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jason c
Joined: 13 Jan 2014
Posts: 1018
Location: Nwi
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 Posted: Mon Apr 07, 2014 10:59 am Post subject: Re: Q drip test accumulator |
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| jdub wrote: | | ok j- i'll try to give it a little pre pump action in that type of starting window for now- |
Can you clarify what you mean by this? |
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larchie
Joined: 19 Jun 2003
Posts: 297
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| Posted: Mon Apr 07, 2014 11:12 am Post subject: |
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I find this interesting and somewhat puzzling that jdub's problem isn't already fixed with the work he's already done. After checking some of jdub other forum threads covering his troubleshooting and rebuilding. I somehow missed this statement in this thread:
| jdub wrote: | | i did shoot some carb cleaner up the screw hole on bottom when I was fuel cleaning before emissions tests a few weeks ago |
I don't know what the material is which makes up the construction of the accumulator diaphragm.
Can anyone confirm if it's possible that the carburetor cleaner could have made its way through the spring chamber and reacted with the diaphragm causing a fissure -- and so causing loss of the normal fuel pressure needed for re-start up to an hour after the engine is stopped? |
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jason c
Joined: 13 Jan 2014
Posts: 1018
Location: Nwi
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| Posted: Mon Apr 07, 2014 11:55 am Post subject: |
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| The diaphragm is rubber. Some Carb cleaners can attack rubber, so can brake parts cleaner. There is no reason to put it in the bottom hole of the accumulator. If fuel comes out of the screw hole, the accumulator is bad. |
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jdub
Joined: 04 Mar 2014
Posts: 72
Location: AZ
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| Posted: Mon Apr 07, 2014 1:41 pm Post subject: |
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(new check valve too)
Update: so iblasted out the accum. fromthe bottm screw hole again, this time more thoroughly. it still had a varnish smell (the last fuel part on my car to have that still)
after some driving and sitting, it didnt have the
problem starting,
but, i need to give it a longer trip an see if its fixed for sure. will ipdate. thanks!
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81 924 non-turbo |
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11733
Location: PacNW
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| Posted: Mon Apr 07, 2014 2:52 pm Post subject: |
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Yes, if gas comes out the screw hole the unit is bad. . .blown diaphragm.
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Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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jdub
Joined: 04 Mar 2014
Posts: 72
Location: AZ
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| Posted: Wed Apr 09, 2014 4:40 am Post subject: |
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so far, after some shorter drives where engine did get to fulltemp., there has been no hard starting problems ,
(i blasted out the accumulator with cleaner in case there was gunk)
i still want to do a longer drive, give an hr. , and see if it's fine now
stay tuned
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81 924 non-turbo |
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jason c
Joined: 13 Jan 2014
Posts: 1018
Location: Nwi
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| Posted: Wed Apr 09, 2014 5:17 am Post subject: |
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| As I stated before, there is nothing to clean out of the bottom of the accumulator. If there is fuel in the bottom, its bad. |
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Harm
Joined: 02 Apr 2009
Posts: 1376
Location: Holland
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| Posted: Wed Apr 09, 2014 5:56 am Post subject: Re: after an hour hard to start, but starts good otherwise |
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^dito…
> Bottom being the Spring Chamber
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Porsche 924 NA 1982 LY7A/A3A3 _ Greater driving pleasure never harmed anyone. |
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larchie
Joined: 19 Jun 2003
Posts: 297
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| Posted: Wed Apr 09, 2014 8:29 am Post subject: |
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Several posts were lost here prior to Harm's. This summary is as best I can remember what was posted.
jason c said in effect the accumulator is faulty and "test, test, test" -- referring to the CIS pressure tests.
SilverGhost pointed out your warm-start symptoms were much like his hot-start problems -- i.e., engine would re-start up to 10 or so minutes after shut off but not start well from that point on to up to an hour -- so the suggestion was to check and clean the hot-start valve off the fuel distributor
After replacing the fuel accumulator, I suggested you redo your CIS fuel pressure leak-down test making sure the valve open, and if you get the same result as before clear the restriction in the fuel return line and in the hot-start valve and/or the pressure value in the fuel distributor. (Either of these problems are indicated if your earlier done leak-down test, as posted in a different thread. was done with the valve open.) |
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jason c
Joined: 13 Jan 2014
Posts: 1018
Location: Nwi
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| Posted: Wed Apr 09, 2014 9:47 am Post subject: |
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Yes, always do the proper tests and do them properly before saying a part is bad. Measure twice cut once.
I said silverghost could be correct but Jdub has stated that the accumulator was the only part in the system he didn't clean out. His car will start while hot, there is just a time issue.
I'm not saying I'm 100% sure its the accumulator, I wouldn't without testing it, that is where I would start though. I did say it is bad if fuel comes out of the bottom screw hole whether it fixes the problem or not. The bottom line is jdub has to do the tests. |
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11733
Location: PacNW
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| Posted: Wed Apr 09, 2014 3:59 pm Post subject: |
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| larchie wrote: | So, I'm thinking the accumulator might be OK since it seems to hold pressure for an hour -- which otherwise seems good to me.
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My prior response to this assertion was weirdly deleted. Must be a bug.
Accumulator is about fuel volume, not pressure. Bad accumulator and good check valve will give the result described.
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Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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jason c
Joined: 13 Jan 2014
Posts: 1018
Location: Nwi
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| Posted: Wed Apr 09, 2014 4:21 pm Post subject: |
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| Rasta Monsta wrote: | | larchie wrote: | So, I'm thinking the accumulator might be OK since it seems to hold pressure for an hour -- which otherwise seems good to me.
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My prior response to this assertion was weirdly deleted. Must be a bug.
Accumulator is about fuel volume, not pressure. Bad accumulator and good check valve will give the result described. |
The server transfer wiped out posts and PM's from yesterday. |
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larchie
Joined: 19 Jun 2003
Posts: 297
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| Posted: Thu Apr 10, 2014 3:47 am Post subject: |
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| Rasta Monsta wrote: |
Accumulator is about fuel volume, not pressure. Bad accumulator and good check valve will give the result described. |
Right, I agree. Essentially, the purpose of the accumulator is describeable as when the fuel pump stops running, the accumulator maintains primary pressure at rest pressure allowing for re-start, and also the accumulator acts as a damper to smooth out the fuel pump pulses.
The point I was making in the post quoted doesn't conflict with Rasta Monsta's post excerpted above. What I was pointing out was just this:-- When the accumulator fails there will be a rapid loss of rest pressure. This was not observed
when jdub connected his gauge and did his pressure tests.
-- So if there's no drop in pressure, there would be no leak in the accumulator. Admittedly this thread has become a bit confusing since relevant information was lost in the process of Website's transition and other relevant information is in jdub previous thread " ? pressure tests Q, results CIS gauge" where in the CIS testing I took him to state cold-control pressure and warm-control pressure were measured at 5 bar -- where the former should have been about 1.5 bar and the latter should have risen to about 3.6 bar. And his leak-down test showed 2.5 bar after an hour, (which if so, would be excellent).
So two questions are still hanging fire from requests for more information from previous posts: did jdub replace the check valve when he solved his problems with the fuel pump, and did he do the fuel tests after final clearing of the screen restrictions in the WUR.
So when I wrote ...
| larchie wrote: | | So, I'm thinking the accumulator might be OK since it seems to hold pressure for an hour -- which otherwise seems good to me. |
... the reasoning was at that point in the diagnosis that a pressure of 2.5 bar for an hour in the leak-down test wouldn't be possible with a ruptured diaphragm in the accumulator (since pressure would be lost through the spring chamber). |
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jdub
Joined: 04 Mar 2014
Posts: 72
Location: AZ
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| Posted: Thu Apr 10, 2014 4:58 am Post subject: accumulator. link? |
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Goin to replace accum, due to having a little fuel coming out if drain hole at bottom, but the IRS is taking months on my refund !!!!!
(Gov can send millions overseas instantly for questionable civil wars...
great diagram above. Thanks!
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81 924 non-turbo |
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jason c
Joined: 13 Jan 2014
Posts: 1018
Location: Nwi
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| Posted: Thu Apr 10, 2014 7:41 am Post subject: |
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What do I win? 
Keep in mind it may still not be the complete problem.
Btw; When did you do the original pressure test that larchie keeps quoting, before, during or after the hot start problem? |
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