Help Tuning a 603 IP - Page 3 - PeachParts Mercedes-Benz Forum

NZScott · #31 06-08-2017, 05:27 AM

My understanding is black smoke is partially combusted fuel, white smoke is raw unburned fuel vapour. As Diseasel said EGT rises as the fuel is later combusted after peak pressure is reached in the cylinder as so goes out the exhaust manifold partially burning. Plenty of videos around showing locomotives and trucks with flames coming out the exhaust from excessive EGT causing the soot in the near-glowing manifolds to burn....

Maxbumpo · #32 07-25-2017, 01:53 PM

Diseasel, Did you ever adjust the fuel cut-off RPM? How is mileage?

I finally had some time to adjust the ALDA on my wagon over the past weekend. Smoke was not too bad before, it's better now, but I think I can find even more improvement. I only turned the screw in (CW) 1/2 turn. It is a pain, I have to remove the injection lines for cylinders 4/5/6, but I think I will go CW another 1/2 turn.

Diseasel300 · #33 07-25-2017, 05:23 PM

I never did adjust anything on my IP other than the ALDA. The ALDA adjustment did help significantly with smoke and with MPG when on-boost, but did nothing for off-boost issues. My city MPG is ~24 and highway is ~23 (though my highway speed is 80 around here) with A/C on. Not spectacular.

The body seals on my IP are leaking oil and since it has to come off for a re-seal, I'm just going to source a proper 3.0L IP and do the job once. You can bet after all the issues I've had with IPs that whatever goes in will be spit-shined and given the 3rd degree before it touches my vehicle!

Maxbumpo · #34 07-26-2017, 09:32 AM

Quote:

Originally Posted by Diseasel300

The body seals on my IP are leaking oil and since it has to come off for a re-seal, I'm just going to source a proper 3.0L IP and do the job once.

Could you "baseline" your current IP by measuring the 0-60 time, and then repeat test with the new IP? That would be nice to know. If I'm not getting any extra power for my decrease in mileage, I'll probably follow you.

FYI, it is possible to replace the seals for the bottom plate and the side plate with the pump installed, just a huge pain. BTDT. I'd do that again before I'd R&R the pump.

Diseasel300 · #35 07-26-2017, 10:55 AM

I will definitely do a timed run before/after the swap to determine if there is any improvement at all. Given how early I have to have the transmission shift with the 3.5L pump, I'd imagine it will be faster with the correct pump that revs to the correct RPM range.

My pump leaks from the rear and bottom plates. Given the limited access to get in there and my lack of patience for putting up with BS, it's a job best done by pulling the pump and doing the deed on the bench. If I'm going that far, I'm going to put the right pump back in instead of this beast. I had reservations about putting that pump in in the first place, but at the time I'd already been through 2 defective ones and was in a "screw it" phase. Pump works, car runs, been super reliable, but I'm growing tired of the ONLY oil leak on my car being the IP and really growing tired of the black smoke at low RPM's when pulling away from stop lights from the tranny shifting up quickly.

The compromises just aren't worth it. I'll have time to devote to fixing a few mechanical issues this winter and I'll likely tackle the IP at that point if I've been able to source the correct one by then. I'd imagine the 3.5L pump would be great for someone who knows how to tune it and plays with the turbo to match the extra fuel, but I'm not that knowledgeable and I'm not a modder.

southofantarctica · #36 07-27-2017, 10:25 AM

Have you done any adjusting of the Bowden cable since you changed the IP? The transmissions are very "tuneable" on these car with just a simple tightening or loosening of the cable.

I had a SDL that was sold as having a bad transmission because it would hardly upshift and they could not get it into 4th. After messing with it, it became apparent that the transmission was fine, just out of adjustment. Loosening (I believe, it has been a few years) brought the shift points down to a normal level and the car drove perfectly.

You might just need to tighten the cable so the transmission knows that you are still wanting to hold gear. It's free and extremely easy to do, just give it a couple of turns and take it for a drive around the block, repeat until you are happy or decide that it doesn't help. I would suggest making large adjustments until you get a feel for it, then smaller tweaks until you get where you like it.

Just be sure to mark the position it is in before you move anything and count the turns so you can get back to where you were if you need to.

southofantarctica · #37 07-27-2017, 10:27 AM

Also, if you do decide to swap pumps down the road, let me know if you want to sell the 3.5 IP. I'd be interested in taking it off your hands possibly.

Diseasel300 · #38 07-27-2017, 11:01 AM

Quote:

Originally Posted by southofantarctica

Have you done any adjusting of the Bowden cable since you changed the IP? The transmissions are very "tuneable" on these car with just a simple tightening or loosening of the cable.

I had a SDL that was sold as having a bad transmission because it would hardly upshift and they could not get it into 4th. After messing with it, it became apparent that the transmission was fine, just out of adjustment. Loosening (I believe, it has been a few years) brought the shift points down to a normal level and the car drove perfectly.

You might just need to tighten the cable so the transmission knows that you are still wanting to hold gear. It's free and extremely easy to do, just give it a couple of turns and take it for a drive around the block, repeat until you are happy or decide that it doesn't help. I would suggest making large adjustments until you get a feel for it, then smaller tweaks until you get where you like it.

Just be sure to mark the position it is in before you move anything and count the turns so you can get back to where you were if you need to.

The valve body/governor in the SDL transmission is set up for shifting at WOT ~4600 RPM with fuel-cut in the IP ~5150 RPM. The 3.5L IP has fuel-cut ~4500 RPM which is below the WOT shift point of the transmission.

When I first installed the 3.5L IP, you really had to play with the throttle to get any sort of upshifts. The IP would run to 4500 RPM under hard acceleration then just sit there. Backing off the pedal a bit and the tranny would upshift. Not ideal.

I adjusted the bowden cable to do a WOT upshift ~4300 RPM which has taken care of the failure to upshift problem, but has made it to where it likes to be in 4th by 35mph when driving around town and not wanting to downshift unless the button is pressed. It's a workable compromise but annoying and all limited by the 3.5L IP having the governed fuel-cut set ~600 RPM too low.

I could send off the 3.5L and have it calibrated correctly for the 3.0L pump, but by the time I did that I could have just sourced the proper pump in the first place. When I do the swap I will have the 3.5L available for anyone interested in it. It's reliable and has only run pump diesel, runs fine just the wrong fuel mix and RPM settings for the 3.0L engine. I'm not a tuner/modder and have no intention of tearing into the IP to try to tune it.

For anyone wanting a 3.5L pump, if you have a 3.0L pump that is *KNOWN GOOD* (aka from a working car), PM me.

Maxbumpo · #39 07-27-2017, 01:33 PM

Quote:

Originally Posted by Diseasel300

For anyone wanting a 3.5L pump, if you have a 3.0L pump that is *KNOWN GOOD* (aka from a working car), PM me.

That is tempting, I have squirreled away an OM603 + transmission with only 143k miles, saving that for a swap into a '95 gasser wagon...

southofantarctica · #40 07-27-2017, 02:13 PM

So much for an easy fix.... Sounds like you really have exhausted most all the options.

If I has standard pump, I'd be all over that. Maybe I'll ahi me across one down the road.

Maxbumpo · #41 07-27-2017, 04:27 PM

The last "fix" would be adjust the max. rpm set point from 4600 to 5100. I'm going to do that some day when I can budget the time.

Diseasel300 · #42 07-27-2017, 04:44 PM

Max RPM adjustment will fix the shifting issues, but still won't address the fuel injection quantity issues. If I knew what the hell I was doing I wouldn't be so adverse to adjusting the IP, but finding a proper writeup of what does what and how to adjust it seems to be missing (I've spent hours looking). I'm not going to "wing it" on something that important.

Maxbumpo · #43 07-28-2017, 09:47 AM

I've got my set-up ('87 wagon w/ OM603, #17 head with oblique injection, 3.5 liter IP) running very well. Almost no smoke at all on hard acceleration, even from a stop. When I adjust the RPM setting, I'll lean the ALDA another 1/4 turn in, and I expect that last bit of smoking will be eliminated.

One thing that helped quite a bit was adjusting the turbo boost back up to spec (~13 psi). Have you tested the boost to see if that is correct?

Diseasel300 · #44 07-28-2017, 10:20 AM

My car is an '86 300SDL, OM603, #14 head with vertical injection, Monark injector nozzles, and the 3.5L IP.

Like yours, it runs fine, but I can't say the same about the smoke. Gentle acceleration will produce a very fine fog, but if you give it a boot full (say you're trying to cross an intersection), it'll leave a black cloud across the intersection. Another VERY common issue is when moving in slow traffic (say 30mph) and have to climb a hill, transmission is in 4th and you roll coal all the way up the hill.

Stomping the pedal to drop a gear or two isn't an option since you can no longer match speed with traffic (too many blue-hairs), and besides, it will shift right back up after you back off the pedal again.

Keep in mind, most of my issues are OFF boost. Once the turbo spools up and I'm running on boost, there's virtually no smoke at all unless I'm really on it.

The turbo is building just a hair over 13PSI, and usable boost starts coming on ~1800 RPM. Unfortunately city driving is usually well below that.....1200-1500 RPM which produces smoke.

Timing is dead on, I have <1˚ of chain stretch, gaskets are all tight on the intake and exhaust, turbo is spooling and wastegate functioning, EGR blocked off with a plate, Federal car so no ARV, DV's in the IP polished and sealed, lift pump serviced and making >15PSI.

Everything is in spec and doing what it's supposed to, it's just the IP metering the incorrect amount of fuel. I've fiddled with the ALDA and the screw is now turned all the way in and then back out 1/4 turn. That has it acceptable on-boost, but OFF-boost it is still very much unacceptable. The IP is a used one and I know nothing about the history of it. It's entirely possible someone messed with it in the past and turned the fuel up.

My biggest concern is EGT. The smoke is irritating, but the EGT's are important, especially with the original #14 head. I don't have a pyrometer installed (and don't plan to install one), but the temp gauge can show what's going on when pulling up a long, steep hill at highway speed. Temp comes right back down when you get off the skinny pedal. I've never had it overheat, hasn't used a drop of coolant in the 9 months I've had the car on the road, and the cooling system has never been pressurized, so I'm in the clear there, but for how long running it like this? The 603 #14 head guys will probably understand my concern.

If I knew how to turn the fuel down and RPM limit up without causing a runaway, I'd do it in a heartbeat. The information to do it correctly seems to be what's lacking.

Maxbumpo · #45 07-28-2017, 03:12 PM

I've been gathering up the info, I've got the part about increasing the max RPM figured out, and I could give you a couple things to try to turn down the fueling.