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Hot / Warm Start Issues R33

R33silverS2
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R33silverS2 Mentor

R33silverS2

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My car has problems turning over when the motor is warm. On cold start it will turn over fine and first go. IT has a bosch 040 pump in it which has been flow tested and everything appears a ok. Everytime i start the car i prime the pump for 3 seconds or however long it takes for the whine to stop, in the morings it is fine, along with starting after leaving the car for a few hours. However the problem occurs when i have been for a decent drive, then switch off the engine and come back to the car about hlf an hour or an hour later. Pump primes as per normal and the car cranks like normal but it doesn't want to start and cranks for about twice as long before the motor then tries to start and then splutters off. Turning the key again at this point and it will start no probs.

This issue seemed to have arised after the bosch pump went in, so at first i was convinced it was something to do with the pump, but i have since had the pump looked at and tested and everything seems fine, that car also holds fuel pressure fine when driving. So the problem appears to be a combination of heat and time. My question is what could be causing this to happen? A shot sensor maybe? what sensors would be associated with startup? Could the fuelline be affected by heat? I'm really struggling to work this one out, cos it only happens afte the car has been driven for a bit then left for about an hour or so... :P

Any idea's??? anyone has simular hot start issues???

thanks heaps for any help

Jordan

Edit: Replaced the pump and it fixed the problem, turns out the pump was the issue all along. :D

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evil_weevil Grand Master

evil_weevil

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The only time I have had similar problems was a track day at EC in 38 degree heat.

Just heat soak or whatever its called. However though just with your normal day to day driving, yeah Im stumped!

Fuel lines get too warm/hot?

Has it only been happening now, i.e. summer?

R33silverS2 Mentor

R33silverS2

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The only time I have had similar problems was a track day at EC in 38 degree heat.

Just heat soak or whatever its called. However though just with your normal day to day driving, yeah Im stumped!

Fuel lines get too warm/hot?

Has it only been happening now, i.e. summer?

It has been happening before summer, as in it would happen even when the weather wasn't as hot, but summer has definately made it more noticable / frequent.

frosty_the_snow_man69 Rookie

frosty_the_snow_man69

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i had the same sort of problem with my ca... i assumed coils were cooking under the cover! now having 20 year (or there abouts) old coilpacks u would think they are pretty shagged! i took the coil cover off to release the heat! doesnt happen so often now!

R33silverS2 Mentor

R33silverS2

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i had the same sort of problem with my ca... i assumed coils were cooking under the cover! now having 20 year (or there abouts) old coilpacks u would think they are pretty shagged! i took the coil cover off to release the heat! doesnt happen so often now!

Yeh tried taking the cover off and made no differenence unfortunately

R33silverS2 Mentor

R33silverS2

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Plz I need idea's / answers...

Take car for a decnent drive. Park, return an hour later, prime, turn over and er er er er er er er er er er er - starter motor, and wont turn over, try agin, and it will start straight away...

What the hell is wrong with it!! :)

R34GTFOUR Mentor

R34GTFOUR

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are there any other mods done to the car? have you every had the engine out? any conversions etc?

i would start with coilpacks personally, splitfires can be had for around the 480-490 mark these days, and if you were having problems with misfiring before maybe you just need a new set.

What battery is in it and how old is it? Maybe try measuring the cranking voltage with a multimeter to get a rough idea how many volts the bosch pump is getting whilst cranking. Its pretty suprising with older batteries and efi cars, sometimes they seem like they are cranking over strong, but really the cranking voltage is too low for the ecu to work properly and get the car going, i had simular problems with my r34, new battery and presto.

R33silverS2 Mentor

R33silverS2

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are there any other mods done to the car? have you every had the engine out? any conversions etc?

i would start with coilpacks personally, splitfires can be had for around the 480-490 mark these days, and if you were having problems with misfiring before maybe you just need a new set.

What battery is in it and how old is it? Maybe try measuring the cranking voltage with a multimeter to get a rough idea how many volts the bosch pump is getting whilst cranking. Its pretty suprising with older batteries and efi cars, sometimes they seem like they are cranking over strong, but really the cranking voltage is too low for the ecu to work properly and get the car going, i had simular problems with my r34, new battery and presto.

Mods are Power FC, full exhaust, fmic, pod, boost controller, bosch pump. car runs fine and makes good power. 202 kw 11.5 psi

I changed the battery over last yr as the old one totally died. I haven't suspected the battery through cos it cranks quite fast, whereas when the old one was going it was getting slower and slower, but like you said maybe its still worth checking as could be decieving. But that said, I'm not sure what the battery would have to do with the heat - cos it only struggles about an hour after a drive... Could coils heat up more when the car is off and not function properly on startup?? could plugs be an issue? I dont have any misfire though.

Also the engine has never cutout whilst driving, and is not a conversion or anything. Car runs perfectly smooth when started, just struggles to turn over when the motor is heated up after sitting there for a bit..

And speaking of coils, anyone know if I would have to change the plugs or get anything re-tuned on the pfc if i put splitfires in? atm the plugs are gapped at 0.8.

thanks

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