1979 Seville Help Please...
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 15 of 29
Like Tree1Likes
The Classic Cadillac Forum Discussion, 1979 Seville Help Please... in Past Cadillac Vehicle Discussion; Good morning, Just joined recently, haven't participated yet but been reading heavily to gain info, etc on my car, a ...
  1. #1
    Driver-8's Avatar
    Driver-8 is offline Cadillac Owners Member
    Automobile(s): 1979 Seville, 1999 Jeep GC Ltd
    Join Date
    Jun 2013
    Location
    Midwest USA
    Age
    49
    Posts
    41

    1979 Seville Help Please...

    Good morning, Just joined recently, haven't participated yet but been reading heavily to gain info, etc on my car, a 37K 1979 Seville. Eventually, as I progress with my project, I'll have a link here to a picture gallery for everyone to view.

    There is so much solid info on the EFI system, etc from some very experienced guys here, and it's helping me to gain enough knowledge to feel comfortable maintaining/repairing the system as needed. I have the original shop manual and have ordered the Cadillac EFI diagnosis/troubleshoot supplements as well.

    Anyhow, Since my EFI system is still operating and intact, I wish to keep it going as opposed to a carb conversion (last resort). I want the car to be safe (fire risks) so I have just replaced the injector O-rings and next is all new fuel supply lines from JEGS. Because I also want reliability to take a road trip to shows, etc w/o worrying about dying on the roadside, I've been building a shopping list at RockAuto to get as much of the old important parts as I can and found distributor, sensors, including TPS and more. They showed 2 ECM's 1-ACdelco and 1 SMP #8864 (my OE# is 1615173) but they said that SMP doesn't have any more as demand has dwindled away.

    Can anyone here help me as to where I can get a properly rebuilt ECM #1615173? I am not looking for a used one, as my car runs great right now. This is a backup for my parts storage box (for the next 30yrs of running

    Is it true that there is a member here or on cadillaclasalleclub org who offers to rebuild these, or possibly would sell me a rebuilt w/o core return so I can keep mine? I suppose if I can't find one, it would not be worth buying all the backup EFI parts, as I'd prob have to convert to carb if/when my computer goes.

    Any help or info is much appreciated.

    Thanks, Mark~

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,788

    Re: 1979 Seville Help Please...

    The weak link regarding the computer is the the multi wire harness that plugs into it. Over time the plug gets loose. Once loose it can melt the connector that powers the fuel pumps! car quits! The computer seems fairly trouble free in my opinion. Spares would be 2 coolants sensors. The same part number works for air temp as well as coolant temp in the intake manifold.

  4. #3
    Driver-8's Avatar
    Driver-8 is offline Cadillac Owners Member
    Automobile(s): 1979 Seville, 1999 Jeep GC Ltd
    Join Date
    Jun 2013
    Location
    Midwest USA
    Age
    49
    Posts
    41

    Re: 1979 Seville Help Please...

    Quote Originally Posted by carnut View Post
    The weak link regarding the computer is the the multi wire harness that plugs into it. Over time the plug gets loose. Once loose it can melt the connector that powers the fuel pumps! car quits! The computer seems fairly trouble free in my opinion. Spares would be 2 coolants sensors. The same part number works for air temp as well as coolant temp in the intake manifold.
    Thanks carnut, appreciate the info. I did order the coolant sensors, air temp sensor and throttle positioning sensor from RockAuto so far. I will inspect the connector on the ECM next time I'm working on her and report back with any issues found.

    As I mentioned, the car is running quite well overall. BTW, I did improve a cold start dying/low idle issue after reading all the fast idle control valve posts. Took it all apart, cleaned & lubed it resulting in a steadier idle so far (even w/o shim). Car still has the hesitation accelerating from stop, but it seems to always do that, no matter weather conditions (only driven 1-2K May-Oct), or even after extensive tune-ups.

    Thanks again for replying and for all the other help/info I've seen you put out there for others. Mark~

  5. #4
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,788

    Re: 1979 Seville Help Please...

    A bog or hesitation from rest is usually fixed by adjustment of the TPS. I cannt remember the number of clicks you're supposed to hear as you rotate the throttle very slowly from rest to wide open with the key in the ON position, car off! !8 seems to stick out but that's a guess! Its supposed to click just off idle so see if you can move the TPS down if you think it requires too much throttle movement to hear the first click.

  6. #5
    Driver-8's Avatar
    Driver-8 is offline Cadillac Owners Member
    Automobile(s): 1979 Seville, 1999 Jeep GC Ltd
    Join Date
    Jun 2013
    Location
    Midwest USA
    Age
    49
    Posts
    41

    Re: 1979 Seville Help Please...

    Quote Originally Posted by carnut View Post
    A bog or hesitation from rest is usually fixed by adjustment of the TPS. I cannt remember the number of clicks you're supposed to hear as you rotate the throttle very slowly from rest to wide open with the key in the ON position, car off! !8 seems to stick out but that's a guess! Its supposed to click just off idle so see if you can move the TPS down if you think it requires too much throttle movement to hear the first click.
    Wow, thanks much... man would I love to correct that annoying problem. Will def be looking at that this weekend along with inspecting the harness connector & vacuum line on the ECM. I do have that TPS ordered from Rock also, so I'll check setting when I get new one installed too. Then it's time to get my head outta the engine compartment for a bit and start my interior work this weekend (maybe squeeze in a test drive on Sunday

    BTW, I found re-manufactured ECM's at west coast Cadillac King via their parts link> http://cadillacking.org/index.php?ma...jihs294pnk7qn5 About $400.00 if you dont plan to return core back, otherwise $300 They don't have my OE# right now, but maybe one of you will need one from them.

    I also posted a few pics in my album here for now to get things started. Will be eventually putting all project pics and more into an online link for unlimited access to all.

    Everyone have a great weekend, and enjoy those Classic Cadillacs! Mark~

  7. #6
    Driver-8's Avatar
    Driver-8 is offline Cadillac Owners Member
    Automobile(s): 1979 Seville, 1999 Jeep GC Ltd
    Join Date
    Jun 2013
    Location
    Midwest USA
    Age
    49
    Posts
    41

    Re: 1979 Seville Help Please...

    Hey everyone,
    Hope you enjoyed your weekend. I thought I'd post a link at the end of post here with a few pics of 'Christine'... and, yes, I'm a Stephen King fan. Sorry they are not in any real organized manner as of yet, but I will have a detailed album as things progress and I find time to put them in order with more captions, etc

    Anyhow... as far as the EFI, engine stuff from last week is going: I'm still working to find the right spot for the TPS. Throttle position sensor does have correct voltage and clicks immediately when even touch open the throttle. The thing is I think I heard like 20 clicks on the way up to full throttle position, not 7 or 8. Is this something that tells of worn out/bad or just an incorrect adjustment? If it is bad, I have that brand new one coming from RockAuto and can experiment with that one. May end up having to disconnect the fast idle unit after all, it is idling too high all the time now and even the adjustment screw has hardly dropped that back down. This car doesn't go out in the cold weather anyhow so maybe I should disable it.

    The car is idling smoother (but too high as mentioned), and continues to bog/hesitate accel off stop and on test drive Sunday, got some hesitation/missing while cruising at @ 30MPH. This car has all new ignition parts and fuel filter. I have had my Cadillac factory service manual for a while to reference, but Saturday just received my official 1975 EFI service shop diagnosis guide & 1978 supplemental, so I will read through it and add it to the big bible (and hopefully my memory too

    I did not inspect the ECU connector or attached vacuum line yet, but will do so this week after work. The replacement 2-wire EFI sensors are not here yet, maybe they'll make the difference but these symptoms don't correct when at full operating temp, so doubtful i would think. Maybe there is a leak in the line going to the MAP sensor.

    Hope you enjoy the pics, and yes the pass side valve cover is still blue, peeling and rusty I'm doing that side next spring or I'll never get to driver her before October hits. You could eat dinner off of 90% of the motor or engine comp now though. The burnt copper color really goes nicely with the car, and harks back somewhat to old Cadillac engine colors. BTW, if you have one of these, the fuel rails & connectors polish up beautiful like chrome with #0000 steel wool pads.

    I re-taped alot of the original wiring electrical tape, repaired a few worn wires and add dielectric grease every time I open any connector. There's a K&N lifetime air filter with a billet aluminum ribbed cover. Also repaired the in-op power antenna, but can't get it to go down the final 1" each time. The CB is working again though and so does the 8-track.

    As a boy, I collected those Cadillac 8-tracks & showroom brochures, so I have 1974-1979 tapes to use in the car. The brochures I have are from 1956- up to @ 2003 I used to drive the local Cadillac Dealer sales people crazy riding my bike there daily to hang around, stare at the new cars on the lot and showroom, and buy Jo-Han models each year from the parts guys.

    Anyhow, there's a couple pics of the JB Weld putty (stuff is a miracle product line), repair on headlamp housing, it is solid as a rock, and painted black applied inside, you can't even see it, it's all behind the bulb supports. Also working on the cloth door surrounds and custom 2-tone on interior parts (doing full dashboard, door panel armrests, pull-straps, center armrest uppers in the contrast dark chocolate with the new Lloyd's mats same color. While in there, changing all the bulbs on telltale panel and checking harness connections.

    I hate seeing that pitted chrome on my tail-lamp bezel ... ugh

    There's also a pic of my 1999 (build date 10/2008) Jeep Grand Cherokee Limited w/every option, that I've had since new, only 54K on it near mint condition & $20K+ in interior mods, with hi pro engine, German 2piece wheels, exhaust & suspension mods. The last 2 pics are a donor 1978 Seville I grabbed a few things off of last month (not ez to find around here, trust me)

    Enjoy!

    Link>>> https://www.dropbox.com/sh/6qtr1acy4kdao7i/hrSPijD_PB#/

    Mark~

  8. #7
    orconn's Avatar
    orconn is online now Cadillac Owners 10000+ Posts
    Automobile(s): Cadillac 95 STS, 02 SLS
    Join Date
    Oct 2007
    Location
    Midlothian, VA
    Age
    71
    Posts
    12,751

    Re: 1979 Seville Help Please...

    I had a 1976 Seville, which I bought new and owned till 1986, one of my all time favorite cars! Your pictures of the headlight baskets from your car, that you had repaired, which brought back the one really bad memory of my Seville and the reason I didn't buy another GM product till the year 2000. The head light buckets on Cadillacs (all models) grew brittle after about tow year's use in the cars. They would break and the head light themselves would fall forward and leave you with useless head lights.This was true of my Seville and my friends' Cadillacs, whether they be de Villes or Fleetwoods. The part to fix the problem was only about $20.00 but a Cadillac agency wanted $200. to fix one side. As I said this part failed about every two years, at least in Los Angeles driving conditions. I contacted Cadillac on several occasions to see if their were places to come up with a sturdier replacement for this part .... and was basically told to shove it! These same defective headlight buckets continued to be used on Cadillacs until well into the late 1980's. Although the failure of these headlight buckets could have been corrected GM felt it was better to save a few cents a car rather than correct a potentially serious safety problem. GM's cavalier attitude this safety problem kept me from buying another GM product, and I am sure many of my friends followed suit, and led to my buying European cars for the next 18 years.

  9. #8
    Driver-8's Avatar
    Driver-8 is offline Cadillac Owners Member
    Automobile(s): 1979 Seville, 1999 Jeep GC Ltd
    Join Date
    Jun 2013
    Location
    Midwest USA
    Age
    49
    Posts
    41

    Re: 1979 Seville Help Please...

    Quote Originally Posted by orconn View Post
    I had a 1976 Seville, which I bought new and owned till 1986, one of my all time favorite cars! Your pictures of the headlight baskets from your car, that you had repaired, which brought back the one really bad memory of my Seville and the reason I didn't buy another GM product till the year 2000. The head light buckets on Cadillacs (all models) grew brittle after about tow year's use in the cars. They would break and the head light themselves would fall forward and leave you with useless head lights.This was true of my Seville and my friends' Cadillacs, whether they be de Villes or Fleetwoods. The part to fix the problem was only about $20.00 but a Cadillac agency wanted $200. to fix one side. As I said this part failed about every two years, at least in Los Angeles driving conditions. I contacted Cadillac on several occasions to see if their were places to come up with a sturdier replacement for this part .... and was basically told to shove it! These same defective headlight buckets continued to be used on Cadillacs until well into the late 1980's. Although the failure of these headlight buckets could have been corrected GM felt it was better to save a few cents a car rather than correct a potentially serious safety problem. GM's cavalier attitude this safety problem kept me from buying another GM product, and I am sure many of my friends followed suit, and led to my buying European cars for the next 18 years.
    Believe me, I hear you on this one. The picture does not even show all of the hairline cracks that were there. This car only has 37K on it and was never driven in winter conditions, garage kept it's entire 34.5yr. life and yet has brittle housings that were shattered apart as if hit by another car on that corner... and it was not. When I went to the boneyard Seville, one side I found crumbled in my hands, yet the other side on the same car... well, I could not even crack or tear it with a large pliers???

    When I was a young boy, I wrote letters to Cadillac upset in 1977 that they used plastic and fiberglass headers and bumper fillers, in addition to complaining about the crushed in '77 trunk-lid and too short length! They actually wrote back to me in those days with genuine professional replies, reasons & excuses as to why they were initiating these new cheaper materials and downsizing during the Jimmy Carter malaise era we lived through. I sent them a blank check for pictures and brochures, they mailed me back with a huge pile of showroom brochures, 8x10 promo photos, color chips and more. Lastly, they included a note teaching me the mistake of sending a blank check to anyone, telling me to never do that again and returned it to me, (that letter is stored in a box somewhere), I had received all of the material and a valuable lesson all for free, direct from Cadillac Motor Car Division. Those days are surely gone forever. They have destroyed most of the materials and now charge for each item they do offer by mail... different times, certainly. Anyhow, I digress... I too feel that my 1979 Seville is on of my all-time favorite cars (out of 20+). Thanks again for the story and input though.

  10. #9
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,788

    Re: 1979 Seville Help Please...

    Regarding the high idle, with the air cleaner lid off, can you press down on the choke heater and does that lower the idle? This is assuming the engine is at full temperature after 20 minutes of use. The choke heater is beside the aircleaner stud. If it lowers, then remove the heater and place a thin washer under it to shim it slightly. Remove the air cleaner stud, then push down on the heater and turn counter clockwise. It should pop up out of the Throttle body. The choke heater closes off a designed in vacuum leak as the engine warms up. If it doesn't completely close the vacuum leak, it will idle too fast and might bog or hesitate on acceleration.

  11. #10
    BRUCE ROE is offline Cadillac Owners Fanatic
    Automobile(s): Eldorado
    Join Date
    Jun 2009
    Posts
    216

    Re: 1979 Seville Help Please...

    Quote Originally Posted by carnut View Post
    Regarding the high idle, with the air cleaner lid off, can you press down on the choke heater and does that lower the idle? This is assuming the engine is at full temperature after 20 minutes of use. The choke heater is beside the aircleaner stud. If it lowers, then remove the heater and place a thin washer under it to shim it slightly. Remove the air cleaner stud, then push down on the heater and turn counter clockwise. It should pop up out of the Throttle body. The choke heater closes off a designed in vacuum leak as the engine warms up. If it doesn't completely close the vacuum leak, it will idle too fast and might bog or hesitate on acceleration.
    Hey carnut, have we met in another place? I don't work on the cars much, but test & fix a lot of 70s ECUs. Failures of the fuel pump circuit through the ECU accounts for around a third of ECU failures I see. I
    recommend adding an external relay to eliminate this source of ECU damage. Info on this is on my
    PHOTOBUCKET, and a lot of other 70s EFI stuff in the first few SUB ALBUMs.

    I am going to guess, the hesitation is due to running lean from a failing MAP sensor; accounts for
    another third of 70s failures. Bruce Roe

    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

  12. #11
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,788

    Re: 1979 Seville Help Please...

    Met before?? Don't know. You have no State or Country in your profile! The relay in line is a very good suggestion! The connector was never designed to function for this many years.

  13. #12
    Driver-8's Avatar
    Driver-8 is offline Cadillac Owners Member
    Automobile(s): 1979 Seville, 1999 Jeep GC Ltd
    Join Date
    Jun 2013
    Location
    Midwest USA
    Age
    49
    Posts
    41

    Re: 1979 Seville Help Please...

    Have to say this...

    Bruce Roe and carnut are God's gift to us 1st gen Seville & '70's EFI Cadillac owners. I have already, in such a short time, learned and stored away so much priceless information, ideas fixes, etc.

    A BIG THANK YOU to you both. For myself I can't say enough how much I appreciate how giving you guys are.

    These 2 Cadillac forums are filled with passionate, experienced and helpful members willing to go the extra mile for someone they may never even meet. Glad to now be a part of it all. It's pretty rare these days to find such passion, comradery and invaluable information laid out on a silver platter.

    Thanks to everyone here for working together to help keep our Classic Cadillacs on the road.

    Mark~

  14. #13
    carnut is offline Cadillac Owners Master
    Automobile(s): 1988 Allante' (sold), 1984 Eldorado, 84 Sedan DeVille
    Join Date
    Feb 2003
    Location
    california
    Age
    67
    Posts
    5,788

    Re: 1979 Seville Help Please...

    Bruce is a genuine wealth of information! Glad I could help.

  15. #14
    Driver-8's Avatar
    Driver-8 is offline Cadillac Owners Member
    Automobile(s): 1979 Seville, 1999 Jeep GC Ltd
    Join Date
    Jun 2013
    Location
    Midwest USA
    Age
    49
    Posts
    41

    Re: 1979 Seville Help Please...

    Quote Originally Posted by carnut View Post
    Regarding the high idle, with the air cleaner lid off, can you press down on the choke heater and does that lower the idle? This is assuming the engine is at full temperature after 20 minutes of use. The choke heater is beside the aircleaner stud. If it lowers, then remove the heater and place a thin washer under it to shim it slightly. Remove the air cleaner stud, then push down on the heater and turn counter clockwise. It should pop up out of the Throttle body. The choke heater closes off a designed in vacuum leak as the engine warms up. If it doesn't completely close the vacuum leak, it will idle too fast and might bog or hesitate on acceleration.
    Hey carnut, will be testing out your ideas on the fast idle valve this Sunday, I'll post on this with results. Next step, I will remove the cat for good as well as soon running tests on the ECU/MAP sensor along with Bruces pump relay bypass mod. Mark~

  16. #15
    BRUCE ROE is offline Cadillac Owners Fanatic
    Automobile(s): Eldorado
    Join Date
    Jun 2009
    Posts
    216

    Re: 1979 Seville Help Please...

    Quote Originally Posted by carnut View Post
    Met before?? Don't know. You have no State or Country in your profile! The relay in line is a very good suggestion! The connector was never designed to function for this many years.
    Bruce Roe here, 1.5 hour west of Chicago, details in CLC # 14630 listing. Got into the 70s (first gen) EFi
    keeping my 79 Eldo running properly. In truth it was far more troublesome than my 79 Toro, but most of
    the problems weren't too hard to fix for an electrical engineer. Modified the EFI to run a 403. Correctly,
    not that messing with the temp sensor.

    I saw a lot of burned connectors, burned PC traces, and failed fuel pump relay contacts. It was pretty
    obvious an external relay was needed, as the 2nd gen designers all did. The funny thing was, the contact
    where the current came in was always OK, maybe because it was close enough to the PC board to drain
    away heat. The output contact would fail, longer lead to the PC. The good news is, there is a second
    output contact for the cold idle air valve heater. Tie them together in the car, connect to the external
    relay coil, and the burned connector works again. Better to avoid it though.

    The next biggie is failing MAPs. I finally designed a solid state replacement that fits the same footprint,
    not quite ready to recommend replacing an original before it fails.

    Many of the remaining failures are Integrated Circuits, available for less than a buck. But a few
    are custom, not available except by killing another ECU. Bruce

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting