code help

[Henn28]

My 4.6 swapped E53 has been running surprisingly well, until this am. Funny how it started right up post swap, ran fine for a few days, sat at the airport for 4 days, ran fine last night on the way home... wait for the "but..." I put INPA on it this am to review some live data, look for codes, etc. and after a bit the idle began to drop and finally it began to struggle to hold idle. It finally went into limp mode and was running extremely rough and with no throttle response.

I pulled codes with my foxwell and got three. The first two have been there since I first started it post swap and I'm sure have to do with the SAP delete I've been working on:
- EC: DME Activation intake flap
- 55: DME Activation secondary air valve

The third is new and seems like it must be the cause of the problems this am:
- 86 DME Learn function, lower stop, throttle actuator

INPA shows three codes as well:
- 236 Power stage intake valve
- 85 Secondary air valve final stage
- 134 Check lower stop

I'm not sure how the INPA codes match to the Foxwell codes, and how either match to the "P" codes that I see guys posting, but INPA "134" code seems to match up with the Foxwell "DME 86" code.

Its not like it has a carb and I can adjust the idle. But INPA says to "check lower stop faulty current" along with the following readings:
supply voltage 9.42 v
intake air temperature 15.00 deg C
Voltage DK potentiometer 10.84v
udkp1a_u 0.70V
Error present at the moment

I suppose its possible that my throttle motor failed this am, but that seems a bit coincidental. I'm thinking that I should pull the negative terminal to do a DME reset and see what happens.

Thoughts from the brain trust would be very welcome. Thanks - Brian

[andrewwynn]

It's saying literally it doesn't know where the throttle position is.

I believe there is a process to learn the throttle position and if that fails you get limp mode.

The DME cannot operate the motor without knowing the position

[Henn28]

Originally Posted by andrewwynn

It's saying literally it doesn't know where the throttle position is.

I believe there is a process to learn the throttle position and if that fails you get limp mode.

The DME cannot operate the motor without knowing the position

Thanks Andrewwynn. I'm wondering if I bent a pin, or there is some gunk, etc. in a DME connection. I'll pull them today and clean with CRD QD, or the like. I'll also pull the intake boot and work the throttle valve to see if it is stuck or sticking.

[andrewwynn]

Check the connectors and then clear codes. Read the real-time values on the two TPS

[Henn28]

I disconnected the neg battery terminal and pulled the DME. Sure enough there was what seemed to be oil on several of the terminals' wire bundles, and a film on several of the DME side connectors/housings. I can only think that somehow I drug the harness through some oil, got WD40 on it while cleaning up the plastic/rubber bits, etc. and it took a few days once hooked up to migrate down into the connections.

Hopefully this is the cause of my woes. I cleaned it all with the CRD connection cleaner and am letting it dry now. I also grabbed some mass airflow sensor cleaner and went at mine. Frankly it looked new, but my gas milage was terrible before the motor swap and from what I read the MAS can be a cause. A 20 year old sensor must be somewhat dirty at a minimum. I'll update after I get it hooked back up and try to start it.

[Henn28]

***update: cleaned and blew out the connections and there was definitely oil in them, even after cleaning with the CRD stuff. Residue blew out on my gloves as I hit the connectors with compressed air.

After I got it buttoned up again the car started right up and settled into a nice idle. I recorded the following at idle:
Throttel valve poten. 1 = .66 v
Throttle valve position = 3.92 %
Throttle valve poten. 2 = 4.34 v

Then I ran it up to 2 to 3 k RPM:
Throttel valve poten. 1 = .96 v
Throttle valve position = 11.76 %
Throttle valve poten. 2 = 4.04 v

Anything out of the ordinary here? When I lifted the throttle the car dropped to a lower idle, but it was steady at least. Hopefully the DME just has some learning to do. I'll post again after I drive it around the block a few times.

*** A drive around the block doesn't make me feel warm and fuzzy. I'm sure the oil residue on the DME wires wasn't helping matters, and perhaps even caused my throttle to have problems? I drove the car around the block and it made it fine, but after an initial idle of around 700 or 800 RPM, it settled into what looked like 500-ish on the tach. and seemed to be trying to go lower. Maybe I didn't get all the residue, or perhaps I also have a bad throttle.

[andrewwynn]

Those numbers seem pretty normal. I would have gotten the engine up to operating temp so you can hit wot where the pot 1 and pot2 will cross over.

[Henn28]

Will do tomorrow then. What should I expect to see? Do they monitor different parts of the butterfly valve travel (ie one does closed to half open, the other half open to full open.

[andrewwynn]

They are parallel and both measure full range.

One the voltage goes from 0-5 one goes from 5-0 (volts).

They should cross more or less in the middle. (and zero might be 0.5 and 5 might be more like 4.5).

[Henn28]

It occurred to me last night that the SAP air hose hole in the intake that I had plugged with a rag and zip-tied off while I waited for an appropriately sized rubber cap to come in may be screwing the DME up by adding too much intake air to the mix. I had a problem years ago where the intake boot dislodged and the car wouldn't idle and this seems very similar.

The cap had come in so this am I installed it over the fitting in the filter box where the SAP hose attaches, and zip tied it securely. The car started and ran fine all morning while I ran errands. At first it was seeking an idle a bit lower than that commanded by the DME (600 commanded and the motor would hunt around 580 RPM, then up to 600, down to 550, etc. Sounded cool at the tailpipes, but eventually she worked out to a nice 600 RPM idle, I imagine as the DME learned.

So problem solved...except not so fast. Since I'm popping codes for the SAP electric valve and the special vacuum driven valve that opens in the 4.6 air box at higher RPM (My box is the 4.4 box tho) and uses the same electric vacuum control valve that the SAP system does, I grabbed my old electric valve and plugged it back in. Voila, one code (SAP valve) gone and no service engine light, however, once I started the car up, it dropped down to idle and immediately died. I started it again and it found an idle, so I revved it and it died again at idle. It seems like a textbook intake boot leak, but I've checked and rechecked everything and its tight as a drum from the box to the manifold.

Unless this is a bizarre coincidence, I suspect this could be entirely self-induced by my deleting the SAP system. Seems weird that plugging that little valve back in would cause the motor to not be able to idle, but who knows what the DME needs to see as it learns.

More to follow when I take it back out and see if it will adapt or keep dying at idle.

***Update***
The car ran fine over a 20 mile round trip of both highway and city streets. Strange, but I'm happy about it. Perhaps simply plugging the SAP electric valve back in forced the DME to relearn the idle. The valve did make the SES light and SAP code go away. Now I need another software solution.