AE86 4age engine not starts crank ok backfires to air intake
06-03-2018, 10:09 AM
Post: #1
AE86 4age engine not starts crank ok backfires to air intake
Hello,
I decided to help my friend with his kouki AE86 with 4age the car was sitting for 3-4 years without movement. After discovering the fuel pump is dead and was replaced the engine finally started. First days have been okay with engine running good but after that issues appeared that it got harder to start. What i noticed most that when i started it it was going on 3 cylinders after a while running it catched on all four making some weird noise. Now the engine wont start at all and recently i see when i got the hose of air intake down that it fires to air intake. Another thing i noticed that spark plugs are full of fuel and when i checked engine oil level i smell not burned fuel in it. Another discovery i made i see oil comming from the middle of the distributor cap rotor. Spark was always okay on all 4 cylinders.

What was done so far:
- replaced fuel pump
- replaced engine oil and filter
- replaced all spark plugs
- replaced sparkplug wires
- replaced distributor cap and the thing in the middle (don't know the word in english for it right now)

i have read some things in 4age manual but was hoping someone can point me more to what issue or issues i am looking for.

My guess is timing belt slipped some teeth - timing off, distributor full of oil because of leakage. Can't explain the weird sound after running on 3 cylinders after the 4th catches. The smell of fuel in oil (damaged piston rings?)

I know the engine was rebuilded before the long stay and was running great.

Any help is greatly appreciated. Thank you.

85' AE86 GT coupe lifetime project since 2005
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06-03-2018, 11:57 AM
Post: #2
AE86 4age engine not starts crank ok backfires to air intake
Including the cold start one, check all injectors for leakage.

An analogue brain in a digital World
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06-03-2018, 03:17 PM
Post: #3
AE86 4age engine not starts crank ok backfires to air intake
I have not checked the cold start injector but will do i see no visible leakage from the injectors or damaged rubber insulators

85' AE86 GT coupe lifetime project since 2005
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06-03-2018, 08:08 PM (This post was last modified: 06-03-2018 08:11 PM by totta Crolla.)
Post: #4
AE86 4age engine not starts crank ok backfires to air intake
Fuel can leak past injectors into the the cylinders and the fuel rail is under pressure even with the engine turned off.
I guess the easy test would be to very carefully loosen the fuel rail feed pipe (make very sure that no fuel is spilt that could ignite) to reduce the pressure, tighten it and then remove all of the spark plugs, wind the engine over for a few seconds on the starter motor to remove any fuel residue, dry the plugs and replace them. Turn on the ignition to check for fuel leakage at the fuel rail.
If ok try to start the engine.

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06-03-2018, 08:24 PM (This post was last modified: 06-03-2018 08:52 PM by Bean.)
Post: #5
AE86 4age engine not starts crank ok backfires to air intake
If you got a compression tester run a test, the headgasket might have let go.
Happend to me once after car was standing for a long time

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AE86 ex-daily
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06-04-2018, 12:07 AM
Post: #6
AE86 4age engine not starts crank ok backfires to air intake
Finally today after 3 hours fighting the AE86 is running again.

I have checked timing belt all was within the marks after that i cleaned spark plugs, checked distributor cap, cables, checked cold start injector, checked AFM, cranked the engine checked plugs but they have been clean so i have aimed at injectors after disconnecting first i measured voltage on it my friend tried to start the engine and it started. I have connected it tried measuring the second one connecting the first and it started as well but as i saw no fuel on the plugs and looking at the gauge the car was nearly out of fuel so we put 10L in the tank and tried again with all connected and the car started to run. I have in addition adjusted the timing with the light gun now it looks that everything running. Still i see that insulators on the fuel injectors have damaged rubber seals i must replace that but there is no fuel leakage. And yes i made diagnostics also but there was no error code comming.

Now i must go back to my AE86 after winter the car starts but when i hit the gas pedal the engine shakes and hesitates to run smoothly like running on 3 cylinders i checked distributor, cables cleaned plugs checked timing with the light gun all is in order but i must still look for error codes from diagnostics. Is the diagnostics connector on 85 zenki model on the back of the air inake or by the AFM as i see two yellow round connectors with two cables by the AFM is the one without plug female with thick white and red/blue striped wires and back of the air intake there is one with the plug with not so thick wires right by the fat connector as well plugged. If there will be not error code what issue i might be looking for? Thank you for all your help Smile

85' AE86 GT coupe lifetime project since 2005
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06-04-2018, 08:23 PM
Post: #7
AE86 4age engine not starts crank ok backfires to air intake
The diagnostic connector is usually located near the firewall close to the intake plenum. Black connector with a small cap.
You should bridge some pins there too to set the timing properly.

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06-04-2018, 08:42 PM
Post: #8
AE86 4age engine not starts crank ok backfires to air intake
(06-04-2018 08:23 PM)Bean Wrote:  The diagnostic connector is usually located near the firewall close to the intake plenum. Black connector with a small cap.
You should bridge some pins there too to set the timing properly.

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I think he has a zenki, therefore he doesn't have the diagnostic connector. Two sets of plugs near to the wiper motor, one is for the fuel pump bridge, and the other is for the computer code checking / idle timing.
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06-05-2018, 03:32 PM
Post: #9
AE86 4age engine not starts crank ok backfires to air intake
I have zenki 85 coupe indeed there is no diagnostic connector as on my friends kouki version. Only confusion i was getting that there are two female types round yellow plugs one by the wiper motor with cap on it second in hanging by the AFM without cap. Now i know the right one thank you. Gotta go try the codes if something will indicate more on my car issue.

85' AE86 GT coupe lifetime project since 2005
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06-11-2018, 10:45 PM (This post was last modified: 06-11-2018 10:48 PM by Ryo.)
Post: #10
AE86 4age engine not starts crank ok backfires to air intake
I made diagnostics with not running engine it shows nothing but when i start the engine it shows 11 impulses and than 4.5sec pause than again 11 impulses and it repeats. Trouble is that i don't see such error code in the chart in manual.
I have taken the hachi for a run. Put 10 liters of shell v power (100) in it and taken long run about 70km the car was running perfectly no discovery in power decrease. Response is good as well. So i have trouble to understand why it is that by 800rpm idle if i slowly push the gas pedal i feel the car shaking before it reaches about 1500rpm and it sounds like running on 3 cylinders and from exhaust i hear dum dum sound.
I want to find the cause before winter all was okay only thing i was doing was replacing hose from fuel filter to fuel rail and the pulsation damper. Nothing else was done.
I am thinking about:

- Doing compression test
- Cleaning the injectors putting them out and clean them with carb cleaner.
- Clean the EGR
- Clean the throttle body

I have no visible air leaks and i can say i made diagnostics on all parts regarding distributor, spark plugs, wires and coil nothing discovered wrong there.
It is first time i got troubles like this it is true the car had run not much last years i made a 500-1000km a year. Was not time to play with the hachi.
Anybody had some issues like this?

85' AE86 GT coupe lifetime project since 2005
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