2nd Accumulator Installed!

[Vincent Hill]

I feel that when everything is "Perfect & New" the 1 accumulator is all that is necessary. The problem is, using Horrible fuel and the cars sitting allow the Injectors start to leak a little. Remember the 1976 had a very small accumulator which I replaced with a Large one from a 924. Len Cummings (Autosport Engineering) made 2 Fuel lines for me to do this. I had the connector line made at 8 inches between centers for what I "THOUGHT" I would need. I now realize that I need one about 4 inches between centers for where I ended up installing the 2nd unit Also I would have him add 1 or 2 inches to the main Fuel line. To do this I spent under $100 plus the Accumulator I already had

[Targalid]

Interesting. Let us know if you see a difference. How will you test performance of this enhancement?

[Vincent Hill]

Originally Posted by Targalid

Interesting. Let us know if you see a difference. How will you test performance of this enhancement?

Simple test. I can restart Hot up to about 30 or so minutes before. Now it will restart until Cold start takes over again or so far over 1Hour. I drove the car to Church and it started 2 hours later but I think it was in Cold Start. I cannot do any more testing for a while, my 2 year old Permatune box died. I just bought a MSD unit and will put it in sometime this week. More Later on that. If anyone has compared the Size of the Older 911's Accumulator with the later, you will see a Huge increase in their size. At 1 time they uses 2 small ones. All I am doing is taking the next step with 2 Big ones

[GaryR]

Have you tested the check valve at the tank (or does your car have one?)? Seems like a lot of work to fix what usually works as designed, but that's just me. I do like the "outside the box" thinking though!

[T77911S]

Originally Posted by Vincent Hill

The problem is, using Horrible fuel and the cars sitting allow the Injectors start to leak a little.

fix the leaky injectors, they also cause idle problems. bad fuel, not unless there is water in it or you have a problem with your tank.

replace the check valve at the tank.

[GaryR]

New set of matched CIS injectors (from Tim Marren) are about $350, then send in the old ones for check..

[Vincent Hill]

Originally Posted by T77911S

fix the leaky injectors, they also cause idle problems. bad fuel, not unless there is water in it or you have a problem with your tank.

replace the check valve at the tank.

By Bad Fuel I mean Ethanol! Also Even Porsche has changed their mind about the Accumulators over the years and I think before they added 2 large ones they went to a new system!

My BMW Has this basic system and once it was set NEVER a problem. The 1976 and this one all have the same problem and from reading the boards MANY MANY People here do also. It is called Hot Start after 10 to 15 minutes. Everyone always says the same thing like Check Valve (I am on my second one in a 6 month period the last was replaced in May).

Then they say Leaky Injector. I replaced all of them for $300 in January and eventually I will be back to where I am now.

I simply decided to double the capacity of the system to stay pressurized and allow for the eventual leaking that the Very High pressure causes.

The car runs, Accelerates and Idles very well and except for the Permatune going out in only 2 years running very well getting about 19 to 20 on town and some highway and about 25 to 27 on the road. I know if not for the Ethanol I would be getting closer to 30 on the road and 21 to 22 in Mixed driving.

[T77911S]

what is your residual pressure?

any air leaks?
what about control pressures.

a weak ignition will also cause starting problems, along with old/wrong plugs, too cold a plug, cap, rotor and faulty ignition wires along with a bad WUR.

i could be wrong, but i seriously doubt a second accumulator is your fix, perhaps a bandaide for the real problem.

[boyt911sc]

Vincent,

Glad to hear that the car is running. But you are making the wrong troubleshooting for your problem. The additional fuel accumulators my seem to fix your problem but you'll be back soon looking for answer/s. Check your residual fuel pressure. This pressure loss could be attributed to several things like leaking injector/s, defective FP check valve, bad FA, or a leaking checking valve at FD.

Tony

[Vincent Hill]

Something some of the readers are missing is I am not NEW to the 911. I owned a 1976 "S" for over 10 years which had just under 400,000 Miles when my wife totaled it at 130 MPH. On Purpose I made sure not to get anything newer than a 1983 because I like and understand the CSI (Which my 924 and 320I all had / have).

Understanding this, I got the 1976 to work perfectly but I spent a LOT of money before I came up with the solutions I made to STOP Spending MONEY!! Every time there was a slight injector leak I replaced it. I even had 2 one way valves at the fuel pump. I made all of the lines to watch fuel pressures "While Driving the car". SO I have done it all.

As for my 1982 sc I have replaced the Airbox when I found it leaking. As I said earlier, 2 - one way valves, and 1 set of Injectors, New Accumulator when I am sure the old one was OK, I Checked the Cold Start Valve, New Plugs Gaped to 0.030 then 0.040" because of the Permatune Ignition.

Until this last Saturday I have always had spark. I only posted this for the people that have a Hot Start problem and are tired of making their CSI Controlled Car Perfect and finally want a simple solution. Please also understand that My solution is not a New solution or a foreign to Porsche Solution. Just look at the 911's with CSI from 1974 to 1983. You will see that "PORSCHE" went from a very small Single Accumulator to 2 small one and then a Large one and then before adding the 2nd one they went to DME.

someones 1974 with NO Accumulator and a Hot Start issue


A 1976 accumulator for sale note the size

a 1977 911


1980 and later


Here is a 1977 Porsche 924 that uses 2 small one and in 1979 they went to 1 very large one.


My question is, how many people questioned this decision and asked Porsche if they checked the 1 way valve or did they check the injectors or ignition system? Oh, I forgot, the cars were Brand New and the engineers were improving the cars to "Address Consumer Complaints"!

If OK for Porsche, then why not for me? I know the people that make this change will love the results. Specially for less than $100. Remember I also sold out of 2 inch extensions I made for Porsche OEM and Weltmeister (Well I do have 1 WM Left)

[db_cooper]

I think the "check valve" is in the fuel pump..not the tank.

Could be wrong..its been a while.

[Vincent Hill]

Originally Posted by db_cooper

I think the "check valve" is in the fuel pump..not the tank.

Could be wrong..its been a while.

More like "Attached" to the Fuel Pump which is right at / behind the Fuel tank. Also there is a style that goes into the Fuel line to the engine. I have used both together so if one failed I had the 2nd already there.

[Vincent Hill]

Someone asked about "Bad Gasoline" here is an article about it! The basic story is the RVP has crept Upward causing more fuel to vaporize hence you need more fuel to restart a Hot engine! Hence the 2 accululators. I would suggest that I am "Simply" Ahead of the Curve!

Popular Science - Google Books

[Jay Laifman]

My 73.5 had a check valve near or with the accumulator and filter. I don't recall exactly. But, it might have been special to the 73.5. I do know that it self destructed and cost $12 from Porsche to replace and fixed my hard starting problems.

(Note: I'm not questioning Vincent here. Just adding my experience that may help others that don't have Vincent's problem).

[Vincent Hill]

Originally Posted by Jay Laifman

My 73.5 had a check valve near or with the accumulator and filter. I don't recall exactly. But, it might have been special to the 73.5. I do know that it self destructed and cost $12 from Porsche to replace and fixed my hard starting problems.

(Note: I'm not questioning Vincent here. Just adding my experience that may help others that don't have Vincent's problem).

100% Appreciated! WE (At least ME) are all here to learn what we do not know and to see the different approaches to fix "ANY" Problem we may have. It usually turns out that there are at least 2 or 3 ways to fix everyone's problems.

The Check Valve should always be one of the FIRST things we all check because when it goes bad, it does not matter how many accumulators you have, the car is not going to start when Hot!

[BoxsterGT]

Just wondering if the install worked out as expected.

Any photos?

Len

[Vincent Hill]

Originally Posted by BoxsterGT

Just wondering if the install worked out as expected.

Any photos?

Len

It has now been "3" Months and went on a 1,500 mile trip from Washington DC through Strongsville Ohio to Toledo then to COlumbus and back to Dc through the Mountains. We have been stopped for 10 minutes, 30 Minutes, 45 Minutes, 1 hour, ! Hour and 30 minutes and 2 hours and longer and ALWAYS the Same thing! Never once was there a Hesitation in Immediately getting started!

[boyt911sc]

Vincent,

It's difficult to determine the type of FA you used by looking at the pictures. Are they two-port or three-port FA? Thanks.

Tony

[Vincent Hill]

Originally Posted by boyt911sc

Vincent,

It's difficult to determine the type of FA you used by looking at the pictures. Are they two-port or three-port FA? Thanks.

Tony

Easy! The second one is a 2 port used along with the Stock 3 port so not a lot of work hooking up anything. I used the longer line to go from the Steel line to the 2nd FA and then a SHort line from the 2nd one to the Original one. Everything else the exactly the same as stock.

ALL I needed to do was make the 1st Pic about 1 inch longer and your could see the Bottom! I was more woring about showing the top.

[boyt911sc]

Vincent,

I am impressed with your tenacity and determination in doing some of the projects you have done recently specially the power steering installation. I put off my hat to that. But when it comes to CIS project, you tend to overkill the solution to the problem. I'm not saying it is wrong or bad. They all worked for the wrong reason. Please don't take this personal, we are just discussing concept, ideas, application, etc. in a technical forum.

Installing multiple FP check valves is not a bad idea. But a single working FP check valve is sufficient to do the work. Adding a 3rd check valve is still OK but why? Installing a second fuel accumulator is also a good idea provided you use the correct configuration. Multiple FA application with a three-port FA will not be as effective as you think it would. Using two-port FA's would. Why?

If you have a three-port FA in your set-up (multiple FA's) it doesn't do or offer any advantage at all. You could add as many FA's you like in the system, it does not help at all. Are you familiar with the phrase 'the weakest link'? When a 3-port FA fails, no matter how many FA's are connected to it, the system will lose residual pressure!!!!! So a better set-up is using no 3-port FA for multiple FA set-up. You could find them in older CIS BMW's, Volvo's, MB's, etc. cars.

Like you said, since you installed these multiple check valves and FA's, you never experienced any hot start problems. So with many cars/engines too with mono check valve and FA!!!! Your multiple FA set-up suggestion has merit provided you know the approriate fuel accumulators to use not just any FA you found on the shelve. I have done tests on FA's, WUR's, AAR, CSV, TTS, TV, FP, fuel injectors, etc. and have results to back our technical discussion.

Tony