Fuel injection runs rough when cold

[alfredhamstra]

Hello all
I have a 1981 turbo spider.
When warm, the spider runs nice. Plenty of power, direct power, no misfire.
When cold its easy to start, but not easy to keep it on.
I have to use the throttle to keep it running.
When warm, it runs nice. Fan hits in where it should, so no airbubbles and good thermostat.

Ignition is ok, good spark and timed at 10 degrees
New oil and oilfilter
Good compression, valves adjusted.
Cold start valve is ok: it sprays 4 seconds, then stops
Auxiliary air valve is good: open when cold and closed when hot
AFM i replaced with two other I had laying around (should be very bad luck that all 3 have same issues)
No airleaks, at least not that I can see (sprayed airleakspray over the engine)

What I did not test is the fuelpressure (cant find the pressuremeter...)
But I think that it is ok, it drives nice when hot, so if pressure was the problem, it should starve then also...

Any thoughts??

Alfred, the Netherlands

[18Fiatsandcounting]

It sounds like you have checked just about everything, but there is one additional item to check: The Coolant Temperature Sensor (CTS). This is the sensor in the coolant outlet at the very front of the head, up near the radiator. Not the sensors between the spark plugs (those are for the temperature gauge). There is also an air temperature sensor in the Air Flow Meter, but those don't usually go bad.

Other possibilities are a weak spark that is OK when warm, but not a strong enough spark when cold.

-Bryan

[alfredhamstra]

THANKS
I will check it soon, I have some other sensors laying around.
I will check the values also...
I saw you live in SF, my turbo is also from there, maybe you seen it


greetings
Alfred

[18Fiatsandcounting]

Hi Alfred, I did not see your turbo, but I am (slowly) getting to know all the 124 (2000) spiders in the SF area. I even work on some of them.

-Bryan

[alfredhamstra]

Update, i replaced the cooling temperature sender in the front T housing with a new one.
Now the cool start is good!
But... now it gets rough during warming up, bit irregular running.
I saw that there is little bit of oilleak out of the exhaustmanifoldgasket.
So maybe it gets some false air from there...
Sounds logical? Or can that not cause irregular running...

[trooper26]

Oil leak out of the exhaust manifold? Interesting. Did you mean out of the exhaust valve cover? Regardless, I don't think that would explain the rough running.

My father's '81 Turbo lives in the Oakland hills. It is finally running well and has enjoyed a couple sprints through the Caldecott Tunnel recently. And returns over Grizzly Peak...the fun part.

[alfredhamstra]

Update, the oilleak was from the distributor, new seal curred it.
I will bring it to a Bosch shop to measure all.
I expect the lambdasensor

[bpadda]

Hello Alfred,
Did the Bosch shop resolve your issues?
Was it the lambda sensor as you suspected?

[alfredhamstra]

Hello, I did not send it to a Bosch servicestation.
The spider starts perfect when cold.
Ans runs nice when warm.
Only during warming up its a bitt irregular.
I just have to live with it...
I replaced all sensors that it had..
I once will measure the sensor, I suspect that a new sensor can also have some incorrect readings...

greetings
alfred