Carina II 1991 4A-FE sparks only 5s or so, help appreciated

[PP5858]

Hi,

I recently bought 1991 Toyota Carina II with 4A-FE engine. The car has been repaired by my friend some time ago and it has travelled several people since.

The seller has had it staying parked like 6months bc this issue came that ocasionally it didn't have sparks. When I went buying it it started for 3-5s and has been like that.

So sometimes it does not start at all, it does not have sparks. Ocasionally (don't know why) it has engine fault light and then it starts, runs like 5s and then dies. After that no engine light and no sparks.

What I have checked so far:

- Removed ecu cables and checked there is no corrosion nor broken (visibly seen cables) I have used electric cleaning fluid.

- I have checked that fuel pump starts pumping and gets almost 12v when I start cranking

- I have removed open circuit relay and opened it, cleaned the contacts with 1500 sand paper (it was ok even before) measured that it is about 26ohms and 120ohms and both coils will pull with 12v around 100mA and around 400mA and contacts between +b and fp is close to 0ohms.

- removed almost all electric plugs and used electric fluid to ensure good contact

- measured some of the sensors, some have like 30ohms but some has like 0ohms (did not write them down though 😞 )

- have cleaned the distributor cab (looked worn and maybe scratch but semi good)

- have cleaned distributor, had some grease or black ash on it or something

- have done something else also but dont even remember anymore all

So the issue is that usually it does not create spark. Then ocasionally it gives engine fault light and at that time it will start but dies after abt. 5s. My assumptions are that either some sensor or ecu but have no good idea atm. Any pointers would be appreciated how to continue.

also I dont have picture of the sensor locations so I actually dont know what is what so if there is good picture, that could also help

[PaulinhoT]

Hello and welcome,

It sounds like you have checked a fair few things, fuel, air and spark, that's the order I work in. Maybe worth checking the alternator output, and Battery, also see if each spark plug isn't shorting out ?

 

[PP5858]

Looked this further, purchased used whole distributor but realized when I drove back from the junk yard that probably it is not that. Changed it and same thing.

Had few days to think and then someone said that it gives some codes from the diagnostics plug.

Watched this video: https://www.youtube.com/watch?v=Ogsv2urm9w0

and then this document http://home.exetel.com.au/seasalt/Resources/4afe.pdf which also shows the locations of the sensors.

Went in the middle of the night outside with flashlight and small jumper cable, popped the hood, insert the wire, went back in the car with the flashlight, turned the key until the engine light lighted up, closed my flashlight and......... 22 and 24. Almost yelled from happiness.

Then quickly closed the hood and ran away before someone called the cops.

 

Ok so now it is

22 Water Temp. Sensor Signal Open or short circuit in water temp. sensor signal (THW).

24 Intake Air Temp. Sensor Signal Open or short circuit in intake air temp. sensor signal (THA).

 

Now will have to measure those parts are they ok or is it cable issue or something else.

Most probably it is both sensors so will have to look where to get those.

 

If someone has data on those sensors how and what values they should show in multimeter and what type of sensors are they, that could be helpful at this point. I bet the car will run already next wk.

 

 

 

[PP5858]

Cheapest fix ever, although took a lot of time to find out.

Both Water temp and Itake temp plugs had bad contact. Both sensors measured to be within specs checked STA/IGN also and was good and tested to jump +50ohms when heated.

Although I don't understand why it gave 51 AC error even after reset, but I don't actually mind much about that. So it is running fine.

Now bit of a testing drive and then forward to E85 conversion with speeduino for more power. :)

[PaulinhoT]

Well done 😄