Needs gas at start up - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Pianohawk · 03-21-2010, 09:33 AM

My 99 porsche boxster is turning fine but has a problem catching at start up. If the engine doesn't catch on my first try then I have to wait a few minutes and then steadily give it gas while I turn the key for 10-20 seconds before it'll catch.

Sounds like a problem with the fuel pump, injectors?? I bought some high quality fuel injector cleaner and put it in with my last fill up but no change yet.

Any experience/advice with this specific problem would be great!

Colby

Adam · 03-21-2010, 10:43 AM

Could be a host of various things. When was the last time your spark plugs and fuel filter were changed? I assume you're not getting a CEL or you would've mentioned it so I would start with plugs and filter and change them if it's been awhile or never.

Pianohawk · 03-21-2010, 02:38 PM

I got a tune up six months ago (change of oil, new filters, spark plugs). The check engine light comes on sporadically with a secondary air system error (O2 censor) but I had the replaced a while ago. The mechanic said everything checked out fine and that perhaps the CEL is a result of a CPU/electrical problem. So, I'm not sure if he's right or if he simply did poor work.

I'd be happy to get my hands on a service manual so I could inspect the fuel lines, sensors, plugs, and filter myself.

Any other suggestions besides the standard tune up?

thanks,
Colby

Adam · 03-21-2010, 05:44 PM

Quote:

Originally Posted by Pianohawk

I got a tune up six months ago (change of oil, new filters, spark plugs). The check engine light comes on sporadically with a secondary air system error (O2 censor) but I had the replaced a while ago. The mechanic said everything checked out fine and that perhaps the CEL is a result of a CPU/electrical problem. So, I'm not sure if he's right or if he simply did poor work.

I'd be happy to get my hands on a service manual so I could inspect the fuel lines, sensors, plugs, and filter myself.

Any other suggestions besides the standard tune up?

thanks,
Colby

Are you sure he changed the fuel filter and not just the oil and air filter? How many miles on your 99 Boxster? How long has it been doing this? Do you always have to pump the gas to get it to start or is that sporadic? It starting while you push on the gas may just be a coincidence. Does the battery seem strong and always spin the starter at a decent speed? The 2ndary air pump issues shouldn't be the cause of the non-start issue. You might be better off taking it to a qualfied tech to diagnose unless you have the time and know how to test all kinds of parts yourself. You could perhaps throw a lot of parts and money at it unneccesarily if you're not careful. It could be a bad fuel injector/s, pump, bad ECU, coil, cloggged line ect ect. First thing I would do is isolate the issue and make sure it is lack of fuel and not spark causing the non start problem.

Pianohawk · 03-21-2010, 08:27 PM

Thanks for the quick reply. It has 120K miles on it and has had trouble starting for about a year now; particularly in cold weather. It always requires more gas at start up to catch when the engine's cold. Pumping the pedal doesn't help, I have to hold it steady...sometimes almost down to the floor. If the engine's warm it'll usually start right up without the need for extra gas.

I tested the battery and alternator yesterday and they're both good.

I'm looking for instructions on how to replace the fuel filter. If you know of any, I'd appreciate it. Thanks for the advice, I'll try and isolate the spark/fuel issue.

yimmy149 · 03-22-2010, 11:32 AM

Aren't 99's mechanical throttle instead of eGas? If that's the case, then I'd look into replacing the idle air control valve, it's probably sticking when cold.

-james

Adam · 03-22-2010, 01:37 PM

Quote:

Originally Posted by yimmy149

Aren't 99's mechanical throttle instead of eGas? If that's the case, then I'd look into replacing the idle air control valve, it's probably sticking when cold.

-james

That could also be the culprit possibly, but usually if it's the idle control valve it would die when coming to a stop. He didn't mention it dying at idle, but it would still be a good idea to check it out.

Daniel R · 03-23-2010, 06:09 AM

Fuel pump maybe??

I have never experienced this on my Porsche, however I had a Holden ( think Australian Chevrolet) V8 that suffered similar problems on 2 occasions. The starting got progressively worse until it would not start at all.

The way I used to start it was by opening the air intake tube after the box and filter, then pouring a small amount of fuel in the air intake. Worked like a charm, until I got around to changing the fuel pump.

Pianohawk · 05-24-2010, 06:43 AM

I emailed Pedro (http://www.pedrosgarage.com) and thought I'd share his solution in case anyone else has had this problem.

"The Boxster does not like the accelerator depressed before or during start up.
If the accelerator is depressed, the throttle positioning sensor tells the DME that the throttle is depressed and it automatically goes into safe mode, cutting back on the injectors and retarding the timing. That's why it takes so long to start.
Just depress the clutch (or brake if Tiptronic) and start it up without depressing the accelerator at all."

Out of the dozens of mechanics I contacted, Pedro was the only one who knew I was unintentionally putting the boxster in safe mode, thus requiring more gas at start up and sometimes causing the car never to catch.

No more start up issues!