ENGINE WILL NOT START

BUFFALOTG

MEMBER
1988 MERCEDES BENZ
6 CYL
2WD
AUTOMATIC
83,000 MILES

When the engine is cold it will not start. I give it a couple shots of starting fluid, it will start but has to be left idle without giving it gas. After a minute I can start to give it gas and it comes up to speed. After that there is no problem. There are new wires, sprk plugs, cap, and rotor. Is it possible the cold start valve needs to be replaced?

3 Replies

MERLIN2021

MECHANIC
17,250 POSTS

Model and engine would be of help. Diesel or gas?

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Saturday, October 18th, 2008 AT 7:33 AM

BUFFALOTG

MEMBER
2 POSTS

It's a 1988 300E, 6cyl. Gas engine.

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Saturday, October 18th, 2008 AT 7:50 AM

MERLIN2021

MECHANIC
17,250 POSTS

Generally, if it happens at the AM startup and then it'sOK, the Coolant temp sensor test this way...
CIS-E SYSTEM -1988 Mercedes-Benz 300E
Page 1 of 1
Code 3, Coolant Temperature Sensor
1.Turn ignition to "OFF" position. Unplug CIS-E control unit connector. Check resistance between sockets No. 7 and No. 21. Resistance reading should be as indicated in table. See Fig. 8 . If not okay, check wiring. 2.Unplug coolant temperature sensor connector. Measure resistance between any 2 of the diagonally opposed terminals and compare resistance values from each internal sensor. Resistance reading should be as indicated in table. See Fig. 8 . If not okay, replace sensor. 3.Check wiring harness continuity to CIS-E control unit. Resistance should be less than one ohm. If not okay, check for open circuit.
Fig. 8: Coolant Temperature Sensor Resistance