1985 380sl loss of power

[jsd3024]

Here goes with the symptoms:

1. Cold start every time but when warm must pump gas pedal to start.

2. Idle at 800 rpms press gas pedal no power press a little more then backfires, slowly accelerate and it starts to pick up rpms very slowly.

3. Adjust fuel/air to rich, idle rpms climb to 1500-2000 but as engine warms I have plenty of power on acceleration

Any ideas where to start?

[TnBob]

Welcome to the forum !

Classic symptom of fuel issues.
How long since the fuel filter was changed ?

[jsd3024]

Thanks! Just purchased so not sure if or when it was changed.

[jsd3024]

TnBob, past thru your town a few weeks ago. Went to Murfreesboro for a few days.

[TnBob]

Shoulda sent me a message jsd !
But I see from your join date that woulda been hard.

With no records, you might call and ask the PO. Id sure be picking up one
and changing it.

[nobby]

Sounds like a combination of fuel accumulator and WUR not functioning properly. Best bet is to put a set of gauges on the WUR and see what's up before chasing parts OR adjusting the mixture.

How did you adjust the mixture?

[jsd3024]

I adjusted the mix with a 3mm long hex thru the air cover.

[nobby]

Originally Posted by jsd3024

I adjusted the mix with a 3mm long hex thru the air cover.

Gotcha. Are you the first or have others been there before?

I would seriously think about checking the WUR before anything else.

[jsd3024]

Gotcha. Are you the first or have others been there before? What does that mean?

[Strife]

Originally Posted by jsd3024

I adjusted the mix with a 3mm long hex thru the air cover.

This was your FIRST mistake.

At best, doing this will mask the underlying problem at idle, won't help anything beyond idle, and will have to be re-adjusted as it is an EXTREMELY sensitive adjustment. As Nobby mentioned, it's almost certainly a fuel pressure problem involving the WUR (likely) or fuel distributor regulator (somewhat less likely). It MIGHT be a vacuum problem as in something has "let go" causing a vacuum leak. You do see a pegged to the left gauge at idle, right?

[jsd3024]

Are you talking about the economy gauge? It's pegged to the right all the time even with engine off. PO owned the car for six years. Driven very little and none for the past two years. Was started once a week and ran at idle for 20-30 minutes to keep the battery charged.

[rowdie]

Yes. Economy gauge. It has a simple vacuum line connection. Should be pegged to the left at idle. If not it is either not connected or there is a major vacuum leak.

[Frank Reiner]

jsd:

Before becoming throughly involved in chasing injection problems, which may in fact be very real, please ensure that the ignition system is in perfect condition (spark plugs, wires, dist. cap, rotor, coil, EZL, etc.), and that the ignition timing is correct.

[jsd3024]

Replaced WUR with a working one. Cold and warm starts now every time. Cold idle in neutral 800-1000 after warmup it's now at 1500. Still no power and backfires if pedal is pressed to fast.

[Strife]

If you really meant "the economy gauge is pegged to the right all the time", that represents that the hose fell off the back of the gauge (not impossible) or a major vacuum leak (likely). This engine simply will not run well with ANY vacuum leaks, and just barely with a big one.

Also worrisome is the high idle, but that might be involved with the vacuum, putting the engine into "open loop" mode, where the electronics (idle control, fuel mixture tuning) aren't working to keep in running well.