B18C w/ ITB & S300 won't idle

s300 and SManager software questions & answers
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B18C w/ ITB & S300 won't idle

Post by irtbnightmare » Sat Sep 30, 2006 5:55 pm

Freshly installed S300 into a P28 ECU. I can't spot what's wrong in the datalogs. Car idles high (1500-2000) for about 10 secs and then dies. I have the stock map sensor and idle speed motor plumbed into the ITB. TPS is the TWM supplied unit and its output looks right except for it reading 2% when closed. Car is running 320 cc injectors, B16A head, B18C block. Please help.
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Post by irtbnightmare » Sun Oct 01, 2006 7:55 am

Oops, forgot to mention. Calibration is stock P28 w/ stock injectors 240 & current injectors set to 340 cc.

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Post by Hondata » Mon Oct 02, 2006 9:04 am

Switch the mapping to TPS based for ITBs.

The TPS must read 0% when closed.

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ITB MAP+TPS Tuning Strategy (Street)

Post by Johnny_9 » Fri Oct 30, 2009 8:31 pm

ITB setup with I.A.C.V (Street Set-up). You will need a IACV adaptor plate. See


You can also get the IACV Adaptor Plate from

Keep the vacumm tube to the MAP as short as possible. other you will get a vacumm lag.

1) Primary table (MAP) : 0 rpm to 1,490 rpm
2) Secondary table (TPS) : 1,500rpm to 8500rpm
3) Match the injector duty cycle (%) between the primary (MAP) and secondary tab (TPS) at each load in the 1,490 rpm band to the 1,500 rpm band. Copy and paste the 1490rpm row from the primary laod sites into the seconday from primary to secondary

I hope this can be updated in the Hondata Help as an explantion is sorely lacking in the documentation - Doug (some feedback for you)

If you load the ITB Hondata sample MAP you can see the injector duty cycle between the primary and seconday is approximately the same at the 2500 rpm (It uses 2,500 rpm cutover as oppossed to the 1,490 rpm I noted above - you can play around with this to see what gives the best result - of course if you are doing a track car just use a 100% TPS configuration).

Now you can enjoy ITB, cold start, air-con IACV adjustment with ITB, fast-ilde control