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Have to crank a long time for engine to start when cold.

Posted: Thu Jun 08, 2017 10:11 am
by dabes
I recently brought my 86 back to life. It is a 16v with USDM harness.

I just swapped the fuel pump out with a delphi unit from Autozone, becasue my old pump had died.

It ran fine for a short while, but then all of a sudden, I am running to an issue where I would have to crank for a good 10-15 seconds and the motor slowly cranks to life. Once it is warm, it will crank up just fine.

I have scoured this forum as well as other outlets and am guessing it could be a few possible issues, but I figured I should diagnose the issue before I start replacing random stuff on my car.
- I read somewhere that the fuel damper can make a significant difference in this.
- Could be the fuel filter
- Maybe the cold start? but then I havent heard anyone speak specifically about my issue.

Another maybe important detail is that the car had been sitting for about 3 years. and the gas in there was very old. I did refill it once I got it running again, but this was the reason why I thought maybe it could be my fuel filter.

Can anyone tell me what I should look into or any tests I should perform to get this worked out.

Thanks

Re: Have to crank a long time for engine to start when cold.

Posted: Thu Jun 08, 2017 12:47 pm
by dabes
Just a quick update. I found out that my injector resistor is a little frayed. I dont know if this would cause this issue though...

Re: Have to crank a long time for engine to start when cold.

Posted: Thu Jun 08, 2017 2:22 pm
by CloudStrife
I'd recommend using the AE86 service manual for troubleshooting. It can lead you down a more organized path for troubleshooting other than just randomly guessing; it would help you out greatly.

If you don't already have it, you can download them here:http://www.aeu86.org/technical/ae86-manuals/

*These manuals are broken up by either being engine related or everything else.

Good luck!

Re: Have to crank a long time for engine to start when cold.

Posted: Thu Jun 08, 2017 4:09 pm
by jondee86
Sounds like maybe the cold start injector is not working. Easy to check... just
pull the injector out of the intake manifold and put the end down the neck of a
glass bottle. You hold the bottle and get someone else to crank the engine. If
you don't see fuel squirting into the bottle (only happens while cranking) then
either the cold start injector time switch is unplugged/borked or the injector
is blocked.

Cheers... jondee86

Re: Have to crank a long time for engine to start when cold.

Posted: Fri Jun 09, 2017 5:26 am
by davew7
There is a cold start temperature sensor on the coolant neck that could be a problem. Verify that the cold start injector is getting an electrical signal. Dave W

Re: Have to crank a long time for engine to start when cold.

Posted: Fri Jun 09, 2017 1:46 pm
by Toy86
Here's something you should check. You do have a fuel filter in your gas tank doesn't matter if it's GTS or SR5, check to see if that's clogged. You could also have a small crack in the line some where allowing air to get into ur lines making you loose your prime. That's why it fires back up once the lines are fully primed. Let us know what you find out. Good luck!

Toy86

Re: Have to crank a long time for engine to start when cold.

Posted: Sat Jun 10, 2017 11:24 am
by dabes
thank you guys for all the information.

Its really random but it all of a sudden fixed itself today. I started up the car three times throughout the day. So odd.

Re: Have to crank a long time for engine to start when cold.

Posted: Sat Jun 10, 2017 11:35 am
by taroroot
Your fuel pump died? Did you change the fuel filter too? 3 year old fuel is pretty certain to be bad and gummy. Change and clean what you can. You might consider sending your injectors to a cleaning and testing service, they'll be able to quantifiably tell you if they are clogged. The services are quite fast too, they usually turn around in a day or two. The injectors in my 20v swap were quite clogged. Really should have checked my pump sooner. Had engine smoothness issues, then pump got noisy. Pulled the pump out to find the mesh of the strainer was gone! Hopefully there still isn't bits stuck somewhere in the lines. Will prob do another filter change soon just in case.