83 300sd won't start, runs great - PeachParts Mercedes-Benz Forum

seecreech · #1 01-18-2012, 10:34 PM

So, this is what I have done to the car since I bought it..

Primary and secondary fuel filters 1,500 miles ago
Valve adjustment 1,500 miles ago
Oil change and air filter 2,600 miles ago
Fixed a couple of oil leaks
New Glow plugs, and all 5 are getting 11+volts until the relay cuts off.
Performed Diesel Purge 1,500 miles ago

Known issues..
Runs slow and lacks power when cold, but seems alright when warmed up.
Doesn't want to start, now doesn't start at all.
On Hwy, runs like a champ.

The Problem...
The car has been starting fine until it got cold (athens, georgia 40F and below). I started plugging it in and it seemed to help. I changed all the glow plugs and checked voltage, they checked out (11+volts until relay clicks). Now, the car won't start at all and I had to have it towed home.

It was running fine, cut it off and ate a burger. Tried to start it and nothing. I thought since it's been getting harder to start for the last couple of months it might be fuel related, so I glanced at the primary fuel filter and it didn't seem to be as full as it should. So, I did the following...

Cracked the bolt at the secondary fuel filter between it and the lift pump, and primed until fuel cam out, then primed some more to make sure to get all the air out.
Cracked the bolt at the injection pump between it and the secondary fuel filter and primed as before... then, when I cracked a injector line at a injector.. I couldn't get fuel to come out when I primed.. wtf? And, the primary fuel filter is still about half full. Primer pump bad letting air in? It's the original white style that ya screw in after priming.

Also, if I turn the engine over I'm getting 7-10 psi between the lift pump and the secondary fuel filter. Is that about right?

I think I'm getting air in the lines from the primer pump since I can get fuel to come out of everything it should come out of while priming, except the Ip lines.. please help.

Thanks!

kerry · #2 01-18-2012, 10:54 PM

Do a compression check.

barry123400 · #3 01-18-2012, 11:32 PM

When you prime with the primer pump do not expect to see fuel come out of an injector line. The function of the primer pump is to get fuel into the base of the injector pump.

If you pump the primer pump you should feel more resistance until the relief valve on the injection pump make a little noise as the fuel compressed to around fifteen pounds opens it. If this occurs things are normal.

Get a friend and have him or yourself spray a little wd 40 into the intake with the air filter cover off. The other party cranking the engine. If it starts to run on the wd40 you do have a fuel supply problem in all likelyhood. If it will not fire on the wd 40 after a glow cycle and sprayed while being cranked then it may not be a fuel issue.

If you have a block heater and can plug the car in for a few hours before this test is even better. I have no ideal of where you live or the ambient temperatures there at this time of the year.

vstech · #4 01-19-2012, 01:39 PM

Quote:

Originally Posted by seecreech

So, this is what I have done to the car since I bought it..

Primary and secondary fuel filters 1,500 miles ago
Valve adjustment 1,500 miles ago
Oil change and air filter 2,600 miles ago
Fixed a couple of oil leaks
New Glow plugs, and all 5 are getting 11+volts until the relay cuts off.
Performed Diesel Purge 1,500 miles ago

Known issues..
Runs slow and lacks power when cold, but seems alright when warmed up.
Doesn't want to start, now doesn't start at all.
On Hwy, runs like a champ.

The Problem...
The car has been starting fine until it got cold (athens, georgia 40F and below). I started plugging it in and it seemed to help. I changed all the glow plugs and checked voltage, they checked out (11+volts until relay clicks). Now, the car won't start at all and I had to have it towed home.

It was running fine, cut it off and ate a burger. Tried to start it and nothing. I thought since it's been getting harder to start for the last couple of months it might be fuel related, so I glanced at the primary fuel filter and it didn't seem to be as full as it should. So, I did the following...

Cracked the bolt at the secondary fuel filter between it and the lift pump, and primed until fuel cam out, then primed some more to make sure to get all the air out.
Cracked the bolt at the injection pump between it and the secondary fuel filter and primed as before... then, when I cracked a injector line at a injector.. I couldn't get fuel to come out when I primed.. wtf? And, the primary fuel filter is still about half full. Primer pump bad letting air in? It's the original white style that ya screw in after priming.

Also, if I turn the engine over I'm getting 7-10 psi between the lift pump and the secondary fuel filter. Is that about right?

I think I'm getting air in the lines from the primer pump since I can get fuel to come out of everything it should come out of while priming, except the Ip lines.. please help.

Thanks!

WHIEW! nice first post!
Welcome to the forum!

11+ volts is not much important other than telling if the fuse in the relay is good or not. you need to know either how many amps the circuit is pulling, or pull the harness from the relay, and ohm to ground each plug to see if it's bad. with 11+ showing on the meter, I'll bet you have at least 3 plugs out. my car with all plugs working drops the battery voltage to 10.3V. a good way to see if there are BAD plugs is with an ohm meter. the plugs that have zero continuity (reading infinite on the meter) are open and bad, the ones that read around .6 ohms could be good, above that and they are suspect, and need to be pulled to see what they are doing.
PLENTY of good threads showing what a good vs a bad plug glowing should look like.

seecreech · #5 01-19-2012, 04:54 PM

Thanks for all the replies!

@Kerry..
I'm planning on doing a full comp check this weekend before and after a second valve adjustment. I read somewhere, maybe here that if the valves havent been adjusted in a while and ya do an adjustment, do another after 500 miles for allowing time for carbon so burn off.

@Barry...
It seems like when I fist got the car and had to learn the priming process that I crack and injector line at the injector and gas came out when I primed.. also, I've tried the starting fluid in the intake a couple of times before, the car SLOWS DOWN BIG TIME while turning it over to crank...yea. weird. Funny, it is called "Starting Fluid" not "Slowing Fluid". hehe.

@vstech..
So you think new glow plugs I purchased and installed less than a month ago could be bad? or maybe the wiring harness going to said plugs? I'll put that on the list of things to check this weekend.

Thanks guys.. Update!
Charged the battery over night and plug the block heater in all day today. Got home and still didn't want to crank.

barry123400 · #6 01-19-2012, 05:36 PM

After the glow plug light extinguishes then start to crank. At that time spray the wd40 in and see if the engine will fire up. Takes two people to do this basically.

If it will not fire up after being on the block heater for a couple of hours with the wd 40. Either your glow plug circuit has an issue or something more serious is wrong.

Technically it was luck of the draw if you saw fuel coming out the one loose injector line when you were using your primer pump long ago. The port into that cylinders element in the injection pump must have been open. Once that wd 40 test is done properly it will indicate where to go and what to do.

seecreech · #7 01-19-2012, 06:01 PM

I forgot to mention this car is hard to start after running at norm temp, then resting for like 10 minutes sometimes.

Oh, the night in question the glow plug light stopped coming on, but I can hear the relay close after 45sec or so, and still 11+v at each gp.

seecreech · #8 01-21-2012, 05:39 PM

Update!

I removed all five glow plugs and the only one that wasn't absolutely DESTROYED was #2.. the reason? I read somewhere that you should always clean out the hole said plugs are screwed into.. I only cleaned out the #2 hole with a brush otta a gun cleaning kit.
New Gp are on the way.

I checked the compression of #2 as well, it topped out at 300psi. Gonna do the rest tomorrow before and after I readjust the valves.

kerry · #9 01-21-2012, 05:49 PM

When you say 'destroyed' what exactly do you mean? Pictures? GP's don't typically get destroyed.

seecreech · #10 01-24-2012, 03:12 PM

http://www.peachparts.com/shopforum/members/seecreech-albums-1983-300-sd-picture3659-glowplugs.html

seecreech · #11 01-24-2012, 03:17 PM

That's a pic from #1 to #5 in order from left to right. As you can see, the lenth of all Gp are shorter than #2, that's the only one I think was working.

Also, compression check in. Done cold because the car won't start. From left to right starting a #1... 320,300,240,260,180.

I adjusted the valves when I got the car, and today, and I could not get more than .20 mm gap (calls for .35mm when cold) on the exhaust valve on #5.. guess the head needs to come off and the valve replaced?

I'm pretty sure my starting prob is with the Gp.

Zacharias · #12 01-24-2012, 03:26 PM

Quote:

Originally Posted by barry123400

If you pump the primer pump you should feel more resistance until the relief valve on the injection pump make a little noise as the fuel compressed to around fifteen pounds opens it. If this occurs things are normal.

So little resistance and no noise even after 10+ pumps would indicate that the primer pump is gone? It's the new style.

I have a new one on order but I am wondering about the relief valve on the IP now that I read this.

The symptom is that I'm getting air into the lines when the car sits for more than 10 hrs or so... gets progressively worse as the temps drop.

whunter · #13 01-24-2012, 04:06 PM

Quote:

Originally Posted by seecreech

That's a pic from #1 to #5 in order from left to right. As you can see, the lenth of all Gp are shorter than #2, that's the only one I think was working.

Also, compression check in. Done cold because the car won't start. From left to right starting a #1... 320,300,240,260,180.

I adjusted the valves when I got the car, and today, and I could not get more than .20 mm gap (calls for .35mm when cold) on the exhaust valve on #5.. guess the head needs to come off and the valve replaced?

I'm pretty sure my starting prob is with the Gp.

What state are you in?

I suggest inviting local members over for a quick valve adjustment, compression test party.

It sounds like there may be several issues on your engine.

The compression numbers make me suspect serious valve adjustment issue (carbon valve/seat) or a bad head gasket.

The glow plugs make me suspect bad injector nozzle spray pattern, or serious damage from the previous owner, (starting fluid use/abuse?).

.

seecreech · #14 01-24-2012, 07:04 PM

Update...

I put a couple of oz. of Marvel Mystery Oil (Mmo) into each cylinder via the glow plug hole. Then, installed everything back onto the car, turned it over a couple of times to get the Mmo move around inside of engine. Then let it set for a couple of hours...

IT STARTED RIGHT UP!!!!

The true test will be in the morning. I'll let it set tonight and try to start it first thing tomorrow morn. It's gonna be 40d, so for Georgia drive'n it should work.

Thanks you for all the Replies and suggestions. I'll keep ya updated!

But, if I was to be driving this car into colder climates (10d at night), any suggestions as to what I could do to insure a good start in the morn, minus plugging in the heater on the engine block?