ausgeflippt951

This is driving me nuts. For months now I've been getting a cut-out/hiccuping intermittently which consists of the car shutting down for a fraction of a second and then coming back on. The tach will zero-out and the come back to life.

Occasionally, the car will run on two cylinders.

I've currently tried EVERYTHING, including replacing the Spd&Ref Sensor harness and Injector harness w/ brand new LR units and the problem still persists. The only thing I haven't replaced is the DME.

I will check the TPS tomorrow, but usually a bad TPS just causes the car to stumble, not die altogether.



In addition to the glitch, i'm running waaaaay to rich at boost (i.e. 10.0-10.5:1 when at 0.85 bar on an aftermarket boost gauge). Also FWIW, since replacing the harnesses, I'm running richer than I was before (at full boost I was at ~11.3:1).



Question: could a bad FPR cause the car to cut out like that, tach and all? It could be the cause of my running rich...



Perhaps a bad narrowband? Other than that, I'm thinking it's the DME.






***UPDATE: So I've resoldered the DME, and it didn't fix the fuel issue. However, it's too early to say whether or not it fixed the cutting-out problem. I also replaced the FPR, which didn't fix anything either.

I know the stock narrowband is good because I'm sitting at stoich while at idle. The car pulls well and doesn't put out the inordinate amount of smoke indicative of AFRs of <10:1.

So my theory: the cat. Since the wideband is sitting just before the cat, it reads a build-up of fuel, given that the cat is probably fairly clogged. So tomorrow, I'm going to weld in a section of straight pipe and see where we are from there.


IF that doesn't solve anything, I plan on playing with the FQS at the DME. Any objections?

931guru

With the tach cutting out, it is either the DME or the KLR.

steve944online

i have both units available rebuilt with a 2 year warranty i can also test both of your units to tell you which is bad. fell free to call me toll free 866 944 7883 ask for steve.

ausgeflippt951

Thanks Steve; I'll give you a call when I get a free minute.

However, could a bad DME cause a running-rich condition, or is it more likely two separate problems?

thanks.

ausgeflippt951

FWIW I know my KLR is good but I'm not so sure about the DME...

Jeremy Himsel

Collin, have you opened up the DME/KLR (split the halves) and checked for cracked solder joints? It's a pretty common and a real easy fix.

davepnola

Yes open the DME look for solder joints that lead to the pins that connect to the harness. It will be obvious which ones are bad. They are called cold solder joints !! They will look like the solder is starting to corrode( light grey ,chalky look) But I would resolder every pin , that usually will fix the problem. I am in need of another DME and KLR , if anyone has one let me know. If you do not feel comfortable and trying to solder it yourself. You could send it to me, I will resolder test, verify and return it back to you !! Thanks

ausgeflippt951

Yeah I've opened up both the DME and KLR and resoldered what looked bad...didn't fix anything obviously. I think tomorrow I will spend the day resoldering the DME and see where we end up...

The cutting out is fairly rare (once or twice every bunch of days or so) but what's more disconcerting is the running-rich problem. Given that I'm a proponent of Occam's Razor, I would think that logic would dictate that both the cutting-out and running-rich could (hopefully) be traced back to the same source -- i.e., the DME.


Oh and FWIW the car is in great shape otherwise, meaning that it's not a beater.

ausgeflippt951

Bump -- Could the DME be causing a rich condish?

Musche

Make sure to look under the plastic connector for the plug on the main board. Remove the boards completely. I found a cracked trace under there that had been worn from vibrations/rubbing. Drove me nuts for two weeks.

ausgeflippt951

thanks for the advice. Quick question -- When I put the DME back together, should I use some silicon where the boards "glue" to the plug? I seem to recall there's this yellowish glue that I had to get rid of last time I took apart the DME. Never replaced it.

ausgeflippt951

Read the end of post one, please.

lart951

I have several DME's available also with warranty can ship next day if necessary.