geewizle

So i have a 1990 500sl that I have put WAY to much time into (about 350hrs). I replaced the whole fuel system and lines from tank to pumps and filter 2 years ago all oem. A few weeks ago I had turned on the car for about 2 minutes, turned it off and than when I tried again it didn't turn over. one of the threads on the fuel distributor had been stripped unknown to me and has a bad seal. I replaced the distributor with a refurbished one and checked the internals they were all great and everything went back together fine. (the plunger is level). Car started but ran rough. I tested the injectors and they all failed (shooting streams of fuel). I got new injectors that all tested great and new seals for them. I also got oem spark plugs from Mercedes and gapped them to .42. car still wont start. For info all vacuum lines have been checked and replaced. I currently have the sensor plate out and it seams the adjuster screw is stripped internally.

Regulator in engine bay seems to be working fine. Distributors and wires were replaced 4 years ago. Compression all tested 170-180 cylinder 1 ran a 150. Ill be cleaning the cold start valve tomorrow. Im not sure what to do next.

dolucasi

I tested the injectors and they all failed (shooting streams of fuel)

The above statement if not a typo, suggests you have a busted FD since it was a refurbished old one. It could also be a bad EHA valve but I have not ever seen an EHA valve go bad before they start leaking fuel and when they leak they are generally still still operational.

You can try taking fuel pressure measurements and I suspect they will be incorrect. The system pressure (inlet pressure) may be fine but I doubt the control pressure is incorrect because there is a massive problem with the FD.

Are the spark plugs fouled of fuel and wet?

I

geewizle

When testing the injectors I used a cis injector testing kit. That's when i realized how bad they really were, I replaced spark plugs and did an oil change when I installed the new injectors yesterday 3/7/2023. The EHA has had its fill of gas spilled on it, how would i test if it works.

the car did run when i installed the FD but very rough and stalled. I cleaned it and installed all new internals besides the plunger and all seamed to go in properly. I also leveled the plunger with the nut

Im also wondering how to tell if the regulator next to the FD is bad. I don't smell gas through the vacuum line on it.

geewizle

ive seen were people install a pressure gauge on the plugged FD outlet and wrap it to the connection for the cold start valve on the FD. but in demonstrations the car was running

dolucasi

That is true but when you turn the ignition on, the system pressure (one of those plugged ports is used for this or the CSV port) should shoot up to ~5.5Bars. At least this would vindicate the Fuel Pump and the Pressure regulator.

All I know is rebuilding the FD should be done by professionals, so I'm still thinking something went wrong in your rebuild. And it is true that a non starting car after a rebuild is the worst case scenario and very hard to diagnose.

geewizle

ill try pressure testing tomorrow and hope all is well will get back with an answer to how it goes soon. Thank you for the help its hard finding people who know how this system works around me lol.

if you watch some FD rebuild videos its actually pretty easy and i tried initially on the broken one to make sure i knew what i was getting into. definitely could be a fault though ill keep it in mind

dolucasi

I'm not sure where you are located but here in North America, people have their FD rebuilt at one specialty shop. I think besides cleaning them out an replacing rubber parts you have to make sure proper adjustments are made to tune them up after a rebuild. And after that, I'm sure the professionals have a set-up to test the FD outside the car in a lab/workbench. Remember each cylinder needs to receive the same amount of fuel as well. If that is off, it would be a disaster down the road.

geewizle

Hi. its been a while ive been very busy. I have a new problem I've used 2 different fuel distributors and for some reason gas will only come out the passenger side ports on top the driver side stays dry and I'm wondering if that's the EHA or what could cause this to happen.

geewizle

update. i tried to just put the fuel lines on the passenger side ports and still no gas came out the 4 driver side ports but the car idled for a few second before i turned it off.

geewizle

Im gonna try to rebuild the distributor again but this time ill give the halfs to my brother who can blow out the ports at his shop first. update after