replacing fuel accumulator : time estimate

[Luc Bernier]

taking the car to the garage tomorrow
problems with warn starts.

searched the posts and the fuel accumulator seems a good place to start, along with checking the fuel pressure.

for my info : how long should it take a mechanic to replace the accumulator ?

thanks

Luc

[jmohn]

I would guess it took me about 15 minutes (+ or - 5 min.). But, I was doing other "stuff" at the same time, so it's really a guess.


Jerry M
'78 SC

[tevake]

Yep, 15 min easy. Bet they will charge you for one hour, probably their minimum.
So what is the hourly rate in your area? $110per hr. Here. Seems a lot to do 15 mins. work.

This is one that you can DIY.

Plus in this local shop they seem to charge 50% to 75% over what I can get parts for retail. So with their discount that ends up being close to 100% markup.
Makes it hard to use them. Forced into DIY. Does make for a growing tool collection.

So what are they asking to do the install for you?

Cheers Richard

[docrodg]

DIY it. Of course that means time estimate is directly proportional to beer consumption... logarithmically.

[jmohn]

If you're going to DIY, get the correct (metric) fitting wrenches (unless you already have them), those connections are tight.

Jerry M
'78 SC

[Luc Bernier]

yes I will have to do stuff myself, this toy is getting to be expensive...
I guess I could do a search on how to change the fuel accumulator...
BTW, the rate at the place I go is 75$\hour

thanks

[vash]

could be the fuel pump check valve.

the shop KNOWS it is the FA and not anything else? they tested the system..or they are just guessing.

the part is easy the change out..

[Sunroof]

Usually when you change out the fuel filter the line to the fuel accumulator is loosened and removed. This has to be the easiest job next to changing an air filter, so save your money and do it yourself! And if you do, then you might as well change out the fuel filter. Good luck.

Bob
75.5T

[Peter Zimmermann]

Remember, when a shop does a job the result must be tested/verified. It takes a little time to test drive the car, bring it back to the shop, set a timer for the time period that the owner usually experiences the problem, and then stop everything to test-start the car. This will probably be done twice at most shops that really want to make sure the problem is fixed - before giving the car back to the customer. It also requires that an invoice be made for the work, and time to check the car in, and check it out at pick-up time. From a shop's perspective one hour labor is justified.

[Luc Bernier]

oh, maybe a clue for you guys : when cold, the car seems to backfire a bit before starting properly
thanks for your advices, this really helps

[lonewolf]

when it's the accumulator . On hot days and restarting the car when warm it will take a while to fire ,when it does it chuggs like it is flooded .sometimes you have to flutter the pedal to get it to clear up.
When it's the check valve. hot or cold days ,after running for a bit and when you try to restart it won't.car has to sit for a bit but when it fires it runs normal ,no chugging.

also ,it's alot easier to remove the filter and acc as one unit and then take apart.
when putting them back in ,leave all the fittings lose untill you get everything in position and have the hose clamps snugged up.then tighten fittings. it gets pretty tight in there and you need the right combo of small wrenches to do the job easily.

[tazzieman]

Originally Posted by Luc Bernier

oh, maybe a clue for you guys : when cold, the car seems to backfire a bit before starting properly
thanks for your advices, this really helps

Yours is a cold start problem!
FA failure manifests as difficulty in starting after the engine is warm and has been sitting a while (typically after you get back after a bit of shopping).
What happens after the car backfires after replacing the FA?
Maybe you have a vacuum leak or faulty WUR , or...
Is your mechanic a P car guy?

[Luc Bernier]

took the car to the garage again: checked for vacuum leak, the check valve, did some adjustments, let the car warm up, shut done the engine, started it again, all seemed to work fine.

this weekend, had the same problem twice (warm start issues)
1- drove the car for at least 20 minutes
2- tried to start it after a while (at least 30 minutes)
3-wouldn't start, had to wait for an additional hour
4-finally started, had to give it some gas

once running, no problem.
this morning, after a night in the garage, tried to start it, it did after a few turn of the key.

I'm getting pissed....called my mechanic, told him that the problem may be the fuel accumulator, he seems to hesitate to change it,

so, I think that I will try to change the fuel accumulator myself (!?)
1-by any chance, anyone out there took pics while changing this part ? anything that can guide me ?
sick of spending money.
I'm reading the 101 projects for your Porsche 911
there's a section on the FUEL SYSTEM
any info to guide me in that book ?

all infos will help
thanks

[NeedSpace]

Luc,

1) With car off and cold (so you don't burn yourself)
2) Put on some rubber gloves, you'll get fuel on your hands and it takes about a day for it to go away. Have some paper towels available, put one underneath filter and accumulator. You will get some drippage of fuel, I got a few tablespoons worth.
3) Take both the filter and accumulator out together, I found it much easier doing it this way than doing just the accumulator. In the photo below, disconnect the fuel hoses (orange circles). I would start with the top ones, then do the return on the bottom of the accumulator (depending on your car year, you may not have the return at the bottom). When you put the hoses down, you may get a little more fuel draining. You will need 2 wrenches to take these off, one on the line, one on the fitting. I cannot remember the sizes, but 17mm and 16mm are coming to mind, but not sure.



4) Then, with a screwdriver, loosen the clamps (blue circles) that hold the filter and the accumulator to the car. The clamp straps wrap around a piece of sheet metal that is attached to the car. You will have to loosen them quite a bit to get them completely off. They will drop DOWN. You might have to push the strap back toward the outside of the car to get them past the lip of the sheet metal holder.
5) Pull both the filter and accumulator out. Now removing the hard line to the top of the accumulator and switch with the new one.

When reinstalling, do the process in reverse.

When starting the first time:
1) remove any towels or tools in the engine compartment.
2) When starting, it will take a little time for the fuel to come back through the lines to the engine. Plus, the engine may start immediately, then stall, this is normal while fuel is making its way back to the engine.
2) Make sure to check the engine IMMEDIATELY for leaks in any of the fuel lines you touched. If you see a leak, stop engine immediately before the engine warms. Clean up the fuel first, then tighten your fittings. You probably should have a fire extinguisher handy, thankfully, I have never had to use one but an ounce of prevention....

If you get stuck, send me a PM.

[boyt911sc]

Luc,

The FA (fuel accumulator) is very easy to test. Remove it from the car, blow dry the inside of the FA using compressed air or simply let it air dry. A good FA will hold fuel without leaking fuel to the bottom port. The diaphragm could be tested by simply applying pressure (gas or liquid) into the upper chamber.

Apply air pressure by mouth to the top port and blocking the other one. Listen or feel for any sign of leakage at the bottom (drain) port. A more effective test is running the FP (jumpered) and observe for any fuel leak coming from the drain port. The disconnected drain fitting should be plugged. Run the FP for 2 - 3 seconds (max.).

I would suggest to check the residual fuel pressure. A low residual fuel pressure could be caused by a defective:
Fuel accumulator
FP check valve.
FD relief/return valve

Don't replace CIS components unless verified defective. Each component could be bench tested by DIY'ers like you or me using simple test procedure. Keep us posted.

Tony

[Luc Bernier]

thanks for the great infos

Luc

[Luc Bernier]

Guys,

while building up the courage to follow all your great advices, I went for a second opinion to a well known Porsche mechanic in my neighborhood.

drove the car for a while, let it sit, tried to start it, it wouldn't.

opened the hood, tested a few things, and for him it was clear that I had a vapor lock problem.

had his hands behind the air filter, told me that he did a few adjustments to what ever it was, and told me that from now on, before trying to start the engine when warm, I should turn the key, wait for about 20-30 seconds, and at the same time that I start the car I should put the gas pedal to the floor.

I works, but only after 4 or 5 tries.
concerns : will the starter suffer from this ?

Curious that the 2 mechanics that I went to, none suggested the FA....
you guys still think that I should tackle the FA issue ?
afraid to make things worst doing it myself....

well maybe a 911 is not a car for me...
monday blues.

thanks

[boyt911sc]

Originally Posted by Luc Bernier

Guys,

while building up the courage to follow all your great advices, I went for a second opinion to a well known Porsche mechanic in my neighborhood.

drove the car for a while, let it sit, tried to start it, it wouldn't.

opened the hood, tested a few things, and for him it was clear that I had a vapor lock problem.

had his hands behind the air filter, told me that he did a few adjustments to what ever it was, and told me that from now on, before trying to start the engine when warm, I should turn the key, wait for about 20-30 seconds, and at the same time that I start the car I should put the gas pedal to the floor.

I works, but only after 4 or 5 tries.
concerns : will the starter suffer from this ?

Curious that the 2 mechanics that I went to, none suggested the FA....
you guys still think that I should tackle the FA issue ?
afraid to make things worst doing it myself....

well maybe a 911 is not a car for me...
monday blues.

thanks

Luc,

Your problem is very simple. The way to determine the root cause of your problem is to check it. Stop guessing and locate the culprit. By your descriptions, your residual fuel pressure should be checked. I'll put my money on residual fuel pressure. There are a few things that could affect the residual fuel pressure.

BTW, 911 CIS do not suffer to vapor leak!!!!! The gasoline (fuel) is an incompressible fluid and would be displaced any gas/air present in the system by the high pressure FP. This is another myth people propagated and been accepted for many many years.

Did your mechanic ever checked the residual fuel pressure or hook up a pressure gauge? Find someone who knows and understands well how CIS works. CIS is an antiquated technology and many good and talented mechanics don't work that frequently with 911 CIS anymore.

Tony

[GothingNC]

Did you replace the fuel pump check valve and/or check the fuel pressure hot and cold?

I had a hot start issue and it was the red fuel pump relay causing the fuel pump to run with the motor off and a bad fuel pump check valve.

I do not agree with the recent shop telling you to depress the gas pedal while starting the car, this could cause the air box to blow.

Good luck, hope you find the culprit soon.

[kach22i]

Originally Posted by Sunroof

This has to be the easiest job next to changing an air filter, so save your money and do it yourself!

Bob, I recall this being a delicate operation, having to be careful not to twist and bend those old fuel lines. I was cursing God for not giving me a third arm the whole time.

I just changed the fuel filter last week, now that was easy.