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Engine starting help. 1JZ Haltech 2500

Practical Standalone Tuning

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I have a 1JZGTE with Bc 264 cams (stage 2) Haltech 2500. The engine starts pretty good cold, it requires the iac to be open almost 100% between idle base table and the added on post start add on at 0 seconds. Once it starts it idles well cold.

Trouble is when at operating temp after sitting for 30 minutes or so, when trying to restart it does not start unless I feather the throttle. Once starting it takes a second to sound like it firing on all cylinders and clear itself. It smells rich when starting hot. I want to get it so that I don’t have to feather the throttle.

I think I can get it to start by running a lot of air with post start iac duty at 0 seconds but wondered if I should be trying to add air or reduce fuel when hot. Reduce cranking fuel or something else.

The tables in the HP videos show low amounts of post start offset. I’m having to add 50% to get it to start. I didn’t know if this was a side effect of aftermarket cams. The iac is set to be only 2% open at warm idle. Cranking timing is set at 2 degrees when warm and 4 degrees when cold.

I’m also at high altitude so less atmospheric pressure as well, 5300 ft.

Thanks for your help.

I would look at the Fuel Cranking table. See what happens when you reduce the fuel at higher temperatures. Opening the IAC more is just compensating for too much fuel being supplied. Reduce the fuel and the IAC should be able to remain closed.

Also test with more advanced cranking timing. 8 or 10 degrees is not too much. You should need more timing at higher temps.

Thanks for the reply I appreciate it. I will give it a try

BTW -- the Fuel Cranking is an adjustment to the main fuel table at the cranking RPM. You might want to make adjustments there first, and only change the cranking fuel if needed. The key is understanding exactly what cells are used when cranking, and immediately after starting -- logging is your friend.

I pulled some cranking fuel and it fixed it. Thanks.

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