back to my original unit and while I don't want to jinx myself....job done. Double reps for you!

**EDCivic** · 05-10-2012 05:55 PM

Glad to hear, but better wait for a few days before the accolade !. I had a few false hopes there as well, but the gremlins showed up pretty quick ie within a day or so. Ours would flood more often than not and was a pig to start, but once running was all good. Since the vac box was changed it starts like a new one one but we still get the odd time where we get that fuel smell........but as long as it starts we're smiling !

**shake** · 05-10-2012 11:08 PM

I know what you mean, when I changed the carbs I thought I had scored after I rechecked all the vac hoses (2 needed to be swapped). But the next cold start..thumbs down. Hopes are still high at the moment.

**shake** · 06-10-2012 11:18 AM

I don't think we are out of the woods yet

Probably the warm weather yesterday afternoon masking the issue. Though, even this morning it's still an improvement on before changing the VAC box.

So when the car is cold the idle should be made to rise until the car warms up. By adding fuel and air. I'm getting the extra fuel, while cold, but not the extra air to boost the idle.
I think the wax thermo valve is suppose to push the fast idle cam to bring the revs up when cold.
I might try one of these "Lisle Radiator Cooling System Spill Free Funnel 24610" I found on ebay to make sure the cooling system is air free. Then adjust the fast dle screw, which is acessed from underneath the carbs to the right of the power valve (on intake manifold with one vac hose on the top of it).
http://www.ebay.com.au/itm/Lisle-Rad...item5d26a4adcf

**EDCivic** · 06-10-2012 07:32 PM

I must also add to the melting pot of remedying ours I also changed over the solenoids on the carb itself, well 4 out of the 5 that I could get to without taking the carby off.

**shake** · 09-10-2012 06:09 PM

I discovered today that the choke opener (right hand side of carbs, black, 2 hoses, push rod on under side, 3 screws to disassemble) had a hole in the diaphram. Since I have my old carbs I went to source the diaphram off them. But it had a hole in it too. Anyone see a trend here...So I looked around the shed... "no more gaps"... give it a try I think. If it works I'll buy a new one.
Just went for a drive and so far so good.

Try again in the morning.

**shake** · 10-10-2012 07:30 AM

Fixed, cool morning, no black smoke, good regular idle. Job done case closed.
Thank you all!

**EDCivic** · 11-10-2012 08:54 PM

Excellent ! As you said these ED's are getting old and take that extra TLC to keep them going. Though they are not your classic Camero or Vette
LOL, I'm still keen to one day moth ball ours and bring it back to life in around 10 yrs for our "Bay to Birdwood" run. Paint/body wise its in pretty good original nick (always garaged). I already have a spare auto trans and other mechanical bits, but just need to get some interior trim bits and we are done.