Check all the fuses with a test light or DVM first.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Will do and thanks a lot for all your help, Sugar Bear! I will continue to follow up on my progress. Stay tune.

Welcome...good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

An afterthought...gas in the tank has been confirmed correct? Don't rely on the gauge.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Since it fires up for a few seconds when you prime the intake, you can rule out a spark issue. It's easy enough to check for fuel pressure at the port on the rail by simply pressing the valve after cranking. fuel should spray out. If you have the means to hook up a fuel pressure gauge, you should be around 50psi. If the fuel pumps aren't running during crank, check to see if they are getting power. More importantly, since this is a 1994, I would check the condition of the engine wire harness unless you've already had it replaced.

Yes sugar bear I do have enough gas in the tank, fuel guage is working properly on the instrument cluster panel.


I got the fuel pressure gauge from autozone as a loan-a-tool. Although I had to pay in full for the pressure gauge, I can return it back to Autozone within 90 days and get a full refund. Good Deal! Set up fuel pressure gauge to the schrader valve port on the fuel injector rail (no adapter needed) as I assumed the thread on the schrader valve port is universal. Tight fit on the schrader valve port. Turn the ignition to on. Readings on the pressure gauge was barely above 0. See the picture below. I then proceeded to start the engine, same results on the pressure gauge readings. What did I do wrong? I suspect that the fuel pump motor is not producing power. There should be some pressure readings on the gauge. I need to investigate this issue further.

The fuel pump relay behind the battery is good as far as I can tell. The 30 amp fuse is not broken. However, I have additional spares of the same type of fuel pump relay. Will double check that fuel pump relay.


Afterwards, with ignition turned off and removed the Fuel pressure regulator hose to find out if the fuel pressure regulator is defective. According to sources, if there is no gas leaking or coming out of the fuel pressure regulator, then the fuel pressure regulator is good.

I am having problems trying to check the fuses and relays. I do have both the test light and the Digital Volt meter (DVM). I just need to educate myself more fully in understanding how to test the fuses and relays using the test light and the DVM.

It seems to me so far I have a lot of electrical gremlins/issues. The trick is to pinpoint exactly where is the location of the electrical problems, if any, and elsewhere. I try not to get frustrated and discouraged, just focus with a positive attitude and keep challenging myself that I can do this.

Also, while I checked the fuse box and the relays behind it, something caught my eye. Knowing that the parking brake, abs/asr lights on instrument cluster panel that started the series of issues/problems to begin with and the engine runs fine at that time. According to the fusebox diagram/chart, there is no relay for ASR/parking brake listed. See the picture of the fusebox chart. It is exactly the same as mine. I wonder if there is a relay for the asr/parking brake somewhere on my mercedes? See the video: https://www.youtube.com/watch?v=SSugX9TZKc0. Notice as the descriptions of the fuses and relays and its locations, See the Relay I and the descriptions said "V1 Power Seat Diode (Replaced by k24 as of by 1990 and also V5 Parking Brake/ASR/Electronic Accelerator (as of 1992 models 400/500E) However, on my 1994 E320 wagon, there are two relays on the ABS/ASR pump module, the 12 volt relay and the ABS pressure regulator.

I am tempted to get a new OVP relay brand mercedes or KAE Kaehler Overload Protection Relay (OVP). I need to do more research/studying on how test the OVP using DVM and other issues as well. Comments, feedback, advice is greatly appreciated it. Stay tune.

Attached Thumbnails

   

Paul Roberts, thank you very much for your last comment. I appreciated it. As mentioned earlier about fuel pressure, I am still working on it. You are correct, however, I suspect the fuel pumps are not running during cranking the motor. I will check the power of fuel pump to make sure if it is running. As for the wire harness, Yes, I remembered about that infamous eco junk wire harness awhile back. Fortunately my wire harness is good and not eco-junk.

Look in the fuse box cover diagram, is anything marked fuel pump? If yes, is there 12VDC to AND through that # fuse with the key in the run position? I don't know if they are the same but my '91 recently had no power to fuses 5, 6, and 7 causing a crank but no start. Traced it back to a bad connection at the ignition switch. Also try tapping on the the fuel pump relay, IIRC it's a green cube relay behind the battery near the OVP.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Update:
Got two new fuel pumps and fuel filter yesterday and today, which is why I am delaying my follow up until now. First, I tested the old fuel pumps on the 1994 Mercedes E320 wagon that were already on using the 12 volt maintenace charger. Hooked both the positive and negative terminals on the fuel pumps. The larger size terminal is the positive, the smaller size terminal is the negative, 8mm and 7 mm, respectively. I tested both fuel pumps feeling the vibrations and hearing of the electric motors on the fuel pumps. Both were running. The fuel pump and the fuel filter connected together, located further away from the gas tank, under the rear passenger side seat, I felt the vibrations running, hearing the fuel pump running and stopped about 30 seconds. I tested it again, same thing happened. Is that normal due to building up pressure on the fuel line or should it continue to run? I then turned on the igntion to start, nothing happens. Crank and no start. For now, I decided to leave the older fuel pumps and the fuel filter alone and intact.


I also noticed the starter when turning on the igntion is rather faster than normal. Is that a sign of little or no engine compression? If the engine compression is bad, then fuel delivery system (two fuel pumps, one with fuel filter attachment) would not work or is that a separate issue? I also tested the new two fuel pumps using the 12 volt maintenance charger and both worked fine. What else to check for engine compression? Get a engine compression tool and test the psi and if so what is the normal psi on this 1994 Mercedes E320 wagon? I read somewhere that the engine compression is around 55 psi. Is that true? Other areas to check? Crankshaft position sensor? camshaft position sensor?

I tested the fuel pump relays using this video for guide/help: https://www.youtube.com/watch?v=ieyr63wDqG0.

My four spare fuel pump relays shows the following results: 72, 78, 82, and 71. So I suppose that all four fuel pump relays worked. I used the fuel pump relay reading 82.

I also tested the copper fuses in the fuse box using the light tester with the starter ignition on, All of the fuses showed positive light beaming on the light tester, except 3, 4, 8. Also, 13, 14, 15, 16 were turned off due to headlights low beam, high beam. However, when turning on the light knob, all of the 13, 14, 15, 16 fuses location were working with the light tester. So basically, 3, 4 and 8 were not working with light tester.

See the fuse box chart I enclosed in this post.

According to the fuse box chart, #3 refers to parking/tail light right, headlamp cleaning unit, illumination: license plate, instrument control elements.

I wonder if the #3 fuse is relating to the parking brake light on the instrument cluster panel that is still on after I started the engine was running before the current problems/issues now?

Fuse box chart #4 refers to Fog light.

Fuse box chart #5 refers to stop lamp, instrument, front roof light, electric bulb control unit, cruise control, tachometer.

Do any of the above fuses #3, #4, and #5, are related to the current issues of crank, no start? How can I get fuses #3, #4, and #5, on the fuse box to get working when using the tester light? All three copper fuses #3, #4, and #5 are good. No signs of broken, wear and tear fuses. I wonder if the wiring is short on those 3 fuses? If so, how do I fix the wiring short and where are they?

Next is to test the crankshaft position sensor. Both of my Mercedes wagon have different crankshaft position sensor numbers. On the current wagon, crankshaft position sensor number is 003 153 4928 AR 93 M10. I looked up that part number on this website: https://mbparts.mbusa.com/oem-parts/mercedes-benz-engine-crankshaft-position-sensor-0031534928. According to the fitment chart, none of the vehicles shown to fit on my 1994 Mercedes E320 wagon. How strange!! When I looked up for the correct year, model, it shows part number 003-153-75-28-64 and the fitment type. https://mbparts.mbusa.com/oem-parts/mercedes-benz-crankshaft-position-sensor-003153752864?c=Zz1lbGVjdHJpY2FsJnM9cG93ZXJ0cmFpbi1jb250cm9sJmw9MSZuPVNlYXJjaCBSZXN1bHRzJmE9bWVyY2VkZ XMtYmVueiZvPWUzMjAmeT0xOTk0JnQ9YmFzZSZlPTMtMmwtbDYtZ2Fz

Also, another crankshaft position sensor different part number: https://mbparts.mbusa.com/oem-parts/mercedes-benz-sensor-0031530128?c=bD0yJm49U2VhcmNoIFJlc3VsdHMmYT1tZXJjZWRlcy1iZW56Jm89ZTMyMCZ5PTE5OTQmdD1iYXNlJmU9My0ybC1 sNi1nYXM%3D.

How is that two different part numbers of the crankshaft position sensor are one and the same?

The other 1994 Mercedes E320 wagon without the ASR crankshaft position sensor number only show on the top end connecting to the wiring near the battery is 09 967 without the long numbers on the cable as shown on the current wagon. When I research this particular part number, none of them show up. How strange!


Are both crankshaft position sensors are one and the same even though different part numbers?


Also, doing some research on the OVP. Excellent post on OVP below:

https://www.benzworld.org/threads/ovp-basic-function-and-test.1572015/

I have 4 of OVPs (over protection relays) that are supposedly good and will test them all.


Thanks to all for reading and written comments on this post. Any comments, advice, feedback is greatly appreciated. Stay tune for further adventures of the 1994 Mercedes E320 wagon electrical gremlins issues.

Sugar Bear, there is nothing in the fuse box cover diagram that shows anything marked fuel pump that I am aware of. I did checked the fuel pump relay, green cube relay behind the battery near the OVP and so far, it appears to be fine.

I finally got the crankshaft position sensor out of the Mercedes without removing or loosening the starter. I used this particular video as a guide as shown below:

https://www.youtube.com/watch?v=6xAS3aFoQH0

After jacking up the left front tire (driver's side) and removing the tire, I put in the jack stand under the rubber boot. The best way to get under the crankshaft position sensor is to have me facing around 11 o clock position on the ground under the wheel rotor just with my right arm under the opening where the starter motor is located. Going through the process of trial and error, I was trying to get the CPS out. Since I cannot see the crankshaft position sensor, it is basically feeling the location of the bolt that holds the crankshaft position sensor just above the starter motor in the bell housing. Follow through the cable/wire by feeling it and stops at the bell housing. I then put in 5mm hex socket by itself in the hole. After securing the 5mm hext socket in the hole of the bolt, I used a small socket rachet to get in the 5mm hex socket. After loosening the 5mm hex bolt, I removed the socket ratchet, and turn the bolt manually as it was easier to do so to removed the 5mm hex bolt.

After removing the crankshaft position sensor, I visually inspected both front ends as well as the cable/wire. It appears to be ok but worn at the tip end. Nevertheless, I ordered a new crankshaft position sensor. Stay tune for further updates.

Got the new crankshaft position sensor (CPS) today. I did a resistance test using the multimeter at 2000 ohms on both of the old and new CPS. using this video as a guide: https://www.youtube.com/watch?v=0W_NghGZ3Xk&t=198s

The new CPS shows 874 readings, and the older CPS shows 817 readings on the multimeter. Does that make any difference?

I put in the new CPS inside the hole. It was a very tight fit and constantly turning back and forth and pushing inside the hole. Why so tight fitted? Can I use some kind of lubricant such as motor oil on the rubber sides of the CPS without damaging the magnet on the tip of the CPS just to make it easier to put the CPS inside? I made a comparison side by side of both the old CPS and the new CPS and sure enough the newer CPS is a little bit wider than the older CPS. I got as far in as the width of my thumb space left. I had to make sure that surrounding wires are not in the way. Also, the CPS had to be placed in between two walls so to make sure it goes in properly contact with the 5mm bolt hole. That does not give me enough space to turn back and forth trying to get that CPS inside the hole. The older CPS came out much easier pull it out. Has anyone out there has this similar problem/issue? If so, how did it work out? Comments, advice, feedback is greatly appreciated.

I don't think the difference in the readings is enough to matter. Could use dish soap or glycerin to lube the CPS.

Does the tach needle move at all when cranking? If yes and it isn't erratic that is a sign that the CPS is working. It's not an absolute test but it's a good sign.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Hey Sugar Bear, great to hear from you! Good idea about suggesting dish soap. I will use dishwashing liquid as a lubricate. Also, I do not think I have a tach on my instrument cluster panel. Stay tune for further updates.

Sugar Bear are you referring to the rpm needle as a tach?