[Nathan300ce]

Hey everyone I’m at a stand still here. Prior to today my 1992 w124 , 300ce (m104.98) ran flawless. It had trouble starting, would fire up then die - on the third cycle would always stay running. Today however it won’t start at all. Battery is 1 year old and has 12.6v, within the last year I’ve replaced the fuel filter, ovp relay, distributer rotor and cap, and spark plugs. What would be the best route to go as for testing, I’ve checked and it is producing spark; after setting to start a few times I can smell fuel so I’d assume it’s getting fuel, brand new air cleaner too. Anything helps just want to be back driving it again!
Thanks in advanced

 

[speedn_j]

Did any codes pop up? Can you hear the fuel pump run? Check fuses.. tap relays..

 

[Nathan300ce]

Did any codes pop up? Can you hear the fuel pump run? Check fuses.. tap relays..

it’s a 92 so unfortunately it’s a obd1 for whatever reason this model doesn’t have a cel light either, I’ve replaced all the fuses when it was purchased- and none of them are blown I checked with my multimeter- yes when I turn the key before startup I hear the pumps priming. What relays should I try to tap?

 

[khomer2]

Bad FPR?

Check FP?

How to check fuel pressure

How to check fuel pressure,I bought a gauge and need pic or info on where exactly I hook it up for testing.:confused:

www.benzworld.org

 

[LTYLER]

Does it crank? Just wont fire?
Where do you live? Checked for condensation in the cap?

 

[neanderthal]

Get on of those starting thingamajigs. (starter fluid in a can?) Have someone crank it while you spray a little of that into your intake.

If it does start then you've isolated the problem as fuel.

 

[J.A.W.]

You can still read the blinking OBD 1 fault codes,
get a basic 12V LED for a couple of bucks, &
plug it into the proper ports & count/record them.

Perhaps a clean/check of all major electrical joints
that coordinate with the KE-Jetronic unit, under the
air filter unit?

Safety protocols will cut the fuel delivery, with
some faults.

 

[Nathan300ce]

Bad FPR?

Check FP?

How to check fuel pressure

How to check fuel pressure,I bought a gauge and need pic or info on where exactly I hook it up for testing.:confused:

www.benzworld.org

I hear the fuel pump prime but I’ll still do a full pressure test to be certain, where is the relay on my engine ? I checked where the ovp was and I couldn’t seem to locate it

 

[Nathan300ce]

Does it crank? Just wont fire?
Where do you live? Checked for condensation in the cap?

It cranks, just won’t fire up. I’ve checked and there’s no condensation or corrosion in the dizzy cap it’s about 3 months old aswell- I’m in southern Ontario just outside of Toronto

 

[Nathan300ce]

You can still read the blinking OBD 1 fault codes,
get a basic 12V LED for a couple of bucks, &
plug it into the proper ports & count/record them.

Perhaps a clean/check of all major electrical joints
that coordinate with the KE-Jetronic unit, under the
air filter unit?

Safety protocols will cut the fuel delivery, with
some faults.

Noted- I’ll see if I can get one of those ASAP and if not I’ll make one, are you referring to the ezl ?

 

[khomer2]

I hear the fuel pump prime but I’ll still do a full pressure test to be certain, where is the relay on my engine ? I checked where the ovp was and I couldn’t seem to locate it

Search on YT - FPR m104 pelican parts and MMWA

 

[Real1shepherd]

Lots of old posts on making your own code reader for the OBDI system. Don't assume that you're getting fuel, test it. You can rent the gauges and use the two ports on your FD. You could also rig a test on the fuel line feeding the FD. There's a micro screen screwed into the FD....replace that and the fuel filter in the back. Could even be your tank screen....that's why you need to test the fuel pressure & volume coming into your FD.

You have to figure out if it's fuel or spark related and proceed from there. Lots of old posts on testing for spark too. Not knowing anything about your car or its history, we're just guessing and therefore you have to do the work.

Kevin

 

[Nathan300ce]

Lots of old posts on making your own code reader for the OBDI system. Don't assume that you're getting fuel, test it. You can rent the gauges and use the two ports on your FD. You could also rig a test on the fuel line feeding the FD. There's a micro screen screwed into the FD....replace that and the fuel filter in the back. Could even be your tank screen....that's why you need to test the fuel pressure & volume coming into your FD.

You have to figure out if it's fuel or spark related and proceed from there. Lots of old posts on testing for spark too. Not knowing anything about your car or its history, we're just guessing and therefore you have to do the work.

Kevin

Thanks will do I’ll try to get a hold of that tomorrow, a new update the tachometer is bouncing when trying to start now it goes above 2k rpm which it’s never done not sure if this helps, working on making a reader currently

 

[Nathan300ce]

Update- so I know it’s a fuel issue or I’d assume I sprayed the instant start stuff into the intake and it fired up then died shortly after, until I can get a hold of a fuel pressure gauge (covid restrictions where I’m based limit me from renting anywhere) I disconnected the fuel line connecting into the k-jet filter, fuel came out upon cracking it loose then when positioning ignition and the pumps prime it came out again, I think this eliminates the fpr and the fuel pumps as I would imagine it would start in general so long as there is some fuel . Is there a way to clean the k-jet filter while it’s out or should I just replace it ? Where is my next step to test ? Should I pull the injectors ... TIA

 

[plinker17722]

If there is a filter in the fuel distributor then clean it out with a can of injector cleaner and a brush .If you have fuel in the hard lines to the injectors then your injectors need replacing . Test - Remove one hard line that goes to the injector then put the injector back on and hold the injerctor in a jar and get someone to spin the engine to start .See if fuel is coming out of the injector . You will need to do this with them all Be carefull the hard lins are easy to damage Once you know they are working then its another problem .

 

[Real1shepherd]

The FD micro filter is really not servicable. It it's still available, replace it. You could take each hard line off(carefully) at each injector and do a volume test while cranking.....Robert did that in here yrs ago with great pictures, but he said he was taking down his site for security reasons. On this site up above is an indexed FSM. I would read their section on testing the FI system and adapt to do it without special tools wherever possible.

This could turn out just to be the fuel filter and/or tank screen....just because you're getting gas up there, doesn't mean you have enough volume or pressure to make the FD function properly. Plink's test will tell you if you're getting good spray from ea injector, but it won't really indicate volume.

Kevin