Hard start when warm (30min to 2hrs after shut off), no issue with cold start

[IS300E30]

If I drive the car (87 325i) for the temp gauge to go to the middle, then I shut off the car and let it sit from 30min to 2 hours and attempt to start it, it will hesitate for 10 seconds or so.

If I shut it down during the hesitation and attempt to start it a second time, it starts right up. It is just the initial attempt after being warm and sitting for 30min to 2hrs that this issue occurs.

*Fuel Pressure tested and it held, also new refurbished fuel injectors were just added as well to hopefully solve the issue but it did not fix.

Curious, would a faulty CPS or misaligned CPS cause such a specific starting issue? Or could I rule out the CPS as the issue for something so specific, since other starting processes works perfectly

[82eye]

most common causes are bad fpr, leaking injectors, or a failing fuel pump. tee a gauge on the rail to check fuel pressure both running and at rest.

refurb injectors aren't worth the money, if they leaked before they will likely leak after, the originals are simply too old now. upgrade the injectors for better running. i went to a modern 4-pintle which solved several minor running and idle issues.

if the fuel pump is failing it can overheat, which will keep it from supplying fuel on a start until the fuel in the tank cools it sufficiently. once they get going they will continue to run until shut off and cooled again. eventually they simply stay in a fail state.

edit : did the rail and fpr hold the pressure?

[IS300E30]

most common causes are bad fpr, leaking injectors, or a failing fuel pump. tee a gauge on the rail to check fuel pressure both running and at rest.

refurb injectors aren't worth the money, if they leaked before they will likely leak after, the originals are simply too old now. upgrade the injectors for better running. i went to a modern 4-pintle which solved several minor running and idle issues.

if the fuel pump is failing it can overheat, which will keep it from supplying fuel on a start until the fuel in the tank cools it sufficiently. once they get going they will continue to run until shut off and cooled again. eventually they simply stay in a fail state.

edit : did the rail and fpr hold the pressure?

Yes it did hold pressure, that is the problem.

[82eye]

Yes it did hold pressure, that is the problem.

indicates injectors and fpr are good. points more to fuel pump as a possible.

edit: forgot about the blue temp sensor for the ecu. it can cause start and run issues when it fails. honestly can't recall if it's related specifically to warm start though.

[IS300E30]

indicates injectors and fpr are good. points more to fuel pump as a possible.

edit: forgot about the blue temp sensor for the ecu. it can cause start and run issues when it fails. honestly can't recall if it's related specifically to warm start though.

Recently changed the fuel pump and blue temp sensor. Maybe I got defective ones?

Would the CPS play into this?

[82eye]

Recently changed the fuel pump and blue temp sensor. Maybe I got defective ones?

Would the CPS play into this?

cps would be a more consistent fail not tied to temp.

edit: defective parts are possible but not high on the list. it would depend on the parts/brand etc. first thing i would suspect is the injectors. do you notice any fuel odour when it won't start? have you tried pulling a plug to check if it's dry or wet?