Help! 3.2 engine

[WI wide body]

The engine sputtering and refusing to rev is back again.

At first I thoght it was throttle linkage related. Not.

Then someone suggested the DME relay, and even tho I had replaced it less than a year ago, I put the old DME relay back in and...like magic...it seemed to run fine. Took a few short 10-15 mile trips and it was okay. Until this morning.

Then after going a few miles the sputtering and refusal to rev more than about 1100 rpm came back. It would start fine and idle fine but simply would not rev.

When I reached under the seat the DME relay felt a little warm so I put the newer one back in and the damn thing immediately ran fine.

So what the heck is going???

FYI: the engine is stock with only about 80K miles and the plugs, distributor cap, rotor, and ignition wires were recently replaced.

[DUK]

Relays over heating/ breaking down?

[DRACO A5OG]

You may have to crack open the DME to see if you find cracked solder joints or melted/nurned connections.

[Tigerrat]

If you haven't, check or replace the CHT. Sounds similar to my CHT adventure years ago. Ken

[Por_sha911]

Don't just start throwing parts at it. Do some diagnosis. Have you checked the ECU board for loose/broken solder joints? All you need is a little time and a magnifier if your eyes aren't great. You can also test the CHT-do a search or ask someone to loan you their Bentley's manual.
The next time it sputters, consider taking the relay out, wait a minute and put the same one back in and see if the problem goes away. The situation may be changing due to time rather than the relay.

[WI wide body]

To all:

Yeah, everything you guys said makes sense.

I called the Porsche shop where I had some work done a few years ago and he also said it might be something as simple as the cord at the DME relay having a bad or weak connection.

He suggested taking a look and trying to bend the connection leads inside the cable to make a more secure connection to the DME relay.

Also, where's the CHT and how do I check it out after I go thru the cord connections? And, even tho I'm now sure the issue is not the DME relay, is there any way to check a DME relay out besides the trial and error method?

Thx much.

[r_towle]

Heat would make me look for corroded grounds and clean everything from the battery, fuses, and ECU grounds.

Rich

[WI wide body]

If I dig out and open up the ECU, what am I gonna see...besides a bunch of gizmos I don't recognize?

Looking at it under the seat, the wiring harness end looks a bit suspect. For some reason I am not aware of, there is quite a bit of black electrical tape wrapped around it, especially where it connects to the ECU.

[Flat6pac]

Jump the fuse to the fuel pump and do a pressure check or at least see if it runs consistantly.
Bruce

[DRACO A5OG]

CHTS sits inside #3 Cylinder Head and the connector sits right behind the big black plastic banana heat tube in the engine bay, you can remove that and you will see a mounting bracket with three connectors, the CHTS is white or should be white, heat may have discolored it to a dull yellow.

Bentley will show how to take a reading with a DVM.

[Flat Six]

Originally Posted by DRACO A5OG

CHTS sits inside #3 Cylinder Head and the connector sits right behind the big black plastic banana heat tube in the engine bay, you can remove that and you will see a mounting bracket with three connectors, the CHTS is white or should be white, heat may have discolored it to a dull yellow.

Bentley will show how to take a reading with a DVM.

CHT resistance should vary by engine temp; try this:

[Por_sha911]

Originally Posted by WI wide body

If I dig out and open up the ECU, what am I gonna see...besides a bunch of gizmos I don't recognize?

Look for these bad solder joints:

Opening up the ECU is easy. I'm sure the instructions have been posted but you can also find them at http://www.911chips.com/C1INSTR.pdf

[WI wide body]

Bruce, DRACO, Flat Six, Joe:

Thx for the info. All good stuff that I should have known...or forgot. Could be the alzheimers kicking in! Now I have to decide what order to do the things suggested. I think that I will:

1. Make sure the female connectors at the cord for the DME relay are okay.
2. Check the fuel pump.
3. Have someone check the CHTS.
4. Take a look inside the ECU.

I'll let you know what develops. Right now the darn thing is running just fine!

Ed C

[dshepp806]

Fuel pressure check for sure.....betcha' your fuel pump is acting up.....is it original?

Doyle

[WI wide body]

Doyle,

Yeah, as far back as I can check, the fuel pump has never been replaced. I did change the filter.

But would a faulty fuel pump cause the sudden sputtering and lack of revs while allowing the idle to stay normal?

I would guess that a bad fuel pump would result in a total die-out of the engine. Seems unlikely (to me) that a bad fuel pump would allow just enough fuel for a normal idle.

But, we've all seen stranger things!

Thx.

[agfours]

Just a thought here, and this may be waaaay off base, but top of mind only because I've been reading up quite a bit on Ethanol problems - how long has your car been sitting? Sounded like it may have sat a while.... I've read E10 is only stable for 2-3 months in the best of situations, and sitting long periods allows time for water separation and corrosion issues to take their toll, esp. on the fuel pump, lines, etc.

Again, just a thought...

[NutmegCarrera]

For what it's worth - if you do need to change the CHT sensor, I just did this.
Pain in the butt to get to. Had to go out to the garage 3x to find it, after looking at the forums here. Also might want to have one on hand before testing - as I had to cut the wires in order to remove mine.
Factory sensor is a 1-wire. I replaced with a 2-wire. They have different wrench flat dimensions. I had a deep well socket milled to allow the wires to clear while turning with a wrench - but unfortunately that socket was the wrong size to grab the old one. I had to cut wires to get the old one off - so no go on testing it afterwards.

If you'd like to borrow the socket (if it comes to that) let me know. I'm within an hour of you (or quick post office trip).