RngTrtl

Hein and Scottman,

When the slight boom happened I was not cranking the engine...So is what y'all are thinking is that there was fuel in and around the intake from all the previous cranking and that when the MAF activated the platinum wire burn-off cycle that it ignited some fuel in the intake? That actually makes sense b/c the smell was not electical (i.e. burnt insulation) and did smell like normal fuel combution...Maybe we should ponder this.

Shark Attack

I sure hope that part is that easy

the flyin' scotsman

I did ponder that fact hence the response..............if you have the stock eproms in the correct brains and oriented correctly disconnect the battery. This essentially resets the brains. With the battery out of the circuit ensure all is good elsewhere, reconnect the battery and see what happens.

I've got spare eproms here also but a little far away to effect to timely fix.

RngTrtl

You and me both.

PorKen

Putting the chips in backwards, then powering them up, probably zapped them, likely filling the memory with random values. The EZ-F may fire the plugs as soon as you turn the key, hence the boom. With mine, I could tell the EZ-F was nutty as soon as I turned the key to '2'. The EZ-F was telling the LH the engine was running, so the LH turned on the fuel pump.

Since y'all are here. Does your LH motherboard look like mine? I guess there are different versions, but with the same part#. Notice the orientation of the crystal next to the EPROM (up and to the left), the stand-off resistors, and the large red (capacitor?) tower.

John Speake

No need to reset brains on an 85/86 - they have no stored adaption paramters like the >87.

Almost certainly you fried the EPROM(s) by inserting them 180deg out. VERY unlikely you have damaged the ECUs.

When do you expect to get the new EPROMs ?

If the throttle plate was closed when you heard the "boom" then it is very unlikely you have damaged the MAF.

Sleep easy tonight :-)

the flyin' scotsman

Y'all can't see your motherboard pic...........wantta re-attach?

the flyin' scotsman

Got it now Ken............no, my boards look quite different.

John is here...........we'll get her for sure now.

PorKen

Malcom,

My query was directed to those who have LH2.2. You've got LH2.3 in your '88.

RngTrtl

I did not put them in 180 degrees backwards...I put the "new" and old chips in the computers but had the wrong chips in the wrong computers...they always had the correct orientations.

the flyin' scotsman

.........and I've got Johns GT eproms, your cam timing , Daves X (exhaust that is), soft rubber, good suspension .................Vroooom

John Speake

Hi Ken
Your LH board appears to be a slightly later version than any others I have seen yet. But I have seen identical boards used on Volvo 740 turbo (which I bought to strip the connectors off).

So your version of LH board seems to have started very late in 928 85/86 production.

EZ-F boards all seem to be thge same 85/86

Hi Malcolm
Ken's boards are 85/86 (LH2.2) - your S4 are LH2.3 and so are quite different.

PorKen

For reference, my '86 is serial# 1955, built in February, 1986.

(2780 sold in the US in '86, according to 928 Spec.)

John Speake

OK Ken,
And the box is marked 928 618 123 04 I understand ? Most cars appear to have 03. There is also an 05 listed in PET but I've never seen the board in one of them.

PorKen

John,

I'm pretty sure that it was an 04. Would the 740 brain drop in, with an EPROM swap?

That must mean why my car gets such good numbers on the dyno - with a superior brain box, and all. Or, I suspect it might be the dyno guy. For some reason he puts the atmo sensor right next to the exhaust manifold when he tests his own car.