Replacing '86 3.2 DME with a later unit?

[craigyirush]

Has anyone done this - swapped an early 3.2 DME for a later one?

My mechanic has just told me that my ECU is bad. He recommended replacing it with a rebuilt unit which has got me wondering if it's a good idea to upgrade to an '87-'89 unit and get a better chip with a bit more power (I'm assuming that the extra 10 hp was from the chip).

[jazzbass]

I updated my 1985 DME internally to run the 1989 ROM and had no problems. You can run an 89 DME just fine.

I've since upgraded it to a 1994 DME, but that was a LOT more work.

[craigyirush]

Originally Posted by jazzbass

I updated my 1985 DME internally to run the 1989 ROM and had no problems. You can run an 89 DME just fine.

I've since upgraded it to a 1994 DME, but that was a LOT more work.

Did you get a noticeable performance increase? My mechanic said it will run and idle smoother.

[175K911]

aren't there a couple of places that rebuild DME's? I've seen them in Pano and Excellence. Can't vouch for the work they do, just a thought is all.

[craigyirush]

Originally Posted by 175K911

aren't there a couple of places that rebuild DME's? I've seen them in Pano and Excellence. Can't vouch for the work they do, just a thought is all.

I am getting a rebuilt DME from Loren (who is known to many Pelicanites).

It is from a later 3.2 so I am hoping will have a bit more power.

[jdbunda]

I would not expect more power just by updating the DME. There was an early version of the box, but I think the only difference was the size of the mapping tables. See Steve Wong's web site.

911Chips.com - Motronic DME Update

[craigyirush]

Originally Posted by jdbunda

I would not expect more power just by updating the DME. There was an early version of the box, but I think the only difference was the size of the mapping tables. See Steve Wong's web site.

911Chips.com - Motronic DME Update

I was assuming that I'd get the later chip too? And hence the extra HP.

[jdbunda]

Originally Posted by craigyirush

I was assuming that I'd get the later chip too? And hence the extra HP.

I am suspicious that there is much of a difference. The. 87-89 cars were rated at a whopping 4hp more. But the bottom line is the DME will just drop in.

[dshepp806]

Difference was in the part throttle range, too. (improved). Stock aside,....

DME's a drop-in. Steve's chip's a winner.....

BEST!

Doyle

[WI wide body]

Does it make any difference if the car is a Euro version (ZZZ in the VIN) when replacing or changing the DME in the 3.2 engines?

[craigyirush]

Originally Posted by dshepp806

Difference was in the part throttle range, too. (improved). Stock aside,....

DME's a drop-in. Steve's chip's a winner.....

BEST!

Doyle

Wasn't it an extra 7HP in the later cars? Still not that much, I agree.

Doyle - did you see who I got the rebuilt DME from? Don't think there'll be a Steve Wong chip in it!

I drove it home last night. It did feel smoother though not really more powerful.

What I need to find out is if Loren put my old chip in the later DME or whether it has the later chip with slightly more power.

Now onto the next problem. My mechanic had trouble getting the mixture right and thinks it's the AFM. Has anyone had theirs rebuilt recently?

[E Sully]

Carrera 3.2 Performance mystery and Chips (long) - Rennlist Discussion Forums

[ischmitz]

You can use any DME for any of the 3.2 - the differences are two-fold from a hardware point of view.

1. Some versions of the DME do not have the O2 sensor input electronics. This is mostly true for early ROW version

2. The internal ROM socket is either 24pin (early) or 28pin (late). You can add the extra pins to an early DME to make it compatible with the later chips.

All the rest is in the chip. Either a stock or an aftermarket. Plenty of choices both for stock and tuned versions. Finally, you need to get the idle adjusted properly to match the DME (later SW versions had a different setpoint) and all will be well. And yes, as long as the DME has not been in a fire or under water you can repair it and that is usually the more ecconomic choice.

Ingo

[slodave]

Originally Posted by ischmitz

2. The internal ROM socket is either 24pin (early) or 28pin (late). You can add the extra pins to an early DME to make it compatible with the later chips.

I did this, along with the necessary jumpers. Now I have a basically late model DME conversion.

[craigyirush]

Inigo - what is the advantage of the 28 pin over the 24 pin? And did all the G50 cars have chips with more HP?

Dave - what difference did you notice with the later box? Did you keep your old chip from '84?

[ischmitz]

The later software on the 28pin chips is a little more refined and has better maps for igntion and fuel from what I understand. Other than that nothing really.

[slodave]

The reason for the upgrade, was to fit a SW 28 pin chip. The DME can no longer run the 24 pin unless I move some jumpers around, which I am not planning to do. With the SW chip, I also have a 28 pin stock chip that I use only for a day. I really don't have anything to compare with on the stock level. Yes, I have my old chip, but it's been retired to a box that sits in a drawer.

The 28 pin chip allows for more memory. If memory serves, Steve mentioned that he did not know what the extra coding did, but since it over-rode a portion of code that was the DME itself (early 24 pin DME's only stored the fuel map on the chip.), it must have been an improvement over the original code.