Need some advise 308 GTSI

I need some advise on two problems that I need to fix on pre-existing owner problems.
I have a light on slow down 5-8 which was on when I bought the car. The previous owner had it checked and was told by two mechanics that it was a short. The left one 1-4 comes on at start up and goes off the right one comes on and stays on the entire time-some times it will go off but most of the time it stays on. When it does rarely go off it will do it driving down the highway. The temps in the cats was measured and they are normal. I read the manual and it seems if I am reading them correctly that it would blink if it had an actual problem.
The second problem is the cold start valve.How does it work and has anyone replaced it?
Thanks

 

The control box for the CAT’s and slowdown lights can be found on the passenger side floor well. Remove the carpet in the foot well and there is a panel there that can be removed. Attached to the panel is the controller.

I would start by removing the connectors and cleaning them with contact cleaner. Might just need a good cleaning. Check for loose wires at the connection and also check for good grounds. I have solved many problems with my 308 by just cleaning the grounds and removing any old corrosion and paint from them.

The cold start valve is on the plenum on the passenger side of the engine. It is held on by two cap nuts. Very expensive part but not hard to find. BOSCH part number for 1980-1983 308 GTSi is 0 280 170 401.

There is a sending unit on the left side of the thermostat housing, which measures the temperature of the engine. I am not sure what it is set at, but it will send a signal to the start valve when cold, to fire the injector for about 5 seconds. This is to aid in starting like a choke on a carburetor. They do leak from time to time and this can cause the engine to run very rich.

I would not mess with it unless you are having troubles with cold starting or a rich running engine. There is good information here in F-Chat you can search on for more detailed info.

Jeff
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Thanks Jeff!
I thought that the cold start had something to do with the idle up when it was cold.
My 308 fires up beautiful but it does not idle up like I thought it was suppused to do.
When it is warming up it just idles low with the light on ( sounds kind of sad ) but when the light goes off it sounds great.
Am I chasing the wrong ghost?

 

Not really sure. Mine did the exact same thing as yours. I changed the Warm Up Regulator (WUR), and the cold air valve. Checked for leaks and replaced all the vacuum hoses. Still did the same thing.

I changed my Digiplex units just a month ago and now the fast idle is working like it is supposed to. Jumps to about 1800 rpms then a slow increase to 2000 right before it warms up, then the light goes out and the car runs normal. I am not sure how the Digiplex figures in to this unless it is an advance thing. I replaced the units because one was failing. The old units were MED 801’s and I replaced them with the Euro version MED 802. There is a 1° difference in the advance. Maybe that is what is making the difference, I am not sure. Some have suggested that because the original units were old, the advance circuit was shot in them and not working to spec.

The DIgiplex units do receive a signal on pin number 6 from the temp sender in the expansion tank. And it is this same sender that controls the electro-valve connected to the cold start air valve, allowing vacuum from the manifold to allow additional air into the plenum, this by-passes the throttle plate and causes a higher idle.

So, since the Digiplex receives the same signal as the cold air valve electro-valve, maybe there is something in the Digiplex on pin #6 and allows for less advance timing while cold? And if so, if this part of the Digiplex fails, the timing is too advanced and causing the coils to fire too early which in turn causes the engine to stumble while it is warming up and run rich because all the fuel is not being burned at the proper time. After warm up, it runs normal.

Sounds good but this is just a SWAG (Scientific Wild ASS guess). The MED 802’s are work out great and I have seen an improvement in the performance. I was un-able to locate the original 801’s or even someone who could repair them. Also, I was not sure which one was failing so I just replaced them both with NEW OLD STOCK items I found.

I would make sure that I have looked at all the vacuum lines and connections first before I started thinking about changing Digiplex units. If you decide to change them, I know where you can get NOS MED 802’s.

Jeff

 

I have 803's in my 1984 euro 308 is that correct?

 

From the Info I have, Yes thats correct.

MED 801's were 1980 - 1982 US Market (Must be Smog)
MED 802's were 1980 - 1982 UK Market.

1983 - 1985 QV US Market used MED 805's and I believe that the 803's were UK

 

I don't think so because my 84 308 US has the 805's

 

Jeff,
You were on the money!!! I cleaned the contacts today but it didn't clear the light at first....... When I left the airport tonight the light cycled like the one on the right at start up and cleared exactly like it is supposed to do.....
THANKS