1995 E300D non turbo ( 606 engine ) I need Tech Help.

127,000 miles with MB maintenance records.

I bought the car in September. It ran very good with no engine noises. I did a number of searches on this engine and found a list of things to check
Vacuum pump and special gasket, belt tensioner, tensioner shock (it was making noise ), Fuel O-rings ( they were all leaking ).

In October my wife lost coolant while driving the car to the store. The yellow light came on. She kept driving thinking yellow is caution, but when it turns to red stop. She informed me that night that the light came on and I might what to look at it. The car had lost all the coolant down to the bottom of the reserve container. Big leak. Oh, the PO had a jug of antifreeze in the trunk and said that the car had lost some coolant on a recent trip. Not much was used from the container.
I parked the car and did some extensive searches to find info on what I needed to do. I rented a coolant pressure tester and found that an aluminum pipe behind the fire wall, running from the battery side going to the driver side was leaking. I replaced it and pressured up the system and it held. I replaced the water pump, vacuum pump, serp. belt , belt tensioner pully, tensioner shock, fuel o-rings, fuel return lines, intake manifold gasket, trans. filter and fluid and pollen filter.
It took me until yeaterday to get all this done working in an unheated garage.
I fired the car up yesterday, I added 50ml of oil to the vacuum pump as I started the car. I took a while to start because of the fuel lines.
When the car started it made a banging noise in the front ( cylinder 1 area up towards the head).
It is loudest at idle, It seemed to get quite as I reved the engine but it made a loud bang and jerk while I was reving it. I turned the car off. I started it again and it still banged.
I forgot to mention when I was changing the vacuum pump I noticed that the timing chain was loose. This was after I drained the oil and the car sat for a month.
I did not do a measure of chain stretch because the CD manual does not indicate how to measure stretch.
Questions. Could it be a bad chain tensioner?( reading the manual it seems to be hydraulic)
Could it be an injector nailing? I did have to remove the injector lines
Is it a rod problem?
And what do I need to do to diagnose it? And fix it.
Also the fuel is still leaking and looks to be coming from the IP. The IP has a gasket in the middle.
Any Ideas would be appreciated.

Thanks Mike

__________________
1983 300DT 173,000miles sold
1983 300TDT 320,000miles sold
1985 735i 189,000miles sold
1986 528e 210,000 miles sold
1991 740 Volvo 250,000 miles
2002 VW Jetta TDI 32,000 miles sold
1995 E300D 137,000 miles
2004 Dodge Sprinter 26,000 miles
1986 325e BMW 94,000 miles
1986 325e BMW 148,700 miles
Mike