89 accord carb problem?

[rjjensen]

Cold starting has become troublesome. It starts right up then in about 20 - 30 seconds starts to misfire and I smell a rotten eggs kinda smell. As it warms up the misfire smoothes out. So if I leave it sit there sputtering for about 5 - 10 minutes without doing anything it returns to a normal fast idle. If I immediately put it in gear and go down the street about a quarter mile it also returns to normal(most times). Also after it warms up it won't return to idle without kicking it down via the ex. pedal. Seems choke related but exactly how I don't know. Can you service the choke? Any ideas?

[BDaccordguy]

i dont know bout the whole choke thing, im have similar probs, but i have know a rotten eggs smell coming from a plugged cat.

[shepherd79]

i have to agree about catalitic converter. you can remove it and punch the insides (if you don't have emission test) or you can replace it with high flow cat or standart OEM one.

[rjjensen]

Thanks for your comments. I pulled out the service manual and performed a couple of tests. The results are a little confusing. Perhaps someone could give me some advice. First I observed the action of the carb. and choke when cold. This all seemed normal. That is the choke closed all the way then opened slightly after starting. As it warmed up the choke gradually opened but would not come off of the high cam of the choke so it continuted to run at cold idle rpm. After warming up I noticed that the choke opener did not pull the choke open. My service manual says that after warming up Tab A should be tighly seated against the carb. It was not. I disconnected the two vac hoses to the choke opener and applied vacuum to the outside port and held my finger over the other port. I could get the opener rod to move back and forth but it would not hold a vacuum. Does this mean that it is bad and should be replaced? Does anyone have any experience with replacing this? Also I do not get any vacuum at all from either vacuum hose on the choke opener. Does this mean a Thermovalve A problem. How much does a Thermovalve A cost? Should there be vacuum at the choke opener when warmed up? How do I diagnose if the Thermovalve A is bad?

[DanG86LX]

Vacuum source to Choke Opener comes from - Choke Opener bracket - Carb internal passage - Intake.
So, with engine warm, unplug both lines #18 and #26 and plug the two prongs @ Choke Opener, then Tab A should be tightly seated against the carb, unless Choke Opener diaphragm is leaky..
Ur prob might be that lines #18 and #26 does not hold vacuum coming from Choke Opener...
https://www.3geez.com/showthread.php?s=&threadid=23242

[rjjensen]

Thanks. During normal operation with the lines still plugged in and warmed up should the choke opener be constantly moving back and forth? How much vacuum should I get via 18 or 26? Note that previously I wrote that the fast idle unloader does not work as well. What exactly is the problem here? If I perform the test you described and Tab A is still not seated against the carb. then what?

[DanG86LX]

"..During normal operation with the lines still plugged in and warmed up should the choke opener be constantly moving back and forth?.."
Definitely NOT, tab A should be tightly seated against the carb housing..

".. How much vacuum should I get via 18 or 26?.."
Normal manifold vacuum @ idle speed, say > 17in. My engine ~ 20in @ 800rpm. Use #26 for test and plug #18 prong @ Choke Opener.

".. If I perform the test you described and Tab A is still not seated against the carb. then what?.."
As I mentioned, Choke Opener DIAPHRAGM could be leaky. The Choke Opener should be removed from carb (2 screws) for plugging the hole in the bracket, then if the diaphragm is ok, both #18 + #26 prongs should hold vacuum.

[rjjensen]

Thanks. I'll try that. Should I get vac via 18 or 26 with the choke opener still connected? That is is the vac coming from the Tvalve A or from the opener?

[DanG86LX]

..using current thread, please fill in the blanks:
"Vacuum source to Choke Opener comes from ............................."

[rjjensen]

If it's not too much trouble to answer. What's invloved in replacing the choke opener? Is it necessary to remove the rod from the choke linkage? If so how? Can the diaphram be repaired? Can I get to the diaphram without removing the entire opener? TIA.

[DanG86LX]

"..What's invloved in replacing the choke opener?.."
2 x 8mm screws, careful with the small O ring.

"..Is it necessary to remove the rod from the choke linkage?.."
yep. Pop it out with a flat screwdriver :lol

"..Can the diaphragm be repaired? Can I get to the diaphragm without removing the entire opener?.."
another 3 screws and u get to diaphragm. I dont think u can repair it. The diaphragm was not in my carb rebuild kit. Get a replacement from junkyard.

[rjjensen]

Thanks. I can do it on the car, without removing the carb? It's the rod end that has me worried. It looks as though it is fastened completely around the choke shaft like a rod and piston setup and there is no ends to the shaft. Is it poss. to purchase one new?