Who is the best dme rebuilder

[TomK911]

I believe that I have a bad dme. Who is the best? I have heard a lot of positive feedback for Steve Wong and everybody seems to rave about his chips. Had a rebuilt dme from Specialized ECU in Fort Lauderdale and it didn't work, it's now sent back to them for follow up. Bought a used dme to have as a spare, and it worked right away but now I have a funny no start condition. Car will fire for a couple of revolutions but won't keep going. Can smell fuel after, so it seems to be getting fuel. DME relay is new, all grounds are good, sensors check out ok for resistance, fuel pump will run if jumpered at the dme harness.
Also, my car is an 85 Euro spec Carrera. As far as I can tell, it's the same dme. Is this right?

[TomK911]

Here is the car when it was running. Unfortunately, the GT3RS is not mine, but the kid is.

[Joe Bob]

try ingo, screen name ischmitz

[Joeaksa]

Have you checked the cylinder head temp sensor? This will cause the symptoms you are talking about.

Either Steve or Ingo are both very good and both very trustful.

[rusnak]

I don't believe the DMEs are the same, but I defer to others on this.

If you have a spare, and one on the way back, then it's time to diagnose the no start condition, not try to get a third DME, or second DME rebuilder.

[TomK911]

Here is the long story. My car let me down 8 hours drive from home July 30th. I met a very nice Porsche mechanic who helped me. After 2 days diagnosis, he concluded it was the dme. We couldn't get a dme for a few days, so a friend/client of his offered to lend me a dme from one of his cars (89 model). The car ran perfectly all the way home. I sent the borrowed dme back and waited for my rebuilt dme to come back from Specialized dme in Fort Lauderdale. It came back and didn't work.
I was just kind of worried of being stranded again, so I thought that I would buy a second dme to have as a spare. But, it didn't work either. I'm just trying to prepare myself for if I have to get a dme repaired again, who is reliable and good.
Now, the cylinder head temp sensor was replaced, I was still running the original 1 wire sensor. The Crank Reference sensors are from an 89 model and were confirmed to be ok. The only difference is the ecu. As I said, the car ran perfectly with the borrowed dme from an 89.
I can only conclude that the no start condition that I have now has to be the dme.
Is a repaired dme not as reliable? Has anyone had the same problems that I have had with Specialized ecu Repair not delivering a working product?
Just want to get the car running again.

[rusnak]

Try grounding the cht connector. Remove the cht sensor wire, and if you have a 2 wire connector, jumper the two with a paper clip or a jumper wire. The car may start right up.

[rick-l]

I hate to refer anyone without direct contact but from what I've read on this board this guy seems ok. I also recall reading where he tested a DME for a very reasonable fee instead of the standard "rebuilding" fee that everyone charges. I did a search but can't find a picture of his simulator/test bench.

Maybe you should have him test your "dead" dme and see if you need to start searching for a marginal external sensor or intermittent wiring issue.

Pelican Parts Technical BBS - View Profile: ischmitz

[Joeaksa]

Rick,

Many of us here on the board have known Ingo for years now. He is honest as the day is long so no worries there.

Course so is Steve Wong. Hard to go wrong with either of them...

[TomK911]

Guys, thanks for the recommendations. When the time comes, I will contact either of these guys.
On Rusnak's advice, I jumpered the CHT and it started! Couldn't keep it going though, and it ran really rich. Does this mean the CHT sensor is bad? It was brand new and checked within speck with an ohm meter. The connector does feel a little loose on the plug.

[dshepp806]

Let's not forget about the seesence of coincidence!!!!!!!

Spunds lie it's time for fresh Sensors..

Doyle

[rick-l]

Shorting that makes the DME think it is really cold outside.

[TomK911]

Sometimes, I'm a little slow. So, the car ran really rich thinking that it was really cold outside (actual air temp, about 14 C or maybe 60-65 F). So the sensor must be bad as it was probably making the dme lean out the mixture too much based on the ambient temperature?

[Wayne 962]

Eh, it's probably a mixture of both. There's probably something wrong with at least one of the DMEs that didn't work in your car, and there's probably also something amiss. Cylinder head temp sensor may be it - you need to check all of the sensors and wiring...

-Wayne

[TomK911]

Thanks Wayne, that is this week's after school project.

[ischmitz]

Gents, thanks for the vote of confidence. Rick, you were looking for the thread about my DME test station - here you go.

Yes, I do rebuild and test 3.2 DMEs. With the test station I can simulate any condition and then compare the fuel signal to a reference DME. This will allow me to gauge whether the DME under test would make the car run rich or lean compared to a known good box. The length of the injector signal correlates directly to the mixture. See some examples of fuel injector timing signals here

Cheers,
Ingo

[rusnak]

Time to ohm out the new 2-wire cht sensor.

And St. Ingo is the go-to guy for no start on 3.2 911s.

[S ECU Repair]

Here is one of our test benches we use for Early type Motronic units , note the ML31 harness adapter for the Porsche 35 Pin Dme's .

[aston@ultrasw.c]

I have a DME from specialized. It has worked flawlessly.

Jose was very helpful in troubleshooting my electrical issues that had nothing to do with the DME. Highly recommended.

[Joeaksa]

Tom,

First check if you have the old or new style CHT sensor. Believe that the old style is a single wire unit, while the new version has two wires, with the new wire being a ground. This is a mandatory upgrade to any 3.2 engine as the older sensors will fail, its just a matter of time.

Bad or not, if you still have the single wire sensor, change it out now.

Joe A

BTW, our host sells the new CHT sensors!