Hey everyone,

OK, so I knew that my car (a 91 560SEL) needed new fuel injector seals and o-rings, so I got all my stuff together with some great instructions and started the job.

The first 3 injectors came out fine, but the last one not so good. The hex nut that hold the bracked on top of the injector stripped itself. This is that 5mm hex nut inside the clip bracket on top of the injector. It's the last one on the passenger's side, closest to the firewall, so its the hardest to get to. Very frustrating. Anyone have any ideas on how to get that bad boy out?

Also, I noticed that one of the injectors is not the correct injector for my car. I know I need to get the right one, but I'm wondering what kind of symptoms that would cause. I originally took this project on because the car misses. Sometimes dramatically, other times hardly noticeable. My mechanic (who is aware of and totally in support of my DIY mentality for certain projects) was the one who said I needed new seals and holders. From the gunk around a couple of the injector holders, I tend to believe him when he said they are leaking.

I wasn't planning on replacing the injectors because the mechanic and the dealer told me that the car shouldn't need new injectors at 114k. I'm kind of lost on what to do here. Is it worth just spending the extra $400 bucks on the injectors? Should I just take my 7 of 8 injectors somewhere and have them tested? If so, where do you take them?

As always, thanks for being out there, and thanks for any information you can provide.

Craig

You certainly should replace the mismatched injector but I would stick with the original plan - clean them, put in the new seals, etc. and see how it does. You can mail off your injectors to be tested at places like www.cruzinperformance.com (google search for others) but you'll be down for a week. if I were in your shoes I would just finish the job and road test.

As I understand the CIS injectors are made for a life span of about 100K and cleaning them typically doesn't work well. They're not like the Bosch EFI ones, can't simply install new o-rings, filters, and pintle caps and expect them to work well.

I have new brass injectors to stick into my 420 once the M117 swap is finished, along with new insulators, o-rings, etc.

Remember, you're driving a vehicle that was probably $75K or so new... don't expect parts to be dirt cheap to replace. May want to consider new fuel pumps too as they like to take out the fuel pump relay with excessive amperage draw.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Last month I did the heads on a 1990 420 with a jumped chain. 132K and good maintenance. As part of the job, I cleaned and tested the injectors, and they were perfect. So I would replace the odd one and clean and test the others.

As to the stripped bolt, go buy a set of 6" hex bit 3/8 sockets. KD makes them and most good auto parts places will order them for you. When you use the right size, make sure than the tip is all the way down - tap it with a hammer to be sure - and drizzle a little PB Blaster around it.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Strange, I read on here that the injectors weren't to last a while.

My 420 also jumped and killed the head, I picked up a complete pull out 560 driveline for less than what the timing chain, guides, and tensioner cost alone!

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

When I tested them, on the first pump of the tester, they all had a fine spray pattern and opened at the correct pressure. It was not necessary to soak them or pump a bunch of cleaner through them.

I thought about another engine, but this car was so perfectly maintained that I elected to do both heads, the chain, tensioner, and rails. That ended up at about $1100 and it turned out really well.

With the open checkbook maintenance at dealers and specialty shops, the shame is that no one recommended guides at 100k.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Mine made it to 221K before blowing up, but heck... $227.27 out the door for the motor and trans was a no brainer to me. I am not even sure if I can get a top end gasket kit for that cash.

I bought mine on a gamble as a non-runner and didn't really come out that bad considering the condition of the interior and exterior. I'm curious how a stripped 560 will run.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

I realized I never posted the resolve to this one.

So I ended up putting all new injectors, holders and seals on the car, just to be sure. I got the injectors from an eBay seller (though not from an auction), and paid less than $300 for all 7, so I was stoked.

I got the stripped screw out by drilling it a bit (with the intent of using a screw reversal drill bit which worked like crap), but ended up wedging a regular screwdriver in the now drilled space and easing the screw out. That worked quite easily.

Sad part is, it didn't solve the problem. It turned out to be the fuel distributor. I bit the bullet and found a rebuilt unit for $700. Although that was a marked improvement, the car still vibrates a tad bit. The missing, backfiring, and intermitten gas flow problems were solved though.

Thanks for all the excellent responses you guys!

Craig