Date registered: Apr 2014
Vehicle: 1998 MB E300TD, 1997 MB E320
Location: LA, CA
Mentioned: 117 Post(s)
Quoted: 735 Post(s)
Do you have SDS? Take it with you and when you get one of those crank no start, check the live data in the ECU.
You're looking for three things -- exhaust backpressure, lpfp pressure, and hpfp pressure.
Exhaust backpressure is supposed to be within 10 hpa from the MAF and charge air pressure. If it is over that, the car will start....sometimes. If it is WAY over that, no start at all. Common problem on 642. Faulty sensor typically reads high. I've seen exhaust temperature read 1100F....in a stone cold engine. No start. Replacing the bp sensor repaired the no start.
Second, you're looking for lpfp pressure -- 4 to 6 bar is nominal.
Third, hpfp pressure sensor reads between 200-1600 bar. 250 bar is the minimum required to start the car.
lpfp failure can cause no start, but relatively uncommon in bluetec unless dirty diesel. Can measure this with a gauge by putting a t-line in the fuel filter on top of engine and crank the car. Also can do a flow test, actuating the pump with SDS or similar device, the pump is supposed to fill a 500ml bottle in 9 seconds or less. The flow should be smooth, no aeration or splurts.
--1998 MB E300TD 291k
--1997 MB E36 Frankenstein'd AMG 199k
--2011 Suzuki DL650 58k
--1997 MB E320 161k. SOLD...loved that stupid car.
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--1997 MB C36 AMG 273k -- stripped and junked
Last edited by Deplore; 05-12-2019 at 04:50 PM.