4AGE Misfiring and Stalling - Problem found...maybe

[LeeRoy]

Howdy,

To start with the car is an AE93 sx with the red top 16v. Car has a k&n filter and an exhaust but is otherwise stock.

Recently the car has started to develop an intermittent misfire at around 2500rpm under around 10-20% throttle on relatively flat ground so not under heavy loads. When it misfires it was losing around 100-500 rpm and you could see the tacho drop before it rose back up to around 2500rpm. It would also slightly jerk when it did this. This is ahppening at operating temp and when it started happening it was happening at night and it was also cold.

More recently, ie yesterday, it threw up a check engine light and then later that day it stalled for the first time but only stalled once over covering say 50km that day and also only threw up the one engine light.

Now today on my way to uni is really started to misfire under the same conditions as above and was now dropping to around 1000-1300rpm. Now here it didnt feel like it is losing a few sparks, it feels more like your switching the engine off as if to do some keybangers.

Now today, when leaving uni, car was just registering temp on the gauge and was also idling high (which is normal) and when reversing check engine light came up and the car really died and just about stalled. Now by the time i got to the uni exit i was sitting there for about 1 min and it stalled but then started up straight away.

It also stalled about half way home while waiting at the lights but started again easily.

Is home now and i have hooked up the diagnosis and its given me a code 14 which is Ignition signal circuit.

Any ideas?

SOLVED: Was the wiring from the distributor just back from the plug. Suspect wires were shorting out on each other.

- LeeRoy

[LeeRoy]

I have also recently replaced the distributor cap and button as they were fubared.

- LeeRoy

[EVOSTi]

im gonna take it your air filter is clean and you have recently changed the fuel filter and plugs? these would be the first obvious places to look.

otherwise perhaps check your coil.

[LeeRoy]

Air filter is pretty clean, plugs also fairly new ie less than a year. Fuel filter could prob use a change. Will check that out.

- LeeRoy

[EVOSTi]

id change the plugs too, id recomend doing them once a year. when you have them out you should be able to get some indication as to whats going on, ie they may be oiled up causing missfire etc.

[LeeRoy]

But the misfire is intermittent as in doesnt happen for ages then comes on and happens a couple times then goes away. Even in the same conditions its not always doing it.

- LeeRoy

[EVOSTi]

could be shit fuel, but im guessing coil.

[LeeRoy]

Ok well i just pulled out the plugs and they seem fine. There is a little carbon/black stuff build up round the edge of the tip but the plug itself is pretty free from any contaminants. I will check coil tomorrow but ill need to probe the ecu yeh?

To do check coil ive got that voltage between IGT and E1 should be between 0.7-1.0V.
If thats fine then it may be distributor wiring, ecu wiring, or ignitor wiring or the ignitor itself. But dont ignitors and so forth normally work then dont work as opposed to intermittently working?

- LeeRoy

[andy jay]

i had a similar prob on my st162 celica, turns out it was the dizzy (i don't know what, but it wasn't the leads, cap or rotor), i'd also suggest coil and fuel filter

[Cuzzo]

I have been having issues with my fuel tank pressuring on hot-really hot days. When i open the filler the air rushes out and idle goes back to normal. I think my charcol cannister isnt plumbed up correctly or blocked.

But with the code it could be something to do with the dizzy or ignitor.

[nb86]

Sounds like a coil problem, that would be my first port of call. Sometimes the coil can play up even if it shows correct voltage and resistance. Best thing to do is swap it with another car or just replace it. A bosh or similar coil will do nicely and theyre only about $50.
You're right with the ignitor, usually they just give up in one hit, not this intermittent carry-on.

[poida]

I've got a similar intermittent problem on my 2tg... I share your pain, scrambling my brain for ideas. Mine also seems to surge and sometimes lose ignition and keybang. sigh

[LeeRoy]

Yeh but lucky me with my diagnostics codes

Driving to work tonight it didnt play up at all. Im just about to leave work so will report if it shits itself on way home. My dad said it could be the hall effect sensor in the dizzy which is what would have happened to you maybe andy jay, but this would mean its a fuel problem as the dizzys pickup for engine position has nothing to do with ignition as the car has no electronic ignition (ie controlled by the computer). This is contrary to an ignition signal circuit fault so im leaning more towards coil or ignitor or even loose/shagged wiring.

Any more ideas greatly appreciated.

- LeeRoy

[Grega]

check you have a good ground from just need the drivers side strut to the side of the cylinder head (to where that engine lifting hook is)

(my 4agze levin had this problem - thats what it turned out to be)

good luck man.

[LeeRoy]

Car didn't do it on way home from work either and i spoke to a mate and due to the tacho dropping - you can see it drop on the dash, he seems to think hall effect sensor. Have picked up a dizzy that he had lying around and will test this on weekend.

- LeeRoy