SR won't start when it's hot out...

[freakyjason]

I’ve got a strange problem for you gentlemen. I’ve got an s13 sr in my s13 running off an apex-I power FC. This problem was present before the install/tuning of the power fc. The car runs and drives GREAT! However, after starting the car 2 or 3 times on maybe an hour period, it won’t start again. I’ll have to leave it sit for over an hour sometimes before it will start again. The engine will crank, but it will just not ignite. Fuel pressure is fine (I have an in-line pressure gauge), the spark plugs are new, new walboro fuel pump, new fuel filter, all the coils are good, new coolant temp sensor etc. It seems to happen more when it’s really hot outside. This problem has the exact same symptoms of when a ‘main relay’ goes bad on an older Honda. However, I’ve replaced both the EGI and EGI pump relays, and it still does it. I beleive it's not getting spark, but I will verify this the next time it happens. Any help would be greatly appreciated. Thanks!

[freakyjason]

Bump. Could it be vapor locking?

[freakyjason]

Bump. No one? Not even the obligatory "search, newb" comment? Seems to do it more readily when the tank is low... It happened this weekend when I stopped to get gas. Didn't really have time to see if it was getting spark, but it did pop start SUPER easy.

[Lobo240sx]

How is your seal on your gas cap?? Fuel pressure regulator could be faulty. Instead of throwing parts at it, it might be time to take it to a shop and they can tell you what could be wrong with it.

[Hijacker]

Most times I've seen this happen, it's been the coolant temp sensor. Make sure you have the right one. A buddy of mine had a very similar issue (it would crank too rich and not start), and he had put on a blacktop sensor when he needed a redtop sensor.

[Sideways~S14]

Most times I've seen this happen, it's been the coolant temp sensor. Make sure you have the right one. A buddy of mine had a very similar issue (it would crank too rich and not start), and he had put on a blacktop sensor when he needed a redtop sensor.

So Curious im having a similair problem if I have a redtop ecu #62 on a black top sr so would I need a redtop temp sensor????? an a red top o2 sensor etc just trying to get an idea. I mean car starts fine most the times will just need to crank a lil bit. Except when cold it starts right up every time.

[freakyjason]

Most times I've seen this happen, it's been the coolant temp sensor. Make sure you have the right one. A buddy of mine had a very similar issue (it would crank too rich and not start), and he had put on a blacktop sensor when he needed a redtop sensor.

This is a very good suggestion, and naturally where my head went first. However, I tried both my red top and black top sr sensors. I even bought a new red top sensor.


UPDATE* I went on a long road trip (out to Boston for a 240 swap meet) and noticed that this seems to happen mostly when the tank is low (less than a quarter tank). I also noticed that my fp will fluctuate a few psi rapidly when it's running before it does it. I.e. when I have a quarter tank or less, if I pop my hood and check my fuel pressure, it's skipping up and down rapidly like 3 psi in either direction. Then if I shut the car off and try to restart it 5 mins later, it won't start. All other times (when the tank is full) it will start fine. the fuel pump has less than 1000 miles on it. I tried checking the voltage on the FP and got 13.9 (should be getting twelve as far as I know). However, I was kinda unsure of how to check voltage.



Did I do it correctly?

Most times I've seen this happen, it's been the coolant temp sensor. Make sure you have the right one. A buddy of mine had a very similar issue (it would crank too rich and not start), and he had put on a blacktop sensor when he needed a redtop sensor.

So Curious im having a similair problem if I have a redtop ecu #62 on a black top sr so would I need a redtop temp sensor????? an a red top o2 sensor etc just trying to get an idea. I mean car starts fine most the times will just need to crank a lil bit. Except when cold it starts right up every time.

Yeah, your problem actually sounds exactly like what Hijacker was referring to. You need the correct O2 and more importantly (for your issue) the correct coolant temp sensor for your engine/ecu.

EDIT:

P.S. Thanks for the picture, Yoshi of Zilvia.

[freakyjason]

SOLUTION!

As it turns out, Hijacker was 96% correct. My tune was not fueling properly during hot starts. It actually wasn't getting enough fuel. A simple value change in the pfc seems to have helped. We'll see if the problem persists. I apologize that this solution probably isn't very helpful to a lot of people on here. Good luck with your issue, Sideways~S14.

[PhopsonNY]

Hey ... Thanks for at least posting the solution... it is appreciated and may help someone in a few years time.