Long starting time

[Gawernator]

So, I just purchased quite recently a 1986 Porsche 944 N/A. The car has great records and the engine was just rebuilt, every single seal, gasket and belt is new. New rollers, tensioners, water pump, thermostat, engine mounts, fuel filter, oil filter, air filter, hood and hatch struts (irrelevant), fuel pump, clutch, heater hose, distributor rotor and the list goes on. However sometimes when starting the car it will take two to three seconds to ignite instead of the usual 1/2 second or less. This is more common when the engine is cold. If the engine is warm, then turned off, then turned back on, then it will start up right away. What is most likely to cause this? Timing issue, dirty injectors, spark plug issue? Thanks 127,000 miles

[porschetub]

Originally Posted by Gawernator

So, I just purchased quite recently a 1986 Porsche 944 N/A. The car has great records and the engine was just rebuilt, every single seal, gasket and belt is new. New rollers, tensioners, water pump, thermostat, engine mounts, fuel filter, oil filter, air filter, hood and hatch struts (irrelevant), fuel pump, clutch, heater hose, distributor rotor and the list goes on. However sometimes when starting the car it will take two to three seconds to ignite instead of the usual 1/2 second or less. This is more common when the engine is cold. If the engine is warm, then turned off, then turned back on, then it will start up right away. What is most likely to cause this? Timing issue, dirty injectors, spark plug issue? Thanks 127,000 miles

Interesting ,mine has always started very quickly,even with a low battery,the motronic efi is always good for start up and I know that from my work on BMW's.
Ok,you have new rotor what about the cap and plug leads,you shouldn't have a timing issue,and forget the injectors,go for new Bosch plugs and report back,cheers

[Gawernator]

Bosch Platinum 4's good? Pelican sells them and I have a set of four.

[Outback Porsche]

There's a non return valve just after the fuel pump. It's supposed to keep fuel pressure at the injectors. I'll bet my left nut it's letting the fuel pressure drop after sitting for a while. Not an expensive part to replace.

Cheers

[John_AZ]

Originally Posted by Gawernator

Bosch Platinum 4's good? Pelican sells them and I have a set of four.

Not recommended--although Porsche does mention.

Cheap, single tip copper are the best for the Motronic DME.
The best conductivity and performance.

This has been discussed for years...
BOSCH platinum 4, good/Bad - Rennlist Discussion Forums

The 2 to 3 second delay could be a fuel pressure problem. Outback Porsche mentions the antidrain back valve attached to the fuel pump.

You could replace the part or get a set of new copper crush washers, remove the part and just clean the steel ball inside. There may be a fuel varnish deposit causing the problem.

I would check the injectors and get them replaced ($$$) or send them to Witchhunter WitchHunter Performance - Injector Cleaning & Flow Testing Services to clean, test and reseal--about $100.
You may have a leaky injector or an injector with a bad spray pattern.

If the FPR & FPD are OEM, you should replace.

Does your starter "explode" when you turn the key or does it go wheeerrrr--wheerrr befoe it catches? Could also be the cause.

Have you ever changed the fuel filter screen in the fuel tank?

and on and on and on....

GL
John

[kfray]

Fuel pressure test information.
http://www.clarks-garage.com/pdf-manual/fuel-01.pdf

[Gawernator]

Okay, thanks for the help! I guess I'll get to work...

[Cocacolakidd]

While you are in there check also the battery - Our 944's love plenty of voltage power, and sometimes if the voltage/power is a little off with an old or week battery the car will be sluggish to start often.

[Gawernator]

Roger that

[AKCJ]

I agree it could be that your fuel pressure is leaking off (I wouldn't bet my left nut on though like Outback). I would try putting a pressure gauge on the end of the fuel rail to check it. I had to make an adapter to get the thread right for my fuel pressure gauge.

[Outback Porsche]

Originally Posted by AKCJ

(I wouldn't bet my left nut on though like Outback).

Agree it's a bit of a risk, but it doesn't get much use these days

It could also be a weeping hose/joint that's causing the pressure to drop - You mention you get the smell of fuel inside the cabin on another thread. Check the condition of your fuel lines near the engine bay?

[Gawernator]

Okay I will check that. I am pretty sure every hose is new, but I'll have to double-check. I am under the impression right now that smell is leaking exhaust coming in through the absent shift boot