4A-F troubleshooting questions - Toyota Nation Forum : Toyota Car and Truck Forums

icurays1 · 07-07-2007, 11:24 PM

Hello, everyone. You've got a great forum here, im glad I found you and look forward to getting involved.

I was recently (i.e. today) given (friend of the family) a "totaled" 89 with a 4A-F engine. I've been spending the day working on getting it up to speed.

The car has been sitting untouched for about 4 years. It has been started maybe once or twice during that time.

I have changed the oil, flushed and filled the coolant, changed the fuel filter, air filter, and checked the plugs. I also charged the battery for a few hours. I've never worked on a carb before so I haven't really looked at that yet. (same with the distributor)

My question is this: the car seems to idle real rough and spasmastic. it'll rev, then come close to dying, then rev itself again, the almost die, then rev...it continues this cycle until it finally sputters out (sometimes takes 5 min). If i keep my foot on the gas just a smidge, the problem goes away.

Could this be as a result of old gas? Or...? do I need to adjust idle speed? The first couple times I started the car today, before i changed the oil, it dieseled after turning it off for just a couple seconds. After I changed the oil this has ceased to occour.

Thanks in advance for any help, i can post a video with sound if it would help.

I'll try to post pictures of the wreck tomorrow.

~Nick

eage8 · 07-08-2007, 09:58 PM

I would say it's most likely old gas, drain and refill the gas and let us know if it still happens. there should be a bolt on the bottom of the gas tank. it's pretty easy, I had to drain a full tank of premium out of my rx-7 after it sat for a while, it was sad :-(

freakinbox · 07-09-2007, 01:14 AM

Dirty carb?
Try running some 91 octane fuel in it.
When my carb was dirty that helped my idle, I was to lazy to clean it lol. Take it for a long drive after too to get everything warmed up to clean stuff out.

madking411 · 07-09-2007, 09:51 AM

VACUUM LINES!!!!!!!! Replace ALL of them and ~95% of all your carburetor problems will most likely go away..(if you don't have an actually bad carburetor in need of a rebuild that is....) I would know cuz i have this same car and i had issues with the carb that were worse than this.

edit: you might also need to re-adjust the throttle cable just a TAD also...to make it so it sits tight, but not TOO tight b/c then ur engine won't idle, it'll just sit there and rev up real high, and you'll end up having an idle speed of ~4,000 RPMS.........

retiredat44 · 07-09-2007, 12:32 PM

Throttle cable needs small bit of slack.. and probably doesn't need any adjustment.
IMHO

Quote:

Originally Posted by madking411

VACUUM LINES!!!!!!!! Replace ALL of them and ~95% of all your carburetor problems will most likely go away..(if you don't have an actually bad carburetor in need of a rebuild that is....) I would know cuz i have this same car and i had issues with the carb that were worse than this.

edit: you might also need to re-adjust the throttle cable just a TAD also...to make it so it sits tight, but not TOO tight b/c then ur engine won't idle, it'll just sit there and rev up real high, and you'll end up having an idle speed of ~4,000 RPMS.........

icurays1 · 07-09-2007, 11:38 PM

Thanks for the replys guys!! I spent about 30 minutes working on the car today, but i was busy with electrical problems (my battery seems to drain overnight...could be a short, could be faulty battery, not sure yet)

I'll try draining the gas and driving it around for a while tomorrow, we'll see if that does anything.

I adjusted the slow idle speed on the carb, that at least kept it from almost-dying every time. (but the roughness is still there)

I'll take a short video tomorrow and post it.

Thanks again for the help.

~Nick

diver9000 · 07-10-2007, 09:01 AM

Quote:

Originally Posted by madking411

VACUUM LINES!!!!!!!! Replace ALL of them and ~95% of all your carburetor problems will most likely go away..(if you don't have an actually bad carburetor in need of a rebuild that is....) I would know cuz i have this same car and i had issues with the carb that were worse than this.

edit: you might also need to re-adjust the throttle cable just a TAD also...to make it so it sits tight, but not TOO tight b/c then ur engine won't idle, it'll just sit there and rev up real high, and you'll end up having an idle speed of ~4,000 RPMS.........

Yes, definitely change all the vacuum lines, even the little tiny ones up near the injectors. Some are a pain to get to, but once youve changed them, you shouldnt need to again for a long time.