Fixing my 420

[King13ls]

Hello everyone thanks in advance to all who take time in look at my post, but I’ve been fixing up a 95 e420(California based).
It was sitting for around 3-4 years until I had finally decided to start working on it, so fast forward I got it running about 8 months ago the car was driving fine for the most part and then one day it just turned off and didn’t wanna turn back on untill let’s say 10 minutes past by and then it would start,I’ve replaced the ezl n it seemed to had fix the problems for a bit and then it came back I replaced the fuel pumps and the problem left for a bit but then came back, except this time it was worse, like let’s say if I would turn the car on and let it idle it would maybe idle for about 10 minutes before turning of from a cold start so I read a bunch of post here on the 500e board, I read something about unplugging the maf and I did n let the car idle for 30 minutes without it turning off even drive it for a while and it didn’t turn off, im not giving up on the car because I love the car and also im in too deep to pull out, but if you guys could let me know what else I should get please let me know I’ll post a video of what I got in my shopping cart

 

[JC220]

car was driving fine for the most part and then one day it just turned off and didn’t wanna turn back on untill let’s say 10 minutes past by and then it would start

This sounds like the very common m119 distributer issues - please read the thread below:

FYI - Essential M119 Ignition "Tune Up" mods [Distributor cap vent / slot] | M119 Engine

Hi all, I have been meaning to address this on my little used 500E for years.... it is a problem I myself recognised about 5 years ago when I first looked at an m119 distributer cap..... Compare to any other distributor cap of the era such as an m104 and you will see there are NO ventilation...

www.500eboard.co

If the car currently starts up then do that until it dies out and go ahead and remove both distributer caps and look for moisture drops in there to confrim.

 

[King13ls]

..

 

[King13ls]

This sounds like the very common m119 distributer issues - please read the thread below:

FYI - Essential M119 Ignition "Tune Up" mods [Distributor cap vent / slot] | M119 Engine

Hi all, I have been meaning to address this on my little used 500E for years.... it is a problem I myself recognised about 5 years ago when I first looked at an m119 distributer cap..... Compare to any other distributor cap of the era such as an m104 and you will see there are NO ventilation...

www.500eboard.co

If the car currently starts up then do that until it dies out and go ahead and remove both distributer caps and look for moisture drops in there to confrim.

Yeah I’ve read all of that thread I’m going to buy, new distributors and ignition parts for it

 

[Gatorblue92]

Have you checked the codes using a blink reader?

I agree the caps and rotors are certainly a pain point but I would also check the fuses in the BM which is under the hood where the battery goes on the non V8 cars. I had similar symptoms on a prior 400E and one of those fuses was blown and it ran wonderfully after replacing them.

 

[King13ls]

Thanks for your reply and yeah I’ve checked the codes and one of the codes talks about the maf sensor

 

[King13ls]

This is currently what I’m gonna replace

 

[JC220]

This is currently what I’m gonna replace

It's unlikely you need to renew the fuel injectors. Just get your own ones professionaly cleaned if you wish. But it's up to you on that one. Suggest refreshing ignition system first.

The fuses you can buy in larger qtys on eBay. Ceramic Flosser fuses. May work out cheaper than buying the little genuine kits which may also not have enough blue and reds.

 

[gsxr]

Fuel injectors are a waste of money IMO, they are not the cause of your problems. And you do not need the rotor brackets, plus URO is garbage you don't want on your car. Skip the Bremi plug wires as well, if you insist on replacing the wires, at least get the Beru set from Partsgeek.

Throwing a bunch of parts at the problem without additional troubleshooting is an expensive way to go about the repair, and may not fix it.

Don't forget to check the crank sensor (CKP) when it dies and won't re-start. Ignition issues will cause misfiring, not the engine shutting off. If it runs smooth and never misfires, the ignition system may be fine.

 

[a777fan]

Just curious: has the upper wiring harness been replaced? Has the throttle actuator been rebuilt?

Not to channel sbaert but I thought I’d mention the eco junk wiring.

 

[JC220]

Not to channel sbaert

 

[gerryvz]

sbaert =

 

[King13ls]

Thanks for the reply’s, I’m still new workin on cars but I’m learning, the harness was replaced in 2010, and the lower harnes I rebuilt not to long ago, but the car runs ruff with the maf connected and if I press on the gas heavy sometimes white smoke or black smoke comes out the exhaust, but I disconnected the maf and tried driving around with it and the car didn’t turn off at opperating temp, drove pretty good other than the fact the it felt like the throttle was a bit delayed

 

[gsxr]

Smoke of any color is a BAD sign. These should not smoke at all, ever.

 

[King13ls]

Ahh man

 

[King13ls]

Smoke of any color is a BAD sign. These should not sm

Smoke of any color is a BAD sign. These should not smoke at all, ever.

Ok so let’s say the worst has happened, is there anything that I need to look for or tell the mechanic anything in particular to look for, I’m going to take it to a shop and just have them inspect everything,,,, also I’m curious what kinda 124 do you have?

 

[gsxr]

Start by figuring out what color smoke it is (white, black, blue, etc) and does it smoke all the time, only at startup, only when hot, etc etc.

I currently have 124 diesels and M119's. No M103/M104 though.

 

[King13ls]

Well it’s smokes white when start up and then stops smoking once warm but smoke on the hwy when I’m merging onto traffic when I have to accelerate to catch up the traffic if I accelerate too hard it’s smokes white and then if it’s harder it will turn black, I will take the car for a spin Saturday and check for sure

 

[King13ls]

ok so I just took the car for a spin and I stepped on the gas a maybe like 3/5 of the way and it blew a little black smoke but it felt like it only blew the smoke out when the trans shifted, then I did about maybe like 4 pulls letting the car get up to 60+ , and it didn’t smoke at all, witch I found a bit odd

 

[a777fan]

I think you need to keep driving it, and keep an eye on your coolant and oil levels. That’s the only real way you’ll figure out what it coming out of your tail pipe.

If coolant and oil levels remain constant, then the smoke you’re seeing is coming from incomplete combustion.

 

[King13ls]

I think you need to keep driving it, and keep an eye on your coolant and oil levels. That’s the only real way you’ll figure out what it coming out of your tail pipe.

If coolant and oil levels remain constant, then the smoke you’re seeing is coming from incomplete combustion.

I had to look up what it exactly was, but I’d love to drive the car but it’s randomly dies on me just now when I was driving it, it was with the mas unconnected, but idk if this has anything to do with it but when I gas it, it almost sounds like air is getting out from the engine Ik it sound dumb but i wouldn’t know how else to explain it, and for my coolant it’s fine, my oil how ever leaks but I’m not sure where from I haven’t really had the time to fool around with her with work and all

 

[Jlaa]

I had to look up what it exactly was, but I’d love to drive the car but it’s randomly dies on me just now when I was driving it, it was with the mas unconnected, but idk if this has anything to do with it but…

Yeah, you probably need to get the mass airflow meter properly hooked up and operating correctly, because otherwise, you car is not using the optimal fuel/air ratio. Otherwise it is impossible for you to begin to troubleshoot as @a777fan notes whether you have incomplete combustion, coolant leak, oil leak, or what. Otherwise it will be like throwing darts on a wall unfortunately.

 

[King13ls]

Yeah, you probably need to get the mass airflow meter properly hooked up and operating correctly, because otherwise, you car is not using the optimal fuel/air ratio. Otherwise it is impossible for you to begin to troubleshoot as @a777fan notes whether you have incomplete combustion, coolant leak, oil leak, or what. Otherwise it will be like throwing darts on a wall unfortunately.

Thank you for the reply I will get back at it once I’ve gotten one

 

[King13ls]

ive finally gotten around to working on my car i kinda lost motivation, but here what ive done so far ive replaced, caps rotors insulators, ignition coils, fuel pressure regulator and cpk sensore and also the temp sensors, i started driving the car and it was driving decent but ruff it would die but unlike before when it would die it would restart this time,and it would jerk when accelerating , then i unplugged the maf and the car was running great a little slow on the response time tho but would still run good without jerking at all, then i got replaced my maf with one i got from ebay it was running great i literally drove it all day long id say over 4 hours in total and it randomly start idling ruff and almost like it wanted to die and then when giving it gas it almost like the car was struggling to go almost like the engine was not getting gas or something and then it would snap and go so so i just pulled the codes from it and i checked them out and honest im not sure whats wrong if it could be my wiring harness, elz, maf, or my cpk im kinda stuck and not to sure what my next step should be on what i should do but here are my codes if someone could give me some guidance ill be very very much appreciated

 

[gsxr]

That's a lot of codes. Clear everything, drive the car a bit, and see which codes return immediately. Had you cleared codes previously, after purchase?

 

[King13ls]

Yeah I definitely did

 

[King13ls]

I cleared as many codes as it would let me some just wouldn’t delete

 

[King13ls]

okay so ive been driving the car for about 2 days nows id say maybe a total of 100 miles driver maybe, but nun of the codes have come back, witch i think i know why they came on in the first place, i think its because when i bought a new battery and was installing it i forgot to tighten up the ground, so i believe thats was caused all of those codes to come on but i could be wrong, i should drive it a bit more i guess , its been driving pretty good, although sometimes depending on how im accelerating its can take sometime for it to build boost i guess,

but i currently need an alignment both of my front tires at bald on the outside and inside, i was thinking shouold i go ahead and just rebuild the front suspension, but id like to get quotes on about how much ill be to rebuild the whole thing,

but for now im just glad shes back running decent


thanks for all the reply's <3

 

[gsxr]

...sometimes depending on how im accelerating its can take sometime for it to build boost i guess,

Wait, what? Boost? I thought this was a stock E420?

but i currently need an alignment both of my front tires at bald on the outside and inside, i was thinking shouold i go ahead and just rebuild the front suspension, but id like to get quotes on about how much ill be to rebuild the whole thing,

In general it's highly recommended to only get alignments at the dealership. Many other places won't get it done properly. But a dealer alignment may cost $200 (call yours to ask), so you only want to pay for ONE alignment. Which means replacing as much of the suspension / steering components as you can afford, assuming all are old/original. Search the forum for info on this. The tie rod assemblies are NLA from MB but you can use the R129 tie rods instead. Get OE MB parts, most aftermarket stuff (including Lemforder) has changed to offshore mfg and I no longer trust them. Don't forget the rear suspension, the rear subframe mounts are usually shot and are not expensive, but will take a day to replace all four as DIY. There's a detailed HOW-TO on this forum.

 

[King13ls]

Not like as in turbo boost , just normal power I’m not that on what the correct term is it, but question what suspension parts have to be installed by the actual dealer, because I would like to Change as many parts as I can myself, I’ve really enjoyed working on this car, but I’ve been driving the car

lately it’s been driving pretty good other than sometimes the idle I’ll randomly start jumping, hasn’t happened as much but is definitely a problem, also sometimes when I come to a dead stop like at a light or something when I give it gas the rpm drops slightly almost as if it was about to shut down but then I’ll jump and the car I’ll jump n go, and the trans is shifting a bit ruff

I’ve cleared the codes about 3 times sence my last list I posted most of those codes didn’t come back but however my Cpk sensor is somehow defective, I might have installed it wrong? I don’t see how tho, here are my most recent codes

4(8)
6(21,30)
7(14)
8(17)
17(6)
19(6,13,22)

 

[gsxr]

I’ve cleared the codes about 3 times sence my last list I posted most of those codes didn’t come back but however my Cpk sensor is somehow defective, I might have installed it wrong? I don’t see how tho, here are my most recent codes

Use the PDF file linked below to look up what each of the codes mean:

https://www.w124performance.com/docs/mb/diagnostics/DTC_List_W124_M119.pdf

4(8) = CMP sensor (L5/1) signal, open/short circuit​

6(21,30) = ABS/ASR hydraulic unit, pressure switch (A7/3s1), charge / data bus interrupted​

7(14) = Closed throttle position switch (S29/3)​

8(17) = Module box blower motor (M2/2), short circuit​

17(6) = CMP sensor (L5/1) defective​

19(6,13,22) = Idle speed control inop / Camshaft position sensor signal ​

Chase down the camshaft (CMP) sensor and throttle switch S29/3 errors. The latter could be related to throttle cable adjustment, check that too. Cam sensor L5/1 is at the driver side intake cam.

Ignore the other codes for now.

 

[King13ls]

Yeah I’ve been using that link to check my codes, and for my Cmp i replaced it with one I got from Mercedes-Benz OEM Parts | Get Mercedes Parts
(The cmp is the sensors that’s goes from the ezl to the trans right?), and is there anything in particular to look out for, or should I just uninstall it and try installing it again?,

and as for my throttle switch, I have no clue as to where to even start looking but I will do some research on what to look out for when having issues with a defective cmp/the throttle switch error, and as to the throttle cable I messed around with it a bit because when I was driving my car, the gas pedal started acting up like it felt almost like the gas pedal got hard and I had to really put effort into pressing the gasfor it to go, But I didn’t mess with it to much I might have spun the thread maybe one or 2 times bc it felt hella loose but then again I think it was like that for a reason not sure, and also idk how the throttle works on m119 but I know like in most cars when u press the gas down all the way the flap on the throttle opens up all the way but I noticed that mine didn’t open up all the way with the gas pressed down, witch I tought was funny and then I tried opening it up with my hand and it opened up all the way I wonder if that’s what’s that problem is about or does the throttle body

Also thanks for the patience and reply’s I’m still a rookie, my 420 is the first car I’ve actually worked on, so there lot of terms and whatnot I don’t know off so please bare with me

 

[gsxr]

Yeah I’ve been using that link to check my codes, and for my Cmp i replaced it with one I got from Mercedes-Benz OEM Parts | Get Mercedes Parts
(The cmp is the sensors that’s goes from the ezl to the trans right?), and is there anything in particular to look out for, or should I just uninstall it and try installing it again?,

CMP = Camshaft position sensor L5/1, located at the front of the engine, driver side intake cam. See attached photo. Check the wiring also. The engine will have very poor midrange power with a bad CMP signal.

and as for my throttle switch, I have no clue as to where to even start looking but I will do some research on what to look out for when having issues with a defective cmp/the throttle switch error, and as to the throttle cable I messed around with it a bit...

Don't mess with the throttle cable. The drive-by-wire throttle control is very picky. There should be a small amount of play at the end of the cable. It should not be pulling on the linkage at all.

because when I was driving my car, the gas pedal started acting up like it felt almost like the gas pedal got hard and I had to really put effort into pressing the gasfor it to go,

That sure sounds like "limp mode". Did the ASR+ABS warning lights come on in the cluster when this occured?

But I didn’t mess with it to much I might have spun the thread maybe one or 2 times bc it felt hella loose but then again I think it was like that for a reason not sure, and also idk how the throttle works on m119 but I know like in most cars when u press the gas down all the way the flap on the throttle opens up all the way but I noticed that mine didn’t open up all the way with the gas pressed down, witch I tought was funny and then I tried opening it up with my hand and it opened up all the way I wonder if that’s what’s that problem is about or does the throttle body

Cars with ASR have a throttle body (ETA) that is drive-by-wire. It senses the requested throttle opening from the throttle cable via the ETA, but only opens the flap all the way electronically. Move it by hand and it only opens halfway. This is normal.

 

[King13ls]

Ahhhhh gotchaaaa thanks youuu and yes mine does come with asr witch I wish it didn’t but I have a lil bypass for it, I will mess around with the cmp tomorrow when I’m off work

 

[gsxr]

You can add a switch to shut off ASR temporarily for burnouts & hooning, but there's no way to fully bypass without swapping a lot more parts - not worth the hassle. Just fix it.

 

[King13ls]

yeah I’ve swinged my 420 around a few times, ok so I looked under my hood and look around my cmp and I meant it looked pretty normal and fine to me but is there any way you test it to know if it’s bad or going bad?

 

[gsxr]

You can't tell by looking. If you get consistent CMP fault codes that return after clearing, and your upper harness is new, and the connection is solid... might be worth replacing. If you have a Pick+Pull type salvage yard near you with M119's you could grab a used one to swap for grins.

OE is NLA so you are stuck with Hella China now for ~$35.

Mercedes Camshaft Position Sensor - Hella 0021539528

Mercedes Camshaft Position Sensor - Hella 0021539528

www.fcpeuro.com

Don't buy ÜRO, Facet, FAE, Meyle, or Delphi. I'd try a used one before any of the other offbrands...

 

[King13ls]

Will do I was reading the forums and I did see something about someone saying that swapping there ezl fixed the problem, witch idk I feel like maybe I should try it because after all the ezl that my car currently has is one I got from eBay because before when I first started working on it it would turn off and I asked around and someone said it could be the ezl but now that I think about it I dint think that was the case, so I’ll try and replace mine with the original it had, and I will try and look if I can find any m119 in the junk there arnt many around here the last one I found I had to drive 6 hours just to get to shell of the car

 

[gsxr]

Well, the CMP signal goes to the EZL, so there's a slight possibility the EZL could be at fault. If you have a spare EZL of the correct part number (015-545-60-32 only), swap it out. If you get the same fault codes, it isn't the EZL.

What part number EZL did you install, btw?

 

[King13ls]

made sure that it was the same number as the original but of the top of my head not sure what number exactly

 

[King13ls]

yesterday I went to a junkyard to see a 92 400se, I got the MAF sensors because it was for a good price, and also the cam sensor from it and some vacuum lines the vacuum lines were great condition, so I replaced the the cam witch I found odd that the one my car had looked really clean compared to the one I got from the junk yard, then I cleared all the codes took the car for a drive it was driving good drove it for about like 20 minutes, came to a stop and the car started jumping at idle like crazy, turned the car off for maybe like 5 minutes or so and started it up started good idling stopped took it on the interstate and it was running the best it’s ever has, how ever this morning I noticed that my cars temp gauge on the dash didn’t move at all it stayed down didn’t move at all, not sure what it could be, any ideas as to where to look at?, last night when I drove it was working

 

[gsxr]

Temp gauge - check the wiring at the 1-pin sensor at the front of the intake manifold. Also smack the cluster with your hand to make sure the needle isn't sticking.

 

[King13ls]

I already tried smacking the cluster , no good, will check pin one tho maybe, something got disconnected last night while doing a l little speed run, but thanks you @gsxr your such a big help!!!!!!

 

[King13ls]

Welll I just got of work started my car up n temp is functioning, could that mean that my wiring is going bad?, because I notice at one point my antenna would go up and down as I turned ignition on but one day it just stopped working

 

[gsxr]

The wiring for the temp sensors is part of the upper harness, which you said was replaced in 2010 (and I'm assuming it was replaced with the good/updated version). If all the gauges work normally except the coolant temp, it's something between the sensor and cluster, or the gauge itself. Pretty simple system, if it happens again start tracing one thing at a time... measure resistance of the sensor, etc etc.

Antenna is a separate issue, they are notorious for causing problems. If original it may need replacement, if already replaced it may need cleaning / repair internally.

 

[King13ls]

It did end up happening again, but I will check it out now

 

[King13ls]

I figured out why the gauge stopped working I guess it was because i disconnected when i put the intake on but I solved that, but I went to my local junk got the cam sensor off a 92 400se and the car drove the same honestly not much difference I probably cleared the codes about 3-4 times, then I went to a different junkyard n got another none from a 91 sl500 n the engine was super clean on it I got the heads off of it for a good price n also I took every other sensors that was in the front of the fuel rail n they were all pretty good my car is reading the outside temp more correctly now,but I replaced the cam sensor n cleared the codes took the car for a spin felt like it was driving good until i parked n restarted the car it’s like it went back to the gas pedal feeling hard/heavy n it’s running pretty good honestly best it’s ever run, doesn’t idle as bad now u can hardly tell its idling a few hiccups but nothing bad, how ever I’ve noticed that something when starting the car cold or hot sometime the car will start jerking n the idling jumping, but once I restart the engine it starts driving normally however the issue with the pedal is still there, I I cant seem to get rid of the cam sensor code everything else erase,. I’m not sure on what the issue could be? These are the codes I’m getting 4(8),,6(21),,7(1),,8(17),,19(13,19)

 

[gsxr]

I figured out why the gauge stopped working I guess it was because i disconnected when i put the intake on but I solved that, but I went to my local junk got the cam sensor off a 92 400se and the car drove the same honestly not much difference I probably cleared the codes about 3-4 times, then I went to a different junkyard n got another none from a 91 sl500 n the engine was super clean on it I got the heads off of it for a good price n also I took every other sensors that was in the front of the fuel rail n they were all pretty good my car is reading the outside temp more correctly now...

You do realize the 1991 500SL has a completely different M119 engine, right? It's a tall-deck block with mechanical injection. Very few parts from that engine will work on the E420.

...but I replaced the cam sensor n cleared the codes took the car for a spin felt like it was driving good until i parked n restarted the car it’s like it went back to the gas pedal feeling hard/heavy n it’s running pretty good honestly best it’s ever run, doesn’t idle as bad now u can hardly tell its idling a few hiccups but nothing bad, how ever I’ve noticed that something when starting the car cold or hot sometime the car will start jerking n the idling jumping, but once I restart the engine it starts driving normally however the issue with the pedal is still there,

You need to confirm if the "pedal issue" is limp mode or not. Does the ASR warning light come on when the pedal feels funny?

I I cant seem to get rid of the cam sensor code everything else erase,. I’m not sure on what the issue could be? These are the codes I’m getting:

4(8),,6(21),,7(1),,8(17),,19(13,19)

4(8) = CMP sensor (L5/1) signal, open/short circuit​

6(21) = ABS/ASR hydraulic unit, pressure switch (A7/3s1)​

8(17) = Module box blower motor (M2/2), short circuit​

19(13,19) = Camshaft position sensor signal ; Fuel injectors open/short circuit or LH adaptation at limit​

Most of these are the same as before. You need to focus on the ones that keep coming back. The cam sensor itself may be fine (you've tried three, right?) so it's time to check the wiring next, between the sensor and the module [EZL, not LH]. If the wiring is good, you could try another LH EZL module.

The ASR fault code looks like a faulty ASR unit, which will be fun to replace, but can be scored from a junkyard. If the engine is running smoothly the code 19(19) probably isn't injector wiring, it's likely adaptation at the limit... could be a lot of things, and you can't view adaptation without live data, but start by checking rail fuel pressure with the regulator vacuum hose connected / disconnected while engine is running.

 

[King13ls]

You do realize the 1991 500SL has a completely different M119 engine, right? Its a tall-deck block with mechanical injection. Very few parts from that engine will work on the E420.

No I did not, i did notice that the engine seemed a lot more bigger than mine but I just thought that was bc it was a 5.0 and a roadster, But I did not put the head on i just thought they looked nice so I got them and they were only like 40 dollars

You need to confirm if the pedal issue is limp mode or not. Does the ASR warning light come on when the pedal feels funny?

I forgot To mention about the light, so when I start the car the asr light doesn’t come on right then usually ill come on later on, sometimes while idling and sometimes while driving but i usually let the car warm up so it already on by the time I’m driving, but literally after I had posted about the pedal the pedal became at ease again -_- then pedal has been feeling fine sense but like if I press on the gas to get it going it feels like it takes forever to get going like the taking off part is okay but like you said Dave the mid range is no good

Most of these are the same as before. You need to focus on the ones that keep coming back. The cam sensor itself may be fine (youve tried three, right?) so its time to check the wiring next, between the sensor and the module. If the wiring is good, try another LH module. The ASR fault code looks like a faulty ASR unit, which will be fun to replace, but can be scored from a junkyard. If the engine is running smoothly the code 19(19) probably isnt injector wiring, its likely adaptation at the limit... could be a lot of things, and you cant view adaptation without live data, but start by checking rail fuel pressure with the regulator vacuum hose connected / disconnected while engine is running.

well I’ve tried two, 3 including the one it already had, the all feel the same the only different is once replaced it feels like it changed and I’m sure it does but once the car restarts it goes back to normal, and I’m not sure on how to really check the wiring specifically but I will look in the forums, also with the live data how would that work exactly or is there a forum explaining it and it function, if so i might just purchase one, because i do plan on getting another w124 later on,
As for the fuel pressure would th car idling be fine for the test ? Or will i have to drive it ?

 

[gsxr]

I forgot To mention about the light, so when I start the car the asr light doesn’t come on right then usually ill come on later on, sometimes while idling and sometimes while driving but i usually let the car warm up so it already on by the time I’m driving, but literally after I had posted about the pedal the pedal became at ease again -_- then pedal has been feeling fine sense but like if I press on the gas to get it going it feels like it takes forever to get going like the taking off part is okay but like you said Dave the mid range is no good

If the ASR light comes on and that's when the accelerator pedal does nothing for the first 1/2 of travel, that is classic limp mode. Search the forum for more details. Restarting the engine should cure / reset it temporarily. Odd thing is none of your codes seem to indicate limp mode. If the ASR light comes on and the accelerator pedal feels normal, that's different.

well I’ve tried two, 3 including the one it already had, the all feel the same the only different is once replaced it feels like it changed and I’m sure it does but once the car restarts it goes back to normal, and I’m not sure on how to really check the wiring specifically but I will look in the forums,

You'll need to look at the wiring schematics in the ETM (Electrical Troubleshooting Manual). Click here, scroll down neart the bottom of the page. Click on the one with "(LH-SFI), page II" at the end of the title. Make sure connector X47/2 behind the CAN box is plugged in tightly, measure from there to the sensor connector with an ohm meter to verify the wiring is good. Looks like the signal goes to the EZL (connector B), not the LH module, sorry about that - edited previous post.

also with the live data how would that work exactly or is there a forum explaining it and it function, if so i might just purchase one, because i do plan on getting another w124 later on,

For live data you need an SDS (Star Diagnostic System) C3 or C4 that supports HHT-Win, a kit with a quality MUX, and also fully-populated 38-pin cable... Jlaa recently discovered some of the Chinese kits come with defective MUX's or cables. This isn't cheap, figure ~$750 or so total with the laptop. Read from this post to the end of the thread. Watch the video in post #109, this shows some of the live data available from your car.

As for the fuel pressure would th car idling be fine for the test ? Or will i have to drive it ?

Idling is fine. No need to view fuel pressures while driving unless there's a significant power loss under acceleration that goes away when lifting off the pedal. Read the HOW-TO thread below:

HOW-TO: Checking M119 & M104 fuel pressure | "HOW-TO" Tutorial Articles

GSXR edit: Click here for "How to" on replacing FPR. For diagnosing issues with the M119 such as difficult cold and hot starts, it's important to be able to check the fuel pressure. This gives an idea as to the pressure at the injectors during various running conditions of the engine. It can...

www.500eboard.co