16V ignition fault, at regular intervals

[ke70dave]

howdy folks, this has me at my whits end!

right the setup:

16V 4age, jap apparently
jap ecu (orange label)
stock as a rock

the problem:

ok, motor runs great when first started drives great full power. however. drive for around 20-25 mins and it just goes stupid. it starts misfiring very badly, idles like its missing cylinders. in capable of driving at all.

here is a video of what it is doin. i know the sound is a bit out of sync, but just listen to the noise. sounds like the timing is right out:

http://www.youtube.com/watch?v=SqZ9_Aq5PpM

(that video sais something about it not being processed yet....i only just put it up so hopefully it comes good)

now the funny part is, if i turn off the engine for about say 5-10mins or so. it goes back to normal working, 100% power all systems go.

however this only lasts for around 20-25mins. and then you have to wait 5-10mins...and the cycle goes on and on.

how long has this been happening? im not entirely sure. in the last few months i have not driven that much at all. i only drive locally under 15mins and thus have not noticed problem. though a few weeks ago i drove out to QR, and on the way home it happend for the first time. but only once. and i thought my fuel pump was dead (it makes funny noises, you may remember my question about that a few weeks ago). so i replaced it thinking it was done. though it wasnt...

i have done the following since:

-changed distributer to a jap one (with the cap/roter that was on it)
-put back on original ae82 dizzy, with a new rotor and cap
-tried a different coil and igniter

i am yet to check the leads and spark plugs, as it runs so good 90% of the time i don't think they would be the issue. the leads were brand new ~9 months ago, and the spark plugs are prolly 3months old.

after the cool down period of 5-10mins, the engine is considerably more difficult to start. just crank and cranks and cranks. then eventually fires. once its going it runs fine though.

it also seems that the distributer cap contacts are coroding themselves. its brand new and already there is a build up of white crap on each of the contacts, im not sure if its normal for there to be a little bit. (this is brand new cap, and brand new rotor)

and......go tech heads!

[Skylar]

You know what to do.

Eliminate all sensors from the ECU except MAP and crank position sensor. If it still does it, blame the components which are still working, coil, dizzy, etc, not the sensors.

How hot does the surge tank/fuel tank get at the point in time it does this?

[ke70dave]

You know what to do.

Eliminate all sensors from the ECU except MAP and crank position sensor. If it still does it, blame the components which are still working, coil, dizzy, etc, not the sensors.

How hot does the surge tank/fuel tank get at the point in time it does this?

yer i know what to do...and ive done it! and its still not fixed! haha

the problem is its a pain in the ass to "make it do it" since i need to drive for half an hour...then im prolly stuck in the middle of know where. i did it to get that video, and i was stuck on the side of some random road, and needed to push the car off the road!

and i have changed the coil and dizzy like i said, and it still does it it seems.

as for surge tank temperature... i have no idea.....you think the fuel might be getting hot or something? what on earth can i do about that....fuel cooler?

[Skylar]

haha, fuel cooler would be funny.

Return into main tank, not surge tank.

If the AIT isn't triggering it then it's CTS and if it's neither then something's breaking down over time/from heat. I'd say it's not spark related unless you have your coil mounted to the extractors, (normal spot on strut tower, yeah?). Have heatshield on distributor?

Otherwise it's fuel. I know you got a small surge tank tucked up high. and surge tanks can heat fuel. I dunno if it affects engine running aside from decreasing knock resistance but just throwing it out there.

[ke70dave]

haha, fuel cooler would be funny.

Return into main tank, not surge tank.

If the AIT isn't triggering it then it's CTS and if it's neither then something's breaking down over time/from heat. I'd say it's not spark related unless you have your coil mounted to the extractors, (normal spot on strut tower, yeah?). Have heatshield on distributor?

Otherwise it's fuel. I know you got a small surge tank tucked up high. and surge tanks can heat fuel. I dunno if it affects engine running aside from decreasing knock resistance but just throwing it out there.

haha i have seen some dude using a fuel cooler

http://www.integy.com/C22623GUN.jpg

kinda just a heatsink in the form of a pipe...

what do you mean by AIT and CTS? i assume they are inputs on the ecu?

and yer i have the coil/ignitor mounted on the "front" of the strut tower. between strut tower and battery.

and yer the ae82 dizzy (one on there now) has a little head shield on it.

ive noticed that there is a fair bit of oil inside the dizzy, the stupid seal is leaking. but i wouldn't think it would account for the problems. especially the time involved..

the heated fuel thing is an interesting idea. though i wouldn't think it would cool down that much in 5-10 mins?

the small "cool down" time, to me suggest a component that heats up relatively slowly, but can cool down relatively fast.....

[Cerby86]

when my lift pump packed it in my 4a started loosing power and coughing and shit. Also popping back up through the quads. Wasn't cool.
Basically the lift pump shat itself and the surge was running dry.
So I would check to make sure you are getting full pressure fuel. Obviously firs thing to check is fuel filter.

[Skylar]

AIT = air inlet temp
CTS = Coolant temp sensor

[Tim.duncan]

i had somthing simpilar on the way to work. i removed all the plugs going into the ecu then put them back in and away we went. im assuming there is some dodgy wires that i will check out soon. so maybe check that there is nothing earthing out on your loom and causing the ecu to freak out. Also i rember reading an issue some guys had with the capacitors in the ecu failing and this would normally happen on a hot day. so whip off the ecu cover and check that nothing is leaking? also look for dry joints, may not be the problem but it only takes 5 min to check?

[ke70dave]

hmm it better not be a stuffed ecu. i just sold my spare!!

ill open it up and see if i can see anything fried. and do what you suggest.

im starting to think it may not be ignition, as skylar has said....

[ke70dave]

ok a new spanner in the works.

i hooked up my check engine light (nice little bezel in the dash permanent like)

and i get a error code of 3

now from this website

http://mr2wiki.com/MKI/EngineErrorCodes

it seems that is an "ignition signal" error.

ive checked the wiring from the igniter, and the wires are all in good order.

where does the "ignition signal" come from?

Edit: it seems that the igf and igt terminals are what it is referring too. and these appear to come from the igniter.

starting to think my ecu is the problem..

[skit]

Hey mate, perhaps you should use a multimeter to check the continuity of the 3 wires from your distributor plug. Use the wiring diagram to find which plugs they run to, I can't recall ATM.

I had similar problems (though not exactly as you described) which led me to swapping every sensor, ecu, coil and dizzy, and fuel pump to no avail.

In the end I tore it all out and went to an aftermarket ecu. I then autopsied my removed loom and found a broken dizzy wire within.

Bottom line is I went through heaps of frigging around and money trying to solve something that was easily diagnosed with the right approach.

[Skylar]

Ugh.

So, today, my misfire went from 'slight-misfire-while-warming-up' to 'always-a-little-misfire' to 'won't-idle-no-more' misfire.

TIGHTEN YOUR SPARK PLUGS and replace the front main seal.

Maybe something you should check. On the upside, I got compression back in the motor and of course more power but now the starter motor can't be bothered turning the motor over while I wait for the oil to pressure up.

[ke70dave]

yer im stating to think its something dumb like a wire.

when the engine is running ive given the wiring loom a fair viperous rough up, pulled, jerked, stuffed around with it. doesn't appear to be a loose connection. if what i did doesn't break the circuit nothing will!

spark plugs hey...another thing to check. i think my battery is a bit on the small side, if i dont get my engine started by the third attempt. its a non event...

lets just say i aim for nice slopes when parking my car...

far out sounds like your not having alot of luck with your beast skylar.

ive driven the car a few times around locally, no problems. though i have noticed its idling lower than normal (700-800 instead of 1000-1100).

heap of crap. tempted to buy a mega squirt and be done with it!!!

least then i can read what each sensor is doing and then throw said sensor into a fire.

funny you should mention the front main seal, mine leaks so bad. though doesn't drip on the ground, just a nice oily mess on the bottom front of my engine. its on the "to do" list.

hey heres a thought. what does it usually mean when an engine is harder to start when its hot? isn't that something to do with compression? maybe it is spark plugs for me too....

[Skylar]

I seem to have all the luck in the world in that, that engine is still somehow running with everything that's wrong with it.

I would look into that not starting issue. For some reason mine starts first time, err'time.

I don't think my issue is the front main seal, more the exhaust being too small and pressuring up crankcase causing it to leak. Oil then gets spat out into the spark plug valley and causes misfires too.

Does the ECU get a start signal?

[Golberg]

Sounds to me like the capacitors in your ECU. Pop the lid off the ECU and take a photo then post it up.

I managed to get a code three by not having the coil earthed properly, but at the same time the engine wouldn't start at all because of it.

I really do think its capacitor plague though.

[ke70dave]

yer i thought it was capacitors too. ive had a look inside and everything looks like its in good order. nothing is leaking (from what i can tell)

there doesnt look like there is many round cylindrical capacitors (dialectric? the ones i expect to leak). and the ones that are there dont have bloated caps or anything. there are heaps non polarity sensitive ceramic capacitors. but they shouldnt give any dramas.

i will get that picture though...

ive tracked down a spare ecu to try, but i wont be able to get it untill the weekend.

does anyone have a picture of a ecu with said "Capacitor plague"? id be interested to see. soldering new capacitors on isnt a drama, just i don't want to replace all of them!

and as for the ecu getting start signal, that is another one of the errors im getting, another one of my jobs...explains the hard to start though. but it is significantly harder to start after it does its "breaking down" monouver as desctribed above. just seems to crank and crank and crank (seems to crank quite easily too, like its got no compression....)

[ke70dave]

right here we go!!!

its not looking to pretty, think ive found the culprit.

but it doesnt appear to be the capacitors.....

the top of the board looks fairly good, then i turned it over....

http://www.ae86drivingclub.com.au/dcimages/2/0/2/28333.jpg
http://www.ae86drivingclub.com.au/dcimages/2/0/2/28334.jpg
http://www.ae86drivingclub.com.au/dcimages/2/0/2/28335.jpg


and on the other side of that mess is this thing, its a high wattage resistor, have a look at the dark stuff at the base of the component

http://www.ae86drivingclub.com.au/dcimages/2/0/2/28336.jpg

looks like its been getting VERY hot.

there is also these marks

http://www.ae86drivingclub.com.au/dcimages/2/0/2/28337.jpg
http://www.ae86drivingclub.com.au/dcimages/2/0/2/28338.jpg

on the other side of those is the transistors, chunky looking things that are bolted to the chassis. so i assume they are for switching the injectors or something.

here are the capacitors, they all look fine to me. they even look brand new.

http://www.ae86drivingclub.com.au/dcimages/2/0/2/28339.jpg
http://www.ae86drivingclub.com.au/dcimages/2/0/2/28340.jpg

[Golberg]

Yeah your caps look fine, but that resistor doesn't look too happy.

[ke70dave]

Yeah your caps look fine, but that resistor doesn't look too happy.

yer im hoping to try and get one from jaycar and solder it in.

hopefully that fixes my issues....

[slide86]

its refreshing to have some people on this forum that have some idea what they are doing.

dave, good work mate. have you had any mechanical training before?

[ke70dave]

its refreshing to have some people on this forum that have some idea what they are doing.

dave, good work mate. have you had any mechanical training before?

haha cheers mate.

im just completing my bachelor of mechanical engineering degree at the moment. (1 subject to go..woot!).

as for mechanical training, not really. dad taught me a fair bit when i was a kid, always working on his boat or the car.

but most of it is self taught, and by working with mates on cars. dunno if you remember a guy called "bahnugget" on here, greg his name, hes not around on forums much anymore, hes my best mate and we have pretty much tackeld allmost every job on cars, done a few engine conversions between us. lots of learning (and fun) has been had.

and spending many hours reading the interwebs (learning from other peoples mistakes!! haha)

as for this stupid ass ecu, i gave those connections a re-solder last night. the joint looked a bit dry (specially that one at the back of the picture, the darkest looking one). the car started fine again after my soldering so thats a bonus. picking up an adm ecu on saturday to get me going, then ill get to replacing that part...

ill go for a bit of a drive and see if i get that error showing up (the check engine light appears to flash when an error is logged)

[slide86]

it certainly seems to be your ecu.

after the circuit board heats up and expands, it forms an open circuit at some point.

very common to happen on 5.0lt holden v8 trigger modules and v6 ignition modules

[thu187]

If you're trying to get the car to start misfiring after 25-30 mins and don't wanna end up in the middle of nowhere just do laps around ur local area :P

Good luck!

[ke70dave]

If you're trying to get the car to start misfiring after 25-30 mins and don't wanna end up in the middle of nowhere just do laps around ur local area :P

Good luck!

haha i took your advice!

took it for a spin this arvo. and as expected right on que 30mins of driving it all went to crap. so my re-soldering has had no effect.

the funny thing is, it started doing it slightly just as i pulled into my driveway. i could just feel a hesitation as i gave it some stick up my street. pulled into my driveway, got the thermo fan going and let it idle.

after about 5mins it was fairly evident that it was missing a bit on idle, and it woudlnt rev happy, but it was reving.

another 5mins goes by and its geting worse and worse as i look at it, gradually getting worse, but it was getting worse at a steady rate (if that makes sense)

another 5 mines and its barly idling at all, im having to play with the throttle to keep it going.

at this stage i chuck my timing light on number 1 cylinder and notice that the timing is inconsistant, it is missing flashes, so its not firing. so definately a spark distribution problem. and not a fuel issue.

it eventually died on its own accord, and i checked my error codes. no number 3 error code this time.....

i got all excited and thought it might be as simple as one of my spark plug leads was stuffed, but no i checked them all with the multi meter and they are all within spec. i also checked my coil and as expected it is with in resistance (both primary and secondary).

i also opened up my ecu while the engine was running (dangerous yes, but oh well) and i put my finger on that resistor that is in the previous pics (the white box, and yes even more dangerous..) and it is not getting hot at all, cant feel any heat at all coming off it. not to say it isnt stuffed.

oh and i found a place to buy some of those resistors, like 10$ for 5 of them, bargain.

however...the chassis of the ecu was quite warm, and much warmer where the transistors bolted to the chassis. now i know the transistor uses the chassis of the ecu for cooling, but im wondering how hot is too hot for a transistor? do transistors break down when they get hot?

my thinking is my car subwoofer amplifier gets nice and hot after a music session, so transistors do get hot not denying that.

yer im clutching at straws i know...

i thought some of you may enjoy one of my additions to the system, when i thought it might be the igniter overheating:

http://i168.photobucket.com/albums/u166/ke70dave/heatsinkonignitor.jpg

[Golberg]

Chances are even though the area around the resistor looks overheated, its probably not heating up again because its already burnt itself.

But all in all it really does sound like an ECU problem, just due to the randomness of the symptoms (effecting different things at different times) and the fact that it doesn't happen until things have warmed up a little.

[Andy San]

i had a very similar problem where i would get a misfire and a flash from the check engine light, was distributor wiring related, think it was a broken wire to the dizzy, because if you bumped the wiring in the wrong spot the car wouldn't start at all, the only main difference between your problem and mine is that mine happened at the same rev point every time, if i was you i would check continuity of all your wiring off the dizzy and coil etc, sounds like the heat off the exhaust is causing a join to soften up and come loose over time when driving.

[ke70dave]

well folks it seems to be the ecu, got an ADM one today off trev from rollaclub (nice bloke!) been for a nice drive today and it all went well. no errors thrown up at all.

interestingly i can definitely tell that this ecu is not as fast as the jap ecu i had. not that much difference but the "bight" isn't there as it was. ill see about what the timing is doing, might be able to wind it up a bit.

ill see about replacing those components, after the re soldering it has burnt out a bit more where i soldered it, so something isn't right. ill see how i go..

first step is to hook up a speed sensor....

[Golberg]

You don't have to hook up a speed sensor, I made up a little circuit that generates a pulse to trick the ECU into thinking there is one connected. I've had my prototype one in the car now for 2 months and haven't got a single check engine light.

Has 2 effects, gets rid of the 180kph speed limit on JDM ECU's and also allows you engine to go to a higher RPM (as the ECU caps this if you don't have one connected).

I'm planning to make a few of them in a batch soon as I've finalised my design, if you're interested, pm me and I'll sort one out for you.

[ke70dave]

right folks..

THE PROBLEM IS STILL THERE!!!!!

GAAARRRRRR

i have no idea, ive changed everything now.

[Skylar]

I had an idea on how to fix this problem a few days ago but I can't remember what it was now.

What have you replaced and what is yet to be replaced?

[ke70dave]

replaced or exchanged:

ecu
coil
ignitor
high pressure fuel pump
dizzy
dizzy cap
dizzyrotor
(leads checked for resistance)

yet to be replaced:

spark plugs
low pressure pump (lift pump)
any sensors on the engine i havent mentioned (coolant temp sensors...thats about it, but that has been replaced not long ago)
fuel regulator
the whole engine?

i have a theory it might be the lift pump, only because my mate (older knowledgeable guy) reckoned it sounded like it was fuel starving. i was round his house this arvo and it started to stuff up.

i really need a fuel pressure guage.

[NIZLAH]

hopefully you have the problem sussed man.... I was one of the people who thought the ecu capacitor leaking problem was the cause of my drama's as I had tried everything to fix the issue, which is similar, although the car would just cut out randomly whenever it felt like being a bitch... cbf explaining it in detail but theres a thread about it floating about, maybe the old forums actually.. meh....

But since I have done a 20v swap, adapt ecu, full new loom/relays (like everything except for the wiring for the lights and some other minor functions), new switch on the back of the ignition barrel etc... Pretty much everything is new.......... you would have though that the problem would no longer exist....

so what happens on my first test drive down my street....? you guessed it, same old shit happening still.... WTF?

My wiring guy is going to come and check circuits and whatnot today prob... We are thinking its the fuel pump as its the only old thing left from the previous set-up.......
I bought a new one anyway to eliminate that from the equation...
But I swapped pumps way back when these issues first started and the pump I swapped it to was a fake and fucked out so I threw the old pump back in..

Also so far it has only happened under light load (haven't driven it hard as its not tuned properly, nor in a roadworthy state lol) but seems to idle and rev fine when stationary....

I'm getting sick of typing now so I'm gonna end it here...