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engine wont start after warmed up normal driving

Posted: Tue Feb 14, 2017 2:53 pm
by bong_ae86
stock bluetop. starts cold no problem and strong, just after normal driving, motor wont start again until at least a good min or two. new spark plugs and fuel pump and still same problem. im pretty stumped on this.

Re: engine wont start after warmed up normal driving

Posted: Tue Feb 14, 2017 4:16 pm
by aukword1
what happens when you try cranking it after the engine is warm? Does the starter operate as it should?

Re: engine wont start after warmed up normal driving

Posted: Tue Feb 14, 2017 4:54 pm
by bong_ae86
Yup, cranks strong and effortless.

Re: engine wont start after warmed up normal driving

Posted: Tue Feb 14, 2017 5:02 pm
by bong_ae86
Normally I would follow the troubleshooting tree from the manual but it only talks about not starting at all. Something must be getting a bit to warm for immediate restart

Re: engine wont start after warmed up normal driving

Posted: Tue Feb 14, 2017 5:14 pm
by s24a
Might be vapor locking due to pressure regulator leaking (or maybe injectors).
Throw a pressure gauge on the rail and after you start it, watch the fuel pressure.
Then shut it off and watch the pressure decay.
A good regulator/injectors will hold pressure for over 30 minutes or so.
If yours starts to drop after a minute or two, then check first the regulator for leakage.

Then injectors.

Hope this helps.

Hank

Re: engine wont start after warmed up normal driving

Posted: Tue Feb 14, 2017 5:19 pm
by bong_ae86
Makes sense, when I did remove my fuel pump and disconnected lines, there wasn't must fuel coming out so maybe it's not holding pressure well. I'll check it out. Thanks!

Re: engine wont start after warmed up normal driving

Posted: Wed Feb 15, 2017 11:35 am
by Jeonsah
When its warm and wont start, trying doing the basic checks:

1. Check for air (any blockage)
2. Check for fuel (return line/fuel pressure)
3. Check for spark

There a couple parts that could cause this issue (i.e. fuel pressure, injectors, coil/ignitor). Once you do the basic check, we will know for sure where to narrow the problem down to.

Re: engine wont start after warmed up normal driving

Posted: Sun Feb 19, 2017 1:06 am
by AE86Kai
I had very similar issue on my old Levin.
Starts fine at cold but, after driving for a while, (may be 20-30min) stopping at gas station, my car did not start.
In my case, I had to wait until my engine gets cold...

After some research, it seems like it was common issue for AE86...especially if your starter is 30 years old stock.
My solution was replacing to a rebuild / new starter & modified some wires. (Direct power line w/relay from battery to the starter.)

May be not same issue as yours but, just my little input....good luck. :P

Re: engine wont start after warmed up normal driving

Posted: Sun Feb 19, 2017 2:01 pm
by bong_ae86
Update: ran fuel pump for a few mins by jumping terminals per diagnostic, left spark plugs out to see if I could smell any fuel, none whatsoever.

My starter cranks no problem and continues to crank numerous times.

I did however notice #3 spark plug noticeably wet and piston is wet of suspected oil leak. But even if it is a slight oil leak I should have burned. The spark plugs are new and double checked the gap today. Wires and distributer cap are only about 4K km old and still look good. No diagnostic codes. Will do further insp when I have time.

Re: engine wont start after warmed up normal driving

Posted: Tue Feb 21, 2017 1:43 am
by bong_ae86
found my problem, distributer cap was nasty enough that #3 did have the worst resistance check of them but was still within the limit from the book. from looks i didn't think it was TOO bad and wasnt a big deal so was overlooked and was starting cold no problem. but now it restarts no problem. Thanks everyone for inputs and reminding me to go back and check the basic stuff more carefully.

Image

Re: engine wont start after warmed up normal driving

Posted: Thu Mar 02, 2017 7:01 pm
by allencr
That dist. cap looks pretty normal/unremarkable & shouldn't have caused any warm start problems.
If you don't like the ascetics or the slight resistance increase, just scrape it off with your favorite knife or screwdriver or scissors & it'll be fine cause 40,000+ volts doesn't disappear that easily.
Did it or did it not spark when not starting and have or not have any residual fuel line pressure in less then minute?
Hold the throttle down/open 1/4-1/2 way when starting warm worked for me.

Re: engine wont start after warmed up normal driving

Posted: Sun Mar 05, 2017 6:22 pm
by bong_ae86
allencr wrote:That dist. cap looks pretty normal/unremarkable & shouldn't have caused any warm start problems.
If you don't like the ascetics or the slight resistance increase, just scrape it off with your favorite knife or screwdriver or scissors & it'll be fine cause 40,000+ volts doesn't disappear that easily.
Did it or did it not spark when not starting and have or not have any residual fuel line pressure in less then minute?
Hold the throttle down/open 1/4-1/2 way when starting warm worked for me.



the resistance for the rest were good except this one which was a little over 20. FSM states max is 25. not sure how much the heat can affected it but after i cleaned it up, but i can now restart it normally