Double Click Start Ups - 89 300e
 

Just getting tired of it. It always start on the second try, but rough with vac. gauge in the red. I searched many thread re vac. leak, which I believe it to be but could not find any.

After reaching normal temp. vac. gauge rises a bit, but not totally to the left and idling is better but not smooth.

What I've done so far:

1. cap and rotor replacement quite recent.

2. replaced fuel filter, accumulator, and check valves, very recent.

3. replaced air filter, spark plugs H9DC, very recent.

4. air / fuel ratio is in the 50's.

5. sprayed propane gas to all connections, in the hunt for vacuum leaks.

6. ICV sprayed clean.

Hot starts are 100 %. Warm starts and 50 /50.

This is my daughter's and wife's transport, so I just wanted to make it right.

Thanks for any inputs.

anyone?

have you checked the temp sensor for the fuel inj.?correct me if i'm wrong but i gather from your post that the problem is cold start.

Another cause can be leaky injectors and or seals.

thanks for the reply.

yes and no. yes, i have to double click in the mornings or at cold starts, and most at warm starts.

and no, if i do not use the car for say 2 to 3 days, it fires up at one crank.

is it the cold start sensor you're referring to?

thanks for the reply. i am debating this issue but am not sure which injector is leaky. any idea on how to trace it?

Nope. A fancy Bosch machine could probably figure it out but I'm not sure there is a great way to shade tree it. I think thats why it plagues so many M103 owners who have done everything right and still can't track it down. I think you might have to remove them all and take them in for testing to get real data.

on the drivers side of the head at the rear[firewall] you will see a green double pin sensor with two separate plugs plugged in.your car is on the edge of a change so it could also be one single black sensor with one four pin plug.this is the temp sensor for the f.i. and the ignition module[spark].

Thanks David.

As in the foto, I got both the green double pin sensor and the single black sensor infront of it. Could you ID these, pls. and how to know if they are in good working condition. Thanks again.

I'm pretty sure it's the green one. The single pin black one is for the temp gauge on the instrument cluster.

When you first turn the key to ON, but before turning it to start, can you hear the fuel pump run briefly to pressurize the system?

From the bottom...
(black 1 pin = coolant temp to coolant temp gage)
...this is not the sensor you are looking for...
test-
Courtesy ~Arthur Dalton
OHM 110 = 60C
67 = 80C
38 = 100C

(green 2 pin = coolant temp to CIS)
test-
Ohm's range from the temp chart in the /Engine Manual-Combustion Manual-07.3 Mechanical/electronic gasoline injection system (KE injection)-121 Testing electrical components of KE injection system. page 60

Temperature °C........Resistance k?
-20........................15.7
-10.........................9.2
0............................5.9
10...........................3.7
20...........................2.5
30...........................1.7
40...........................1.18
50...........................0.84
60...........................0.60
70...........................0.435
80...........................0.325
90...........................0.247
Same resistance values apply to KE intake air temp sensor.
I think this chart applies to these 2 sensors for all KE systems but don't know for sure.
__________________

both these guys are right,the theory here is if the f.i. comp.thinks the engine is too warm it won't provide sufficient fuel to allow engine to run cold at idle.

Yes, I do.

Thanks Marty.

Thanks David. I will run the test against the chart.

But I am more inclined that I have a leaky injector/s.

I bit the bullet, have ordered 6 and all attachments.

Do I also have to change those metal pipings from the distributor to the injectors?

no.

BTW, are those metal pipings flexible enough to push aside to replace the fuel injectors? Looks fragile to me.

Are they also readily available, jjust in case?