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Mechanicals / Re: egine rough at idle.
Last post by s class - 07 August 2022, 02:31 PM
Djet is notorious for running rich when cold, which leads to the fouled plugs.  You can try leaning it out a bit at the ecu and/or mps.  You could also try going one heat range up on the spark plugs.  A contributor often is a tired AAV that isn't giving enough additional idle air when cold.
Mechanicals / Re: Intake boot at throttle bu...
Last post by s class - 07 August 2022, 02:28 PM
That vertical drive band is also used on the 4.5.  Getting it off isn't too much of a problem, but the success rate of trying to reuse it isn't great.
Mechanicals / Re: 280se - new to me, warm st...
Last post by s class - 07 August 2022, 01:05 PM
Those fuel filters have a specific flow direction indicated by an arrow, and it looks to me like that old one was installed backwards
Shop / Re: Looking for a W116 Grill
Last post by Zimmersci - 07 August 2022, 01:00 PM
Believe it or not, look on
Mechanicals / Re: Exploded Ignition Coil
Last post by daantjie - 07 August 2022, 12:52 AM
Maybe also just an example of how crappy quality has become nowadays.  Bosch used to be rock solid quality but even they seem to have fallen by the wayside :'(
Mechanicals / Re: Exploded Ignition Coil
Last post by Randys01 - 06 August 2022, 07:11 PM
Coils are basically filled with oil to cool them.
 I can't see the fuse gizmo?
If this coil exploded under the described circumstances..trundling along the road in is only the 2nd occurrence of that type I'veever  heard of. ...irrespective of make/model.  :o
Mechanicals / Re: 450 transmission swap Ques...
Last post by s class - 06 August 2022, 02:21 PM
I'm in agreement with Aaron, the transmission will fit, but whichever one you use,you should consider resealing it.  If budget is a constraint,at the very least you should replace the front radial seal where the torque converter neck goes into the primary pump,plus the o ring around the primary pump.  Those are two notorious leak sources.

If either of the cars is a euro spec, the transmission will be a 722.001 iirc,but even so it will be a bolt in interchange
Mechanicals / Re: K-jet troubles - totally s...
Last post by s class - 06 August 2022, 02:10 PM
Next try to confirm and resolve the air ingress at the fuel pump package.  I've only seen this once before, and the culprit was the hose from the tank to the damper which had gone slightly porous.  The result was pinging under acceleration due to being too lean.

As you then chase down your acceleration issues,you need to be sure the ignition system is good,and that timing is correct with proper advance characteristics.

You loss of static fuel pressure is highly unlikely to be the cause of your troubles, it's just not fast enough.
Mechanicals / Re: K-jet troubles - totally s...
Last post by s class - 06 August 2022, 02:06 PM
Dave,in any complex problem it pays to fix the known problems first before looking for more problems.  I think you need to get that acceleration control pressure sorted first.  I recondition warmup regulators and then set up the system on the car.  In my experience you really want no less than 2.9 bar at acceleration.   Warm control pressure with vac is a little bit more forgiving. All the good condition unmolested wurs I've seen seem to have been 3.5 bar from the factory, but anything up to 3.8 bar should be fine.  As you point out the differential between readings with and without vac is crucial.  Aim for 0.5 to 0.6 bar.  Then set the exhaust gas CO correctly with vac applied.  As I'm sure you realize, CO is set with vac applied, which means that if the differential between control pressures with and without vac is too great,you will be going too rich under acceleration.
Mechanicals / Re: K-jet troubles - totally s...
Last post by raueda1 - 06 August 2022, 01:53 PM
Quote from: Randys01 on 01 August 2022, 03:57 AMIt seems you are nearly there in terms of the correct values for everything except hot control pressure. You have to get that down. At 4000+ feet SLC has slightly less than the ave air pressure but at times it seems it is only by a gnat's whisker. Frankly, I feel as tho it is  a red herring.

There's a million cars a year go to 6000 feet in the Victorian snow fields and no one is in crisis. Indeed my own 6.9 travelled from sea level  up to the mountain top every day for 10 years with a standard WUR.
So forget Hi altitude WUR's .
You have to get the control pressure down to 3.6 then let's see.
Thanks much!!  Got some progress to report.  First, the system pressure is now exactly 5.5 bar and stable.  I played around with a few WURs and seemed to find a good one.  Hot control pressure is 3.5 bar.  Cold pressure is a bit low, ~0.9 bar at 30C ambient.  Should be more like 1.8 bar at that temp, but never mind for the moment.  The car starts instantly and idles very smoothly.  It revs freely and is drivable, kind of. 

So far so good.  But problems remain.  It still bogs down under heavy throttle.  Basically, anything beyond about 1/3 throttle doesn't have any effect.  There are a couple further issues:
  • Static pressure - The system holds static pressure OK for a few minutes, but gradually creeps down.  There don't seem to  hot start problems, though I haven't tried a hot restart after sitting 10 minutes.  So, there's a leak someplace.  For the time being I'll assume it isn't the fuel pump non-return valve since it's new.  Regardless, the leak doesn't seem severe enough to cause lack of power.  Or is that a bad assumption?
  • Fuel pump sucking air - there's a variable hissing noise emanating from the fuel delivery cluster.  It sounds as if air is getting sucked in somehow.  Can that mess things up?  Probably it can, but the power loss was present from the start, so seems unlikely.
  • Full load vac enrichment - Manual indicates that malfunction causes stumble on acceleration and/or lack of power.  Disconnecting the vac hose drops control pressure from 3.5 down to 2.5 bar.  The spec is a drop of only about 0.4 bar as I understand it.  But I tested 2 WURs and both did the same thing.  When the vac hose is disconnected at idle the engine speeds up.Maybe a candidate?

Next steps:
Check fuel accumulator for a leak
Check cold start valve for leak
Confirm air leak and eliminate
How to really check vac enrichment?

That's where I'm at.  Any ideas or suggestions would be wonderful.  This is killing me.  Thanks again,