Car hard to start below freezing after sitting outside all night

K-Series Programmable ECU installation questions / support issues
snyderkj717
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Joined: Mon Jun 22, 2020 8:11 pm

Car hard to start below freezing after sitting outside all night

Post by snyderkj717 »

'05 Civic D17A2, problem is starting the car after it's sat outside through the evening & overnight in below freezing temps. It won't start this morning after the temp hit 0F, last night. IAT & ECT is 22F, right now, the next morning. It'll crank for several minutes, if I try.
-It seems like my ECT's fuel trim + ECT ignition advance are way off.
-The car runs perfect at this temperature when it does start, its just getting it to start. It refuses to start when I've left it out in the cold all night.
-The problem isn't happening when the ECT is above freezing. If I crank it long enough below freezing, it'll eventually start, but, that's just killing my battery, and starter. Once, the sun comes out, and the ECT has some temp in from the morning drive, it'll start right up perfectly in the afternoon.

Mods: K-Pro V4 PND, AEM D17A timing gear, everything else is factory D17A2, factory intake system, factory exhaust system.

ECT gets below freezing, ECT ignition advance + ECT fuel comp is making it near impossible to start.

I don't like tweaking cranking fuel trim, because, then, it's just harder to start once ECT, and IAT temps aren't freezing during the same day, temperature here fluctuates too much to adjust cranking fuel trim. below freezing in the morning, 40F in the afternoon.

I started having this problem after installing a k-pro 2 yrs ago. it did the same thing last winter. it starts perfect every time outside of below freezing temps.

KPro SN: K-Pro4 52738
ECU PN: 37820-PND-A06
ECU SN: 2062-602504-0C25
k-manager 4.4.4
Attachments
10 minute drive above freezing.kdl
(4.52 MiB) Downloaded 64 times
1 minute crank below freezing.kdl
(734.76 KiB) Downloaded 55 times
K-Pro Stock VTEC D17A2 EX 5-Speed 010722.kal
(162.32 KiB) Downloaded 67 times
TTR
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Joined: Wed Mar 31, 2004 8:48 pm

Re: Car hard to start below freezing after sitting outside all night

Post by TTR »

Add fuel to (parameters,fuel trim) Cranking Base injector pulse under freezing.
snyderkj717
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Re: Car hard to start below freezing after sitting outside all night

Post by snyderkj717 »

TTR wrote: Fri Jan 07, 2022 12:43 pm Add fuel to (parameters,fuel trim) Cranking Base injector pulse under freezing.
Decreasing number for injector pulse (ms) increases fuel, correct?
I adjusted the numbers for below freezing under Cranking base injector Pulse by -30%. Car still won't start. I can't tell if it's lean or rich. Still 20F outside.

It's odd that it's at ECT 32F the car refuses to start.
Looking at my 10 min drive graph, the car started at 32.7F, ECT; 28.4F, IAT; INJ pulse: 45.86ms. Ign Adv. 5 degrees.
It's 20.8 ECT currently, 44.46ms INJ pulse. Car will not start. Ign Adv. 5 degrees.

Still need to decrease cranking base INJ pulse (ms) to add fuel?
TTR
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Re: Car hard to start below freezing after sitting outside all night

Post by TTR »

You need to increase the number
snyderkj717
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Re: Car hard to start below freezing after sitting outside all night

Post by snyderkj717 »

I doubled the fuel from base for the ECT ranges below ~50F. Engine still will not start w/ ECT below 32F. I followed this thread below. I plugged in a brand new, room temperature, water temp sensor into my engine harness, with ECT actually at 15F. The car fired up immediately. K-pro gets 70F ECT reading when ECT is really at 15F. I shut it off after letting breathe for a moment. I plugged my engine harness, back into the water temp sensor, still inside the water housing. The car would not turn on when k-pro registers a water temp below freezing.

So, using the fuel corrections from 70F ECT reading, the car starts with 15F ECT, but, will not start with the ECU reading 15F, or anything below 32F.

I'm not the only one who has seen this problem w/ a k-pro d17.

https://www.7thgenhonda.com/threads/kpr ... ery.21586/

viewtopic.php?t=12312

It definitely seems like the ECU is commanding the spark at the wrong time when it gets an erroneous ECT reading below freezing point.

Maybe, it has something to do with this ECU getting a reading from the wrong part? J/K-series ECT sensor vs. D/F/R-series ECT sensor?
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Hondata
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Re: Car hard to start below freezing after sitting outside all night

Post by Hondata »

Ignition advance is fine.

First you need to determine if the ECT and IAT and reading the temperature correctly. Seems to me from the datalog they both are as they read almost the same as each other.

Then the next step is to change the cranking fuel until you get it starting. The rule of thumb with cranking fuel is to make big changes - typically halve or double the fuel. So when it is 20F and the car has been sitting overnight change the cranking fuel and do a short crank. If the car does not start after a couple of seconds then change the fuel and try again. If there is too little fuel generally the engine with fire a few times but not start. If there is too much fuel then once the engine does start it will stumble for 10 seconds or so until it clears all the fuel out of the intake. I'd try adding fuel at first (BTW increasing the injector duration add fuel).

Also keep in mind if the engine does not start without a couple of seconds and you keep cranking you can go from a lean condition to a rich condition as you flood the intake manifold.

Keep datalogs.
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bryantrinidad
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Re: Car hard to start below freezing after sitting outside all night

Post by bryantrinidad »

We have the same problem. A lot of us using the KPro with the D17 engines. I thought at first it was only me because its turbocharged.
But then I kept researching and researching; I am not alone with this problem.
And that's how I start my car every morning during winter times. I have a spare ECT Senor that sits in the garage and its always around 40F. The car starts right up no problem. I have tried to manipulate the calibrations like stated above. Even with a professional tuner, he did the same thing.
This has been addressed here several times but I have not read a permanent solution. I have so frustrated that the problem is said to be with the tuning. My guy is one of the best in the East Coast and featured in several Honda/Tuning Magazines. I guess they always blame the tune. Never really looked into that the KPro for D17 has an issue or corrupted file.
I have attached a datalog of cold starts less than a couple of minutes apart, changing the ECT sensor on the second one with 42F.
Anyone can help us with a permanent solution I thank in advance. Its frustrating.
Attachments
cold start ect below 32.kdl
(73.63 KiB) Downloaded 61 times
cold start ect above 40.kdl
(156.92 KiB) Downloaded 64 times
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Hondata
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Re: Car hard to start below freezing after sitting outside all night

Post by Hondata »

Please can you provide the calibration as well?
Hondata
bryantrinidad
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Re: Car hard to start below freezing after sitting outside all night

Post by bryantrinidad »

Several calibrations I used you can look at. Thanks
Attachments
COLD START FIX 2.kal
(19.52 KiB) Downloaded 58 times
MOST RECENT.kal
(159.73 KiB) Downloaded 53 times
6-17-2020 .86AR.kal
(163.93 KiB) Downloaded 58 times
5-22-20 DYNO TUNE.kal
(159.43 KiB) Downloaded 56 times
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Hondata
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Re: Car hard to start below freezing after sitting outside all night

Post by Hondata »

The next time the ECT and IAT are below 50F can you disable closed loop operation and see if there is any change.

The other test would be to upload a PRA calibration rather than a PRB to see if that affects the starting.

I know nether are long term solutions but it will narrow things down.

Note that you cannot do one test, start the car, then switch it off and do another test immediately afterwards. The ECU remembers what it did and the start will be different.
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bryantrinidad
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Re: Car hard to start below freezing after sitting outside all night

Post by bryantrinidad »

Hondata,
I can do this test a day apart, several days, or weeks apart, it will give me the same results.
I only datalog a couple of minutes apart to show that changing the ECT sensor started the car immediately.

At 50F, the car starts no problem. The problem is if its below freezing temps, but I will try to upload a PRA and see if it makes a difference.
Thanks.
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Hondata
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Re: Car hard to start below freezing after sitting outside all night

Post by Hondata »

We did some testing here with the scope on the ECU to check the operation, and did not see anything unusual.

- Tested both PRA and PRB calibrations at different temperatures, from 50F down to -5F.
- Verified ignition timing was what the ECU claimed it to be (typically 5ATDC)
- Verified injector pulse was what the ECU claimed it to be.
- Verified cranking base pulse table.
- Verified injector voltage compensation table.
- Verified that the spark was at the correct cylinder.
- Check operation at lower voltages.

Only think I did notice is that the injector coil dwell time gets fairly long when the battery voltage is low and the ECU is cold. This should not cause any problems (the coil is not going to overheat) but it was an observation.

I did notice on the datalogs that the battery voltage was fairly low (under 8V in one datalog). I'm not sure where the coils would stop working.
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bryantrinidad
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Re: Car hard to start below freezing after sitting outside all night

Post by bryantrinidad »

Thanks for looking into it.
I cannot run your recommended test right now since it’s fairly warm.
Hopefully it gets to freezing temp again and see what I can do. Maybe it’s just the D17 engines causing. I don’t know anymore.
I did see the battery voltage drop but again it’s the same battery that started the car after changing the ECT sensor.
bryantrinidad
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Re: Car hard to start below freezing after sitting outside all night

Post by bryantrinidad »

COLD START Above 32F
Attachments
COLD START 39F OUTSIDE TEMP (SITTING FOR 2 WEEKS) PRB.kdl
(704.65 KiB) Downloaded 59 times
bryantrinidad
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Re: Car hard to start below freezing after sitting outside all night

Post by bryantrinidad »

bryantrinidad wrote: Fri Feb 18, 2022 12:20 pm COLD START Above 32F
I will update once outside temp drops again and on a PRA calibration
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