Engine won't start when warm

**enzo_dlc** · January 27th, 2007 09:36 PM

sirs, what could be the problem if the engine starts fine when it's cold but won't when it's warm? it cranks but won't start when you try it after you've used the car for a while.

**niky** · January 27th, 2007 10:34 PM

What car and year model, po? And what engine?

One big possibility is a sensor problem. If your engine bay is too hot, a sensor might be going haywire. If I understand you, it'll run hot, but it won't start if you turn it off and try to start it again?

**BoEinG_747** · January 27th, 2007 10:49 PM

Originally Posted by niky

What car and year model, po? And what engine?

One big possibility is a sensor problem. If your engine bay is too hot, a sensor might be going haywire. If I understand you, it'll run hot, but it won't start if you turn it off and try to start it again?

niky, malaki ba factor kung old model na ang engine (ae92)
ang ride at saka nasa malamig na place (tagaytay)
hirap sila start sa umaga lalo na kung super lamig

**enzo_dlc** · January 28th, 2007 01:04 AM

Originally Posted by niky

What car and year model, po? And what engine?

One big possibility is a sensor problem. If your engine bay is too hot, a sensor might be going haywire. If I understand you, it'll run hot, but it won't start if you turn it off and try to start it again?

tama po sir, that's what my problem is even though the temperature gauge never goes above normal levels. my car's an exalta sta but the engine's an sr20det.

**niky** · January 28th, 2007 12:25 PM

Originally Posted by enzo_dlc

tama po sir, that's what my problem is even though the temperature gauge never goes above normal levels. my car's an exalta sta but the engine's an sr20det.

Ouch! Had the same car before, with an SR20 swap. That's a difficult problem to diagnose. There are a lot of things that can go wrong with a swapped car. There may be circuits or grounds that are overloaded by the heat and pop, or sensors or electricals that may be fried by the intense underhood heat from the DET.

It might be coilpacks, but if it is, the car should die when you run it hard, too. There are various idle controls also that might go loco when you turn off the car and try to turn it on again. This could happen if your MAF gets really hot during running... it's happened to me once or twice. Have the impedances of all your sensors on the intake checked, then have a decent mechanic look at your throttle body.

Mahirap talaga pag turbo at medyo luma na yung mga sensors. While your temp gauge reads normal, that just means your coolant is okay. It doesn't tell you squat about how hot the plastic-bodied sensors, coil packs, distributor and high tension wires are getting. And with a DET, they can get very, very hot.

Worst case scenario: Your computer box is busted and is shorting out when you turn the car off, then acting normal when it's cool again. Big headache there.

There are more guys who can help you with this on nissanforums.com, allnissans.com (nissan forum old-timers, pero the activity there is kinda low) and sr20forums.com as the SR20DET is a common swap for these boys.

A quick fix that might work... if your custom intake tubing is metal (you do have an intercooler, right?) wrap the thing in aluminum foam insulation. It works for some people, and it can't hurt. Just don't place it too near the exhaust, as it might melt or catch fire.

Best fix? Buy new sensors and coil-packs... even if some of them are new. Expensive, but it saves you a lot of headaches down the road.

Hehe... my biggest regret was never having enough time or money to do a DET conversion properly, or to fix all the niggling problems I had with that car. Busted quite a few computer boxes, too, due to grounds and short circuits in the chassis.

I might try it again in the next year on a simpler car, an older Sentra with no stock electronics or ECU.

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RE: old model, cold place... pansin ko medyo sakal ang local tuning at stock air filters on some cars for mountainous areas... but tagaytay isn't really that high. Pero medyo sensitive nga ang carbs kung madumi o barado.

**reaganyun** · January 28th, 2007 12:35 PM

Believe The Advice If The Adviser Is An Expert Mechanic Otherwise Junk His Advice And Better See An Expert Mechanic

**niky** · January 28th, 2007 01:32 PM

Originally Posted by reaganyun

Believe The Advice If The Adviser Is An Expert Mechanic Otherwise Junk His Advice And Better See An Expert Mechanic

Which is why I told him to check:

www.nissanforums.com
www.allnissans.com
www.sr20fourms.com

because I know the guys there, and there are some very good and very experienced mechanics and engine-swappers there.

Also, enzo_dlc, ask around on www.nissanbayan.com , as there are people there who can point you at the best SR20-swap electricians and shops, people in the Philippines who can help you.

Good luck.