Only starts with gas pedal floored. Hot start problems.
 

I've owned the car for 2.5 years now and this has been an ongoing issue since day one. On any startup cold or hot you have to crank for 2 seconds then when it bites floor the gas pedal or it will flood. On a hot start you usually have to hold the gas at about 2000rpm for 20-30 seconds or it will stall. When the car shuts off after idling breifly (not warming up) it will flood and take a bit of effort to start.

I have kept up with tune ups and my timing is good. What am I looking at here? Injectors? Resistor pack? FPR? a solonoid?

I appreciate if anyone can help since right now this is the only thing wrong with the car. Other than needing a new o2 sensor... Just got code 17 about a week ago.

It could be possible you could have a leaking injector. Rich conditions generally get worse as an engine goes up in temp. Leaking injectors are fairly common on these cars.

Low compression. Rebuild?

simplest check first - compression test. At least you will know if its more serious

Well I don't know anyone here with one I can use and a real tester is pricey right? The car gets 21mpg and pulls pretty hard so I'd think it would be something electronic.

for anti perculation reasons when the car hot starts it should be switching the PRCv ( solenoid ) on the rack
and this isolates the FPR from engine vacuum ( ie a higher fuel pressure ) for a period that is determined by the engine coolant sensor and by the air intake sensor
this period will be 90, 70 or 50 seconds depending on how hot air and coolant is ( hotter = longer )

the engine will also raise itself to 3000 rpm on start for about 3 seconds ( opening the air supply valve on side of mezzanine and the BACv )

there is also basic changes to ignition timing for the first 5 secs
( leading and trailing both 8 BTDC ) and then for the next 65 secs at both 5 BTDC

if your engine is not surging to 3000 on hot start for 3 secs then tapering down,, either the flags for air temp or coolant are bad
or there is a fault in the operation of the BACv ,, or the ASv

my guess is your getting the timing change,, the raised fuel pressure and injection amount,, but not getting the extra air via BACv or ASV

The solonoid by the oil filler neck under the dynamic chamber? I have noticed on this one I don't get the aws 3000 startup while in nuetral. I didn't know it came on on a hot start as well. The BAC works on everything else though so must be the solonoid. I bet it's bad.

I was thinking about replacing the coolant temp sensor. It has only two outputs right? Full cold and full hot?

no, this flag is from the coolant ecu sensor ,, and the ASv is a small solenoid on the side of the plenum against the firewall
the solenoid you describe on filler neck is for boost control,, and so your engine is s5

info i give above is s4 generic,, as jap s5 often lacks the Asv,,but i do have some s5 turbo manifolds outside with the ASv
so methinks its still used in those countries with AWS/ cat longevity strategies
and its a combo of ASv and BACv ,, its quite possible s5's with the delete use mostly the BAcv for bypass air

ASv is usually fed from a small nipple on the side of the top mount IC,, see if its there

ASv is also used as PS idle up,, and it may be simpler just to unplug the wire feeding into the flow switch under the PS pump and earth it while idling to see if a 100 rpm idle up occurs

PS issue may just well be that neutral switch !!

Car is na s5 btw. Does it matter how the neutral switch is wired? It got cut from road debris and I couldn't tell what was - and + so I just guessed. I'll try reversing the wires to see if it changes anything. I usually start in gear anyway so I never noticed.