No Start help- fuel issue orrrr.??? - PeachParts Mercedes-Benz Forum

coachgeo · #1 02-21-2009, 05:48 PM

85300sd

Here is last thread on topic but since symptoms have evolved I think a new thread is due.

Synopsis

then- Car will not start when cold and fuel a leak
Work done-
Cracked fuel line replaced (rubber line that was from steel line end to lift pump under hood) 12v fuel pump installed back by tank, GP's tested and replaced, Regulator fuse tested, Ohms tested thru wirings from relay to plug. All with in speck now ohm wise.

Notes:
. cigar hose has a straight hose now.
. NO WVO FUEL system on the car or in the tank EVER. I dont install such till things are running right. This is suppose to just be a back up car/parts car for my Unimog anyway so I never put one on the car. Unimog is dissasembled right now.

Now- car almost no starts in warm weather too.
Symptoms-
. no fire you might say same as before in cold weather.
. How do I start it?
.. turning on Aux. Fuel pump,
.. bleeding canister filter by pushing fuel with pump and loosening top bolt
... followed by using cold start technique of holding starter going while engine tries to crank.
...Takes 4 or 5 times of this to get it to finally start. After that it starts easy every time. Starts fine after sitting few hours in the local bar

In cold weather the batter would crap out before reaching a start is my guess. When this first started I did not have the Aux fuel pump and did not bleed filters. So the battery drain would be worse cause starting attempts would be bleeding the system too (would take more starter spins, usually crapping out before enough bled?) Still though in cold.... after so many glows and holding the key on would it not be expected to crap out? (battery tested ok too by Autozone)

sooooo...... now what since symptoms evolved?

fuel / Air issue?

Where and why can fuel bleed back allowing air in? Apparently it takes 6 or so hours to happen.

Using Aux fuel pump the cannister bleeds quickly, as if there is not much to no air in fuel line from tank to cannister filter. With this I would think any air egress must be real close to the front of the car. Can the IP be allowing air in somewhere?

Can IP have air in it?.... that wont get bleed out when driving so it keeps showing up as an issue when startng after sitting?

I will check compression.... I just do not have the time right now to remove Inector lines to remove injector's'; or do you use GP port's. ... well..... not really... guess I do have time I just have horrible luck with fittings like those on the IP. I've cross threaded simular so many times in my life tryng to get simular (brake lines, fuel lines etc.) alligned proper and screwed back together.... that Im hesitant to pull these lines. My luck just makes me nervous cause if I cross thread one Im screwed and can not get to work. yeah I know... STUPIDDDDD

If it was a compression issue though..... why would it start so nicely once its been started once. Can I loose compression only to regain some back by turning the engine over with the start so many times?

Only piece of fuel line NOT new (besides metal line) is the one from inline fuel filter under hood too bottom of lift pump. 2" long?
Any other ideas?

blackestate · #2 02-21-2009, 07:40 PM

sounds like a definate air leak.
I would replace the crush washer on the bolt that holds the fuel filter on, replace all rubber hoses, and clamp tight. And with the elec. pump, bypass the manual, for now. There is a slow leak causing it to loose prime, Also check the filter housing for only 1 gasket, and no scratches.

coachgeo · #3 02-21-2009, 07:53 PM

Quote:

Originally Posted by blackestate

... bypass the manual, for now. There is a slow leak causing it to loose prime,

when you run the aux pump with or with out the manual inline.... how far does the fuel go? Does it circulate thru a portion of the IP, out the overflow and back to the tank or does it dead head somewhere?

coachgeo · #4 03-17-2009, 07:47 PM

update and questions.

One- seems to be electrical..... well it seems to be combination of things.

Bypassed lift pump and going all 12vpush pump back at tank.

keep it on a trickle charger even though Autozone said bat. was ok (tested in car). Why? Battery drains very fast when cold starting and becomes to slow of a spin to start car in only a few tries.

Warm weather starts like a charm unless it has sat for a day or two. Then it takes a little longer

Cold (40f and below) its a PITA but less than before.

so via these events potential diagnosis is

. bad battery?
. bad charging system?
. battery drain that worsens due to cold

in combination with:

Tired ol motor with marginal compression?

QUESTION that may be related

Am I harming my alternator

kerry · #5 03-17-2009, 10:15 PM

You need to rule out poor compression because those kind of symptoms can be caused by poor compression. You can check thru the glow plugs holes. The Harbor Freight diesel compression tester is not that expensive and checking the compression should take less than an hour. No reason to spend time chasing down other possibilities before confirming good compression.

Diesel911 · #6 03-17-2009, 10:41 PM

Have you changed the O-rings on the Bolt that holds the Spin-On filter on? The ones with a Crush washer at the top have only 1 O-ring while yours which is an 85 should have a filter bolt with 2 O-rings inside.
The commonly available electric Aux fuel pumps do not put out enough pressure to open the Overflow Valve on the side if the IP; so will not bleed the air out of the IP itself.
The stock Lift Pump has valves inside of it. It may be that some of those valves are allowing fuel to leak back.
Also If you can remove the Overflow valve on the side of the IP; take it apart (some cannot come apart some can) clean it out and check the little ball bearing that is used as a valve or for spring wear.
The best way to avoid cross threading is to turn the part in by hand as far as it will go before touching it with a wrench. If it is binding your hands will feel it.
Something like a brake tubing that is under tension or a sideways thrust or does not line up easily is harder to keep from cross threading.

TMAllison · #7 03-17-2009, 11:52 PM

Bolt #200 on the block side of the IP is a check valve sealed with a crush washer. Has it been sprayed clean or replaced? http://www.detali.ru/cat/oem_mb2.asp?TP=1&F=123193&M=617%2E952&GA=722%2E120315&CT=M&cat=143&SID=07&SGR=120&SGN=04

coachgeo · #8 03-18-2009, 02:37 AM

Much thanx folks. This is the first anyone has ever mentioned these particular items. Will look into it.

mplafleur · #9 03-18-2009, 06:54 AM

My fuel air leak was the washer for the hand primer on the IP.

coachgeo · #10 03-18-2009, 11:26 AM

Quote:

Originally Posted by mplafleur

My fuel air leak was the washer for the hand primer on the IP.

hand primer is on the lift pump not the IP.

lift pump and hand primer are out of the equation. They have been completely bypassed.

Graplr · #11 03-18-2009, 11:43 AM

Quote:

Originally Posted by kerry

You need to rule out poor compression because those kind of symptoms can be caused by poor compression. You can check thru the glow plugs holes. The Harbor Freight diesel compression tester is not that expensive and checking the compression should take less than an hour. No reason to spend time chasing down other possibilities before confirming good compression.

I agree with Kerry. Although I am not 100% sure that compression is the problem, it is best if you can rule it out. Do a compression check.

If you want to look for air leaks, go to your local race shop and get a few feet of 5/16 poly hose. It is transluscent so you can see through it. The one I get it from is pink but have also seen it blue. Take off the cigar hose and put this in place of it. Then let the car run and examine the poly hose. If you are sucking in any air anywhere it will show up getting pushed back to the tank. A flashlight on the poly hose may help.

In answering your question as to why it would start better after it has been started in relationship to compression...once you start it the internals are warmed up. Even though you may let it sit for a few hours or even half a day the internals will at least remain warm and it will start better. To me this may be a clue that it is indeed compression but if there are other problems it may start better after being started earlier in the day.

But, get a compression check. You could be chasing dead ends forever. Rule it out first or find your answer. The kit costs $25 at Harbor Freight.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93644

coachgeo · #12 03-18-2009, 03:44 PM

Quote:

Originally Posted by Graplr

The kit costs $25 at Harbor Freight...

I have one already. Will check it when I can do so. Hopefully soon. Will I need any seals (crush washers, O rings etc.) to reinstall the injector lines or anything else that will be dissasembled for this test?

kerry · #13 03-18-2009, 06:46 PM

Quote:

Originally Posted by coachgeo

I have one already. Will check it when I can do so. Hopefully soon. Will I need any seals (crush washers, O rings etc.) to reinstall the injector lines or anything else that will be dissasembled for this test?

Do it thru the glow plug holes. No need to touch the injectors or injector lines.

coachgeo · #14 03-19-2009, 01:08 AM

Quote:

Originally Posted by kerry

Do it thru the glow plug holes. No need to touch the injectors or injector lines.

geeeezzz you guys make up your mind...... took me 7 hours trying to snake my hand around injector lines to remove the GP's when I replaced them a few months ago. Got alot of replies say I should have just removed Injector lines.

Now your telling me not to remove injector lines.... so which is it?

There is NO ROOM for tools under injector lines, much less snake my hands in there to use smaller tools to remove GP's with out tons of agrivation and a full working day to get it done.

Side note. Car sat all day. Literally....slept in my office last night cause I knew I needed an early start on today... joys of owning a biz..... anyway..... 11pm... thought I would go get a beer. In the 60's out side.

Dead battery. FLAT dead. Nothing left on that I could tell.. hmmm

kerry · #15 03-19-2009, 09:08 AM

Quote:

Originally Posted by coachgeo

geeeezzz you guys make up your mind...... took me 7 hours trying to snake my hand around injector lines to remove the GP's when I replaced them a few months ago. Got alot of replies say I should have just removed Injector lines.

Now your telling me not to remove injector lines.... so which is it?

There is NO ROOM for tools under injector lines, much less snake my hands in there to use smaller tools to remove GP's with out tons of agrivation and a full working day to get it done.

Side note. Car sat all day. Literally....slept in my office last night cause I knew I needed an early start on today... joys of owning a biz..... anyway..... 11pm... thought I would go get a beer. In the 60's out side.

Dead battery. FLAT dead. Nothing left on that I could tell.. hmmm

Hmmm? I've never suggested removing injector lines to do the glowplugs. I can change out all the glow plugs with the lines in place in about 20 minutes. Can do a compression test thru the plugs in about 45 minutes or so. Perhaps our hands are different in size but my hands are not real small.

You need to check and see if something is drawing your battery down with the key off. Perhaps this is part of your problem. You're losing battery power over time. Try disconnecting the battery when you shut if off and see if this makes a difference with the next cold start.

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