W124 Fuel tank removal + Flushing questions... - Page 2 - PeachParts Mercedes-Benz Forum

JohnM. · #16 04-08-2011, 10:09 PM

Jumper pins 30 and 87.

ps2cho · #17 04-08-2011, 10:14 PM

Quote:

Originally Posted by JohnM.

Jumper pins 30 and 87.

Perfect, thanks John.

Tomorrow is the big day then! I got my (personally) rebuilt fuel distributor ready to go. I also have a rebuilt CIS Flow Tech distributor, but I don't want to put that one in until I've driven for a few weeks and know for sure its good to go!

I'll post back tomorrow with results.

ps2cho · #18 04-10-2011, 09:10 PM

OK....

2 things:

1) Jump'd fuel pump relay and gas came out clean (phew...) I also took the opportunity to test fuel quantity from the fuel pump.
So....According to FSM it states 1L in 40seconds....I weighed a total of 1628g in 60seconds, so that calculates out to be 2.24L/min == 1.68L/40sec.

Only thing is that it mentions testing it at the fuel return line at regulator, not where I tested it. I assume I should be OK where I tested it right since the distributor is new, there will be no restrictions there.

2) New fuel distributor in...but power still sucks. I have a feeling its probably contaminated the injectors.

Unless doing the fuel return line makes a big difference, fuel quantity is GOOD so I believe I should look at injectors right? I may go buy an ultrasonic cleaner since those injectors literally have no more than 300-500mi on them.

Cal Learner · #19 04-11-2011, 09:41 AM

Robert, your flow calculation is not correct. In 40 seconds, it should be less than in 60 seconds, thus (1.628 x 40/60) = 1.085 liters.

ps2cho · #20 04-11-2011, 11:18 AM

I changed from g to L first though since gas has a density of ~0.66g/mL. I think I have it right?

ps2cho · #21 04-12-2011, 09:15 PM

Drove the car today really well on the freeway. It "seems" feel fuel starved at higher RPMs, although its slow across the entire power band. I feel like it has a huge knock at about 5000rpm right before it shifts. Feels like it hits a wall.

I think the only way to go from here is to physically flow test the entire fuel system starting at the injectors working backwards

Gotta find whats failing -- something is.

Can anybody else check my math on the fuel pump test?

Ferdman · #22 04-13-2011, 05:11 AM

ps2cho, you said "the FSM states 1L in 40 seconds" so no calculation is required. Either the fuel pump meets that flow rate or it doesn't.

ps2cho · #23 04-13-2011, 11:20 AM

Quote:

Originally Posted by Ferdman

ps2cho, you said "the FSM states 1L in 40 seconds" so no calculation is required. Either the fuel pump meets that flow rate or it doesn't.

Yes, but there is a conversion factor because gas does not weigh 1g:1ml

"I weighed a total of 1628g in 60seconds, so that calculates out to be 2.24L/min == 1.68L/40sec."

I just want someone to double check my math on this^

Ferdman · #24 04-13-2011, 02:58 PM

ps2cho, please explain why you are converting a volume measurement to a weight measurement. If the FSM says a properly operating fuel pump delivers 1L of gas in 40 seconds the specific gravity of gas is irrelevant.

ps2cho · #25 04-13-2011, 08:39 PM

I weighed my gas on my scale, which was 1628g, sorry if my post was a little confusing.

ps2cho · #26 06-14-2011, 10:01 PM

Bumping thread...

Moving house this week so will begin the diagnosis again. I want to flow test each injector.
Anybody done this before? Just curious what the best approach for this is?

This is what I am thinking....

-6x fuel lines grabbed from the junkyard (as not to ruin and bend the ones on the car)
-6x plastic water bottles with each distributor line (injector removed) placed inside
-Jumper fuel pump relay
-Lightly press airflow plate to simulate idle/partial/full load per minute

Specs state:
idle: 4cm^3/min
partial: 10c^3/min
load: 100cm^3/min

Sound like this is the best way to approach this or is there a better way or technique?
If the values come to spec, is there anyway I can check to see if the injectors (that I only replaced within the last 100mi or so) are contaminated? Is there a way to clean them since they are so new or am I SOL?

KJZ78701 · #27 02-27-2019, 08:53 PM

Robert, Did you get it figured out 8 years ago?

For anyone else, I flowed my system with plastic bottles under the injectors and adjusted the distributor to match the flow rates. I think the entire write up is on this site. The fuel lines bend enough to allow this, but be careful nonetheless. Doing it any other way might lead to unmatched fuel delivery.

Mechanical injectors can be cleaned with carb clean and compressed air with a rubber tipped nozzle. That is also a good way to check the break pressure. Just keep turning the regulator up until the injector opens. What's spec? About 30 psi? Anyway, if yours are clogged, a bit of carb cleaner and 100 psi at the nozzle will clean them up.

QUESTION: How long does it take to remove the tank and what tools come in handy? I need to grab one from a junkyard this weekend.

tjts1 · #28 02-28-2019, 12:39 AM

Junkyard fuel tanks are usually punctured.

KJZ78701 · #29 03-03-2019, 04:52 PM

I cut a 12 x 12 x 12" U into the original tank to get in there and clean it out and then welded that up years ago. The internal return line finally split so I need a replacement. Capping the hole is not an issue for me.

Let me ask this way....If I cut the hose from the tank to the pump, how much more needs to be done above that cut to get the tank out? As I recall there is a seal of some sort between the trunk and the pumps/filter etc. but I don't remember what I had to do to deal with that part of the removal.

Thanks!