TravisB

Ever since I bought my car, it has never really been happy to re-start if it has been heat soaked. The routine usually goes crank, it almost fires and dies, then I will have to sit there and crank it for a few seconds before it fires again. Searching directed me to check out the fuel pump check valve or CPS/CHT sensors..

However, one thing I noticed is all of these threads talk about cars that won't start at all, and have to cool for 20 minutes or longer before they fire again. If this happens and I crack the gas open a little bit before I crank for the second time, it starts completely normally, other than the slightly higher than usual jump in RPM's immediately after firing. I am wondering if there's possibly a different problem I have with a similar symptom to the sensors and valve? Maybe a sensor in the throttle body? Injector issues? Just trying to figure out as many possibilities as I can before diving in to diagnosis mode (I have to rent wrenching-friendly garage space at the moment as I am in a parking garage ).

mongrelcat

I had similar issue with my car for the first year I had it, except the issue would only happen when the car hadn't fully warmed up, and I stopped, then tried to re-fire. So sort of the opposite of your issue. I only had it happen a few times, as I usually always fully warm up the car. But I think it was consistently repeatable. I never figured it out, problem went away when I had the big drop service a year ago.

I have a spare CHT sensor, let me know if you want to try it.

I thought you had the injectors serviced when you did the drop at the Holidays?

TravisB

Yeah I usually make it a point to not make short trips..it may do it luke-warm, but I'm not sure, 99% of the time I get in the car, I'm driving for at least 30 minutes. I want to rule out injectors, but the symptom kind of fits..but yeah, I did have them rebuilt in January, and they didn't really even need it (~$260 later, they tested exactly the same before and after). I may take you up on the sensor, I may just wind up replacing those two just as PM, reading through threads they seem to be potential problems as they age..

Coleman

I had a similar issue- It was solved with replacing the fuel pressure regulator.. It's a 10 minute job..

f8vr993

Ive been monitoring this as well.
My symptom of hard start comes up on the 5th and beyond start up during the day...
I was planning on replacing either fpr or cht sensor as suggested from past threads.
Has anyone actually changed and solved the issue?

Paddy

Yep, sounds like a leaky FPR.

TravisB

I'm heading to the track tomorrow; how worried about this should I be (if it's the case)?

jo-hans

Hey Travis,

I have the similar problem and started after I re-installed my cleaned fuel injectors. Same here - didn't really needed it.
Recently I replaced both the HTS and the FPS and no improvement. I had read a while back it was recommended to replace the FPR when installing the cleaned fuel injectors and I didn't. So this may be my next move.

btw - was great to meet you on the 993Fest.

Paddy

It sounds as if the diaphragm in the FPR failed and is dumping extra fuel into the intake system. You might have some oil dilution issues or potentially damage the cats from a too rich mixture. That said, I think you'll be fine at the track.

Pull the vacuum line off the FPR to test. If you get a fountain of fuel then you know you have a faulty FPR.

FWIW: The dealer will have this part as it's used on many cars: Boxster, 996, 996 GT3

Part number: 993-110-199-01-M14

TravisB

That actually makes sense, I get an over-rich condition at low RPM's that manifests itself as a sulphery smell from the exhaust (I thought I killed the stock cats with the paper towel fiasco, but it still did this, albeit to a lesser extent, with the Dach).

Thanks you guys!!

And Hans, it was great meeting you as well! Hope you can make it down next year, should be even bigger and better!

shamrock

Sorry for dredging up the past!
I have this exact problem .. On second (Luke warm) start, my engine turns and goes to catch but the fails. If I try to restart as per normal I get engine crank for about 10 seconds and then a "messy" sluggish start. If I part depress the throttle, the engine kicks in without complaint.
So have any of you guys solved the problem with a fuel pressure regulator change?
Anyone have a diagram or pic to show me which vacuum line to pull to check for over fuelling?
Or maybe a 'how to' on changing the regulator?
Sorry , loads a questions!!

shamrock

A tentative bump in hope the OP's come back on this!

shadow993

My problem was head temp sensor

shamrock

Shadow, thansk for the reply, can you elaborate?

Were the symptoms as described above?

Did you have hot AND cold start hesitancy or just hot?