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87 420SEL Wont Start

2559 Views 5 Replies 5 Participants Last post by  Benzical
Need some help.
For some time the car has idled rough.
Recently getting very hard to start.
When it does start, it dies as soon as it goes into gear, recranks pretty easy, keep revs up and I can get down the road.
Checked cold start valve, it sprays.
By-pass air valve, cleaned, seems to function. Disconnect and idle goes up to 2000rpm.
To get home last Friday had to disconnect it to get it to crank and got home.
Due to other projects, it sat till Mon morning and it won't start.
I can smell gas after cranking on it a bit, also poored gas down the throat, no change.
It seems to crank over faster, but only seems to hit on a couple of cylinders when I let off the key.
Checked for spark, pulled plug and grounded it, spark seemed good.
Tried to adjust timing with someone cranking, didn't find a point where it seemed like it was firing better, rotated about 5deg back and forth.
Anyway, I think it may have jumped timing. (194K miles)
Is there an easy way to check?
What jumps first, left bank, right bank or distributor?
Also, I can hear the fuel pump running when I am trying to crank it.
Spark, check.
Gas, I think so.
Air, check.
Timing, don't know.
Compression, I think so, no reason for it to change suddenly.
1 - 1 of 6 Posts
Hey Benzical. My advice is for you to take it to a Mercedes Benz mechanic before you really mess things up. Remember this is not a Chevy that you're working with.
1 - 1 of 6 Posts
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