rx7withtimhui

Dear all,

I've started this project a few months ago, swapping a 1994 c36 engine and tranny into a 1992 320CE. I've taken the C36 engine apart, cleaned and examined all the internals, found that everything was in a healthy stage. Gave it a good wash and bolted everything back together again, with new gaskets and rubber seals. Used the 3.2 wiring harness, as the c36 harness was all hacked and is disintegrating. Everything bolted on fine to the car as other forum members have stated. Plugged in the 3.2 ecu. Used my 3.2 engine's throttle body, intake manifold, Installed the best performing 6 injectors out of the 12 I had, But at startup, it had a rough idle, runs super rich, black smoke out of the exhaust, and fluctuating a bit.

FYI, I have in hand, a c280 ecu flashed with c36 data by speedtuning, (Oliver was a wonderful guy to deal with btw ) but Shows it was programmed to run with a car equipped with ASR. Ive tried plugging the speedtuning ecu into the car, starts fine, but idles at 1000+rpm, and fluctuating, also with black smoke coming out of the exhaust. Engine would die out when I try to rev it. Maybe it's doing this because my throttle body does not have ASR?

I'm kinda stuck now, and desperatly need your help

1. I've read about the c36 engine running without problems with the 3.2 ecu. Is that true? Or do I have to send in my 3.2 ecu to Oliver at speedtuning?

2. Am I supposed to use the throttle body from the c36 engine for this swap? And if so, as the c36 engine has a bigger plug, I'd probably have to change out the wiring harness too?

3. I've realized that many other forum members have said the c36 exhaust cam sprocket has a "U" mark to show the AMG drilled dowel hole, but for some reason mine doesn't have the mark. It's got 2 dowel holes on it though. but then again, I've used the hole that the dowel was originally in before I've taken the engine apart.


Will post all photos when I get home and also show some progress pics too














I'm desperate. And will answer all questions you throw at me. Thanks guys

ccrelan

A couple things here. Where are you located? I think the 92 coupe had a CIS injected m104 and not a hfm injected m104. Please confirm what was originally in your car. My answers below are assuming you had a late model hfm m104.

You definitely need to run the 3.2 w124 ecu and not any w202 ecu. The w202 ecu only works if you are using the w202 wiring harness (which you are not). A stock 3.2 w124 ecu will work fine as is. You should send off the 3.2 ecu to be chipped by Oliver at Speedtuning. They run about $100 second hand. I know David Hendy has a few 3.2 ecu's available f/s.

You did not say what you did with the air pump from the C36. I am assuming that you swapped over to a belt driven air pump from the 3.2 engine. The w202 C36 engine uses a electric air pump that has a electrical connector from the w202 wiring harness.

You should use the throttle that was on your original 3.2 engine. There is no difference between the 3.6 and 3.2 throttles aside from if it is asr or non-asr.

rx7withtimhui

Hi
It's a 320CE located in Hong Kong. The m104 runs hfm.

I've managed to find another 320ce from a local scrapyard, took its ecu, and is now on its way to Oliver.

And I'm assuming you're talking about the secondary air pump thing? I've just taken it out, and bypassed it.

ccrelan

Yes, secondary air pump.

Did you install the 3.2 ecu in the car before sending it off to Speedtuning? It would have been a good idea to do that as the car should have acted normal with it installed.

rx7withtimhui

Yessir, the secondary air pump is bypassed, and a shorter belt was used in doing so.

rx7withtimhui

Idle problem solved? i think? I've put in another throttle from another 320ce and ran with the 3.2ECU, and the idle was less rough, but still running 1000rpm idles, even after its warmed up. therefore i'm suspecting the throttle and or even the maf is probably shot. however, if you say the 3.2 ECU should run normal/ smooth, then i think there still another problem i need to tackle?

maybe i've installed the Cams a bit off? i've been trying to look up c36 cam timing but havent had much luck understanding the info...

Oh and yes, I have my original 3.2 ECU here with me, while i've sent in another 3.2 ECU to Oliver.

sleeperdc

so how was it?

QVHK

Could it be a problem caused by the O2 sensor or an air leak in the system?

rx7withtimhui

i'm afraid not... problem persists



I've checked up and down for a leak on the intake side and couldnt find anything out of the ordinary... maf (new), intake crossover, throttle body(new), the intake huge plastic thingy, rubber seals.. all were in good shape...

02 sensor, tried disconnecting it to force the ecu to run the factory default settings. idles fine in cold start, but revs fluctuate again 2 mins into start when engine warms up.

QVHK

Seems like you are almost there with your project. I am laymen but have read about various conversion posts in various forums. The erratic idling is most probably electronic rather than mechanical-related. About the ECU, you may have read the following post:
http://www.benzworld.org/forums/w124...cu-tuning.html

You said that you also installed a new Throttle Body. Here is a post about resetting after TB replacement.
https://mbworld.org/forums/c32-amg-c...on-needed.html

Other possibilities that come to mind is whether the ECU is reading accurate data from various parts that handle engine management, such as the camshaft position sensor, thermostat. Last thing is perhaps not conversion related, but basic stuff like coil and spark plugs.

I also notice that your instrument cluster warning lights are still on after starting the engine. Could this be caused by the engine harness?

Good luck getting you car fixed. It will be awesome to see a super-124 running in Hong Kong.

rx7withtimhui

i do have a gut feeling that its electronic related, just of the pure fact that i was able to get it idling normal at one point... when it was cold and o2 sensors unplugged

i've sent my ecu to speedtuning two weeks ago, and hopefully, its the 3.2 ECU's conflicting messages thats causing the rev fluctuations, since now its running 3.6 and sucks in more air.


its funny though, talking about the air sucking... my original maf that i've used in the 3.2 engine was giving me numbers of 63-68 kg/h, while the engine rev fluctuates

so i went to a scrapyard, and picked one up from another 320ce, also 63-68 kg/h, engine rev fluctuates

then i went to my friend's 320ce which is running perfectly, took his maf and used it on my car, 15-160kg/h fluctuates up and down as the fluctuating engine revs.

I thought i had a faulty maf... so i went and got a new bosch maf. and when it came up with numbers of 63-68 kg/h... engine rev fluctuates


this does not make any sense...


however these greater than normal number values do explain why the car is running rich. got new spark plugs too... but is kinda pointless cuz the engine is running so rich, a few mins in, and the spark plug tips will be all smoked out black already

QVHK

Major symptom is engine running very rich with an erratic idle. If the car's breathing system in working order - is the MAF cleaned, air filter, cat and exhaust freed from blockage? Am just thinking out loud. Others please chime in, as the C36-W124 swap-in has been a can-do project with many success before.

rx7withtimhui

MAF New, air filter N/A (as i havent hooked up the air box yet, been testing engine without airfilter), Cat and exhaust (ive cut two holes to let exhaust gases out right before the cat to make it an open exhaust, hence the loud sound in the video clip.

rx7withtimhui

still having problem... what could go wrong here?

does it have anything to do with the wire harness, throttle body, ECU from a 320ce, but working on a 3.6 engine? is it because the increased amount of intake air is that is confusing the 320ce ECU?

ccrelan

The 3.6 engine will run perfectly fine on a 3.2 stock ecu. There is some other issue going on. Is there any one with a Mercedes Star tool near you?

QVHK

I am just laymen but have come across many discussions in various forums about no start and erratic engine behaviour. Some seemingly complicated cases were eventually resolved by simple solutions. In one case the forum member the problem disappeared after the owner replaced the coil and the ignition cable. In another case, problem emerged after the owner had replaced many parts at once, backtracking cured the problem - the new distributor was found to be faulty. What if you go back to some of the old parts that worked fine before the conversion? By any chance, was there a mix-up of parts for M103 and M104, like crankshaft position sensor, cam sensor...... I also notice that you have fitted an instrument cluster that was intended for the M103 rather than M104, and wonder if the vital information so detected might confuse the ECU. The check lights were still on after engine start up. The rev counter for M104 maxs out at 8K, not 7K.

About the engine harness, you said you re-use the one from your E320. Are you sure your engine harness is in order? The M104 is notorious for the degradable engine harness. Has it ever been replaced before. There should be a date on the harness if it has been replaced.

You have also have changed the ECU. There have been some discussions about the use of thermal conducting paste when replacing ECU/EZL. Heat dissipation can be an issue. Here are some links for more reading.

http://www.peachparts.com/shopforum/...tor-paste.html

https://mbworld.org/forums/mercedes-...-compound.html

Just my two cents. Other forum members may have other ideas.

QVHK

I have been rethinking the problem. The symptoms, I recall, are engine running rich with black smoke and erratic idle after engine has warmed up, and the engine dies when adding more gas. This happens when air filter, O2 sensor, cat and exhaust system are yet to be connected.

The mixture is determined by the ECU which looks at engine temperature, AFM data and rpm. Heard that idle was relatively steady until engine warms up. Assuming the engine harness is in order, is the engine temperature sensor reading accurate? A bad sensor may wrongly tell the ECU that the engine is colder than it is and result in the ECU supplying more fuel than necessary. Also, are the cold start valve and idling control valve working properly according to changes in engine temperature? These valves tend to gum up due to age. Also I pointed out earlier, the rev counter is a mismatch with M104 possibly sending inaccurate data (higher rpm than real) to the ECU.

Back to the basics, engine running rich means more fuel than air. Possibilities are air leak, fuel pressure too high, some injectors flowing more fuel than necessary (leaking?) or one or more spark plugs not firing or firing relatively weak. I have also heard that mis-adjusted valves may interfere with engine breathing and cause idle misfires.

Hope you will also get other advice from tech experts.

rx7withtimhui

Hey, That is what i've seen on other posts from other members too. there is a Mercedes star tool at the mechanic's, what data would we need though? codes? temps? rev speed?

rx7withtimhui

I've been thinking about that too. Temps seemed fine from what the star tool was telling me. Fuel pressure was fine, according to the star tool, injectors have been pulled out and tested on the machine thing (I forgot what its called), spark plugs are new (or at least they were, they're all black now from the engine running rich), mis-adjusted valves might also be a problem... cuz the timing chain had been removed for the engine rebuild. and my mechanic was a bit too sure he knew so much about M104 engines that he didnt draw any markings before he took it apart . Yea, hes took enough beating on that from me already.

So now we have the cam stuff adjusted to what WE think is right...(theres a chance we might be wrong too) we'd like a definite answer on how the cams and sprockets should be installed too, so i can get "mis adjusted valves" being the problem out of my head.


would you have anytime to meet up? and maybe take a look at it?

QVHK

I have no technical background so my earlier views were entirely guesswork; hope other forum members would help. I have the opportunity of discussing your issue with a technical expert today. His comment is that the engine clearly tells you that the mixture is super rich even when the engine warms up. His advice is for you to connect the O2 sensor and the cat to help the ECU verify and adjust the airflow and fuel mixture rather than relying solely on data from the MAF. I agree with his suggestion, as the MAF measures the air flow at one end the O2 sensor helps calibrate the data at the other end. Moreover, the Cat and O2 are temperature responsive, and would let you observe if the idling behaviour improve upon reaching operation temperature. There is no harm experimenting this to see if the problem persists.

rx7withtimhui

Hi, I appreciate your help man. the mechanic the car is at right now seems to run out of ideas, and is pointing the problem at the ECU, which i'm still waiting for. Wheres your technical expert? is he really busy?? i'd kinda wanna find someone else to finish the job... its been sitting for a good few months already. and thats why i'm desperate too.sigh.

QVHK

Unfortunately he is extremely busy and will be away next week, but I may have other possible leads for you. Pl check PM.

ptoro01

The problem is that the steering wheel is on the wrong side.

The crank was removed in one of the pictures. Did you take apart 2 different engines at the same time? Could parts have been swapped? Which timing wheel & sensor are you using?

Get us pictures of the cam timing marks. There are guides on how to time an m104, did you follow the instructions for setting the advance mechanism? I don't hear it advance when revved.

How did you plug the EGR line? Did you replace the rubber breather hoses under the intake?

Why do you have oil pressure before starting the engine? Also, is it low on oil? Was the lower engine harness replaced? Which leads me to ask, is the harness on the throttle body good?

There's not much fuel in the tank, how long did it sit? Is it watered down fuel?

ohollenbeck

LOL, was scrolling down to make the same comment, you beat me to it...

Great project BTW... Always had a wish to build my 92CE into a 500CE

I've got an intact and good running SL500 (Salvaged for heavy impact to drivers door) sitting covered in the back yard. very tempted to attempt the swap..

anyway, love this project, good luck

QVHK

More research done. I know you have new throttle body and MAF, but any bad wires might explain why you didn't have the right mixture. Please also make sure that there is no missing pin inside the connector. Some web resources also suggest that a bad connection inside the OVP might cause the problem you described. The OVP is a relatively cheap fix so there is no harm replacing it or keep one as spare if replacing it does not fix it.