Ignition cable question

[ahwe190e]

I replaced the spark plugs on my 1988 190E 2.3 yesterday. The engine has problems starting (takes about 4 to 5 attempts at cranking). Once it starts, everything runs smoothly. The ignition cables seem to be old and on their way out. Could the cables be the problem? How difficult are these to replace?

[Mike Richards]

Did the starting problems exist before the plug change?

[ahwe190e]

Before, I also had problems starting. Idling was rough and the engine kept surging a little. I cleaned the fuel injectors (BG44K) and yesterday changed the spark plugs. Idling and surging problems are resolved but the starting problem remains.

I am planning to put new ignition cables on next - a bit expensive. Is this what you would do too?

[Mike Richards]

I'll start out by saying a thing or two you already know.

Starting problems can be traced back to faulty electrical systems/connections, fuel, ignition; compression.

If diagnosis indicates the problem to be plug wires, you do not need to change the entire wire, but merely the resistor tip end - 3 to 4 inch long metal piece. These literally screw on and off the wire, at least they do on my vehicle.

You can buy them in a number of places, including this site. Changing the entire wire involves pulling the other side off the dist. cap. It's not really hard, but rerouting the 6 wires thru the plug wire strips that snap on to the cyl. head is a pain. The wire itself is metal vs. the junk used in Asian/Domestic cars. It's not likely to wear.

[ahwe190e]

I didn't know you could purchase the connectors separatly. Thanks for the tip. It is the metal connectors (resistor tip ends) that seem to be corroded/damaged. As the rubber housing (above the connector) is cracked as well, I'll replace the entire set - wires and connectors. Besides, I think these are the original wires - 14 years old and they are probably due for renewal.

I'll see if that helps. If not, I plan to look at Fuel next.

Thanks once again.

[ahwe190e]

Well, put in new cables and made no difference to the hard start problem. So now I need to look into fuel related problems.

Did some research and found problem could be related to Cold Start Valve. I want to diagnose the Temprature Sensor but am having problems. According to the Manual the temp sensor on a 1988 190E 2.3 should be of a 4 pin design. However, on my engine it looks nothing like a 4 pin design. It has 2 poles and each pole has a round connecter attached to a single wire. Where should I measure the voltage on these and should I have the ignition on when I check voltage on the temp sensor? Any one know?

[Mike Murrell]

Steve Brotherton has reported that the cold start valves duty is very short-lived. Used only at initial start-up. I believe that if your present climate is warm enough, it may not be a factor at all.

You'll need juice going thru the circuit to measure pressure(voltage). Check the sensor in parallel.

Go to the SEARCH facility and key in:

coolant temp sensor

in the search field. Click on "titles only" - 7 hits. Good info between all 7 posts.

[ahwe190e]

Thanks for the tips. I looked at the above posts and there is a lot of useful information there.

I poked around for a while (temp sensor, etc.) and couldn't pinpoint/diagnose the problem as I don't have all the tools. In the end I took it to a mechanic to diagnose the problem. He measured the fuel pressure and checked the fuel distributor, fuel pump, etc. It turned out to be a defective EHA (Electro Hydorlic Acutator). He replaced it, and the engine runs real smoothly now - cranks up without even touching the gas pedal. Problem solved.