Ae86 GTS starting problem

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RLZ
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Ae86 GTS starting problem

Postby RLZ » Tue Feb 05, 2013 12:15 am

Hey guys, I got a starting problem with my 86 gts, every cold start I have to turn it like 2-3 times and it starts up. The story is: A month ago I drive 50 miles away to pick up something and my gas almost empty, so I pump 3 gallons of Mobil gas, that's my first time run Mobil gas, I always run Chevron on my car. So Everything still good and I back home, the other day morning I try to start the car but it won't start on the first time, before running Mobil gas it starts up every time on the first start, but now it needs to start 2 even 3 times to start up. I just doubt Mobil really that sucks? And is there some dirty **** goes into my feul injector so it's hard starting? This problem only happens on cold start, other than that car runs awesome.
Hope get some help here, than you!
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Red
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Re: Ae86 GTS starting problem

Postby Red » Tue Feb 05, 2013 7:47 am

I've run mainly Mobil gas for 25+ years, there's nothing wrong with it. No brand of gas is going to make your car hard to start, and nothing you get from one dirty gas station is going to make your car hard to start but let it run OK. Unless you removed the fuel filter, nothing should be able to get to the injectors to clog them, and during starting you are using a fifth "cold start" injector that isn't used when the car is running.

There are all sorts of 'cold start' circuits in the car. Injector, timer, second ignition circuit, could be a problem with any one of them and the Mobil is just a coincidence, don't pay any attention to it. More likely there was a temperature change and that's got something upset.
-- Original owner, 1985 GT-S

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Re: Ae86 GTS starting problem

Postby dcdcdc » Wed Feb 06, 2013 8:03 pm

What is it doing during the 2-3 turns when the car doesn't start? Is the engine turning over or is there just a dead click?

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RLZ
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Re: Ae86 GTS starting problem

Postby RLZ » Wed Feb 06, 2013 11:43 pm

On the 2-3 turns the engine run up to 3-4000 rpm then die. And now the cold start idel seems like lower and lower every day, before idels at 2000rpm, few days ago at 1800rmp now down to 1600rpm, kind of weird!
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Red
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Re: Ae86 GTS starting problem

Postby Red » Thu Feb 07, 2013 7:40 am

RL, I had a similar problem that eventually came down to a chafed wire where the AFM leads run through the firewall to the ECU, and corrosion on the connections under the fuse box in the engine compartment. There's a lot of wiring in these systems, one bad wire is all it take to create a problem and the only way to find it is to run hands and eyes over the entire harness. Since that takes a lot of patience but no special tools or skills, I'd suggest trying that first. From the AFM to the ECU, the fuse box, the distributor, the injectors, look over all the wiring an dlook for anything that isn't 100% clean and tight. Also check the EFI MAIN fuse, in mine it didn't blow but it was melting from excess heat from the bad connection under it.
-- Original owner, 1985 GT-S

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RLZ
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Re: Ae86 GTS starting problem

Postby RLZ » Thu Feb 07, 2013 11:10 am

Hey Red, mine AFM not works well before so I replaced it with a Mr2 AFM on it, is there cause of this problem? But it runs well after I replaced it tho, the problem begin when I pump Mobil gas. Anyways I will check the wires what you say, thank you!
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Red
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Re: Ae86 GTS starting problem

Postby Red » Thu Feb 07, 2013 12:01 pm

RL, forget about the Mobil gas. Maybe the station had bad gas but as I said--the filter would stop that. Or the car would stumble if there was water in it. Mobil is top-tier gasoline. If you had to do any splicing to wire in the new AFM, I'd look at that first. Also try using the AFM bypass jumper, to make sure it isn't an AFM problem.

If you haven't changed your fuel filter in 50,000 miles, you might want to change that and check for clean gasoline at the same time. The fuel filter is a "lifetime" part that never needs replacement according to Toyota but after 50,000 miles, who knows what might be in there.
-- Original owner, 1985 GT-S

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RLZ
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Re: Ae86 GTS starting problem

Postby RLZ » Thu Feb 07, 2013 1:11 pm

I didn't spliced any wires to the new AFM, just pluged it on and it works fine. For the filter I don't know it been replaced before but I guess no tho, I'll try to check them, thanks!
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