99 e300d- new fuel line o-rings, how to "prime" system?
 

Hi folks.

While I had my intake manifold off to do my glow plugs, I just changed all the fuel line o-rings on my '99 e300d, and ran new injector return lines.

It's all back together and running fine, but I have 3 questions:

1) When I put it back together, I had a heck of a time getting it started again. For future reference, what's the best way to "prime" the system? These engines don't have the handy little priming pump.

2) When I parked it this morning, I restarted it right away. It started fine, but after about 5 seconds it stumbled for a few seconds then smooths out. I repeated this a few times, and it did the same thing. I've only driven the car ~15kms since doing the work... I'm thinking there are probably still some air bubbles in the fuel lines. Does that make sense?

3) My CEL is on. It was coming on before, along with the GP light, because I had a glow plug out. Does the light need to be reset after the GP is changed, or will it cancel itself out? Or, is there a chance that it has a new code from all the cranking and air in the lines?

Finally, about the o-rings. I got them from Jim Davis at fryerpower.com. I just want to show everyone what a nice job he does when he sends them out:
http://bp1.blogger.com/_p71v9ofBM6w/...400/orings.JPG

(Dirt & smudge marks added by me!)

1) Make certain pre-filter cavity and canister filters are full. Helps if tank is +1/2 full and for nose to be lower than tail. Crank 30 secs, rest 10 secs. Three cycles then let start cool off for an hour and try again. If it acts like it wants to start keep cranking. Continue cranking 2-3 secs after you think it caught; it wont hurt the starter and if it isnt running will prevent you from starting all over again.

2) May be residual air in which case should disappear quickly or that you have a bad seal somewhere.

3) Depends on which code it is. If its PO380, it will turn itself off after 3 cold/hot run cycles. Best way to aviod CEL's is to spend big bucks on a fancy scanner......:rolleyes:

thanks!

I'll remember to make sure the prefilter is filled up next time... I didn't do that! I also had the front of the car up on ramps, so I'm sure that didn't help.

I'm hoping the short little stumble is just from residual air. I'll give it a couple days.

As for the code, someone told me to disconnect the battery for 15 minutes, then hook it back up... that should clear the code. Is that true of MBs? And for code readers, most peopel here seem to be using scangauge2. Will that reset most of the codes I'll ever get?

The ramps def didn't help.

Disconnecting the battery ought to clear the code; problem is it may also clear the memory of the seats, windows, keys, etc causing them to need to be re-snych'd.

Best idea is to go to autozone and get teh code read then earased; at least then you'll know what it was and can do something about it if necessary rather than hoping it wont come back.

Again, thanks!

The code was on before I did the work, because I had a bad GP. Not sure if this is a new code from air in the lines.

I'll try disconnecting the battery though, I had it unhooked for 4 days while I did the work, so the presets are lost anyway.

No code for air.

If it's PO380 and it doesnt reset itself after 3 cold/hot run cyles (typically 1.5 days for a daily driver) there remains a problem. This is why you need to know what the code is.

Any OBDii scanner will work. The SC II is about double the cost of the typical scanner, but is a fun toy also.

Could I have triggered a code by cranking the $chit out of it to get it started?

If you turned the key one time w/o glowing and cranked on cold GP's, yes. That would give you PO380 again which would clear itself (as mentioned previously).

I did that for sure. I'll give it a few days to clear... thanks a ton for your help!

I got a code reader (OBDII) on ebay for <$25 delivered. It's not a Scanner II, but it reads and deletes codes. Works for me!

Well I definately have an air leak somewhere. Watching the return line, it's very "bubbly"... it never had any bubbles before.

Question: how tight should the fuel filter be on? I'm wondering if that's where my air is getting in. I'll pull things apart tonight and vacuum test everything for air leaks.

Did you change the pre-filter O-ring?

Both of them... the one on the fuel fitting, and the larger one around the base of the filter

This is the screen mesh filter not the canister one you are talking of, right?

http://www.peachparts.com/shopforum/showpost.php3?p=724516&postcount=8

Pic 2 item 29

You weren't talking about 11 and 14, were you? 29 tends to leak once you touch it.

Hmmm

A couple question, after looking at that image.

1) o-ring #29... that's the one that goes around the "neck" of the prefilter, correct? Or is #26 an O-ring and not the # for the prefilter itself?

2) I only remember doing one rubber O-ring on the bolt for the fuel filter(20). Anyone have a clearer picture of where 11 & 14 fit on the bolt? Just the same, if those were bad, wouldn't it leak fuel between the filtered & unfiltered ports, not air from the outside?

Correct. 29 is the O-ring for the prefilter. 26 is the prefilter.

Petty much goes by the grooves. It could do both but 29 is the usual culprit for air leaks when you do a fuel filter service. 29 NEVER comes with the filter. You have to get it separately.

Ok, then that's the one I changed.

I'm curious about those two little o-rings on the main filter though

My main filter bolt only uses one oring.

The filters I get from Phil always contain two orings.

The 95 with the push button kill switch intregrated onto the filter bolt uses the 2nd oring.

Well you just saved me 2 hours of head scratching. Thanks!

Removing air from the fuel lines
 

I did a fuel line/o-ring rebuild on my E300d last summer and to prime the system with diesel before starting I used a marine-style fuel squeeze bulb. I disconnected the fuel return line where it transitions from a rubber hose to a rigid plastic line (near the brake booster, but in the main engine compartment) connected the squeeze bulb, and started pumping. This sucked the fuel into the empty lines and fuel filters. Once most of the air was removed, I re-connected the return line and started the engine. It started almost immediately and quickly removed any remaining trapped air.

Effective, but not as easy as pointing the nose of the car down hill and turning the key!

Paul