Jump to content

S2000x on F22c1 Startup Inconsistency


Recommended Posts

I recently finished my install of an S2000x on my 2005 Honda S2000 with a completely stock F22C1 with a few bolt ons. I had the car tuned by Jeff Evan’s and I am very pleased with the performance and quality of the tune and hardware.   

I have one issue that I need some help with. On a cold startup the engine cranks for maybe twice as long as it did stock but then fires normal and idles great. If I take a short drive, stop, and then start it again the engine fires so quickly that it kind of stumbles. Once it fires it idles normally with no issues.   

Jeff has said that there is something odd with the triggers and has reached out to someone at link for assistance. I figured I would post here to see if the community can help.

Link to comment
Share on other sites

If you can give us a PC log of a bad start-up, a trigger scope capture when cranking and a copy of the tune we can take a look.  I dont see any support tickets in the system for evans performance.  If its using the K20 trigger mode, I can say that is fairly well validated as we owned a K20 test car for several years.  Although that doesnt mean there couldn't be other factors such as voltage offsets or similar that could cause a trigger issue.

There was an issue with start up fuel if wall wetting compensation was enabled in some recent firmware, that could potentially fit your symptoms.  

Link to comment
Share on other sites

The log file only has one start-up in it (in the middle when ECT = 90°C), possibly the ecu disconnected during the cold start?

Your engine is using the S2000 trigger mode, not the K20 mode that I assumed earlier, and there are a couple of odd observations related to the trigger.  The trigger scope shows the engine slows down a lot as each piston comes to TDC compression, the crank speed is normal with about 260RPM at BDC, but drops to 120RPM at TDC.  Does it sound like it cranks unusually slow and/or uneven like an engine does with a drained battery?  Is there any known reason for this such as a light flywheel, higher than stock compression ratio or small/relocated battery etc?  Possibly related to this is it appears to take longer than normal for the ECU to determine that the crank is actually turning - in this hot start log there is only about 0.5s delay after the starter signal that the ecu reports RPM, but even this small delay will mess up some startup strategies a little such as the fuel pump is not running when pre-crank prime occurs and a large drop in fuel pressure during crank enrichment etc.   And this delay could potentially be worse when cold.  

Can you get us a log of a cold start and another scope capture with a cold engine. 

If you could also try getting another variation of the scope capture on a different occasion by clicking the capture button at about the same time or just slightly before you engage the starter so we hopefully capture what happens as the crank just starts to move.  


Link to comment
Share on other sites

Ok I have no mods internally that would cause weak cranking, and I don't hear the car struggling it just takes longer to fire. Below are the requested logs and trigger scopes. I also included a normal idle trigger scope as well.

Trigger Scope - Idle

Trigger Scope - Cold Start

Datalog - Cold Start

Trigger Scope - Pre Start

Datalog - Pre Start


Link to comment
Share on other sites

  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...