5SFE trouble starting when warm

[velorossa]

So a buddy of mine has a 93 with a 5SFE. This problem(s) has slowly been getting worse since november and now the car can't really be driven. Basically when cold it starts fine and idles around 1200rpm, but drive it to the store and turn it off and when you come out it won't start, or it will idle really low ( like 300rpm) and then die if it goes into drive, then it will crank and crank but no start. He replaced the fuel pump and filter with no results. I checked spark when cranking and it's okay, and there is no smell of any fuel when it's cranking.
So I felt the ECM relay and it was hotter than the rest. Tapped it when cranking and the car came alive but wanted it idle high (2000rpm). Drove it home turned it off then on and the same cranking but not starting. This time the relay was really hot. Told him to go to the wrecker and grab a couple of ECM relays to see if that might work. So he did it but it's basically getting the same results on the others too. He told me now when it's warm it won't crank at all, as if a dead battery but good headlights and everything else.
So what do you guys think we should check next?
I read about bad coils but that would give a no spark issue.
I told him to clean the TB and IAC, but would them being dirty cause a no start? Seems like it would just have a funky idle.

[JohnGD]

Have you cleaned the idle air control valve? It's a common problem.
See:
DIY removal & cleaning of IAC

[Mister_Perkins]

Check out :
DIY : HELP 92-96 5sfe CAMRY WONT START

Have you measured the fuel pressure its getting?
Turn the key to ON position and monitor pressure and confirm it stays steady pressure, doesn't drop. If it drops, I would check into fuel regulator.


Have you checked the ignition system? (confirmed spark, checked coil, air gap on dist., resistance on ignitor, GE NE on dist., etc..)


Have you looked into the MAP Sensor? (Map sensor may be faulty -- measure resistance)


Could be a problem with the NSS too (If equipped with an Automatic Transmission).
Try this link:
DIY: Neutral Safety Switch Cleaning


If you try everything, replace the ECU with a Known good ECU and re-test.

[Mike Gerber]

"I read about bad coils but that would give a no spark issue."

Not necessarily. It could give a weak spark; too weak to ignite the fuel mixture.

"I checked spark when cranking and it's okay"

What color was the spark you saw? Orange indicates a weak spark. Bright blue indicates a good spark. I would remove the coil from the distributor and inspect it for cracks. This is a common problem as these coils rack up lot's of miles and it usually surfaces as the coil heats up. You can also check the rsistance of the coil with a digital volt/ohmeter and the specs from any manual.

Mike

[Stillrunning]

Originally Posted by velorossa

He told me now when it's warm it won't crank at all, as if a dead battery but good headlights and everything else.

First thing I'd do is remove and clean all battery/starter connections, maybe even replace battery/starter cables. Find as many ground connections as possible and remove/clean them.

[velorossa]

So here's the update. Cleaned TB and IAC. Fixed the non starting issue but still idles low or dies when its all the way warm. Happens consistently still. I'm bring over a fuel pressure gauge for him to check to see if the pressure is dropping or not.

[JohnGD]

Check the engine coolant temperature sensor. Compare it to the temp-resistance chart. See free repair guide on Autozone.com

[velorossa]

Whats the trick to testing the fuel pressure. Seems like all the gas lines are hard lined so my pressure gauge won't work. Is there some sort of adapter?

[Stillrunning]

Originally Posted by velorossa

Is there some sort of adapter?

Banjo bolt adapter for fuel filter connection. Do as JohnGD suggested, if you're only getting problem at idle then doubt very much if fuel pressure.

[doozergreengrass]

I had same issue. Was ECT as JohnGD suggested, but it could still be something else causing it.....good luck!