Good Morning Members- I could use some help with my 1989 240 DL. It was running fine, my wife parked it at work, and it wouldn't start. It will fire up and run for a few seconds, then quits. I followed the Haynes manual, suggested the coolant temp sensor. I pulled on the plug a bit, and it started and ran once, so I figured I was close. I bought a new sensor & installed it, but back to the same problem, runs for a few seconds, then dies. Any suggestions? Thanks in advance for any help.

 

Is it possible to keep it running if you feed the gas? Or does it just stop running straight off as if the key were turned off? I hear lots of folks replacing the coolant sensor...when it fails it just makes the car hard to start, especially in cold weather...but it will start. If yours refuses to stay running and dies straight away I'd suspect the crank sensor has almost completely failed.

 

I did pull out the crank sensor, it's dirty, but the wires appear to be intact. I'll try it next.

 

Well, I changed out the crank sensor, but no luck. It is getting spark, the main fuel pump is working, the filter isn't plugged (will pump gas just fine when line to fuel rail is removed). I don't have a gauge to check the fuel pressure, could that be the cause? Running out of ideas, any help would be appreciated!

 

some things to try:

Even though you are getting spark .. I would still make sure the cam is turning while cranking to verify the timing belt (look through the oil cap).

Try starting it with the air mass meter unpluged.

If you put a jumper wire on the left sides of fuses 4 and 6, both fuel pumps will run constantly. Try starting it during that time.

 

You say you are getting spark but what about injector pulse?

 

I tried jumping the pump circuts, I can hear the pump, but no start. I disconnected the airflow sensor,still no luck. When I check the diagnostic codes, I get 2-2-4, coolant temp sensor. No other codes present. If I clear the codes and try to start again, no start, but code 2-2-4 again. I have replaced the coolant temp sensor (not easy if you have big hands!) and it seems to be firmly connected. Any suggestions!

Thanks!

 

I'm pretty sure 224 is a ignition code, did you see any codes from the fuel system? There are two temp sensors in the block ... one for the guage and one for the fuel/ignition ECU's. Did you replace the one with two connectors?

To verify the sensor you should measure ~2.5K ohms at the ignition ECU .. its the blue/red wire, #2 (with the key off, engine at room temperature).

http://www.ipdusa.com/version.asp?st...=336&V_ID=9668

 

I replaced the coolant temp sensor that is under the intake manifold, it has two red/blue wires. I have a list of codes, 224 is coolant temp sensor. It gets stranger- I disconnected the plug for the sensor, plugged in the old one and grounded it to the engine, and it starts and runs! I took out the new sensor, screwed the old one back in and plugged it in, but it won't start. I suspected the plug itself, one of the little metal tabs that make the connection was broken off. I found a better looking plug at a junkyard and spliced it in, but no luck. I'm getting rather confused!