The M104.980/981 were twins that had VERY few problems. M104.981 was in the 300SL.

The headgasket problem compared to the 104.992/994/995/996 was NON-existent.

I liked those engines as the fuel system was virtually the same as ALL previous 6 cylinders.

CIS-E can be a pain to those NOT familiar with the concept & diagnosis.

Wasn't LH-SFI, only the 1992-93 M104.990 used that fuel system(300SE/S320)

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

That's what I thought.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Thanks guys, I forgot about the CIS-E version.

300ce M104 put out 217 hp, 300sl/300se M104 put out 228 hp.

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1993 500E
http://2phast.com/500e/500e-sig.jpg

104.981/ 980/ 990 CIS-E engines, if I understand correctly, are basically a mechanical injection system with electriconic control, using a distributor with one coil wire and 6 spark plug wires, whereas the M104.992 engine is an HFM-SFI system (hot film mass air flow sensor with sequential fuel injection), combining fuel injection and ignition control in one module.

These 3.0 liter M104 engines might be advantageous because they are simpler. They don't have an expensive throttle actuator which are prone to failure, as well as not having the infamous deteriorating wiring harness problem.

The later 3.2 liter M104 engines have variable valve timing on the intake cam, which gives them much more torque, making the torque curve broader and flatter, developing more hp at a lower rpm, making the power more usable and noticable.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".