Hot Start Question Options

[brianp626]

Hey guys. Back with more questions. Replaced my CHT sensor the other day which looks to have solved my rough engine and running ridiculously rich issue. I’ve got a bit of a sputter mid throttle so I’m thinking probably TPS circuit board. My big issue is the car won’t start when it gets warm. I’ve done quite a bit of reading on this and I don’t think it’s the typical hot start relay thing. I can pump the gas pedal after a little bit and get it to start but it won’t stay running, it’ll just die. Cools off after some time and starts right up. I’ve read somewhere that it could be vapor lock since the fuel line runs directly on top of the engine. Anyone have any thoughts or experience with this issue? I don’t have a tool to check fuel pressure btw in case you were about to ask. Lol. 73 1.7 d-jet - new plugs, cap, rotor, coil, CHT, fuel pump, and fuel filter. I appreciate all the help you’ve all given me. Great community here. (IMG:style_emoticons/default/beerchug.gif)

[Mblizzard]

Cheap inline fuel pressure gauge is a must to install on all FI cars. Look on Amazon can be purchased for about $30.

Where is the fuel pump mounted?

[brianp626]

Cheap inline fuel pressure gauge is a must to install on all FI cars. Look on Amazon can be purchased for about $30.

Where is the fuel pump mounted?

Ooooo. Never thought about that. Great idea! Fuel pump is in the... uhhh front trunk? Not sure the proper name lol.

[Tom_T]

Hey guys. Back with more questions. Replaced my CHT sensor the other day which looks to have solved my rough engine and running ridiculously rich issue. I’ve got a bit of a sputter mid throttle so I’m thinking probably TPS circuit board. My big issue is the car won’t start when it gets warm. I’ve done quite a bit of reading on this and I don’t think it’s the typical hot start relay thing. I can pump the gas pedal after a little bit and get it to start but it won’t stay running, it’ll just die. Cools off after some time and starts right up. I’ve read somewhere that it could be vapor lock since the fuel line runs directly on top of the engine. Anyone have any thoughts or experience with this issue? I don’t have a tool to check fuel pressure btw in case you were about to ask. Lol. 73 1.7 d-jet - new plugs, cap, rotor, coil, CHT, fuel pump, and fuel filter. I appreciate all the help you’ve all given me. Great community here. (IMG:style_emoticons/default/beerchug.gif)

Hey Brian -

1 - You probably spent a bunch of money & time on something you didn't need to do, & which was obviously not the problem.

If you do a google for Porsche 914 vapor lock or similar, then it will turn up the posts you mention, which tells about the 914 hot start issue & the FP relocation solution per the factory service bulletin.

I & others have posted on it many times, & yet newbies & old members alike post asking what to do every year when it gets hot.

Admins - we need a nailed thread or Lupawal on it so it doesn't keep coming up dozens of times every summer/hot season.

2 - If read your owners manual abut starting your 914 - you're supposed to press & hold the accelerator to the floor until it runs. If you do it properly that way, & it still doesn't start when hot - but only after cooling down - then you'll want to do the fuel pump relocation to the front of the car up under the steering rack cover, as Porsche specified in their FSB.

Go read your owners manual & keep it in the car, & if you don't have one, then either download one from someone & print a copy for yourself, or buy one from AA, SMC, Stoddards, etc. that have them FS. You won't regret that investment.

Being a 73 1.7 - you'll probably want to do the FP relo at some point, but I highly recco the factory position, rather than the others which some members have done, since it involves no cutting of body panels, it sits in a protected area behind the steering rack cover, which can be easily removed & FP accessed for new filter & other services. ..... or you can keep throwing money & time at other stuff, additional gauges, etc. which will only step around the real problem.

Good Luck! (IMG:style_emoticons/default/beerchug.gif)
Tom
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[brianp626]

Good Luck! (IMG:style_emoticons/default/beerchug.gif)
Tom
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Tom, appreciate the help. Most of what was replaced was for general maintenance rather than my current issue. I’m not too sure the last time this car has been driven semi-regularly. I definitely need to invest in a manual so I’ll check that out. The fuel pump has already been relocated to the front.

[mgphoto]

If the pump was relocated there shouldn’t be an issue with vapor lock.
Your hot start problem is typical.
Foot to the floor and feather it for about 1 minute before letting the car idle on it’s own.
The hot start issue is to much fuel and not enough air.

[brianp626]

If the pump was relocated there shouldn’t be an issue with vapor lock.
Your hot start problem is typical.
Foot to the floor and feather it for about 1 minute before letting the car idle on it’s own.
The hot start issue is to much fuel and not enough air.

Ok. I’ll give that a shot tomorrow and see if it’ll stay running. Thanks guys.

[brianp626]

Went to test this whole foot to the floor method and the car wasn’t running well. CHT connection seemed a bit loose so I fixed that. Still ran terribly. I think I’m giving up on this enjoying before winter idea and I’ll just start the rebuild early. Here’s to next year I suppose.