94 c280 resurrection, striping, race build - Page 3 - PeachParts Mercedes-Benz Forum

duxthe1 · #31 12-23-2024, 01:35 PM

I don't think its gonna matter. Studying all the different variant coding options, ASR and Non ASR a lot of them have the same coding number. Still, just plug it in and see.

rwd4evr · #32 12-25-2024, 04:32 PM

Quote:

Originally Posted by duxthe1

I don't think its gonna matter. Studying all the different variant coding options, ASR and Non ASR a lot of them have the same coding number. Still, just plug it in and see.

Cool. We shall see. Getting the car got put on ice, literally. It's been like 22°.

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rwd4evr · #33 12-25-2024, 07:19 PM

Went through a few alternators I had including my drift car spare(junk) and found my brand new voltage regulator was bad and all the crappy ones I have laying around are good

. I had to steal the alt off my m120 and re clock the halves to mount and have wires reach. I have charging now

. I've scabbed together exhaust from some leftover r129 stuff , hooked up an oxygen sensor but its definitely not running quite right. Idles great but a quick stab of the throttle and it wants to fall on its face. I have not welded up and sealed the pipe upstream of the O2 sensor so maybe it's reading air leaking and the mixture is way off? I can get it to rev if I roll in slow then give it some but it's definitely hitting something at like 4500. This is all on the lift in park too, so idk if that has any limiter. The second o2 is not hooked up. The engine has zero blow by or making bad noises. Let it idle for a long while and it got to just over 80c and had no exhaust in the cooling system. The running issue could also have something to do with varnishy gas. I pumped out whatever it would pick up and put 5 gallons in it but it still smells like it's running on some stinky old gas. I'll probably get the exhaust sealed up and tires put on it and see what it does on a real drive with a tank of fuel and a strong fuel system cleaner. Could there be stored codes in there causing troubles even if the battery has been disconnected and there's no dash lights telling me anything? I need to whip up a code flasher.

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duxthe1 · #34 12-25-2024, 11:37 PM

There is a hard rev limit at 4K rpm in park / neutral. MB says its bad for the torque converter to rev above that without a load. Have you inspected your plugs? These engines are famous for carbon tracking the outside of the insulator on the 3 cyls with the coil directly above them. Early stages will manifest as a misfire coming off idle. Don't get water down under the coil cover, its a guarantee this will happen. I literally tape off the coil cover gaps to wash a 104 engine.

rwd4evr · #35 12-26-2024, 06:05 AM

I have not looked at plugs. Just been trying to get the big obvious **** handled before going nuts. After I got home from family Christmas stuff I messed with it for a few minutes. I had disconnected the vacuum pump cause it was running a lot and the starter was disengaged. Plugged it back in and it cranked. The battery is definitely not fantastic and was cranking slow and pow! Thing backfired like crazy, puff of smoke under hood and all . Hit it again and it sounded real weird. I thought the thing jumped time for a minute. I let the battery charge for a little bit and it cranked slow. Thought the starter was the issue. Went back a few minutes later and it cranked ok took a minute to actually fire sputtered then cleared up. Running great again. Revved clean cold . Decided to walk away while I was ahead for the time being. Slightly baffled by the starter/backfire/very unhappy sounding cranking thing. I seriously thought it was toast. I even made sure the cam was still spinning then magically it's all good. Very odd. I need to get O2 sensor bungs and seal that exhaust up, plus the mini catalytic converter for the second one. It sounded great for that 45 seconds. Clean quick rev with a stab. I'm guessing it's in open loop and not very angry about massive exhaust leak upstream from O2 1 and no 02 2 hooked up at all. Does O2 2 have tuning effect or just warning/code throwing or what?

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rwd4evr · #36 12-28-2024, 05:00 AM

I got the exhaust all finished up as far as being essentially sealed. No clamps yet but the stock pipe fits inside the 2.5" extension pipe so well it's almost unnecessary. The muffler doesn't sound great with no cat no resonator, straight pipe is a little fart can-ish but whatever. More concerned about it running great for 5 seconds and then as soon as it idles down it's very unhappy about revving. I had the upstream O2 hooked up only with the exhaust sealed up and it still went to **** very quickly. I tried unhooking it just to see if there was any difference and there wasn't. I've got sensor bungs coming for both and the cat simulator, spark plugs and some B12 chemtool. I don't know anything about the two 02 sensors if pulled from the sl600 but it did run before it was crashed. I guess I'll look into testing procedure for them. At least I have the right plugs and I can get cheap universal ones if they are bad. I've also noticed the aux fans come on right when I start it sometimes. That can't be correct or good......

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rwd4evr · #37 12-29-2024, 08:38 AM

I made the code flasher. I got an ass load of codes out of it. Tons about the O2 sensors a misfire or 3 and then the big ones.

These are pin 4 codes
5,8,11,12 13,14,15,16,17,18,19,
24(I think, maybe 23),36,

These are my bigger concerns
42. Camshaft position sensor monitoring signal from engine control module (N3/4)

48, Mass or volume air flow circuit range/performance problem
(Hot film mass air flow sensor [B2/5])

49,Crankshaft position sensor circuit malfunction

I reset them and talked to a buddy of mine. He recommended check fuel pressure. It's 52psi at idle and rises a bit under throttle. Light throttle it's fine and revs but any heavy throttle and it falls on its face, pops and farts. Fuel pressure is good. He said maybe cam timing issue? Messed up phaser possibly? I'm leaning more towards a crank sensor or MAF issue maybe? I didn't do plugs yet but I got them and the bungs for 02 sensors. He said o2's would realy just make it get ****ty mileage and maybe down on power a little bit. Tried disconnecting the MAF and the cam sensor separately to see what reaction it had. Not a ton but it ran a little different. I was concerned about the wiring harness not being replaced because of the 2,8,93 date but then I flipped the tag and it says 18,9,97 (day/month/year in euro speak I'm pretty sure)and the MAF plug says 97. That's a relief. I'm kinda hoping for a bad crank sensor. I need toook into testing them. He also recommended pulling the valve cover and checking cam timing. I need some sleep.

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duxthe1 · #38 12-29-2024, 05:00 PM

Your cam timing is fine.

Your air mass meter sounds kaput. Nothing else in your faults really raise any flags. If anything else pops up after the fault clear, deal with it then.

rwd4evr · #39 12-31-2024, 08:51 AM

Well, "Dolly" the 280C seems to be much happier, but I still feel like there's some things she's not telling me.

I finished welding the exhaust up with new 02 sensor bungs , cleaned both O2 from a sl600 I have for an engine donor with acetone and a torch and got them hooked up, and finished up the exhaust with just the stock muffler. I used r129 muffler to build a fake catalytic converter to hopefully sneak through inspection. They usually just look with a rolling mirror.

To be perfectly honest , the battery that's in it is a little small and it's kinda ****ty. After getting it all put together with the clean 02 sensors and clearing the codes I cranked it and "kapow". Violent intake backfire, again. Woops. Charged the battery up on boil for a few minutes and it started after cranking and sounding weird again. Stumbled and bumbled for a few seconds then was clearing up, really sounded like it blew a big vacuum line off or blew a hole in the intake or something. Kind of a weird pfft pfft pfft sound. Then it cleared up and was perfect. Revs clean idles normal. Shut it off and restarted perfect. All seems well. Ran it on the lift for an extened period, checked and cleared codes again. Just an 11 which was sensor heater circuit malfunction. Left the key on and went to sleep.

. I put tires on it today and turned the key. Kapow! One more time

. Not quite as bad and kinda cleared right up. I need to put a good battery in it though. Took it for a spin after messing with some taillights.

Brakes are awful, they were so rusty. Might have a bit of a sticky pad/caliper in the rear. Fronts have a huge ridge on the outer edge. Cooked. I might have some good 560sl rotors I can cut, I hate to buy Chinese crap if I can avoid it and budget is as little as possible. I think they're the same. Rears are the same as r129 or close enough it will all swap. I've got a bunch. It's got a couple wasted lower control arm bushings. That's gotta all get gone through. I was hoping there was some amg specific bushings for a c36/43 but it looks like they all run the same parts, c208 too. It's barking gears hard and thumping something. Seems a bit quick to want to get into higher gears. Maybe vacuum related. Fairly sure it's got a wasted motor mount, maybe a subframe bushing. Ohhhh, maybe a center bearing. Clutch fan is wasted. It never went over 100c even idling but it's cold out and it was approaching. It came down on the road and stayed at 85.

I'm a bit concerned about aux fans coming on randomly at key on a few times but not when it's approaching 100°. Hmmm the temp gauge died a couple times until I messed with the connections. I'll hope that temp gauge fix handles that. For racing I'll probably remove the mechanical fan and set the aux fans on kill anyway. That clutch fan is really close and there will be some big shots in Dolly's future. Can't afford a rad strike.

I guess it's not surprising that fixing the O2 sensors made it run right, but everyone seemed to think it wouldn't make it as bad as it was. Shockingly the cooling system and engine/head gasket seems happy. No abnormal pressure or blowing smoke/steam after it cooked out the muffler. Not fully convinced it's "fine" yet but maybe it's good, at least to street drive and maybe go drift it a bit to see if it will take a good beating.

It seems pretty gutless below like 3500rpm(or more really)but that's not super surprising. It's going to live between 4800 and 6400 anyway. I put like 8 miles on it. The oil smells like rotten gas. Now it's acting ok I'll do some normal(ish) maintenance stuff so I can try to get it tagged and beat on it for awhile. Front bushings are high on the list. Lots of thinking outloud that's made me see some things.

I went and pulled the 3.2 today in some guys driveway, nice guy. Total thrash to get him to work on time. 3.5 hours arrival to packing up. We stuffed it into the back of my 350sdl on the wood platform back seat area I built. Still there. Sorry about the coolant on the brand new driveway but I told you it was impossible to get it done without!

We shall see how it goes over the next week or two. I got a pretty good idea for a funny/great paint scheme for when its ready.

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rwd4evr · #40 01-03-2025, 04:35 AM

Interesting new thing. Drove it to my dad's to pick up some mail and parts deliveries . Drove fine but wouldn't restart after I was there for an hour or something. Finally got it to sputter to life by foot to the floor while cranking. Fires right up if I shut it off for a few seconds. I'm thinking it's got a leaking injector. Might explain violent backfires too. I pumped some acetone into the fuel rail, pulled a vacuum and got bubbles. Would possibly explain it being gutless under 4000rpm and the rotten fuel smelling oil.

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duxthe1 · #41 01-03-2025, 01:27 PM

Leaking injector is possible but a leaking fuel pressure regulator is much, much more common. Pull the vac line off after you shut it off and watch for a few minutes. ANY fuel at the nipple condemns it. A leaking purge valve will also give flooded engine symptoms.

rwd4evr · #42 01-04-2025, 05:15 AM

I'll check the regulator, but it still didn't want to start with the fuel pump relay jumped. I think that just a leaky regulator would be handled by the pump running balls out for seconds before even trying to start it. By purge valve do you mean the pressure test port, or is there something I'm unfamiliar with?

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duxthe1 · #43 01-05-2025, 11:59 AM

It's the valve that feeds the engine fuel tank vapors. It sits on the left fender with 8mm black plastic line connected to it. It should hold vacuum when no power is applied.

A failed regulator leaks fuel into the intake manifold through the vacuum line, flooding the engine. It's not a failure to regulate pressure.

rwd4evr · #44 01-06-2025, 04:36 AM

Well I owe you a beer or something. I didn't find a single drip coming out of the regulator vacuum line. More of a torrent pouring out. With the amount of fuel dumping into the vacuum line it's kinda surprising it would run at all. Can't upload video. But here's a couple pics. I snagged a good one from a m119 in the hoard and all seems well.

Race car!

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duxthe1 · #45 01-06-2025, 01:26 PM

Damn! That's probably worse than any Ive seen. A few drops will cause issues, it is surprising that it would still run like that.