prostovito

Ok i've got a huge problem with my ml430. Firstly the car started to lose power up hill and than began having problems starting, like it would try to start and eventully start up and idle alright but when i would press on the gas the engine would start to choke up, and when i let got of the gas it would have a sudden surge so gas pedal works backwards. lol.
I checked the obII scaner came up with these codes,
P0300
P0301
P0305
P0307
P0170
P0173
P0110
P0100
So i started trying to find out whats wrong, SPARKPLUGS, MAF, two front O2 SENSORS, were changed, also bought a pass side CAT but still having same symptopms as before. but after the change of O2 sensors the codes came up as p0150, p0170, p0173
Now i've taken of the CPS(which was changed last year) just to test it and and at room temp it was showing 695ohms so that test out good. so i'm sorta running out of option to test and to try.
Another thing i noticed is that the exhaust pipes after the cat on both sides were heating up rapidly to the point at where they RED like glowing RED. well anything would help..................... thanks

boardboy330

Heating your exhaust like that general means you have a plug up in the exhaust or you are running too lean. I haven't looked online for your codes...but someone should chime in shortly.

sosh

Most likely all the cats are bad except perhaps the one you have already changed. Even a lean mixture would not get the exhaust red hot.

prostovito

Well what i've read that usual signs of cats being backed up are missfires, which don't show up anymore.. and another thing that really confusing me is the starting issue. The car starts after trying a few times and than idles just fine. any thoughts???

sosh

I still say CATs and the clue is the red hot exhausts and loss of power. Its also possible but not probable the the mufflers are clogged but I have not heard that on an ML before. As I recall are there not 2 CATs per side?? You also do not state what the mileage is on the ML. Also did you use an OEM CAT when replacing the one?? If not keep in mind that some of the aftermarket ones are pure junk. Could be a result of a previous owner running bad and/or low octane fuel or that the CATS are just done.

prostovito

Thanks SOSH. I'll have both cats tested, and see maybe the driver side is clogged aswell cause they both were pretty red, the thing is that i only noticed the redness after i had installed the new one on the passenger side, which i purchased online OEM exact fit for 350. heck of a deal.
I owned the car for 3 years and it has now 144k and always have used medium grade 89 fuel..
I was changing the fuel filter on my ford ranger and after i tried to start it i realized i was parked up the hill with low fuel and the car showed same symptoms and than wouldn't start at all.. maybe its irrelevant but maybe its the fuel pump or filter????
I am really at a loss but im sure i'll be able to figure it out just don't know if i have the patience.. lol.

prostovito

another thing i forgot to mention is that the fuel pump relay is really hot.. now i've switched them around with another one and still same. maybe that helps.

sosh

First off with fuel MB says a minimum of 91 octane. And, you do not know what previous owners ran. Second re the relay, do not believe it should be that hot, is your E Box fan working??
Is the fuel pump itself getting very hot?? However believe thats a separate issue and not related to the hot exhaust.

prostovito

k i finally "fixed" my MB. It turns out the the electronic fuel pump has failed and only giving out so much fuel and thats why the gas pedal was working backwards. umm check engine still lit so i guess there are a few other problems with it but i haven't checked the codes. will post as soon as i find out..

Savadaba

It is a gas pump fail, its not completly broken, try this over full your gas tank the gas pump will be better wen yuo have 3/4 tank or less the simthoms will return