Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Calibration Help - Car hard to start when hot

General Tuning Discussion

Forum Posts



Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads


After tuning in vacuum only... car will not start unless left for a while to cool.. any ideas?

Haltech ps1000

Mr2 3sgte

When I run into this issue, I first make sure it's not something mechanical/physical wrong (i.e., ignition not firing because plug cable is burnt on exhaust manifold). Once past that, knowing it's a calibration issue - I observe if the engine starts quicker with the throttle opened. If so, then it's likely too much fuel, so I reduce fuel when cranking. If throttle doesn't help, then I try more fuel in perhaps 10% increments.

I forgot to mention - "hard to start" can mean a number of things. If the engine is "kicking back" on the starter, it might be ignition timing related.

The most helpful thing you can do (again, IMO) is to take a datalog of a good startup, and a bad one, and start looking for differences in commanded outputs such as fuel quantity, ignition timing.

If you have more details about the engine or ECU, please share, it might help zero in on the issue.


Hey man! I was havING the same issues double check your fail safe settings. You could have them set close to operating temp. Is your AIT senor calibrated cause it might be going into failsafe mode. Check your coolant too. I like to see a fellow 3sgte man on here I got a 93 with the emu setup.

Emu mr2 3sgte

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?