Caprice wont shut down ?

Hi i have a 1987 chevy caprice with the 305 cu in carbureted 4 bbl rochester when i go to shut the engine off some times it will keep running like it diesels does some one have any idea what i can do to fix this,any help would be great.....Thanks

i cant help you, but my 85 does the same thing after long drives. im rebuilding the carb this week, il let you know if that helps.

i cant help you, but my 85 does the same thing after long drives. im rebuilding the carb this week, il let you know if that helps.

I appreciate that Thanks

dont know what the problem is my 86 caprice does the same thing except it does it all the time ive changed the timing chain and all sorts of other stuff and still havent figured out what it is, somebody told me that it might be the carb but for all i know it could be all sorts of things one person says it could be a bad sensor another says the timing is off and i havent found either one to be true im currently working on the ignition system im going to replace some stuff in the distributor if not replace the whole thing but ill let you know if anything helps.....peace

oh yea i would like to know if the carb rebuild helps at all to, that was my next option........thanks ;)

Sounds like you may be running too hot of plugs? try some cooler, stock-grade spark plugs. Also, try throwing in some octane-booster or 91octane gasoline and see if that helps solve the problem.

ok i have autolites (the regular kind) wich is stock enough and iv used sea foam in the carb (2 times) which still didnt solve my problem,

(EDIT):it also runs on like its just running normaly with reduced fire so im thinkin it might be a bad coil, i have to hold the throttle open until it chokes itself just for it to cut off.......thankfully its not a daily driver:)

I rebuilt my carb, and it solved the deiseling problem right away. Not to mention it gave my car A LOT more power, and much better fuel efficiency. It got rid of my heasitation, and stumble as well. I've never seen such an impressive improvement from just rebuilding a carb... it was really easy too. Just make sure you have plenty of working space. But before you rebuild your carb, try lowering the idle.... sometimes that can be a cause. When the engine's warm, it should idle at 500 RPM.

Pete: does your caprice have a manual carb or one of those automatic electric ones??

automatic electric one (if you wanna call it automatic)..... I wish I had a manual carb, but I'd get an engine code or 2 without the electronics. I didnt replace any of the electronic components during the rebuild if that matters.

what kit did you use pete, where did you get it, and also what numbers would i use off of the carb to find the kit i need by the way iv written down some numbers ive found. this is everything it says on the side of the carb

Rochester Quadrajet
1708600
3385 JMY

help me out a little if you can thanks. Mine is also an electric carb if that changes much. thanks again

You've got an '86 Caprice if I'm not mistaken, so since mine is an '84, and it's got the electronics, then odds are you've got em too. I got the numbers off of my carb as did you, but it turns out that I didn't even need them. I went to AutoZone, and gave em the year of my car, engine size, and the emmissions system (where the car was built).

You can tell this by the first character on your VIN number. 1=US 2=Canada and I think 3=Mexico. Mine happened to be made in canada.

Anyway, after I gave them my model, year, engine size, and emmission system info, they gave a the proper universal carb rebuild kit. I can't remember what brand it was, but it was very good by my opinion. It came with all the necessary O-rings, gaskets, springs, screws etc. Inside there was also an exploded diagram of a basic Rochester Q-Jet carb, with all of the parts labeled, and if that particular part is included in the kit. There was also information about proper float height, and choke pull off measurements, and how to measue them, and adjust them. It even came with a small disposable ruler designed just for that purpose. There were also some precautions noted of what to watch out for in different year carbs.

Rebuilding a carb can be intimidating, and seem complicated. If you give yourself time, plenty of open bench space, and organize all of your parts, its a piece of cake. Just so I was comfortable doing it, I rebuilt mine on the coffee table in my living room (after laying out some newspapers, and opening some windows until all the gas evaporated.) Whatever you do, don't rush it. It took me a day, and a half. It might take you more time, it may take you less. Just be sure to clean all the parts very thoroughly. Blast carb cleaner, and compressed air through all of the ducts, and jets.

I hope this was of some help. I'm gonna be posting some pictures of my rebuild on a web site sometime soon I hope. If I do it sometime in the near future, I'll let you know.

thats great info, thanks.

if my car happened to be built in mexico or canada would it still have to meet the emissions requierments of the states? also what kinda problems were you having before you rebuilt your carb currently my caprice is running rough, it misfires often im not sure if this has anything to do with the carb or the distributor also when i put it into gear it wants to jump and im hearing a sound in the exhuast like i have a burnt valve but im not sure if thats what it is yet, help me out with whatever you can......thanks :)