I drive a 1987 Honda Accord, LX. Standard Transmission, 176k. Lately i’ve been noticing that when starting the car with a cold engine, it runs rough around 1500 rpm and chugs out blueish gray smoke and then tach gradually increases. When tach reaches 2000 or so, the car is running very smoothly with no smoke or engine chugging. I noticed this and a loss of gas mileage around the same time. What could be wrong? I’d like to have a general idea of what is going on before I take it to a shop. Runs and drives great otherwise. Thanks in advance to you experts.
You may have a dirty fuel filter and/or a possible maladjusted idle mixture set screw making the engine run too rich during warm-up.
Is the choke working properly?
Yes, I know you said you’re taking it to a shop, but I thought you might have some mechanical knowledge so you may have some idea of the fault yourself.
Well blue smoke is usually oil. Is it burning oil?
How about some basic maintenance items like fuel filter, plugs and plug wires? Are they all up to date?
When starting the car with a cold engine . . . it chugs out blue smoke. Valve stem seals. Cheap and easy, did them on my 89 Accord when it leaked oil down past the old stem seals. It runs rough at 1500, then runs smoothes out. I agree with Joseph . . plugs, wires, etc. You can buy a bit of time with the old valve stem seals by using a high mileage oil, as it can soften and swell the old cracked seals. Good luck! Rocketman
You should know that the feedback carburetor on your car is beyond the ability of mortal mechanics to rebuild or repair…You may have reached the point of no return…
If the engine appears to run fine after it’s warmed up then you probably have a defective choke pull-off diaphragm on the carburetor.
This pod pops the choke open upon cold start-up and prevents overchoking.
They’re simple to check and easy to replace. They’re also a common problem on any carburetor and not expensive. The rubber diaphragm inside the vacuum pod ages and splits.
If it runs crummy even after warmup then I would make sure the choke flap is opening all the way.
I would check all vacuum lines real close, and replace any that are cracked and or broken. Its possible that a broken vacuum hose/leak could cause a problem like this.
Fuel Filter, Oil Change, Plugs + Wires have all been done recently. I don’t know about Distributor Cap. But the car has been very well maintained.
Thanks, should I mention this to the shop when I take it in to have it looked it. As far as that goes, do you think this is an issue worth having checked out?
If it were my car I would fix it. Either a sticking choke flap or a defective choke pull-off is a minor repair IMHO.
Here’s what the choke pull-off looks like anyway.
The tricky part may be finding someone who understands how a carburetor works! They’re not that bad once one understands a few basic principles and how it all ties together.
Thanks. Actually a friend of mine claims to be able to completely rebuild the carburetor in my car. I wanted to avoid the shade-tree if possible but it seems that most shops won’t go near them so I may not have a choice.
The Honda carbs are not bad. The only drawback is that they’re vacuum hosed and brass jetted to death. Everything should be marked well, laid out in order, and no jets installed wrong or hoses incorrectly routed during reassembly.
If he overhauls the carb, I would think a new carburetor rebuild kit would include the pull-off diaphragm.
First, try really hard to find a shop that understands these carbs. As some have already said, this could be a very simple problem with a complicated system. Second, you can buy rebuilt carbs on line for $200. I can not say if they are any good. Besides, as already alluded to, it could easily be something carburetor-associated and not the carb itself. That could be more difficult to trouble-shoot than the carb!
Since this is a manual trans car you could take off the carb and most of the carb-associated stuff and put an aftermarket (Weber or other) carb kit on it. It is cheap and easy. After you get doe it looks like you could fit another engine under the hood.
These smog carbs had electronic mixture control, with an ECM and oxygen sensor as part of the “system”. They are “tamper-proof”, meaning the idle mixture controls are sealed and must be drilled out to clean the passages. Many times, key parts are riveted, not screwed, together. Finding parts for them, especially the mixture control solenoids, can be a real challenge. By this time, most cars were fuel injected, but not Honda. Too bad…