Stinkin' 928

[drwdds]

Lots of unburned hydrocarbons coming out of the tailpipe on startup...no smoke, but just stong gas-like fumes. Haven't detected any fuel leaks anywhere. Car starts fine cold and runs well at all speeds, but is then a real hard start when hot. Wondering if this is all related...possible sensor or regulator malfunction. 1981 Euro (US conversion). Any ideas? Thanks!

[JhwShark]

Warm start issues can be a Fuel Accumulator that needs replacement.

HC's during running can be sensors...Euro CIS or LH??
HC's at start??

[MPDano]

Fuel Accumulator.

[MPDano]

81 Euro is CIS

[MPDano]

This is how I tamed my K-Jet CIS. Using an Innovative A/F Wideband O2 Set up. Now you can tune it to exactly 14.7

I run mine a little rich since it runs better around 14.

[drwdds]

Really cool video, Mpdano...thanks for the reply. Looks like you used that special adjusting tool I've seen in the catalogs....what is it called and do you have to have one to do the adjusting?

[MPDano]

Not real special. Just a long 3mm allen tool. I actually got mine from Sears online a few years back.

[Normy]

Originally Posted by drwdds

Lots of unburned hydrocarbons coming out of the tailpipe on startup...no smoke, but just stong gas-like fumes. Haven't detected any fuel leaks anywhere. Car starts fine cold and runs well at all speeds, but is then a real hard start when hot. Wondering if this is all related...possible sensor or regulator malfunction. 1981 Euro (US conversion). Any ideas? Thanks!

With CIS cars, you need to buy a fuel pressure gauge, and then tell us system pressure and control pressure, both warm and hot. I suspect the accumulator; you are getting the "vapors". Fuel pressure readings along with the manuals will spell your problem out explicitly.

Dano- that is a GREAT video! My S2 has a wide-band O2 sensor, and the numbers are about the same. I run in the low 15's driving around, down in the low 12's full throttle. I have the same problem with my oil pressure gauge- it's pegged. I replaced the sender a month ago, guess I got the wires crossed (?).

Good luck!

N

[DPW928]

The smell of fuel upon cold start up is normally an indication of leaking injectors. Hot start problems are normally caused by a fuel system leakdown. The leakdown could be caused by the accumulator, check valve or (again) leaking injectors. Think it's time to have your injectors cleaned or replaced. One other area that could cause both problems is a bad thermotime switch which may cause the cold start valve to operate continuously. A simple test for this would be to unplug the cold start valve and see if the hot start problem goes away.

Dennis

[SharkTech]

Where exactly is the cold start valve plug?
I am troubleshooting a somewhat similar issue(cold start runs periodically, during normal driving) and looking to deactivate the valve for again troubleshooting...

[MPDano]

Cold Start valve sits on the very front of the Spider Body. Your a 5-speed so it just under that cap that us Autos use the vacuum port.

[drwdds]

Normy- Thanks for the info. The accumulator looks pretty intimidating. Is that a rebuildable part, or someting to be replaced? Dpw928- Will unhook the cold start valve and see what that does for the hot starting issue...thanks for the tip (and hello from Muskogee!)

[JhwShark]

Not rebuildable...

[SharkTech]

Originally Posted by MPDano

Cold Start valve sits on the very front of the Spider Body. Your a 5-speed so it just under that cap that us Autos use the vacuum port.

Thx Leo... (BTW you have a PM)

[MPDano]

Originally Posted by Normy

With CIS cars, you need to buy a fuel pressure gauge, and then tell us system pressure and control pressure, both warm and hot. I suspect the accumulator; you are getting the "vapors". Fuel pressure readings along with the manuals will spell your problem out explicitly.

Dano- that is a GREAT video! My S2 has a wide-band O2 sensor, and the numbers are about the same. I run in the low 15's driving around, down in the low 12's full throttle. I have the same problem with my oil pressure gauge- it's pegged. I replaced the sender a month ago, guess I got the wires crossed (?).

Good luck!

N

NORM!! <-- Cheers. Thanks for the comment on the video, been useful for a lot of folks so far. I am glad I made it. Sure miss my 81 Euro.

[DPW928]

Originally Posted by drwdds

Normy- Thanks for the info. The accumulator looks pretty intimidating. Is that a rebuildable part, or someting to be replaced? Dpw928- Will unhook the cold start valve and see what that does for the hot starting issue...thanks for the tip (and hello from Muskogee!)

The connector for the cold start valve is normally blue. Glad to see another 928 in NE Oklahoma.

Dennis

[MPDano]

Heres a better pic of the Cold Start Valve

[SharkTech]

Nice Leo, so the red connection is you guys Auto Vacuum, and the blue connector is for cold start??
Or is that entire protruding contraption the cold start together???

[MPDano]

Nah, you see that bolt looking thing to the left of the Red Port, that connects a hard line with some vac lines along the way to the Tranny. It's softens the shifting. If the vac line is leaking somewhere, the shifting if harder.

Yes, Blue Connector is for the Cold Start Valve.

[SharkTech]

Originally Posted by MPDano

Nah, you see that bolt looking thing to the left of the Red Port, that connects a hard line with some vac lines along the way to the Tranny. It's softens the shifting. If the vac line is leaking somewhere, the shifting if harder.

Yes, Blue Connector is for the Cold Start Valve.

Roger Roger
Thx for the school time bro...