I finally tried it. I extended my prom 3 feet to the center forward console. My memcal already has a ZIF socket and I used another ZIP socket for the other end. Now the engine runs, lags very much with the throttle and I have a steady SES light. My scanner also cannot communicate with the ECM anymore.
I used very high quality computer grade 14 pair twisted wire, triple shielded with the shield running to ground.
Has anyone successfully relocted the prom and how far?

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86 Camaro Sport
383 Speed-O-Motive Crate Engine, Raptor 700R4 Tranmission, Trick Flow Twisted Wedge G2's, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Hooker Cat-back, Serpentine Belt Setup, Dual IROC Fans, Jamex springs, 16" IROC Rims, 36mm/24mm Sway Bars, Global West Steering Brace. Hotchkis Rear LCA's,Panhard Bar and SFC's.
My Camaro Project

 

You relocated just the PROM, not the entire ECU?

I was going to make an extension cable(s) for my 165 ECU, just to keep from having to go under the dash all the time...

 

I've never heard of anyone having long term luck with that. Just too much RFI.
Might try an AL wrap of the extension, but I still wouldn't drive the car in traffic.
Probably do better with an extension cable for the ecm.

 

Can you just leave all wiring as-is, but move ECU to engine compartment (like later C4 Corvettes)???

Grumpy, how do you have your ECU setup for easy access???

 

Guarenteed no RFI here. My cable is shielded and besides it's not even installed behind the dash yet. I have it on the floor just to see if it would work.
I really don't want the ECM in the console, I need that space for my junk since these cars don't have glove boxes.



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86 Camaro Sport
383 Speed-O-Motive Crate Engine, Raptor 700R4 Tranmission, Trick Flow Twisted Wedge G2's, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Hooker Cat-back, Serpentine Belt Setup, Dual IROC Fans, Jamex springs, 16" IROC Rims, 36mm/24mm Sway Bars, Global West Steering Brace. Hotchkis Rear LCA's,Panhard Bar and SFC's.
My Camaro Project

 

I found this tip in another post. My question is if I want to try it would I use a resister on every wire? I don't know which are data and address lines. I would assume all are.

 

Well if it was sheilded well enough then it should be working. EPROMs operate at low voltages, and extremely low amp levels, it doesn't take much to mess that up. 28 wires 3' long makes for 88' of antennae length.

 

Reviving this thread from the dead in case anyone has had any luck relocating just the PROM.

I'm still interested in this and am sure it would be a great DIY project if it turns out to be reliable.

 

I don't see the reason for this. I installed a ZIF socket into the memcal, and can simply reach under the dash and pop out my chip in 2 seconds. Reinstalling it is just as simple, and this way nothing looks out of the ordinary, nor do I have wires hanging down everywhere.....I really never understood the need or desire to relocate the prom when if you use a ZIF it's so easy to simply pop out and in from under the dash.

 

I wonder why the Romulator only uses a 9" cable. Or the Prominator.

Or why the early Xtronics emulator with the 2' long cord for the ECM wouldn't work. Or a couple of the other emulators.

 

Sounds like there may have been a short somewhere. When I soldered together my 24->28 pin adapter for my ecm I got a little overzelous with the solder and some of it made its way into the ZIF socket and months later it shorted out and I got the solid SES light jsut like you. No rapid blinking, just solid at all times. Just about pulled my hair out because I couldnt use the car untill I fixed it.

 

I will call you on the "2 seconds". That's just joking right? I mean you have to pull the panel and then the computer. Now you have to remove the access cover and finally change the prom. Now you have crap laying all over the floor. What, are you going to leave it down there while you drive around an "tune" forever? I am always messing with my prom and get tired of the computer up and down routine. It's ugly laying on the floor all the time too. You can't win for loosing.

All I'm saying is it would be SO much easier if the prom could be relocated to say, the ashtray. That would be nice. I could burn all the chips I want and never have to worry about peole stepping on my wiring or ECM.

By the way, I DO have a ZIF socket.

 

No shorts I can assure you of that. Wiring is my business. I completely re-wire corporate jets for a living. I deal with thousands of wires daily. Wiring a simple jumper is babys work. Even a car is SO simple compared to what I deal with.

 

Nothing is laying on the floor. I could never drive around like that.

The ECU is in its original location. All I have done is remove the plastic trim panel to access the ECU and left it off. Not noticable. Then all I do is simply reach under the dash from the passenger side with my left hand, lift the ZIF lever up and the pop the chip out. Reinstalling is an exact reversal of that. It really takes me a couple of seconds, no joke. When I pull my car out in the spring I'll be sure to take a video of this and email you!

I am very ana! about doing things neat and unobtrusive. There is no way I would have wires and ECUs just laying around loose.

And I do prefer this method than relocating the PROM because I am assured that noone will just reach into my ashtray and decide to pop it out when I am not looking, either for curiosity or as a silly joke. Out of site, out of mind!

 

I have another car that leaving the cover off where the ecm is, isnt an option. Making an access hole isnt feasible either. In my case, a relocation would be ideal.

Since nobody is telling anyone what the problem is, I'll stick my neck out and say that the information being transferred across there is certainly being modified by the increased length. There could be RF interference, could be interference between the wires themselves, increased resistance is causing an error, or the increased distance is causing a timing error. I'd bet with enough work to correct any voltage drop and time problem, it'd work... but how many hurdles do you need to jump to do that? Probably way too many to make it worth it.

<----- Not by any means an EE

 

This has been tried in a number of capacities and I have yet to hear of anyone succeeding. Your best bet is to extend the harness to the ECM and put the ECM under the seat or something (I had been wanting to do that myself, but since wiring is *not* my business, I decided not to attempt it).

There are a couple of new devices out there that eliminate the need to change proms at all. You might investigate one or all of them as a solution. :-D

m

 

And what voltage levels are you working with?.
Have you done any EMP wiring jobs?.
If wiring is all so simple, you want to pop the top off of a processor and do some reworking in there?.
Avionics while wired together like a car, is a totally difference environment.

Not to mention that the ecm design spec didn't call for being able to do that so it was never a consideration. The prom is read with incredibly small amperages, so while whatever RF you have might not goof up your radio, it might totally wipe prom reading on a cable.

 

Hee hee! Tested AutoProm with a 6 FOOT cable. Worked about 95%.

 

I just made a similar post with similar interest. And posters here had any luck??

 

as i said in other post... prominator?

 

Im running my AutoProm with a 3 foot ribbon cable and no other cable connections and it works fine. Craig might be able to put together a small circuit board with the same circuits the AP uses to give the prom chip a boost. Shoot Craig an email and see what he says.

 

Done deal, haven't tested, but you should be able to give it a whirl, no reason it shouldn't work:
http://www.diy-efi.org/twiki/bin/vie.../GmecmProjects

 

Awsome! What format is the files in?? I haven't tried to D/L them yet, But I'll pic the parts up and build them in work.

 

Cadsoft Eagle 4.16