djfelip

Hey guys,

I wanted to see if I could get a little help from the master mechanics on this forum. I took my 2001 CLK 430 into the shop today to get check engine light diagnosed. It came back with two codes p0170 and p0173 which are fuel trim issues. After running a star diagnosis the tech informed me I have an under performing fuel pump.

I was given a summary of the work to be performed and I wanted to make sure this sounded correct because this was not a dealer I took the vehicle to.

Replace Fuel Pump - $786.10
Replace Fuel Pressure Regulator - $302.10
Replace Fuel Filter - $143.90

That was the run down of parts to be replaced excluding labor rates so that’s pure parts costs. I have been doing a bit of research on my own and was able to locate the pump & filter at http://www.germanstar.net/208f.htm.

I have been unable to locate a fuel pressure regulator, I was told it was not installed from the factory but it is in fact part of an old recall on the fuel pumps. Is the FPR a separate unit from the pump or is it internal?

I plan to order and replace the parts myself but I want to make sure I am replacing everything with the correct stuff.

Thanks,

sick430

i have the same codes. and think i have the same problems but am running rich i think. i will post up reading from the obII over the weekend.

gregory13lil

Well I can tell you that the fuel filter is external and very easy to get to. It is located by the rear passenger tire. I bought this fuel filter for 38 bucks only and it took me maybe 30 minutes to change it out once I lifted the side of the car with my Hydraulic jack http://cgi.ebay.com/ebaymotors/Merce...spagenameZWDVW

And the pump is a little more difficult to get to buck can save you QUITE a bit of money and it only costs 100 bucks!!
http://cgi.ebay.com/ebaymotors/OEM-M...2em118Q2el1247

You can replace the 2 main parts for 150 bucks and then still have the rest of the money to diagnose some more if it doesnt solve the problem. This is just a suggestion though...I just hate to see most people have to pay for alot of labor when its something that is not too hard to do. Now, if you had an internal engine problem then I would tell you to just cough up the money for the mechanics expertis but not for something like this. Well I hope this helps a little.

Laters,
Greg

djfelip

I am going to clean the Mass Air Sensor and see if that fixes my problem before I replace the fuel components.

I do notice a loss in power, I was told that the output from the pump was lower than it should be. He also told me that he tested the pump output before and after the filter and the output was the same. That would indicate to me my fuel filter is fine but I am going to replace it anyways if I end up replacing the pump. I will let you guys know what happens I might end up making a DIY guide for the fuel pump.

Thanks for the help any other suggestions would be greatly appreciated.

ratha67

As you probably already know, the MAF sensor is the common culprit and it causes those Fuel Trim Error Codes P0170 and P0173. Cleaning the MAF didn't work for mine (I had to replace it), and considering the frequency that these things go out, I would recommend buying a NEW Bosch MAF off of ebay and see if that fixes your problems. If that doesn't work, keep your new MAF for when it does go out.

Those are some pretty expensive repairs. I would spend a little money trying to solve the problem before spending a lot of money at the shop.

When I had the P0170 and P0173 error, I made the mistake of paying a shop a bunch of money to do some BS trial and error style diagnosis. They ended up replacing a bunch of Gaskets, 02 sensors, and the fuel filter and really ran up the bill for mainly LABOR. What ultimately turned off the P0170 and p0173 code was the $95 Bosch MAF sensor I bought off of Ebay.

Good Luck.

MarcusF

You’re on the right track in NOT using the shop that did the diagnosis. The OEM pump is about a third of the price the shop quoted. On top of that, this shop wants to change the regulator, pump, and filter, when *maybe* the filter is due to be changed. Of course, it could be the MAF, but *assuming* the mechanic actually did a fuel pressure test and it came back low, why doesn't he recommend the "normal wear item" first? As you saw, his price on the filter was way high - 40% above retail. Also, how does one tell if the pump is weak if the filter is clogged? Ditto for the regulator (which I can’t find as a separate part from the filter). I’d change the filter, clear the codes, and see if they come back. A clogged filter can kill a pump, but I doubt that’s the case here. Lastly, the Bosch filter is what I use and it costs about $30.

sick430

i just replaced my MAF not to long ago. it dosent seem to be the MAF as i am not experiancing any power problems. not trying to steal tread we just have the same codes.

djfelip

The shop I went to actually tested my fuel pump output and it is under performing by about 25%. I have a dramatic loss in power when trying to stomp the gas. I am going to order the OEM fuel pump and filter from the germanstar site above and just swap them out myself.

I am highly convinced it is the fuel pump due to the low output. I will keep you guys posted I’m ordering the parts today. Failed my damn emissions test and it is keeping me from driving because I cannot renew my registration.

sick430

hey these are the codes and info i got from the cars obdII
code 1 P0170
Fuel Trim Bank 1
code 2 P0173
Fuel Trim Bank 2
FREEZE DATA
READING
Engine RPM 525
Load Value 32.90%
MAP Sensor 37 Kap
Coolant Temp 176 F
Short trim Fuel Trim 1 0.00%
Long trim Fuel Trim 1 -11.80%
Short trim Fuel Trim 2 0.00%
Long trim Fuel Trim 2 -11.60%
Short trim Fuel Trim 3 -100.60%
Long trim Fuel Trim 3 -100.60%
Long trim Fuel Trim 3 -100.60%
vehical speed 0.00%
Fuel System 1 closed
Fuel System 2 closed

I/M MONITORS
READING
Misfire Mon OK
Fuel System Mon OK
Comp Component OK
Catalyst Mon OK
Htd Catalyst N/A
Evap System Mon INC.
Sec Air System OK
A/C Refrig Mon N/A
Oxygen Sensor Mon OK
Oxygen Sensor Htr OK
EGR System Mon OK

Thanks for any info

djfelip

Ok quick update on this one. It was the fuel pump that was the problem i had the output tested. I just finished changing it and the filter out. How do I property reset the self adaptations and the ecu? I cannot currently get it to idle more that 20 seconds.
Thanks guys,