79 928 warm start problem
 

replaced injectors, cold start injector, plugs and wires. Check valve on fuel pump is holding good pressure and seems to be working. Starts good when motor is cold. After it warms up, and you shut it off, let it set a few minutes and it is really hard to get going again. Open the air filter and spray some fluid, (gas or fancy break fluid) and it starts right up. Less than 60K on vehicle. Getting tired of throwing parts at it. The next part runs 860 bucks. Some kind of a regulator that sets on the front of the engine.
Need suggestions.
:(

Fuel AccumulatoR
 

WELL IT SOUND LIKE YOUR Fuel Accumulator IS NOT FUNCTIONING CHANGE IT AND YOU WILL NOT HAVE PROBLEM STARTING WHEN ENGINE HOT IT IS LOCATED UNDER RIGHT HAND SIDE BACK WHEEL ARCH

I do remember rjm65 having the same issue. I also believe he did something to that accumulator to fix that same issue. Check for fuel smell, I think his was leaking.

warm start problem
 

How do I get to rjm65 to find out what he did. I've done a search of the Pelican site for fuel accumulator and don't get much. I don't have any smell of fuel. Just talked to the mechanic and he said the same thing, no smell. I'll send a message to Pelican and see if they can help find a accumulator. I think that owning a boat would be cheaper.

Fuel accumulator doesn't fail that often. Sounds like there is still an injector leak, or else vapor lock..or maybe the timing is off a bit. Does your car have a vaccum hose to the underside of the advance pot on the distributor, and if so is it connected and pulling vaccum? Is the fuel line following the factory routing? Is it close to the exhaust manifold in any areas? My '83 has a factory hot start valve, but I think it is an '83 and up component (for CIS cars).
I don't see the point in getting a new WUR yet. THere are services to rebuild them, but that is still a couple./few hundred dollars.

Have you tested the thermotime switch? If bad, it could be causing the cold start injector to function even when warm. If you can't test the switch itself, try unplugging the coldstart valve when warm and see if it starts OK.

There are two types of accumulators out there. The latest version has a hose that routes leaking fuel back to the tank so there won't be a smell. The early version has the end plugged and often leaks at the screw so you can smell it.

Agree with SMT. The WUR is not normally the culprit in hot start problems if it starts fine when cold and runs OK when warm.



Dennis

I clicked on advanced search, plugged in the username cited above and the term 'accumulator', and directed it to the 928 forum. Two threads came up, one on wur calibration that I look forward to reading again with some dread...and this one:
http://forums.pelicanparts.com/porsche-928-technical-forum/532060-fuel-accumulator-blowout.html?highlight=accumulator

After reading that, I wonder if maybe they don't fail 'partially' (without a large leak) more often than we know..

Luckily, most of my work sorting CIS issues took place before the massive price adjustment...accumulators used to be a couple hundred bucks new, five years ago or so.

SMT,

On the old style, the diaphram could leak but if the housing wasn't rusted/leaking the pressure wouldn't bleed down due to the check valve at the pump. The new style that bleeds the fuel to the tank, will bleed down the pressure and cause hard warm starts. BTW my 78 euro has the new style and my 78 US still has the original old style.

I would just a good used one from 928 intl with a 1 year warranty.

Fuel accumulator on my 79 was bad, it's back in the right rear wheel well. Same issue as yours, easy to start when cold but difficult when warm. Leakage at the accumulator was minimal, there was just a slight hint of moisture up around the top of the accumulator. After removing the bad accumulator, the top half of it was full of gas, so that definitely confirmed it was bad.

The car would pass the fuel pressure bleed down test in the manual even with the bad accumulator, so that threw me off at first, but it was bad enough that it would cause vapor lock on the warm engine.

79 928 warm start problem
 

thanks for all the advice. Will take a copy of it all to the Mechanic. I also provided him with the Shop manual, all 900 plus pages of it. This car has just about everything replaced on it, even mechanically, the clutch has been upgraded to the 83 version. All new boots under neath. All of the steering parts. I've had a lot of alternator problems, think I'm on my 4th or 5th one. The Mech says that I probably should replace all of the air hoses next. i'll post what he finds out. I would be nice to be able to stop for gas and be able to shut the motor off.

Benji,

Have your mechanic test the accumulator by removing the inlet and outlet lines and the plug/screw or line from the top then try pulling a vacuum on it. If it holds a vacuum, the diaphragm is OK. If no hold on the vacuum, it should be replaced with a new one.

I hope he can read. Does he know about Rennlist and this one? I would have hoped he replaced air/vacuum hoses when he was replacing other items. Does he charge by the hour on exploration? 4th or 5th ALT?? something causes that many ALT's to go bad...I hope he has found what is causing the ALT failure! Usually bad wires in the harness from the top 14 Pin connector going down to the ALT, Starter, and senders.

Sorry about my comments but the tail you are chasing...must frustrate you; it does me just following this thread. It is certainly concerning, the Mechanic that is, and the process he is (or isn't) following in problem resolution...

Seriously, do this kinda stuff yourself. Do you really trust this mechanic? I have to be really really stumped to use someone else. Lotta help here and they have been down that road before. Don't waste your money on labor.

I've had this 79 928 since 96, it spends a lot of time stored in a heated shop. Problem with the Alt is partially my fault and where the water pump is located. Seals seem to dry out in Alaska during the winter. Different Mech's at different times. Took car out of storage last spring and the Alt got wet from the water pump, and then the brand new Bosch one didn't last over 50 miles as a bearing in it went bad. Rennlist is new to me, as well as this forum. I really want to thank you guys for you help. Now that I know about these forums, I plan to get help here. Again, thanks for the help.

I've had this 79 928 since 96, it spends a lot of time stored in a heated shop. Problem with the Alt is partially my fault and where the water pump is located. Seals seem to dry out in Alaska during the winter. Different Mech's at different times. Took car out of storage last spring and the Alt got wet from the water pump, and then the brand new Bosch one didn't last over 50 miles as a bearing in it went bad. Rennlist is new to me, as well as this forum. I really want to thank you guys for you help. Now that I know about these forums, I plan to get help here. Again, thanks for the help.

The fuel Accumulator seems to be hard to come by, I'm told that the part number is 928-110-197-07, does anyone know of a replacement that I can get. I've checked about 10 different sites and the response is the part is not in stock and discontinued.
VIN number 9289202247 79 928

928-110-197-07?

I am seeing the last number 6 according to the diagrams I am looking at.

http://www.mailordercentral.com/928intl/prodinfo.asp?number=928 110 197 07

http://www.mailordercentral.com/928intl/prodinfo.asp?number=U928 110 197 07

http://www.mailordercentral.com/928intl/prodinfo.asp?number=U928 110 197 06

Here are links to them at 928 Intl. Did you try them yet? $75 used sounds good to me.

Maybe someone can confirm this, but I thought the only difference between the two styles of accumulators was one has a line fitting at the top so in case the diaphragm failed the gas is plumbed back to the tank and the other doesn't.

That is all I've seen on the 928's. IIRC the 924's went from a small 20 CC accumulator to a larger 40 CC version.

Dennis