Toyota COPs not working well when cold
 

alright I've been tackling this issue for months. I have toyota cops and I recenty rewired them to make sure the wiring wasn't the problem. Here's the deal:

70+ degrees outside: car starts right up and drives fine

50-70 degrees: takes 1-3 tries to start the car, then it misses every now and then for 3 minutes and goes away, presumably when the car warms up a little

now it's gotten to the point where I tried to start it in 30 degree weather, and i had to crank it probably 30 rotations and it finally caught and I had to keep my foot on the gas to keep it running, and it sounds like its running on 2-3 cylinders, but its not constant. the car has to warm up completely before it goes away. before it does, it misses so much that it's pretty much undrivable.

my dwell is set correctly, and as I said I rewired them, made sure they were grounding well, and put some dielectric grease inside the cops. If it was just running on 3 cylinders all the time It'd be an easy diagnosis that one of the packs is bad, but I dont think one in particular is acting up, I think they all operate like shit when it's cold. Would this have anything to do with pulse width settings? any other weird spark cold start settings I should look at? Any other ideas?

Edit: I guess it's also worth mentioning that I've had these installed for two years, and they acted fine last winter.

What do the plugs look like?

they are brown. the tune is otherwise fine, so once they stop misfiring they are ok. i'm sure if i started it cold, ran it like shit for a couple minutes, then pulled them they'd most likely be dripping with fuel.

IRTB's makes this really easy to diagnose. they occasionally blast a fireball out of the runners while i'm keeping it running in that condition.

edit: Also I changed my plugs that were gapped really huge because I thought that was causing the problem. on brand new plugs with the stock gap I'm having the same problem though.

It sounds like cranking pw (fuel) try suggestions from threads like this

i had a bitch of a time to start mine first up, but that was so long ago (everyone was just starting on ms) some searching will help you out with the issues (it has mostly always helped me).

Backfires point to lean fueling. I'd look at Cranking PW's and ASE, After Start Enrichment.

Wideband? What are your AFRs when it catches? Unless it's missing too much, it should give you an indication if your fuel is good. You can always use a spark tester to see if it's the COPs. Did it work fine with stock ignition?

I had the same exact issues with mine...which is why I ended up just running the stock coil and wires for the time being. I'm definitly going to stay tuned to see the outcome so I can hopefully get mine running right with the cops.

i don't think its a fueling issue. it reads a correct AFR about where it should when its running, cold and warm. Also, lets say I am getting it warmed up while its running like crap, and the coolant gauge finally starts to move but its not fully warmed up, i can drive the car at WOT and my afr is good at like 12.0 or so, but i can still feel it miss. Also, I know its getting adequate fuel under startup because if it cranks for long enough without firing, once it does fire, i get a nice loud pop from my exhaust.

also, correct me if i'm wrong but as far as I know there are three stages to startup: cranking, after start, and running. after start only lasts for a few seconds, right? my car will run like shit no matter how long it's been running until it warms up. in the cold weather now, it will behave like shit for 10 minutes. while cold the afr's are at an appropriate level, if not a little rich. I've tried leaning it out, and it shows as leaner on the gauge, but still same result.

right now outside its 30 degrees, and I know if i went and tried to start it it would crank for about 15 seconds with nothing happening at all, then it would start to fire every now and then but still not start (cha-cha-cha-cha-cha-chugchug-cha-cha) then after another 15 seconds of that i can blip the throttle and then it will eventually catch and run like a subaru for a good solid minute. it wont idle by itself for at least 3 minutes.

Maybe the dwell needs to be set higher while its cold?

It seems like to me that all of the coil packs, or most of them, are damaged somehow from two years of use and still work while warm but dont while cold. I have a set of ls1 coil packs lying around, I'll probably swap to those.

I have been having the exactly the same issues with my cops setup. I first tried a different set of COPS and nothing changed. I am having a friend try out my harness soon to see if that is causing the problems. This issue is really annoying because 9psi is SLOW.

update:
i changed my cranking pw to this:
8.9
8.8
8.3
7.8
7.7
7.5
6.3
4.8
3.6
3.1

the numbers were a good bit higher on the colder end of the spectrum, and it started a lot faster (took about 8 cranks in 30 degree weather, i was expecting it to take around 60) and it actually would idle right off the bat, but it was still kinda choppy. I don't know if it misses under load yet. more details after work.

What size injectors?

stock tan tops. 235cc iirc.

ha, nice title change. we'll see if that totally fixes it when I drive to work. I know it helped startup, but i dont know if it helped everything else yet. I suspect that it just helped a little and the problem will still be there. my afr has looked fine through this whole process.

Your O2 sensor might be bad or you have timing issues. You need to check your spark strength and make sure that's even the issue. You might also want to check the voltage at your COPs and make sure you have the 10uF capacitor in there. Most of us doubt the COPs are your problem.

N3v have you switched back to stock coils and seen if you have the same problems? I am highly suspect of people saying it is cold start settings. Mine do exactly the same as yours when it is cold, switch to my stock coils and it runs perfectly. With no change of startup settings at all. I will try to get a video tomorrow morning of how mine runs in the cold.

shuiend, what resistors are you using on your MS for ignition? Do you have the capacitor installed on your COPs? Have you checked your COPs to see if they're good and that the spark is strong?

I'm assuming you at least reduced the dwell time for the COPs.

Which specific resistors do you want to know the values of? It has been 2+ years since I have peaked in my megasquirt so I will have to go look up whats in there.

I have no capacitor installed in the wiring harness. The harness was built well over a year ago before adding them was common. I will look into it.

I have tried out 2 completely different sets of cops. Both have the same issues when they are cold. Yes I am reducing dwell settings when I switch to the cops.

I will hopefully get up a video tomorrow morning.

My dwell time is at 3.2ms for cranking and 2.5 for running if i remember correctly off the top of my head, i looked it up and made sure they were right when i did it. i'm not running any capacitors on my COPs. Do I need to change out the resistors on my ms board?

And hey whoever changed my thread name, this problem is still persisting and is showing to have nothing to do with cold start. :jerkit:

i have fucked with my cold start settings and it makes no difference. It just decided to work a little better when i started the car in the morning. it misfires all the time, i can see it in the tach. now when I say it doesn't misfire when it warms up, it just misfires less. for some reason I dont seem to have this problem in warmer weather at all, but on startup and even on warm cruise this winter i'm having this problem.

i just drove it home from work, it started up better but still i have to keep my foot on the gas to keep it idling for a few minutes before i drive off. also, it still misfired once it got warm. granted, it doesnt make it almost undrivable like when its cold though. but at idle, i could watch my tach sputter and drop every time it misfired. being that the afr was 13-14.5 at idle, and my tach is tied directly to my ignition, it has to be the ignition.

Now I feel like some people are starting to touch on the root of this problem. i'm not running capacitors and all the resistors on my board are the stock ones, whichever ones braineack's walkthrough says to use.

The aforementioned resistors are the ignition pullup resistors, which were specified as 1K until earlier this year when it was recommended to use something like 270 ohms instead. Here's the thread that discusses it, maybe it will ring a bell for you guys.

I'm curious if simply installing the 10,000 uF electrolytic cap on your COPs harness would solve a bunch of this misfire business. I happen to have a couple extras so Lars you can just install one and see if it helps.

he's using 1K ones.

If it's misfiring the whole time, maybe you have a noisy 'input' signal from your cas.
Have you put in the 0.1uF cap between JS8 (input CMP pin) and GND?
Like this thread (I didn't have time to find the right one)

Try the capacitor and change out the ignition mod resistors to 270-330ohm. That'll make sure your COPs are getting what they're supposed to for voltage and signal. It could be part of what's causing the problem. I was originally thinking it could be a CAS problem, but it should happen with the stock coils. It's possible it's still the CAS signal and it's the fact that the stock coils charge over a longer period of time which causes less parasitic current draw allowing a cleaner signal. If that's the case, the capacitor should still fix it, but the filtering capacitor b/w JS8 and GND is still a good idea. If all else fails, add more grounds to everything.

Oh, and another thing, check your COP wiring harness. Make sure all the connections are clean and tight and there are no cold solder joints. Temperature can easily change how well it works if it's degraded in some way. Make sure the gauge of the wiring is correct for the application, too. If you used really tiny wire, that could be a problem.

Have you updated the spark circuit in your megasquirt according to the current DIYAutoTune setup. Namely, they changed the resistors on the triggers.

If I said there was a chance I was still rocking my KingofL337 mods to my megasquirt would you have any clue what I am talking about?

I will pull out my MS tomorrow and take a look at it and see what resistors I am using where. I am pretty sure that Scott and I have updated my MS to something somewhat recent. Not sure If I have upgraded to the Joe is Awesome and makes shit work mods yet.

I will also try to get a video of it running bad.

i'm going to try the spark mod first. if that doesn't work i'll add caps. thanks everybody!

Have a look at your rpm trace in mlv. When I had missfire issues similar to Joe they showed up as either a drop to 0 or a peak to eleventy billion. If that's the case then unfortunalty there is no known cure. Both Joe and I gave up and switched to crank wheels.

this is not the case, when it misfires the rpm value just suddenly drops, it doesn't bottom out or peak.

finish the brap brap brap build and you won't have to worry!

Maybe the problem you're experiencing is different altogether. If your car sits for an extended period of time..overnight, maybe oil or coolant is seeping into the combustion chamber and when you start it, the engine is trying to burn off whatever is in the combustion chamber?

If the CAS wiring runs near the COP wiring, it can cause misfires. This will be much worse without the 10,000 uF (or 2 x 4,700 uF) capacitor.

Then why would I not have the same issues with my stock coils?

Interesting theory, but why would this only cause issues when it is cold out?

Sorry I haven't gotten a vid yet, raining out this morning and it looks like tomorrow morning is going to be to warm. Although I might try anyways.

i know this is partly my problem. my valve stem seals are destroyed, my car blue smokes every time it starts, and this has probably fouled up my plugs to some extent, but i know this is a separate ignition issue.

The cas wiring idea is one i haven't considered. that would make sense why it worked before and now works like crap, maybe the wires moved around a little.

I'm probably just going to swap out the resistors and if that doesn't work just deal with it. my rotary is already rebuilt, i just need a few odd parts here and there before i swap it.

It doesn't. I wasn't trying to explain the cold hard start issue, just a general pointer.

Can you try this experiment. If you are sure you have hard starting every morning, do this.

One night, take your COPs out and keep them warm indoors. Plug them in in the morning, and see if you still have hard starting. This will rule out the COPs themselves as having a cold related issue.

I will try that out next time it dips down into the 30's in the morning. Although I have 2 sets of cops and both do the same thing. So I am highly doubtful it is the actual cops. One of these days I will have my friend try out my harness to see if that is the problem.

There might be some design related issue common to all COPs, not a unit related issue.

It's unlikely the harness if others are seeing the same problem.

What are your dwell numbers for cranking?

I've never had a problem with cold starts since I've fitted mine, I can start/idle the car without problems as low as 20*F, about the coldest I've ever tried. usually stays in a garage if it's that cold and never gets touched.

Whats the verdict on the spark circuit>?

final verdict:
- switched the cops for a stock coil and wires
- pulled plug #1, it was brown, didnt even check the other 3
- set the dwell back to where it needs to be for stock coils
- didn't change out the resistors on the megasquirt yet
- changed no other settings in megatune

car started on the second turn over while it was sleeting. I've since dailyed it with no problems at all. the missing issue is completely 100% gone.

I dont know what was up with my coils, maybe they were damaged? they were from a toyota tundra so their plug was off at different angle from the ones savington likes to use on his kit he used to make. their appearance is exactly the same as the coils everyone else uses though, and they were wired on the same pins. I dunno.

Mine do the same thing when cold, I doubt both of ours are bad considering they run great in warm weather :hustler:

i have the same problem i need to hire joe for a weekend

What's the P/N on yours, so that we can have a "Trully Tried & Tested" list...?

Jim

ill have to double check, one of the ones in the FAQ

ScottFW is currently testing my wiring harness and cops out on his miata. He has not been able to reproduce the problems I had been having. So this is starting to get interesting.

Is it very cold where he is testing them?

We live 15-20 miles apart, weather is pretty much same-same.

In cold weather with my COPs on my car, I have to crank for ~3 seconds, then it fires and stumbles to life. It's not a strong OEM-quality start, but it works. Because I don't drive the car much when it's below 30° my cranking PW and ASE are probably not ideal, but it's good enough to start the car.

When I swapped in shuiend's harness and COPs and tried starting the car on a cold morning (22°F in my garage) it behaved mostly the same. Crank for 3-4 seconds and the engine stumbles to life. It died after running for 3 seconds, which is when my megasquirt switches from fixed MAP mode to ASE. Again, my ASE may need tinkering at that temp. I started the car a second time and it stayed running.
I will try to repeat this test on another cold morning so I have n>1 observations.

I don't know *exactly* the difficulty Lars has experienced on his car (need video) but his COPs & harness did not behave much differently than mine on my vehicle, which is to say, adequate to start my car in the cold.

My COPs harness has 10,000 uF capacitors (two of them, which is probably one more than necessary) and has 12 AWG +12V and ground. Lars' harness has puny +12V and ground wire, probably 18 or 16 AWG, and he has no capacitor. My COPs are 90080-19015 and Lars' are a different Toyota/Denso part number that obviously work. I might expect his small AWG (16 is probably fine since that's what Toyota used to wire them, but 18 is pushing it) and lack of cap to affect operation at high rpm, but it doesn't seem to matter for simply starting and idling in cold weather.

Since the COPs & harness don't seem to be the issue, I'm trying to think of other differences that may exist between our cars, other than the obvious fact that I no haz trub0z yet. My MS has the ignition pullup resistors changed to 270 ohms (or did I use 330, I forget) while Lars' MS likely still has 1K resistors. My cranking advance is 14* and in my idle cells it's 17*, not sure what everyone else runs but it might start easier with more OEM-like timing (less advance). I've got BKR6E plugs with out-of-the-box gap (all verified to be ~0.040"). Then there are whatever differences in MS startup settings like cranking PW which I'm sure Lars has already tried tuning. Maybe his battery is marginal and not putting out enough juice in the cold, and combined with small AWG and no cap he has voltage drop issues at the COPs. I'm just throwing stuff out there. :dunno:

Is it confirmed that the factory coils start the car OK?

Lar's factory coils start the car fine, he's been running with them since it's cold and he's had this issue.

again, I started my car on a wonderful 23*F afternoon, highly untuned as it was first time trying MS-II...had absolutely no issues starting right up and idling perfectly.

Does increasing or decreasing the dwell improve the cold starting?

Have not tried that out yet. How much should I try increasing the dwell by?

When I get my cops back from ScottFW in a few weeks I will try increasing the dwell and I will also try to get a video of the car running bad.

The only difference that I can tell between ScottFW using my cops and myself when starting is I only had problems when I would leave the car outside over night as opposed to ScottFW starting it in his garage. It is a good 10 degrees colder on average right now then when I was trying, so I do not think the garage is playing to much of a roll in it.

My garage is attached to the house, but not insulated. Using my digital thermometer with remote probe (quality lab-grade shit calibrated to NIST standards) over the past four days it has consistently measured 2.0-2.5°F warmer in my garage compared to outside. That deltaT is insignificant for these tests, but it does remind me that I need to insulate that bitch and put a nice heater in there and stop living like a Neanderthal.

I can try messing with the dwell. I'm currently running 3.5/2.5 cranking/running. I'll increase the cranking dwell a bit and see if it changes anything.

I dwell settings when running with the cops are 5.5 cranking, 2.5 running and minimum discharge .5. Does that look to far off?

This has been happening to me as well, seems to be when ambient temp is below 60F. Runs great when warmed up.

It's definately in the coils. Past 3 mornings I decided to experiment, I took the hair drier and warmed the coils up...it works lol. Ran the hair drier for about a minute tops, going back and forth over the coils. Runs perfect after that.

I can't explain, but I'm thinking the resistance is high in some of the coils when it's cold. Going to try measuring them warm and cold.

shuiend try 3 mS cranking.

Does the MS not have a dwell vs battery votlage curve?

The Toy coils have a function where dwell > y when V > x causes it to terminate the pulse and fire way too early. This function may be going awry when cold.

Does the car show signs of way too much advance when cranking? (e.g. motor suddenly stops turning then re-starts, perhaps with a "chunk!" sound).

Yes the MS will trim dwell with battery volts. It is configurable. It also fixes timing and dwell when cranking. Most people lock timing to 10° fixed when cranking.

If memory serves, my settings on my 91 were something like 3 ms running and 5.5 ms cranking dwell. I never had an issue starting ever, even with a true cold start on a snowy day, with 3 really big vents in my hood.

I struggled with cold starts on the 19015 COPs until I fed the signal wire with more than 7.5mA from the 5V rail. I'm using ground switching to fire them. 10ms cranking, 2.5 running, 0.1 min.

Also, capacitors... They're there to filter out the noise. The toyota coils can be very harmful to a v2.2 MS.

I can't find my notes on how much pullup current the Toyota COPs require. However 1k seems a bit wimpy. Indeed 330 ohms may be required, and the cold temps could reduce the "gain" of the internal circuitry, necessitating a stronger pullup.

Jason,
Do you still have the dwell research you did on them? I'd be interested in all the data you have on these coils.

Sounds like their may be a solution finally after 2 winters :giggle:

I've been having some trouble starting cold too.. I wonder if it could be the coils. I'd been blaming it on my cranking PW, but thinking back IIRC it wasn't this hard to start with the stock ignition.

It also sometimes takes a couple cranks when hot, but that has to be either vaporlock, a cranking PW table in need of fine-tuning, or both.

I've already changed the resistors in my MS, I just want to make sure I understand what's going on. Is this a simple relationship of V=IR? So if V=5 and R=1K the wire gets 5mA? If R=330 then I=15mA, R=270 means I=18.5mA, etc?

Also, 10ms sounds like a lot of dwell, but that's just compared to other numbers I see strewn about the internet, not any specific knowledge on my part regarding the COPs. Probably no harm in trying to see if it gives me a more robust startup, since I don't think I'm cranking long enough to damage anything even if it is a bit on the high side. Right?

Not quite, because the input of the coils won't be at 0V. If it's at say, 1.5V, then the resistor is seeing 5-1.5 = 3V, and if R is 300 ohms then I = 10 mA.

10 mS is way too long for the Toy cops - it has a "just fire if dwell is too long" function which I mentioned in an earlier post, and that function may be invoked, and spark will be too early. Even at 8.5V the dwell should be no longer than 3.3 mS.