So I bought an 02 R53 in Feb. this year as a project. I was told it probably needed a head gasket changed, (it did) and the starter was fubar.
I took care of both issues and while I was at it I also changed the fuel filter, water pump and thermostat (since there was quite a bit of Bardahl's head gasket
sealant or something similar). After everything was back together and all fluids checked, I installed a new battery and gave the key a twist, and... nothing.
I checked the EWS and found the plug pins had a bunch of corrosion. I replaced it with a good used unit and tried again. Still nothing. So I disconnected the
signal wire from the starter and used a remote trigger to actuate the starter. I got back in the car, depressed the clutch, turned the key to the run position and triggered the starter.
Hooray! It runs! But not for long...
It was great for the first minute or so, but after that it rapidly started running like crap. I tried taking it for a test drive down my road but only made it about half a block before it sputtered and died. It seemed like it had a fueling problem, so I replaced the fuel injectors. No change.
The fuel filter has been changed, there is pressure at the rail (i don't know how much, I don't have a gauge just yet).
I pulled the BCM and it looks okay, no corrosion, the speedometer binnacle shows the coolant temp full high all the time and the oil pressure light is on.
The high speed fan comes on as soon as the engine starts, this may be unrelated but may not. It has quite a few DTC's and are as follows;
P0118 - coolant temp sensor 1 high input; I changed the one on the head near the thermostat, is there another one?
P1617 - ECM h-bridge controller; pretty sure this means my ECU is screwed..
P0302 - cylinder 2 misfire; that's where the head gasket was leaking at
P1229 -throttle potentiometer adaptation fault ??

I did try sending my ECU, EWC and key to a company that checks/repairs them and was told that none of those pieces had any faults in them. I think I am inclined to not believe that since I did find that P1617 code.
Should I just bite the bullet and find a ECU, BCU, EWS, key and collar combo and swap them out? I can get one from eBay for about $300
I have thrown enough money at it by now that it's not worth selling, and I still need tires..and window motors..and door locks..

Any advice is appreciated

Craig

I did a little more investigating today, I had my scan tool on and watched some of the live data while running the car.
Coolant temperature reads -40* constant - no change while running
Intake air temperature reads 87* constant - no change while running
MAP is 0 constantly, no change blah blah blah
Throttle angle started off around 17 % and only went up to about 24% when I stomped on the loud pedal.
My next step I think is going to be chasing the wiring harness from all those components.

Craig

It sounds like you are on the right track with some kind of wiring issue.

Check your grounds. There are at least two in the engine compartment and others throughout the car, especially just inside the step over at the bottom of the doors.

A little background, when I bought the car, the fellow I bought it from said that it had been running but overheating. He took it to a shop to have it looked at, but they could never get it running (go figure, the head gasket was bad..). They fried the starter in the process and so he/they just gave up. I suspect that in there fumbling around in the engine bay and putting stuff back to get rid of it the shop kinked some wires or didn't reattach something..? I'll keep looking.

C

I did a little exploratory today, found that I had not plugged in the coolant temp sensor when I replaced everything. The broken half of the old sensor was still in the plug.
So now the coolant temp works again, I didn't get a chance to check the live stream data yet as I have to go to work shortly.

C

It seems as though most everything is working but I get no action from the MAP. I probed the harness plug and I get continuity from the ground and power wires but not the signal wire. I turned the key on and I get 5 volts from the power wire so that seems correct. I guess I'll have to trace the signal wire all through the harness to check for breaks now.
Does anyone know offhand which pin in the ECU connector corresponds to the MAP signal?

Craig

Will a bad MAP keep the car from running long term, or just not as efficiently?
I found out that the car will start without the clutch pushed in, so obviously the EWS is either not working or has been bypassed.
I'm going to try and put a gauge on the fuel rail and see what is happening there when it starts running badly. I did not change the fuel pump, only the filter so maybe the pump is not good..or the hoses are collapsing..

Craig

I am not an expert on these yet but I don't think a MAP will keep it from running. I had a run ability issue on my R50, it would idle bad but run just fine down the highway. I started to get lean codes and it turned out to be a bad fuel pump. The new pump totally changed the drivability of the car.

It won’t. I hav3 a dead one right now.

Reminds me of the symptoms I had 30 years ago with a failing coil on my mgb. Fine when started then ran like poo. If you can find an OEM cheap at a junkers I’d try it, or if it has aftermarket swap back to stock.

I may have fixed the problem..
While looking for a way to hook up a pressure gauge without removing the intercooler (I don't think you can..), I found a vacuum line from the pressure regulator that was not hooked up. I pushed it on the correct nipple, checked the oil and coolant and fired up the car. It idles lumpy but revs smoothly. It currently only revs to 2000 rpm but it returns to idle just fine and doesn't die. The thermostat is opening and temp is staying in the middle of the gauge. I'll take it off the stands tomorrow (doing exhaust work) and see if it drives okay.

Craig

I finished the exhaust install, but I haven't tried driving yet. It still won't rev past 2000 rpm and it's slow getting there at that.
I checked the streaming data while revving it and the throttle position seems to be stuck at about 17*. I'm not sure if the throttle pedal is the problem or the throttle body.
Has anyone had a similar problem? I'm getting pretty frustrated with this car..

Craig

That’s a good data point. Do you have DIS? Iirc from the ing my wife’s e83 (same generation as e46 amd r53) you can see both potentiometers to see if one is failing part way thru travel. They are opposite, one starts high and goes low, the other low and goes high. On hers I just cleaned the dang pedal out with simple green cause it’s what I had on hand and then cycled it a few times, flushed amd vacuumed again and it came back,
, but crc contact cleaner would be a better option if you have any.

Have you tried resetting the throttle position/adaption? If the throttle was ever actuated under the hood to rev the engine it’s supposed to throw things out of calibration. Maybe that’s why it’s only showing 17* of throttle.

Do a search to confirm the procedure, but it’s supposed to be:

1. Ignition/key completely off
2. Throttle to the floor and keep holding until step 7
3. Ignition on but do not crank or start car
4. Hold for 30 seconds
5. Ignition/key off
6. Hold for 5 more seconds
7. Release throttle
8. Wait 30 seconds
9. Start the car and check throttle operation

I have not done that yet, but thank you for the info, I will try it tomorrow afternoon

Craig

I have ordered a set of security bits so I can take the throttle pedal apart and clean it. It looks like it (the pedal) has been taken apart before and I don't think the potentiometer is the original as the screws show scarring from being removed/replaced.

Craig

Edit: Re-reading your last post, the below might not apply. Did you already remove the pedal and the bits are needed for the potentiometer, or are they needed to remove the pedal assembly? I don’t remember what kind of fasteners are used.

__________________

Did the car ever run/drive right, or was it a “non-running” project?

I wonder if it has a sprint booster or another brand of throttle control module that’s broken or is in valet mode. If the car has one it should be obvious once you get the pedal loose as they usually plug inline at the pedal connection. If it’s going to be a while before the security bits get delivered you could try looking for a control button/module under the dash that would be used to set the various driving modes.

It was a non-running project. I had to replace the head gasket as it had overheated and blown between cylinder 3 and 4.
The overheating was apparently caused by the fan not coming on, so now I have that to fix also..

The bits are to remove the potentiometer and pull apart the pedal assembly itself for cleaning. There isn't anything plugged in between the potentiometer and the harness.
The pedal assembly mount is broken so the pedal is currently just held in by hopes and dreams and my fat foot.

Sorry I didn’t realize you said order, I read it as get.

FYI, Harbor Freight has a full set of tamper proof bits, like 50-60 different kinds as a set. They were under $30 when I bought mine some years back to get into some electronic gizmo. I haven’t found a tamper proof since that I can’t tamper with.

if the thing is also physically broken, why not get one at junkers/eBay and swap it out? If I’m not mistaken all r50 and r53 are the same but check realoem to be sure, and at least around here, r50s are 9x more plentiful in yards.


or use DIS on a pc to run a test on it.

well worth the $20 for a cable and $20 for a disc with a self installing vm box containing it if your aren’t computer centric

I actually got the bits today, I did get a set from HB but it didn't have the correct 5 point star that this thing used.
I have ordered a new mount from Amazon and it should be here Monday. I actually ordered a new fuel pressure regulator too
as I took the original out of the rail to check it and kinda broke some plastic bits on it...

I did the throttle position reset ( before the regulator removal ) and it seemed to work at first, but I still had the problem of dying after revving it up. I don't think its temperature related as the temp hadn't even gotten high enough to open the thermostat yet ( I was watching it on my scanner with live data ).

Craig

Well.. the new fuel pressure regulator didn't change anything.
It runs but when I press the accelerator it revs a little then stumbles the revs some more to about 3000 rpm and stays there..stumbling.
The only thing I haven't changed by now is the fuel pump itself so I guess that's next.

Some more data points; when trying to accelerate, the throttle position rises fairly smoothly up to about 89% and stops. I think I remember reading somewhere that the throttle does not always open 100%, so that may be normal.
I do not have O2 sensors installed, they wouldn't fit in the new exhaust
As previously stated, the MAP is not working either. It's a wiring problem I believe, or even an issue with the ECM

Craig

Change the map, and get your front 02 installed, lacking both its no surprise it runs like anus.

changed map to correct OEM Saturday and not parts store special and ours runs great now. No more check engine lights or codes, put 5 miles on it Saturday Sunday and Monday and this am it passed inspection and got registered no problem.

It still has the factory MAP sensor, but the wiring harness seems to be the problem, at least for that. I put a meter on the plug and got continuity on the power and ground wires but not on the signal wire. As for the O2 sensor, it will not physically fit anymore. I changed the exhaust and the new one is a long tube type header and the mount location for the sensor is now too close to the underside of the body. If I could find a short sensor that would probably work, has anyone heard of such a thing?

I was watching the live stream data while running and the load value % was kinda all over the place, would no map and O2 sensors do that?

Craig

You are going to have to get a bung welded in pre cat for first one as that is needed for computer to judge afr and fueling, and with no MAP either, it’s truly shooting in the dark as it doesn’t know how much air is coming in either.

I put a fuel pressure test gauge on the car today, as soon as I turned the key the gauge went to ~ 60 psi.
Running it was between 45 and 50 psi. When I purged the pressure while running it went down to 30 psi, with no change in the idle.
I revved the car a little and let off the throttle but the engine died. I turned the car off, purged the pressure and turned the key on. It went to ~ 60 again, I then purged the pressure and it stayed at 0. Shouldn't the pump continue to pressurize the fuel rail even if the car isn't running?

No I still haven't installed the O2 sensors, and the MAP still doesn't work, I just wanted to test the fuel pressure.
This is a project car and I work a full time night shift job so progress is sporadic at best...

Craig