When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
At 265K miles it's time to change out the injectors.
A few years ago I decided to paint my peeling magnesium valve covers. As part of the maintenance I pulled the fuel rail (changed the inline filter), intake manifold, intake "gaskets" and tidied up the valley (the valley is open in the back, and top for that matter, and all sorts of stuff collects.
While the paint was drying, I took the opportunity to change out the injector seals and intake gaskets. I also port matched the intake "gasket" to the intake manifold and head ports.
The painted valve covers lasted about 2 years before I decided to really do the job properly by using powder coating. I powder coated both the intake and valve covers. After 4 years, they still look great.
About a month ago, I noticed a fuel odor in the passenger cabin and figured it for either the fuel pressure regulator or part of the vapor recovery system (charcoal cannister). I had the issue before and it turned out to be one of the 3 hoses to the cannister. This time it was neither. By chance, I noticed that the forward most driver's side injector was wet under the central cover. I figured it was a failing injector seal. I ordered new seals and pulled the fuel rail. I'd done the rail before, so it's only a 3 hour job.
Everything went back together and I went for a test drive as I figured the excess odor needed to evaporate. Well, it didn't. Instead it got worse.
I took a look at the same injector and saw it wasn't just wet, but actively spewing fuel. Not so good. The injectors have a metal body and a plastic top. Apparently, with time and usage, the plastic top to metal body seal deteriorates and leaks. With 50 PSI behind the fuel, it can leak a lot.
I figured all 12 injectors were coming up on their end of life, so it probably wouldn't do to just replace the 1 injector only to have the other 11 fail whenever their time was up. By the way, a single new injector is over $100 and 12 of them is too much. Time to get an education on remanufactured fuel injectors.
FCP Euro uses GB Remanufacturing for their replacement injectors and they were only about $13 each with a $25 core charge. I noticed that the injectors weren't the same as my originals, but I ordered them anyway (not a lot of choice really).
The silver replacements ARE for the M120 and are MB Bosch injectors, but they are different looking. I put them side by side to check their height and where the seals engage and everything looked pretty close. The only really odd part was the green cap and the white nylon washer/spacer above the bottom seal.
The remanufactured injectors come with new seals, so you don't have to order seals too, To my eyes, the remanufactured seals looked a bit smaller and had a smoother surface. They definitely fit looser to the injector body.
If you have never removed the fuel rail on the M120, here's how:
1: Remove your Weichers strut tower bar.
2. Remove the central engine cover.
3. Unplug each coil.
4. Loosen the 2 fuel connections at the end of the fuel rail making SURE to back up the fuel wrench with another wrench so you don't twist off the fitting.
5. Loosen the 4 fuel to intake manifold rail mounting bolts.
6. Disconnect the fuel pressure regulator vacuum hose.
7. Remove the rear fuel rail harness clip and snip the 3 or 4 harness tie wraps.
8. Disengage the big Z tube vacuum equalizer at the passenger front of the valve cover and driver rear of the intake manifold (I remade mine in stainless).
9. With an ABUNDANCE of cushioning, use a tire iron to GENTLY pry up the forward part of the rail and then the rear until it's free of the intake manifold.
It's WAY easier to remove (by pinching and pulling) the fuel injector electric connections with the rail lifted than in place. Also, leave the fuel injector to fuel rail clips in place so the injectors come out attached to the rail. IF YOU DON'T, then the injections stay inserted into the manifold and must be pried out ONE by ONE, possibly damaging the injectors. The injector rail is also installed with all the injectors attached.
Injectors swapped and attached to the fuel rail waiting for installation.
The injector seals are lubed with Vaseline and it doesn't hurt to put a dab on the injector ports on the intake just before assembly.
Carefully reassemble everything, start the engine and look for leaks before putting the central engine cover back on.
If everything works, return the old injectors to FCP Euro for reimbursement.
I did do some research into GB Remanufacturing and found just about as many dissatisfied customers as satisfied. I don't know what will happen in the future, but I'll update this thread from time to time. I didn't detect any performance increase, the car runs as well as it ever did before the maintenance.
I noticed Roncallo on BW is having trouble with his V12 injectors.
I guess it's time for an update on the "new" injectors.
It's not been even 2 years since I did the injector swap and the car has only 273K miles now, but I've noticed no leaks or performance issues. The engine runs as flawless as ever.
These injectors might have been a crazy bargain after all.
I noticed Roncallo on BW is having trouble with his V12 injectors.
I guess it's time for an update on the "new" injectors.
It's not been even 2 years since I did the injector swap and the car has only 273K miles now, but I've noticed no leaks or performance issues. The engine runs as flawless as ever.
These injectors might have been a crazy bargain after all.
Wow, I wish I would have found this earlier. I just sprung $1500 for a new set of Siemens injectors from Mercedes. They are now $114 each from Mercedes and the GB Bosch rebuilds are $31 + $25 core. I had FCP euro contact GB about the 1996 M120 fitment and they said they wouldn't work. All the other companies I found only list the Bosch injectors for up to 1995 model year only. They are also available on E-bay for $400 for a set of 12 without a core charge.
Both 96 and 97 M120 cars take part number 852-12110 and as you said; its a REAL savings over the alternatives.
For $1500 vs $372, I'd see about returning the Siemens injectors (wouldn't be the first part I returned to MB) and get the GB injectors. $31 vs $13 in less than 2 years, talk about Bidenflation!
Plus they look cooler with the shiny metal bodies. The GB site shows their injectors as green, but mine are orange. Never the less, they haven't leaked and have worked flawlessly for almost 2 years. I don't even think about them any more. Also, I like the GB injector seals better. Not just for fit, but because they don't appear to have a seam.
Both 96 and 97 M120 cars take part number 852-12110 and as you said; its a REAL savings over the alternatives.
For $1500 vs $372, I'd see about returning the Siemens injectors (wouldn't be the first part I returned to MB) and get the GB injectors. $31 vs $13 in less than 2 years, talk about Bidenflation!
Plus they look cooler with the shiny metal bodies. The GB site shows their injectors as green, but mine are orange. Never the less, they haven't leaked and have worked flawlessly for almost 2 years. I don't even think about them any more. Also, I like the GB injector seals better. Not just for fit, but because they don't appear to have a seam.
They sure did just like they said and I got my core charge back.
Nothing on the car costs $156 (my price for the injectors 2 years ago), but I'm glad the GB injectors did.
I was able to return 8 of the injectors I purchased from the dealer. I will need to put the last 4 up on E-bay. Purchased a set of 12 from E-bay company called "Injector Planet". $400 for 12 and no core required.
Replacement rebuilt Bosch injectors installed. Samson is back on the road.
So the Bosch injectors used on 93 to 95 M120 engine also work on 96+. In fact the car actually feels faster. So far that was a savings of about $600 and I have 4 new Siemens injectors to sell worth about $100 each.
I purchased these injectors from Injector Planet on Ebay for $400 for a set of 12. They also sent me a card to return my old ones for a $120 credit, which I'm not sure I can avail of since I don't have Bosch cores.But I'm happy with the company.
Do your injectors look like the ones in my photos?
You may be able to read the part numbers on my originals.
My original injectors look just like yours with the purple shells. My replacement Bosch look like your replacement Bosch except mime have green shells.
So the GB Remanufactured replacements would have worked.
I did inspect the weird green cap on the spray end of all the injectors and found one injector's green cap was interfering with the spray. I hope you checked yours.
So the GB Remanufactured replacements would have worked.
I did inspect the weird green cap on the spray end of all the injectors and found one injector's green cap was interfering with the spray. I hope you checked yours.
I do believe the GB's would have worked but since they sent me an email saying they would not, I didn't want to purchase from them in case anything went wrong. Then they would have just tell me "We told you they wouldn't work". I believe the injector re-builders are going by the same information I have available from EPC which states the Siemens only for 96+ and the Bosch for 95-. Injector Planet also stated that these were 95- only, but once I you were successful with them I decided not to ask, to maintain plausible deniability.
I didn't check my injectors for spray, I just put them in, but the caps were not green. They were sort of a translucent brown. The metal case was sort of an anodized brown. Otherwise everything was exactly as shown in the picture.
05-27-2021, 11:10 AM
