missile2511

At what temperature does the cold start valve kick in? My warm up regulator does not seem to be working and at 50 degrees I have no chance at starting the engine. I was wondering if my success at 30 degrees was because I was getting an assist from the cvs and at 50 degrees neither the cvs or the wur are working.
Joe

jpitman2

We know its CIS, but what year please! And you NEED a gauge set to measure whats happening in the WUR.
If the CSV is not supplying any fuel, first suspect is the thermotime switch. Depending on year I think, the thermotime is closed and feeding the CSV for 8 secs. The temp is also stamped on it IIRC - do a search here.
jp 83 Euro S AT 55k

missile2511

The engine is a 1983 m28/11. It is a 300 hp euro. It runs strong if I can get it warmed up, but will not start at 50 ambient. It is difficult but possible to get running at 30 degrees f.
Joe

jpitman2

So it starts , but not easily, at freezing point , but not 20D warmer? Gauges needed to find out what the pressures are - system ~75psi, cold control ~15-20psi, hot control 45psi work well for me at all temps. When you struggle to start it, is there much gas smell at the exhaust (too rich?), or not much at all - lean.

jp 83 Euro S AT 55k

missile2511

Thanks JP.
It is off to the shop to check pressures.

upstate bob

I dimly remember you can take it off the engine and stick it in a can to watch if it squirts. Do it outside the garage and have an extinguisher handy. You have an assistant start the engine (cold) and give him the neck slash when you see it working.

checkmate1996

Before going down this route, I agree with jpitman. Get your readings using CIS gauges and then start ripping and replacing. Thermotine switch is a good place to start. You need to pull that out and measure the resistance of the switch to see if it's in spec. If this is faulty,you will have very hard cold starting no matter what the temperature is.

The Forgotten On

I had that issue. I replaced it and I have had easy starts ever since (also replaced cold start valve). Now if only it would maintain a stable idle after starting it cold for the first minute........

jpitman2

I had unstable idle once, with occasional stalls if loaded too quickly - Aux air valve needed checking and fixing - open more when stone cold, but nearly fully closed when hot. If it doesnt fully close hot, you can adjust with the idle screw.
jp 83 Euro S AT (CIS) 55k