I tend to try the simple stuff first. Replace the battery and then see if you still have the issue.

 

Morning guys. Thanks for the advice. Today I will try in this order: visually examining the k40 relay, switch out the CPS with a spare I have, replace battery, replace fuel filter and fuel pump,

 

I visually examined the k40 relay as well as the fuel pump relay, both looked very clean. i went to my storage and found 2 CPS and 2 cam sensors. I drove around town a bit looking for the fuel filter and fuel pump, but could not find them in stock. I stopped and picked up a beautiful new battery (don't know why I always love new batteries).

As my battery was dead, first thing I did was swap in the new battery. She started right up (could be battery/alternator - MB Star was reading 13.6 on the voltage last time I had it hooked up so not sure). I rolled her up some ramps and I'm going to drop the bottom cover to get a look at the ground and mounts.

Shes also running a bit rough like my 4.3 did (wondering if the MAF off the 4.3 is causing that). I may swap back to the old MAF after I get a look underneath. I've also got a new plug and wire set, but I was waiting until spring for that.

Update:

New battery is really nice, I notice the extra power, but new battery did not solve the stalling issue. MB Star shows voltage at 13.6 on the new battery as well. The ground is a bit corroded and even frayed some, but I don't think that is the culprit although I will order a replacement. The mounts weren't all that tight, the two bottom bolts came right out with hardly any resistance at all. I pulled those two out and covered them in blue locktite and put them back in pretty tight. I was able to get a couple of turns on the top bolt of the passenger side (didn't attempt to take it out though) also was able to get the wrench on the top bolt of the driver's side but couldn't put any power on it because of the angle.

I'll switch out the CPS sensor in the morning. I also checked the fuel rail immediately after I shut the car off and it was under pressure and sprayed me (i want to recheck the fuel rail when the car stalls though). At this point, I am hoping it is the CPS. I still have no codes. If the CPS doesn't solve it then i'm going to do the plugs and wires. plugs were actually very nice when i inspected them but i noticed prior to install the shop had mix my plugs with some bmw plugs. possibly the plugs in the car are mixed and matched with oem and non oem.

 

Just read most of this thread, hope youre replacing the fuel level senders after this

Didnt you notice it had no fuel when you changed the pump???

 

Swapped the CPS sensor and its been running fine for the last hour. Not enough in my opinion to say that the issue is solved but hopefully will know by the end of the day. Have not swapped the plugs and wires yet. Also thinking about swapping on the larger cream injectors that came with the engine. I think they are 283cc v the 217cc green ones. Anyone of the opinion that the original injectors should have been used?

 

Zayed should know. Where are you Zayed???

 

No. You should not.

Your ECU is programmed for the green injectors, it probably will run pig rich with that big of a change, and it could very well be at or beyond the limit of adjustment.

Why did the ML55 have those larger injectors? What was the fuel system pressure on those?

 

its been 3.5 hours with the new CPS sensor (that sensor was a little bit of a B*** to get at) and no stalling. I did however notice that there was a vacuum line unplugged in the back when I was replacing the MAF. Have no idea if I pulled it by mistake in the dark or that was the real culprit of my stalling.

What I did notice was that I stalled only at idle, twice when I was at a full stop and inching forward and also stalled a few times in park. it dropped 30 degrees here so from 73 to 43 today and I do not have the patience to stand in the cold swapping parts unplugging lines to get a definite answer. Looks like it is functioning for now.

Where are you at buddy!




I was thinking that I might have to swap over the fuel pump too, not sure how it'd run. but the injectors are off the 2002 w208 clk55, they are a cream color.

 

Oh ok, for some reason i thought your engine came from an ML55, not sure where i got that.

Swapping fuel pump is not of any use, the CLK55 will likely be the same, and the pressure is regulated by the filter, and chances are that will also be the same.

The issue is not what injectors came with the engine, it is what the ECU is programmed for, and if its the stock C43 ECU, its expecting to see the stock green injectors, part # 0280155839.

You can certainly use the higher flow injectors, they will fit straight in no problem at all, but you will need to flash the ECU with the injector size changed to reflect this.

What is the part number of these different injectors?

 

cats on your car, wudd they get damaged if car is running lean or rich??
do data sent from stock C43 ecu send the correct intel not to run the fuel too rich or too lean with the new E55 engine?
what do you think about ecu and fuel, does it still work as it should with the larger engine displacement?
are exhaust fumes being too rich or too lean after you made the engine swap??

 

Running rich they will, lean wont affect cats but will f*** a few other things if you drive it long enough.

The engine swap has been done a hell of a lot of times and is well proven to run fine on stock ECU maps, but this is not going to work too well if you go throwing bigger injectors on there without telling the ECU that you did that.

Too much trouble, the green ones flow PLENTY for the 5.4ltr, not seen anything to suggest they dont.

By upping the flow rate of the injectors, you generally end up with a less desirable spray pattern, where as a finer mist will be better.

The idea behind smaller injector rating and higher fuel pressure is a finer mist. Its better for a few reasons.

Back in my Corvette modding days i had built a 383 LT1, quite a monster of a thing, the 26lb/hr stock injectors could not keep up. The best deal going at the time was by far the Bosch 36lb/hr injectors used by Ford. The spray pattern on these was not as good, because they were more than 10lb/hr higher flow ( GM rated at 43.5psi, Ford were 37-38psi ) but they did what i needed at the time. The noticable downside was cruising fuel economy was not quite as good. Better option wouldve been up the fuel pressure and use 30lb/hr Ford injectors.

Because i dont know what the part number or actual specs are on these different injectors, i cant say too much about the reason for their use in the original car or what affect theyll have on economy or drivability.

 

when you say running rich they will?
you mean that ecu will go slightly out of whack with the new larger displacement engine causing cats to take possible beating from running rich?

ECU must adapt to all data with the new E55 engine sending out correct specs to cats for them to burn most of the pollution out of the exhaust pipe?

to tweak settings on our cars for rich VS lean performance, do we have to use MB star diagnose to tweak the parameters?

 

You need to tweek the ECU. Don't know if you can do this with STAR or you have to hack the unit...

 

Give me a half hour or so, ill come back and explain better soon.

 

after you do the engine swap, c43 ecu will be a mismatch with the e55 engine.

this must mean ecu will send out wrong data to all components which is run by ecu, engine will run richer or leaner then slowly killing cats?

 

No. Well to most of it.

If you swap any engine, even to one that is mostly the same, the ECU will have to adapt to this, no matter how minor it may be.

Firstly, the ECU has a large number of parameters that it uses to manage the engine, some of these are "constants" and do not change, others are "variables" and the ECU has usually got a number of different look up tables for these.

In the case of a straight up swap from the 4.3ltr to the 5.4ltr, the ECU will have to adapt, but because majority of the engine including sensors is the same, the engine will run quite fine straight up.

This is because the air:fuel ratio is governed by mass air flow, the bigger engine sucks in a little more air, so the ECU knows to add a little more fuel.

That part is really quite simple, in this case the ECU is programmed with more than enough range for this to work, and these are all variable parameters.

Even minor changes to camshaft specs or changes to rocker arm ratios will be mostly transparent to the ECU, provided there is no significant change to duration or lobe seperation angle.

In the event you change the fuel injector capacity to something larger, the ECU must be told this or it will never know.

The size of the fuel injectors and the fuel pressure are both constants, they are not automatically variable like air flow is.

So if the ECU constants say the injector size is 24lbs/hr and fuel pressure is 43.5psi ( for example sake ) and you added 30lbs/hr injectors or adjusted the fuel pressure without changing the value in constants, the ECU will still fire the injectors for the duration required for the injectors it thinks are fitted, but obviously more fuel will flow for this given duration, hence, the air:fuel ratios will be rich.

When the O2 sensors reach operating temp and inform the ECU they are ready for closed loop operation, assuming all other required parameters are met, the ECU can then begin to adjust for the rich mixture by reducing injector pulse duration, and given time, it can learn this condition exists, and will write these new values to it's memory. This does not happen instantly, and is not an ideal situation.

In the event you change out the battery and the ECU forgets these previously learned values, it must again re-learn.

With the larger displacement pulling in more air than the smaller displacement, the ECU sees this air flow reported by the mass air flow sensor, and it will look up it's various volumetric efficiency tables to know how much fuel to spray in and when to fire the spark plugs, based on both air flow and air temperature reported by the MAF, it can use the programmed constant values to know the density of that air, giving a reasonably accurate air:fuel ratio under majority of driving conditions.

So in short, changing anything that the ECU expects to be a "constant" will have some sort of influence on air:fuel ratio that the ECU cant instantly allow for.

This is partly why dyno tuning some computer controlled engines can yield such good results on modded engines, when it generally makes much less difference to a stock engine.

The issue with rich mixture in relation to catalytic converters is excess unburned fuel is being pushed through them, which will cause them to run very hot, and carbon from the rich mixture will begin to block them up.

The catalytic converter is a static component, it has no moving parts and has no external control from the ECU.

 

in other words, doing an engine swap to 55 engine is risk free and harmless to ecu when it comes to air/fuel ratio and rich/lean mixture parameters.

i read on this forum and other UK forum that many people who did the engine swap also re-flashed their ecu.
HP and TQ dropped with the new ecu re-flash to 55 software if I remember correct, instead of leaving stock ecu still use factory c43 software giving a few more ponies and TQ measured @ the rear wheels with the new 55 engine?

what's the point doing a 55 re-flash if ecu from c43 is doing such a great job with the 55 engine?
re-flashing ecu to 55 software is just a waste of dough then?

 

There is a reason they lost a bit of power, and i can only speculate on that reason because i have not got access to both maps here, but ill give you that speculation shortly.

 

So because i have not viewed either stock ECU file, i can only make an assumption based on past experience with GM vehicle tuning.

The biggest cause i would expect to be the spark timing tables, which all things being equal apart from bore and stroke, are probably less in advance on the E55 maps, and that would be all it would take.

The stock maps are quite likely allowing a bit of head room for different grades of fuel, and when using premium fuel could do to have a little more spark advance, which the stock C43 maps probably have due to the lower displacement.

That said, i dont know for sure if that is the reason, but id consider it the most likely reason.

If anything, they wont be missing much, maybe 5 horsepower and 5-10ft/lbs torque, probably barely enough to notice.

With all the constants being somewhat the same, air:fuel ratios should be hardly affected by the extra displacement, given the whole thing is governed primarily by a MAF/O2 setup in closed loop, and the MAF in open loop.

If i could view the two maps and compare the various tables, i would expect them to be very simular in most sections except spark timing, but again, having not seen them i dont know.

 

Flashing to the correct 5.4ltr maps would give a better margin of safety, assuming my speculation is correct or at least on the right track.

Without some live data to see where spark timing is and what it is doing under load, itll only ever be speculation as to which map is actually "operating" the best, just because it gives more power doesnt mean it could not be even better with spark timing set correctly for minimal knock counts and most appropriate advance.

 

that was interesting info to read.
thanks

some people did re-flash their ECU, other people like yourself did NOT re-flash the ECU.

in the long run, only time will tell if ECU with stock C43 software and 55 engine will cause any harm or not to your car?
hopefully not.

 

I love a touch of rocket science from time to time. It shows that all things are not simple even with our older ladies
Thanks for the explaination.

 

It is pretty simple when you have all the info at hand!

 

i found this video on youtube

if you klick info box below video you will see the data dude got after re-flash vs stock data

 

Yep, seen that video.