Hard to start when cold - need help.

Post by **wingFeather** » Wed Apr 09, 2008 4:10 am

I bought a 240sx that was already swapped with a red top sr20det.

It starts & seems to run good when warmed up... but starting when the motor is cold is a chore. I usually have to crank the motor about 5 times, stop, wait a second, crank again then it catches.

**edit: Issue resolved, thanks to BSRJIRONMAN **
Modified by wingFeather at 9:06 AM 8/28/2008

Post by **wingFeather** » Mon Apr 14, 2008 5:41 am

Anyone? I'd be ever so grateful.
Modified by wingFeather at 9:06 AM 8/28/2008

Post by **uberkillerz240** » Mon Apr 14, 2008 12:39 pm

im pretty sure this has been discussed many times before. please use the search button. Actually, ive responded to this question elsewhere, and i have the same problem.

Post by **wingFeather** » Tue Apr 15, 2008 6:51 am

Dear kind sir,

My cold start issue has *nothing* to do with ambient weather temps, is not related to other issues I'm having... unlike the 3 or 4 "cold start" threads I found when I did an initial search.

Other than being difficult to stat, the thing seems to run okay. Idles about 950? RPM.

I'm not familiar with the sr20det motor at all, so I don't know if this is a common issue.

Post by **uberkillerz240** » Tue Apr 15, 2008 11:41 am

ok. ill stop being annoying and attempt to help. note, i have yet to solve my issue, which is weather related. o well.

http://www.240sx.org/faq/

go to this site and look for "hard starting when cold". This is pulled directly from the FSM. It is a checklist that should help u diagnose the issue. I hope that helps you and i wasnt trying to be stupid in the previous post. Just a little tired. sorry.

Post by **onecrazyfoo4u** » Wed Apr 16, 2008 7:43 pm

You guys both need to check the solid orange wire on your ecu, I think it's called the starter signal wire. I had the exact same problem, would take FOREVER to start in winter, and just a little better during summer. Check that wire for voltage, if you have zero volts when the key is on, then that's your problem.

I just wired the orange wire to a 3-wire on/off switch. 1 wire goes to ground, 1 wire to power, then 1 wire to the orange wire. Flick it on right before you turn the key, and it fires right up, then just flick the switch off. I dealt with this stupid crap forever, I was so relieved to fix it finally! Good luck, let me know if you have anymore questions.

Post by **uberkillerz240** » Thu Apr 17, 2008 1:19 am

Thanks. I knew about the orange wire and the starter signal, but i havn't had a chance yet to check the voltage. Also, i didnt know what to do after that, but your advice helped me. I'll hopefully check it this weekend, right after my emissions Thanks.

Just one question. Did u just grab power from any one of the power wires or was one easier/closer than the other? thanks.

Post by **onecrazyfoo4u** » Thu Apr 17, 2008 5:20 am

I think I hooked it up to one of the power fuses down in the drivers side area. Just pick any one that comes on when the key is on. Even something like the power to your stereo would work fine. Good luck!

Post by **wingFeather** » Mon Apr 21, 2008 6:52 am

onecrazyfoo4u wrote:You guys both need to check the solid orange wire on your ecu, I think it's called the starter signal wire.

No dice here. I tried both grounding the wire, and then sending volts it's way (not at the same time of course). No change

But thank you for the advice anyway I was really hoping it was that easy.
Modified by wingFeather at 1:38 PM 4/21/2008

Post by **onecrazyfoo4u** » Mon Apr 21, 2008 8:20 am

No, you def. don't want to ground the wire. First off, check it with a voltmeter, do you have any voltage at the ecu orange wire at all? You should get about 12 volts when the key is 'on'. If you don't have any voltage, then that has to be the problem, try hooking it up to a on/off switch. Let me know how it goes.

Post by **Zilvia33** » Mon Apr 21, 2008 10:54 am

yea def need to try this.

originally i thought it was just cold weather problem...but now that it's warmed up it still does it...and now my started sounds like it did in my ka almost( wants to die)

Post by **onecrazyfoo4u** » Mon Apr 21, 2008 12:41 pm

Do it asap....I went 6 months hating to start my car every damn morning. Now she starts right up everytime! It takes you 5 minutes to check the voltage at that wire, another half hour to wire and mount an on/off switch.

Me and like 3 other guys were having the same problem, I found this solution on freshalloy and it fixed all of our problems!

Post by **wingFeather** » Tue Apr 22, 2008 6:31 am

Any speculation of what the side effects might be if you just left the 12 volts going to the wire at all times (effectively eliminating the switch)?

Post by **onecrazyfoo4u** » Tue Apr 22, 2008 9:14 am

I'm not sure what would happen if you left voltage going to it constantly. I've left the on/off switch on for a few hours and it doesn't affect the car at all. I don't know if I'd trust it to leave it on constantly though.

Post by **slivic** » Thu Apr 24, 2008 6:23 am

OK guys, help me out here. I have a similar issue. However I took the car to a shop and they ran a wire directly from the starter to the orange start signal wire. When this wire is connected it will cold start perfectly, but it will not hot start. Just the opposite happens when it is disconnected. So it will not cold start when it is disconnected, but it will hot start. What is going on here?

Post by **onecrazyfoo4u** » Thu Apr 24, 2008 9:01 am

I'm not sure if that wire goes to the starter or not.....I heard the wire is supposed to go the ignition switch somewhere, but I never could find it. It's really easy, just hook it up to a 2-wire on/off switch and test it that way. At least that way you wouldn't have power running to it constantly.

Post by **slivic** » Thu Apr 24, 2008 9:45 am

Yeah, I am going to run a switch, but I would really like to hook it up the right way.

Post by **onecrazyfoo4u** » Thu Apr 24, 2008 10:01 am

Yeah, the switch works just fine, because I couldn't find that orange wire for the life of me. I looked all around the steering column and ignition switch....I'm thinking it's a different color than what it is at the ecu. Anybody know where that wire is?

Post by **BSRJIRONMAN** » Sun Aug 24, 2008 6:13 pm

Well you may have fixed it already but here goes. I have an rb20det in my s13 and i was having the same issue, I think ecus are pretty similar on both engines. Behind the golve box there should be a rectangular brown plug where the ecu harness (for engine) meets the dash harness (for car). Check you pinout to verify but on an rb20det the start signal wire is red/yellow, and on the car's harness, the start signal wire is solid orange. Alot of people get this confused on swaps, they plug the orange wire from the ecu (eccs relay) into the orange wire on the cars harness (start signal wire), so the ecu doesnt know when to give the engine more gas and timing. If, on both sides of the plug, the wire is orange its wrong (again verify this with the sr20det pinout). To fix it, I simply wired in a 'jumper' wire from the orange wire on the plug, to the red/yellow start signal wire on the ecu (pin 43). This fixed my problem once and for all. Switches can be harmful if left on, as that is sending 12v through the start signal wire and telling the ecu to give it more gas and timing...the whole time the switch is on. I bet you get pretty bad gas mileage while this is on. Anyway I took pictures of the plugs and process, if you would like I can send them to you via email, let me know.

Post by **vanquish2** » Mon Aug 25, 2008 1:06 pm

I would love to have these pics.....could you email them to [email protected]

thanks!

Post by **BSRJIRONMAN** » Mon Aug 25, 2008 1:21 pm

I did a little research on the sr20det ecu, and it turns out that the start signal wire is not at the same pin as the rb20det. Its pin43 on an rb and pin34 on an sr. The dash harness end of it should be the same though, as they are both s13's. As long as the orange wire from the ecu is pinned to the slot that lines up with the orange wire on the dash harness receiving side of the plug, and when the key is in the 'crank' position it gets close to 12v, it should work. If it doesn't, then you need to check the fuse box, i think its fuse 11, and i think its a 7 or 7.5 amp fuse. That should be a fuse dedicated to this wire. If thats not blown, then you need to check it inside the ignition column.

Post by **wingFeather** » Thu Aug 28, 2008 3:09 am

BSRJIRONMAN wrote:I did a little research on the sr20det ecu, and it turns out that the start signal wire is not at the same pin as the rb20det. Its pin43 on an rb and pin34 on an sr. The dash harness end of it should be the same though, as they are both s13's. As long as the orange wire from the ecu is pinned to the slot that lines up with the orange wire on the dash harness receiving side of the plug, and when the key is in the 'crank' position it gets close to 12v, it should work. If it doesn't, then you need to check the fuse box, i think its fuse 11, and i think its a 7 or 7.5 amp fuse. That should be a fuse dedicated to this wire. If thats not blown, then you need to check it inside the ignition column.

That did the trick

Orange from the ECU should be wired into orange from the dash harness (my harness connector was white & attached to the side wall North of the ECU).

Double check the "start signal" fuse, even using a volt meter to check both poles of the fuse for 12 volts while cranking.

Post by **vanquish2** » Thu Aug 28, 2008 4:44 am

this did the trick for me as well!!! A 5 year problem and it is FINALLY fixed!!!

The fuse on mine was a 10a.

The wires at the connector were orange to orange but still no 12v so I think I may have a problem at the ignition switch. This car used to be an auto so that may also have something to do with it.

As soon as I put 12v to the wire the engine fired perfectly.....beautiful!

Post by **wingFeather** » Thu Aug 28, 2008 5:19 am

Same here. Used to be an automatic. Huh...

Post by **Hijacker** » Thu Aug 28, 2008 5:49 am

vanquish2 wrote:this did the trick for me as well!!! A 5 year problem and it is FINALLY fixed!!!

The fuse on mine was a 10a.

The wires at the connector were orange to orange but still no 12v so I think I may have a problem at the ignition switch. This car used to be an auto so that may also have something to do with it.

As soon as I put 12v to the wire the engine fired perfectly.....beautiful!

Being an auto has nothing to do with it. You probably have a broken start signal wire under the dash. It happens on our cars. Best thing to do is to just run a new wire from the ignition switch to the ECU (or dash plug if you want)

Post by **BSRJIRONMAN** » Thu Aug 28, 2008 6:37 am

Yes this is true. BUT be sure you route it through the original start signal wire fuse first! Or of course you can also out in an in-line fuse as well. If the wire is simply broken...fix it, a shielded coupler will do. A continuity test is a great tool when trying to diagnose a wire's condition in low visibility areas (such as under the dash). The best thing to do is test the fuse holder itself, if one side gets the voltage in the crank position, the fuse is good, bu the plug end gets nothing, then re-use the fuse and just replace the orange wire from the fuse box onward...easy!

Waistermike · Post by **Waistermike** » Thu Mar 05, 2015 10:31 am

I am having the same problem with my s14 red top sr20det swap but I can find what color my start signal wire is. Find that the starter wire is black/yellow and second starter wire is black/white. But I don't know which is the start signal wire.. Can anyone confirm that the second starter wire is the start signal wire for helping he engine start up when cold?

Post by **Wol_The_King** » Thu Aug 17, 2017 8:11 am

Hi guys,
I have a -91 s13 ca18det (not swapped) with the exact same issue. I've checked all other things that could cause this.
Is it possible that this could be the problem with my car as well?

Post by **Wol_The_King** » Fri Aug 18, 2017 11:47 am

@float_6969 Is this something you have encountered with the ca18det?

Hard to start when cold - need help.

Red top difficult to cold start... (okay once at op temp)

Re: Hard to start when cold - need help. (wingFeather)

Re: Hard to start when cold - need help. (wingFeather)

Re: Hard to start when cold - need help. (uberkillerz240)

Re: Hard to start when cold - need help. (wingFeather)

Re: Hard to start when cold - need help. (uberkillerz240)

Re: Hard to start when cold - need help. (onecrazyfoo4u)

Re: Hard to start when cold - need help. (uberkillerz240)

Re: Hard to start when cold - need help. (onecrazyfoo4u)

Re: Hard to start when cold - need help. (wingFeather)

Re: Hard to start when cold - need help. (onecrazyfoo4u)

Re: Hard to start when cold - need help. (Zilvia33)

Re: Hard to start when cold - need help. (onecrazyfoo4u)

Re: Hard to start when cold - need help. (wingFeather)

Re: Hard to start when cold - need help. (onecrazyfoo4u)

Re: Hard to start when cold - need help. (slivic)

Re: Hard to start when cold - need help. (onecrazyfoo4u)

Re: Hard to start when cold - need help. (slivic)

Re: Hard to start when cold - need help. (onecrazyfoo4u)

Re: (vanquish2)

Re: (BSRJIRONMAN)

Re: (vanquish2)

Re: (vanquish2)

Re: (Hijacker)

Re: Hard to start when cold - need help.

Re: Hard to start when cold - need help.

Re: Hard to start when cold - need help.

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