I have a 98 jeep wrangler that I installed an 81 300SD engine in. The engine has died a few times on me while driving, it suddenly starts losing power like loss of fuel then dies even with my foot to the floor. I suspect its air getting in somewhere. The primary filter will not fill more than half and the fuel is slowly coming in. I have checked the hose clamps back to the tank and tightened the connections. Any ideas on what would keep the primary filter from filling?

The primary never fills completely. The size of the air bubble is somewhat related to the amount of fuel in the tank. The lower the fuel level, the greater the size of the air bubble. It has no effect on the operation of the vehicle.

Thank you! At times there is barely any fuel in the primary even with the tank 3/4 full is that still normal?

Assuming that the amount of Fuel needed is not getting up to the Primary Plastic Filter; it could be just like in a Mercedes you have Fuel Tank Screen or Fuel Tank Vent issues.

It also could be that your Spin-on/Secondary Filter is plugged.

Also what Fuel are you using?

__________________
84 300D, 82 Volvo 244Gl Diesel

Im using regular ulsd at the pump. Can I try removing the cigar hose to see if im getting a steady fuel flow? If I did that should it be slowly coming out or is it higher pressure?

The cigar returns an ounce or two per pulse--I put on a longer piece of 5/16" ID hose to pump out a tank when necessary; about 10 minutes for 5 gallons at idle.

__________________
James Marriott
2003 Buick Regal
1983 300D (228k, frau Auto)
1996 Suburban K2500 (192k, 6.5 turbo diesel/4WD towmaster 10,000)
www.engineeringworks.biz
1987 300SDL junker 170k
1982 300SD junker, 265k

My clear fuel filter is always half full. Seems to have no effect on the engine.

__________________
JWJ
1983 MB 300D - > 430,000 miles - Deep Blue - Bilstein Comforts - 0-60 in 24 seconds - 27MPG
1985 MB 300TD (wagon) - > 275,000 miles - Manila Beige - Thule rack - 0-60 in 18 seconds - 22 - 25MPG
Biodiesel, Mobil Delvac 1, and Viton fuel lines!

I guess I should start looking to see if i can find an air leak somewhere in the line that could be causing it to stall.

I have a similar issue with my all stock 84 300d. It runs fine for 20-30 min of driving. Then begins to lose power and misfire as well as a very rough idle. It has only completely died on me 3x though. After I let it sit for an extended period (overnight) all is fine again.

I suspect clogged screen or vent or both. However yesterday I performed a diesel flush from diesel giant. With the external tank of diesel flush as the only fuel supply I encountered the same symptoms. I changed my secondary (spin-on) filter and bled all the air from the system and went on a road test. Seemed ok but it was just a quick test around the block. I guess i'll find out a little later when I take it across town.

I have all new fuel lines and just need to make some time to pull the tank and clean everything. This car was ran on wvo for a few years before I got it. its been a hell of a time "de-gunking" the fuel system. If once I change the lines and clean the tank I still have issues, I think i may suspect the IP. although the IP is not known to go bad, so it is unlikely.

To the OP:

You should defiantly check your feed, return and vent lines. Remember the cigar hose is the return to the tank. Your main feed should run into the pre filter then into the air bleed/ fuel pump under the IP.

Does the return line have to be submerged in fuel as well or can it just enter at the top of the tank?

just in the top is fine.

__________________
Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

Checked my connections again everything was tight. I have some tiny air bubbles that sit in the primary filter and once in a while a bubble about the size of a tic tac will enter the primary filter. Would that be enough of an air source to cause the engine to die?

is your fuel tank vented? try driving with the fuel cap off...

OK, we need some details about the benz-jeep swap. i've got a wrangler and i've been wanting to swap a 123 motor for years. how did you do it? what trans? adapters? auto or 5 speed? etc....

__________________
1987 300TDT
1981 VW MKI Caddy 1.6 diesel, waiting on engine swap
1983 D-50 Power Ram 4x4 "Mitsubishi" 2.3 turbo diesel
assorted gas powered crap and motorcycles

RIP: 1984 300TDT, 1982 300TDT, 1984 190D 2.2, 1992 300D 2.5, 1987 300TDT, 1982 Maxima LD28, 1983 Maxima LD28, Isuzu C223 P'ups X3, 1983 Holiday Rambler 6.2 Banks turbo diesel, 1984 Winnebago LeSharo 2.1 TD, 1985 Allegro 6.5

I bought an adapter plate online and a flywheel which was a jeep flywheel fit for the mercedes engine. Im using the nv3550 jeep 5spd tranny. Its awesome but Im guna have to get rid of it if I cant fix this problem of stalling out all the time. I don't understand what can be happening it swill seem fine driving then out of nowhere it starts slowing down and dies. When i restart it, it runs really rough with lots of smoke.