79 Seville ESS

[iamnqr]

I am new to the CLC and wondering if I can impose on some technical expertise.  I bought a 79 Seville (CA model) that had been sitting for three years and needs restoration; water damage (rust, but not too overly much - three small areas on the body where the roof meets the main body; sub-frame, floor pans and trunk are ok), cosmetic issues with the interior (reupolstery) and carpet.
However, one of my major concerns that I came across is the ESS module (part# 1894499) looks to be toast.  The jel protection for the electronics at some point melted out.  I've looked around the net and found them not to be an easy item to obtain. I've found one place that sells them for 395 plus 100  core. I guess my first question is can it be bypassed? If not, will any ESS module work from a 78/79 or does it have to be from a California car, which mine is? Another is what would cause it to overheat like that?
I haven't dug too far into yet because I have a load of other things on it that can keep me busy and I'm still waiting on the arrival of the service manual. I don't want to just put another one in  and find out the same thing happens. If anyone has any leads on where I can get another one that is not too extortionate, or what the issues could be I appreciate it.
Right now, among other things, I'm waiting to get the gas tank back from being cleaned (rust) and sealed, so I haven't tried to start the car yet and with the ESS in the condition it's in I wouldn't expect it to start anyway. Thanks for any help/ideas you can provide and btw I've already picked up some very good info from scouring the forum.  Thanks again.  PLynch.

[bcroe]

I bought a 79 Seville (CA model) that had been sitting for three years

one of my major concerns that I came across is the ESS module (part# 1894499) looks to be toast.  The jel protection for the electronics at some point melted out.  I've looked around the net and found them not to be an easy item to obtain. I've found one place that sells them for 395 plus 100  core. I guess my first question is can it be bypassed? If not, will any ESS module work from a 78/79 or does it have to be from a California car, which mine is? Another is what would cause it to overheat like that?

I'm still waiting on the arrival of the service manual. I don't want to just put another one in  and find out the same thing happens. If anyone has any leads on where I can get another one that is not too extortionate, or what the issues could be I appreciate it.         PLynch.   

Getting the service manual is a very good idea.  Besides the 1979 CADILLAC SERVICE MANUAL, get the 1978 SEVILLE BY CADILLAC Electrical Troubleshooting Manual Catalog No. S-1556 if you can find it, got mine new from the source.  And surely get the 1976 GM Cadillac ELECTRONIC FUEL INJECTION DIAGNOSIS Manual 1099984 / S-1453, I see 6 of them on EB*Y cheap.  Covers the fuel injection well, though not the ESS. 

I am pretty sure any 78/79 ESS module will work for you.  As shown in the S-1556, there is one wire moved over for CA.  It is paired with a unique module in the HEI.  I am pretty sure you could install an earlier 4 pin HEI module without an ESS module, and the car would run OK.  The timing curve might need tweaking to compensate.  OR just install a 76/77 Seville HEI with no ESS and solve the problem.  I haven't actually tried either of these on my 79. 

I have seen a few ESS modules on EB*Y, none current.  Any electronics can die, maybe overheated by the engine.  If you want it tested, send it to me & I'll run it in my 79 Eldo (same engine).  If its no good, I'll send you another used module that does work, for a lot less than $400.  Who has them new at the extreme price? 

You can see a lot of info on 70s Cad EFI on my PHOTOBUCKET. including common problems and ways to fix them.  1st SUB ALBUM is 70s, several down is the internal schematic of your 79 ECU. 

     http://s93.photobucket.com/albums/l71/bcroe/

(that is a lower case "L"71, not an upper case "i"71)

  click on a Sub-Album
  click on a picture to enlarge + description

BRUCE ROE     CLC # 14630  70s EFI technician

[iamnqr]

Bruce,  Thank you very much for the info you provided. I took your advice about getting the 76 Cadillac Fuel Injection Manual and I might take you up on sending my ESS unit to you.  It doesn't look pretty, but I don't see any obvious burn marks where a component might have fried.  I looked over your photoshop page, but too much info for this feeble brain to absorb in one go.  I will definitely be going there often. I actually owned two 78 Sevilles before.  The first in bought in 85 and the second in 98.  Funnily enough both were in Japan of all places, but they were both cherry running cars. I should have kept the last one and brought it back with me.  Anyway enough jabbering - when I get the service manuals I'll start some serious poking around and try to get this one to run.  My plan is to keep the FI, but seeing as I'm in HI where they don't do SMOG I'll change to a carb system if it gets too painful.  Anyway thanks again, Phill  PLynch   

[Gene Beaird]

Phill, do some searches on this site.  Questions regarding the electronics onboard of the 76-79 Sevilles have been asked, with several good write-ups in many of the queries. 

And yes, Bruce's photobucket pages require multiple passes to fully-absorb.  But it's all good info for those bitten with the Seville bug.   

[bcroe]

The blue & white book is about the best info for understanding
& maintaining the 70s Cad EFI; I recommend every owner have
it.  Frequently seen on Eb*y, cheap, from new to greasy. 

Unfortunately it doesn't cover the ESS.  If I get a bad one that
can be dissected, maybe I can add something.  Meanwhile they
are too rare to just destroy by removing the potting. 
Saw these earlier.  Bruce

1976 GM Cadillac ELECTRONIC FUEL INJECTION DIAGNOSIS Manual 1099984 / S-1453

151086305139 Item number:

121002994714 Item number:

330668089237 Item number:

160974526333 Item number:

251307867274 Item number:

220886697598 Item number:

[C.R. Patton II]

Hello Phillip

Congratulations on your latest acquisition! It looks like this era has a place in your heart. The previous advice presented is point on to enhance your Seville enthusiasm. Collect as much technical material to improve your mechanical ability.

If I surmise your prior post correctly you appear to be in Asia? If this is true our International Affiliate Vice President, Mrs. Toni Nabholz Huse would love to have a conversation with you.

Glad to have you as a CLC member.