im a newb and i need some help bad! - Benzworld.org

85 500sel · 07-30-2008, 10:31 PM

i have an 85 500sel and the car has sat for four year. i had to put a new fuel pump in it it bearly stated. and bearly runs it did idle but would only go up to 2000 rpms and after driveing around for tweny minutes around the naighbor hood BEARLY able to get up to 25 mph i came back home and looked under it and the cat was RED hot so i cut it off and the thing was PLUGED as f*&#K. i stated it runs a little better but still bad. do i started pulling spark plugs that were bosch platnim + 4s and ive pulled only three two were fireing and one was like packed with crap. could that be due to plugged cat? and should i run a compression test??? how much pressure should each be at? and when i re do the exhaust should i put a cat back on? i would love some oppinions. THANKS

scott1999 · 07-31-2008, 12:15 AM

sounds like you are on the right track
as for the cat does it have a 02 sensor after the cat , if so , that can be a problem ,
but sure there are more knowlagable people on the forum that can help , good luck
these are great cars to own and run

**a3jeroen** · 07-31-2008, 12:39 AM

Welcome.

Please (re)read the welcome to the forum stickie. It'll tell you how to fill out your profile and how to do a search.
We had some threads about clogged cats.
IIRC someone (AA?) ran his car without the exhaus just to try and then replaced the cats since it revved great without the exhaust.
For plugs I'd change to non-resistor NGK BP6 ES's.

gr J

85 500sel · 07-31-2008, 12:16 PM

no sensor.. but i bought autolite 66's will they work?

85 500sel · 07-31-2008, 02:30 PM

i put the new plugs in and IT RUNS. yay!

scott1999 · 07-31-2008, 08:03 PM

Quote:

Originally Posted by 85 500sel

i put the new plugs in and IT RUNS. yay!

nice one well done

85 500sel · 07-31-2008, 11:07 PM

but it still runs rough and is REALY hard to start. it still has alot of bad gas maybe thats why. what kind of injector cleaner should i run with fresh gas?

tripleblk · 07-31-2008, 11:31 PM

I just had the same problem with my 87 560SEL. It is probabaly just bad gas. Gas gets old and turns to varnish. Drain it all out and put good stuff in. Also, the car proabaly has 2 fuel pumps, bad gas ruins fuel pumps, make sure both are working. Bad gas killed both my fuel pumps, I took them out and got them working again by hooking up power to them and then reversing the power a bunch of times until they broke free again. Then I blew up my fuel pump relay trying to run them on bad gas. I changed that, drain the bad gas, put in new gas and it fire right up.