I am the original owner of this 1991 and it has 149K miles. This has been one fine car.

The injectors have never been touched. Fuel economy is slipping, their is some injector noise and a tad of rough idle (which I improved substantially by repalacing the pressure valve seals recently).

From what I read a lot of people say injectors should be done every 100K miles (?).

One shop told me new injectors are sometimes worse than rebuilds because they come from Mexico (?). Another shop says it is best to rebuild and pop pressure calibrate my original injectors(?). This shop wants to charge me $50 per injector to rebuild/calibrate each injector plus the labor to remove and replace them. Is this fair?

Does anyone sell a matched set of pop pressure calibrated injectors either rebuilt or new? If I get them calibrated locally how can I been sure the shop did the best calibration job possible?

What might be my best course of action here?

Thank you.

150K on injectors shouldn't mean they need replacement. All my cars have original injectors, and only one car has had them cleaned & tested. They all run great. I'd start with a treatment of 1-2 cans of Diesel Purge. If that provides no improvement, then consider rebuilding them. If you buy a new (or rebuilt) set, they still need to be pressure-matched by a good diesel shop. If you insist on replacing them, I'd try buying a set from a Mercedes diesel shop that they have calibrated to be within ~2 bar of each other for break/pop pressures. I think Pacific Coast Fuel Injection (?) in San Francisco are is supposed to be top-notch. The price of $50 each PLUS labor to R&R sounds a little high. I had my set cleaned & calibrated for $125, and I R&R'd them myself. Rebuilts from online sources are usually $50/each.

For the symptoms you describe, after the Diesel Purge I'd also check timing chain stretch, check IP timing (set slightly advanced at 14 ATDC instead of 15), and perhaps switch to Mobil synthetic oil if you haven't already. Some of that "injector" noise could possibly by the hydraulic lifters, which can make intermittent noise when using dino oil....


HTH,

__________________
Dave
Boise, ID
Check out my website photos, documents, and movies!