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86 Nova/Corolla random stumbling/high idle?


superkia
10-11-2010, 12:12 PM
I bought a 1986 Nova that has been sitting in a garage for around 20 years, the car only has 13k original miles. The owner dumped money into it but could never find the cause to their problem and after tearing everything apart we found that the clamps on the fuel lines were original and loose. After replacing the clamps, the car ran good.

Now the only issue I have with this car is that it stumbles like it wants to cut off when at stop signs and such but it only happens every once in a while. The car also will idle very high at times but with no tachometer I cant tell you how high.

The carburetor was cleaned out due to the black gunk from sitting but we still get the occasional stumble in drive at a stop or a high idle every once in a while. From searching the internet, I have only come to the conclusion that there is a small vacuum leak somewhere???

Anyone ever dealt with this problem and have any ideas on where I should start. When the car is driving it runs great, its just the stumble at stop and the high idle on occasion. The car smells of gas so I assume it it running rich but I am not mechanically inclined so it could be anything.

Any input would be appreciated,

Rich

jdmccright
10-21-2010, 12:48 PM
Spray some carb cleaner around all the carb base gaskets and vacuum lines. If the engine stumbles, then you've found a leak.

After that, check for problems with the EGR and PCV valves. post back with what you find

Hope this helps!

superkia
10-24-2010, 10:57 PM
I sprayed some carb cleaner and tried to cover the carb as best as I could with my hand, the motor did rev some but it was spiratic and I believe it was from the carb cleaner mist getting into the carb? I have to look at the manual to locate the EGR and PCV before knowing if they are the cause or not.

From what I have read, the off idle stumble or pause is a definite sign of a vacuum leak, could it also be from the EGR or PCV?

I appreciate everyones help on this.

Thanks,

Rich

jdmccright
11-09-2010, 01:32 PM
The EGR is possible but not as likely. Use the little straw to direct the carb cleaner stream. You can leave the air cleaner on for this. Also aim it at the butterfly valve shaft and linkage. If there is wear around the hole where the shaft protrudes from the carb, then air can get in that way.

superkia
11-09-2010, 01:41 PM
Sunday a friend did a couple of things to try to solve the problems, the first was an adjustment that had something to do with the squirter and that fixed the off idle issue. He then blocked off the EGR with a bolt that wasnt hollow inside to stop air flow so the EGR could be ruled out or replaced if needed.

So far so good but it still smells like it is running rich when warming up and I have only put about 15 to 20 miles on it so I dont know yet if it is healed. Has been running great though, no stalling or anything anymore.

After I put some miles on it, I will post up the results.

Thanks again for checking and helping out.

Rich

jdmccright
11-09-2010, 09:47 PM
Sounds like a general carb tear-down & clean/rebuild is in order as there's bound to be old varnished gasoline in there, along with sticking floats, gummed up jets, even spider webs, etc., to prevent good fuel flow and mechanical action. Plus, the choke may not be working right (dunno if it's vacuum or electric), causing it to run rich. Carb rebuild kit is $26 special order from AutoZone.

superkia
11-09-2010, 10:44 PM
When the guy that picked up the car out of the garage as a donation, he had a buddy of mine clean out the black gunk from the carb. When my buddy worked on the car the other day, that is what he said, get a rebuiuld kit for the carb and he would do it for me.

I put about 90 miles on it today and it did cut off on me once at a stop light from what I believe to be loading up and cutting off? From help from him and people like you guys here, I WILL get it figured out. Its a car with 13k miles on it that has sat for a long time so I dont believe it is anything major.

I will continue to update the thread just in case someone else finds them self with the same issues.

As always, your time Is appreciated with the help.

Rich

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