Start up frustration
 

Hey Guys

This was fun 4 days ago when I started this but my patients is wearing thin. Replaced the primer pump, pumped until I got all of the air bubbles out of the loosened hollow screw. Cracked the injectors on the #1. Turned the key and came as close as it has come so far to starting up. I had someone else turn the key while I bled the valves but still no go. It almost starts but won't. One thing I am wondering is 1. How do I know if there is fuel coming from the fuel tank. 2. should there be any air bubble in the see thru filter. Thanks again guys. I am the closest I have been yet.


BB

You can loosen or remove the spin on filter and crank too see if you are getting fuel from the tank. It is normal to have a marble sized bubbler in the pre-filter. Is your glow plug system working? How is the engine's compression?

1. If there is fuel moving through the clear filter, it must be coming from the tank.

2. Bubble is normal. Bigger than a marble is ok too.

keep it all in the same original thread or the advice is going to get repeated and confusing.
Have you checked the resistance of the plugs yet?

Are you thinking that new plugs would somehow be bad?And the fuel in the filter I put in there because the primer pump was taking forever to fill it up, so i funneled it in. The primer pump only seems to be pushing fuel toward the spin on, but not from the secondary.

Possibly. The number one reason for hard starts on these engines is malfunctioning glow plugs. Before I spent much time chasing down other problems, I'd confirm voltage at the plugs and proper resistance. You've confirmed voltage, albeit somewhat low, but not proper resistance. It's a simple 2 minute test that would exclude bad plugs.

OK Guys

I have somewhat of a success. I got.9 ohms from the glow plugs across the board.But I put the car in neutral and it started up,for about 6 seconds,and then it died. But when I tried to crank again it didn't seem to be firing at all. Whats the deal? I think I am close.

Did you try starting it from a bottle of fuel? Get a 1/2 gallon bottle and about four feet of fuel line. Cut the line in half and attach one line to the primary filter and one line to the hose barb where the 'cigar' hose is attached. pour in some good fresh fuel or two cans of Diesel Purge, stick the loose ends of the hoses in the bottle (making sure the inlet hose is submerged) and try to start the car. Do this before you get too frustrated...

You got it running so know it CAN run. Now you need to find the large air leak that is causing frothy fuel/air to be delivered to the IP preventing it from starting.

I'd check the canister fuel filter and the bolt on top of it. Also the work you did on the new primer pump.

What about it starting in neutral,would that have anything to do with it? Neutral safety switch? Anomaly?

Bad NSS = no cranking.

Its a fuel/air issue.

Here's a wild thought. You should be getting more than 9.5 volts at the glow plugs. Perhaps something about putting it in neutral increased the voltage to the glowplugs, making them hotter, making starting easier. Measure the voltage at the glowplugs while someone moves the shifter around and see if the voltage increases.
The other factor to consider is that if you are only getting 9.5 volts at the glowplugs, you may only be getting 9.5 volts at the starter. If this is true, your starter could simply be failing to turn the engine fast enough to start it.

By the way, I'll repeat my earlier advice WHEN TRYING TO SOLVE A PROBLEM, KEEP ALL THE QUESTIONS IN THE SAME THREAD. The info about the voltage on the plugs is not in this thread, it's in the earlier thread and it's an important piece of information that needs to be factored into the diagnosis. A member reading this thread, who hadn't read the earlier thread, couldn't try to generate hypotheses using the info.

At the main fuse I am getting 9.5 during the glow cycle.What should the voltage be?

I think you should be getting close to 12 volts. Check to see if you are getting 12 volts to the starter when it is cranking.
If you have the ability, take a video of the engine cranking and post it on YouTube, then link it here. Someone familiar with the engines should be able to tell you if the starter is turning the engine fast enough.

Nss
 

If you're having to put it in Neutral...It's either the NSS playing with you or a
Transmission linkage Bushing (s)...Maybe Both.

I'm gonna obfuscate the direction even more...Does the Starter crank the
Engine over each and every time you turn the Ignition Key to the Start position?
(In other words ,do you ever turn the key to Start and get no action from the
Starter???)
I'm starting to suspect the Electrical portion of the Ignition switch.Especially
with the lower Voltages you're showing at the GPs and the Starter.Of course
that could very well be a Bad Ground or the Dreaded Super High Resistance
Conductor.(Old Wire, 'Don't conduct so well anymore Burns Up lots of your Volts)

EDIT:

Even better...the NSS is Bad and when it does Semi-Function it ain't delivering the Full Voltage.
(Yeah,yeah, I like that hypothesis[If it's possible]
It'd be an easy FIX too... R+R the NSS... and be DRIVING!)

It's also come out that This Starter sometimes suffers the Heat Sink Blues
and the PO has just happened to remember having a Replacement that he
did not have time to replace.

No, it's not Jinxed. It's a Mercedes
(Without an RF Transmitter to call Stuttgart,for some much needed TLC)

One thing to rule out is do a intake and exhaust valve adjustment. Having tight valves might lead to enough compression loss to cause a hard starting situation.

O.K. No Prisoner(s)
 

I'm going to PM you all this in case you don't/can't find it.

1. log onto the forum...Click the Search button at the almost top right...
Click the Advanced Search button...type your "Screen Name" in the box top right...
Run down to the bottom center of the page...Click Search.
It will display ALL your posts (so that you can "find" them)
(SO, That by the time this MB finally starts,
we'll have less than 100 posts on the subject)

2.Before you do any thing else to this MB check the Valve Clearances.

3.Look at the Stern (Backside) of the Injection Pump...You'll see a little round
"Dashpot" (Vacuum Actuator) with a single Vacuum hose[That's the Fuel
ShutOff]. Gently pull the Vacuum hose off the ShutOff Nipple.'Leave it off
Whilst you Attempt to start the engine!
(This is to rule out the vacuum hoses being "crossed")
(You will have to use the red STOP button on the side of the IP to turn
The engine off when you're through)

4. One Last Time,Crack the Injector CapNuts loose ever so slightly and
crank the Starter to see if you get fuel to the Injectors.Tighten CapNuts.
4 a. Got Compression (Valve adjustment)?
4 b. Got Fuel to the Injectors ?
4 c. Got HOT Glow Plugs ?

5. Have your assistant Glow the Baby + leave the key ON.
6. 'Cross the terminals in the Starter terminal box.

No Start? Do they Still keep the "Crusher" In Mableton...
'Cause this MB is now Officially, Possessed!

[OR the Lift Pump is Totally Dead]
[Or the IP committed Sepuku when nobody was looking]

One Last Look at Miss "Fay" before I call it a Day
Oh,Oh The Eye is East of the East Coast of Florida ,below Cocoa
and She's proceeding to Suck Energy out of the Gulfstream.

I am looking for the starting block you speak of yet I do not see one on this car. It is not where the picture says it is.



BB

Some 123's lack the starting block.

HOOOOOOOOOOOORRRRRRRRRRRRAAAAAAAAAAAYYYYYYYYYYY


Running LIke a little sewing machine. Thanks for all of your help guys. I have some issues to sort thru but it cranks and recranks. I am certain it needs the valves adjusted.I will read up and attempt it.




Bob Bridges

Halle De Yulla!
 

Do we have any idea why this particular refugee from Deutschland finally threw
in the towel and started?
(Tired of you impugning its heritage,verbally?)
(Tired of you praying at it like Jehovah's Witness?)
(Just Plain tired of being messed with?)