This could be a problem

Seraph · #1 06-20-2002, 01:53 AM

This is the second biggest problem I have with my 92. I need some advice. In the morning and sometime in the afternoon, when the car is rested well (as in engine is cold), I have to literally pump on the gas while starting up the car. Once the car is started, I can turn it off and restart without problem. Also if the engine is heated (under the sun), I have less problems starting up the car.

What do you think is happening? What needs cleaning? I don't want this car to follow the road of the 94.

Lwin

kuoh · #2 06-20-2002, 07:00 AM

Try just holding the throttle all the way down instead of pumping. The symptoms sound similar to mine, which I suspect is a slightly leaking injector. You could try cleaning the throttle body, but that seemed to only affect the stalling after starting on my SVX, not the initial startup.

KuoH

RSVX · #3 06-20-2002, 07:07 AM

I had this problem on mine about 1 and a half years ago... I was so kindly informed that I should clean the throttle body... there will be black 'stuff' right around the intake and the flappers... it fixed mine...

#4 06-20-2002, 07:30 AM

just go get a rather large old pot, a few bottles of carb cleaner, a few old tooth brushes, and a roll of paper towel. take off the throtle body, drop it in the mix, let it sit for an hour, brush away w/ it in the mix, then dry w/ the towels, and you'll be set

Beav · #5 06-20-2002, 04:10 PM

I agree with Kuo, it could be a leak-down injector. Most cars with electronic injection have a 'clear-flood' feature that won't allow the injectors to fire when cranking with the gas pedal on the floor. When it does start look to see if there exhaust is black and/or if the engine has to be 'cleaned out' before it idles correctly. If so you're a candidate for an injection cleaning. If the cleaning doesn't work let me know, there is a procedure for determining which injector is leaking down.

Whatever you do, don't let it go too long and take a chance at replaying EveryShadeofBlue's dilemma.

kuoh · #6 06-20-2002, 04:52 PM

Hmm...I must have missed his posts. I've actually had this "problem" for several (more than 2) years now. It hasn't gotten any worse or any better, but seems to be more pronounced in cool to cold weather.

As for injector cleaning, I know I had the dealer run some of their cleaner in a can at $49.99 through it way back when I would still let them touch the SVX, and it didn't seem to improve the situation. I also run a bottle of Techron through about every 10th tank or so without any noticeable improvement, but at least I feel better.

Since it doesn't happen all the time, I wasn't extremely concerned, until now.

Part of my "diagnosis" of a leaky injector was the fact that when I changed the fuel filter, I had only let the car park overnight and had no pressure in the lines when I went to change the filter. I thought that this was normal, but from the other messages I've read, I guess there should be pressure in the fuel lines for quite awhile.

So what is this cleaning process you speak of and can I do it without involving a shop with speciallized equipment? I'm not averse to removing them and cleaning them the hard way, as long as it doesn't take any special tools or materials to remove and reinstall. And how do I find the leaky injector(s)?

KuoH

Quote:

Originally posted by Beav
Whatever you do, don't let it go too long and take a chance at replaying EveryShadeofBlue's dilemma.

Landshark · #7 06-20-2002, 08:09 PM

from the Porsche list i used to haunt, Marren Motorsport was highly recommended for injector re-building and cleaning. you'd have to remove the injectors and send them out to them. i can't remember where they're located, but i remember the price was reasonable with quick return. maybe try searching for them on the web? hope that helps,

Alan

vkykam · #8 06-21-2002, 12:06 AM

Beav,

What's the procedure for determining which is the leaking injector?

I think it's my right front one, since I remember a distinctive fuel smell when I removed the spark plug...

VK

immortal_suby · #9 06-21-2002, 04:03 PM

Vykam - have the injectors made it up to your doorstep yet?

Beav · #10 06-21-2002, 05:21 PM

I was in a hurry when I made that statement and will prolly be chastised for it, deservingly. The easiest way for a driveway/diy diagnosis is to check the spark plugs. A crappy looking plug will direct you to the probable culprit. Another test uses a pressure gauge, a jumper switch and a stopwatch. The most reliable is to remove all the injectors and take them to a diesel/injection shop and have them tested.

#11 06-21-2002, 08:23 PM

Before you start pulling apart the engine... you might want to do the procedure for checking engine codes (not tranny codes). I had similar symptoms and it turned out to be a coolant temp sensor flaking out.

Just a thought..

kuoh · #12 06-21-2002, 08:40 PM

Hmm...my Chilton's manual does not seem to have a picture or description of exactly what a "crappy" looking plug is like. And the other option does not exactly sound easy. If I take out my injectors, how do I get to the diesel shop?

Is there anything I can do in the driveway, like soak them in something to clean them safely?

KuoH

Quote:

Originally posted by Beav
A crappy looking plug will direct you to the probable culprit. Another test uses a pressure gauge, a jumper switch and a stopwatch. The most reliable is to remove all the injectors and take them to a diesel/injection shop and have them tested.

vkykam · #13 06-21-2002, 09:49 PM

Yeah, they did yesterday. Thx a million. I tried to pull it out of the engine today, but it wouldn't budge. I'm going to have to remove the rail and push it from the inside.

Forget A beer. Name your preference on a case of Canadian 2-4.

VK

Quote:

Originally posted by immortal_suby
Vykam - have the injectors made it up to your doorstep yet?

Beav · #14 06-21-2002, 11:01 PM

Quote:

Originally posted by kuoh
Hmm...my Chilton's manual does not seem to have a picture or description of exactly what a "crappy" looking plug is like. And the other option does not exactly sound easy. If I take out my injectors, how do I get to the diesel shop?

Is there anything I can do in the driveway, like soak them in something to clean them safely?

KuoH

It depends on what's keeping the injector from sealing properly. It could just be a piece of crud not allowing it to close fully, or it could be a worn pintle/seat. Cleaning off car is best done ultrasonically. On car the best bet would prolly be the Motorvac system.

A crappy plug would/could be black, have a clump of deposit(s), have a bridged gap, etc. It would look different from the other plugs.

In the shop we would try to determine it by firing voltages, and/or a cylinder balance test done by removing each injector's electrical connector. If you think about it, an injector that's leaking slightly will still allow a small amount of fuel to pass through and produce power in its cylinder. Doing a power balance test by disconnecting each injector, one at a time, and noting the rpm drop you'll probably notice one injector/cylinder not dropping as much rpm as the others. Not 100% indicative, but it would be the suspect injector.

If you're concern is the loss of fuel pressure overnight, yet no black smoke or chugging is evident when started the next morning, I would suspect the fuel pump check valve or the fuel pressure regualator is leaking back into the tank.

Beav · #15 06-21-2002, 11:04 PM

Quote:

Originally posted by vkykam
Beav,

What's the procedure for determining which is the leaking injector?

I think it's my right front one, since I remember a distinctive fuel smell when I removed the spark plug...

VK

Are you sure you have an injector problem? Sounds more like an ignition problem, unless the injector is dumping a lot of fuel.