new injectors, now worse mileage? - PeachParts Mercedes-Benz Forum

shadetreemechan · #1 12-28-2009, 08:14 AM

I just installed a set of rebuilt bosch injectors and took off on a thousand mile road trip to NY in my 85 300TD. So far I have dropped 2 mpg and have noticably rougher idle when cold.
The smoke at idle and under heavy acceleration that prompted the injector change is gone, but I can't figure out why my mileage got worse.

These injectors were sold to me as bosch rebuilds, but look like new ones manufactured in India. I have not yet sent in my old ones as cores and am wondering if I should wait and have them rebuilt and return these new injectors since my old ones are the german made originals.
Has anyone had similar experiences with an injector swap?
I am guessing that I had at least one leaker in my old injectors that caused my smoke, but I am wondering if the spray pattern may be poor on the new ones causing the poor mileage.

#2 12-28-2009, 08:33 AM

Injectors from India have had problems for a while now. I would highly recommend a set of Monark injector nozzles.

oldsinner111 · #3 12-28-2009, 08:49 AM

With Bosch injectors,you need to check pop pressure.Don't use them with veggie.Monark nozzles are the best.

Murkybenz · #4 12-28-2009, 12:29 PM

Over here in the Uk the Bosch made in India are not known to last long.
My set of recon injectors in a 94 Bmw 525tds lasted 41k before they started to go bad.
Took them apart to find made in India nozzles.
Ok no big deal because they are cheapish to buy but 41k is not very good.

shadetreemechan · #5 12-28-2009, 07:25 PM

I think I am going to rebuild my old injectors when I get home. I can throw these new ones in an SD that I have. Poor SD it always gets the hand-me-down parts.,

layback40 · #6 12-28-2009, 07:45 PM

Get rid of the veggie oil & your problems will go too!! If you want to save on fuel and the world, buy a bicycle and a draft horse!!!!
Dont put WVO in your JD, you will stuff the pump & injectors.
Sell your WVO to some idiot & buy proper fuel. The Indians dont bother with WVO, they sell it & use proper fuel.
You only get what you pay for when you buy 3rd world stuff!! -Junk!!
Down here we wont even buy Korean Muzzo stuff & its made under license from Mercedes.

shadetreemechan · #7 12-28-2009, 09:03 PM

Quote:

Originally Posted by layback40

Get rid of the veggie oil & your problems will go too!! If you want to save on fuel and the world, buy a bicycle and a draft horse!!!!
Dont put WVO in your JD, you will stuff the pump & injectors.
Sell your WVO to some idiot & buy proper fuel. The Indians dont bother with WVO, they sell it & use proper fuel.
You only get what you pay for when you buy 3rd world stuff!! -Junk!!
Down here we wont even buy Korean Muzzo stuff & its made under license from Mercedes.

Too late for the fear factor. I've been doing WVO for too many years and in too many vehicles.
I also gave up arguing with people online about the subject.

Happy New Year.

Diesel911 · #8 12-28-2009, 11:00 PM

Quote:

Originally Posted by Murkybenz

Over here in the Uk the Bosch made in India are not known to last long.
My set of recon injectors in a 94 Bmw 525tds lasted 41k before they started to go bad.
Took them apart to find made in India nozzles.
Ok no big deal because they are cheapish to buy but 41k is not very good.

Here the Monark made in Germany Nozzles are about $23 and the made in India Bosch Nozzles are $27 on up into the $30s+ range.

I have also read that the Rebuilt Injectors themselves are rebuilt overseas some place.

glenlloyd · #9 12-28-2009, 11:12 PM

This rebuild quality thing concerns me. I have been pondering replacing the injectors in the W140 with the Bosch rebuild units (NA35X) that are supposed to have the better spray pattern. If these turn out to be crappy as some have suggested the Bosch rebuilds are I'm not going to be happy about it.

If I could find Monark nozzles around here I'd likely buy them and have the local Bosch shop do the work, but I don't know anyone who carries these.

thanks for posting up about this!

steve a

Diesel911 · #10 12-28-2009, 11:13 PM

I guess what is left is to check your Valve Timing (timing chain stretch) and retime your Fuel Injection Pump to see if it helps your mileage situation out.

I am guessing you did the Valve Adjustment already.

layback40 · #11 12-29-2009, 07:32 AM

shadetree,
I dont use scare tactics! If some one has years of experience then how come they (you) are having injector trouble?
We use about 3-5000 liters (>1000 US gallons) of diesel a month here.
We have looked at WVO etc. The only successful trial we have done was on a 50/50 blend of used atf/diesel, but we cant get our hands on enough used atf to make it worth our while.
My old 300d did nearly three times the mileage that your TD has done. The injectors have never been out of it.
If you look on this discussion site 99% of the threads with injector/ fuel problems are on or have been on WVO.
When some one can come up with a high mileage diesel (>600k miles) that has run all that time on WVO with out problems, let me know.
Until then I think its best that I keep WVO away from diesels like $500k+ scrapers & dozers that need to be reliable. I cant afford to have them broken down under some shady tree !!
I think my 123 & 124 deserve better also.
For those who like to play and enjoy pulling their fuel system to pieces, good luck, I prefer not to continually be banging my head against a brick wall.
Long term true down time and maintenance costs make even free WVO uneconomic. We have done the sums several times and have the incentive ($$$$) to make changes if it is worth it.

shadetreemechan · #12 01-02-2010, 07:59 AM

Quote:

Originally Posted by Diesel911

I guess what is left is to check your Valve Timing (timing chain stretch) and retime your Fuel Injection Pump to see if it helps your mileage situation out.

I am guessing you did the Valve Adjustment already.

I was hoping that the new injectors would be the final piece of the mileage puzzle. In the last 6 months I had the dealer install an offset woodruff key to correct timing stretch, set pump timing and adjust valves while he was there. With the old injectors I have been getting 25-27 on family trips (with loaded car) and 27-29 solo. We just returned last night from a 2500 mile road trip with the family and averaged 24 with a top of 25 and low of 22.
I checked compression when installing new injectors and have consistantly around 400 psi.
I think I am going to let Sean rebuild my old injectors and put these bosch rebuilds in my SD. If nothing else it will be an interesting experiment to compare the two.

3pointstar · #13 01-02-2010, 10:19 AM

While you replaced the injectors -- I would wonder if it was the blended fuel that is contributing to the lower mpg. Also it may be something as simple as tire pressure -- You add these things up and before you know it you have reduced your mpg.

these are just thoughts.

3pointstar

shadetreemechan · #14 01-02-2010, 11:23 AM

Quote:

Originally Posted by 3pointstar

While you replaced the injectors -- I would wonder if it was the blended fuel that is contributing to the lower mpg. Also it may be something as simple as tire pressure -- You add these things up and before you know it you have reduced your mpg.

these are just thoughts.

3pointstar

I wondered about blended fuel as well, but one of the best tanks of the trip was after a fillup in Syracuse, NY

.I think if it were blended anywhere it would be there. I was looking for pumps listed as blended fuel, but didn't see much. One pump in PA showed a cetane rating of 40 and then had an undyed K-1 pump right next to it, so I guess it was a blend-your-own spot.
I ran 35 psi all around in the tires.
I have also had a much rougher cold idle since putting in the new injectors. It acts like an air leak, but I replaced the return lines with the injectors and don't see any leaks.
Priority now is to get all the road salt off the car. I cringe everytime I take one of my old southern cars up there.

Crazy_Nate · #15 01-02-2010, 11:24 AM

Winter diesel?