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Security System - 85 Eldoradoi

Started by Dan85Eldo, May 25, 2008, 11:39:13 PM

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Dan85Eldo

Greetings! A CLC friend suggested this as a great forum to learn and share information. I just bought an 85 Biarritz, which will need a lot of TLC to bring it back. First problem: cannot get the car to start. From what I can tell, the security system will not disarm. Followed owner's manual instructions (power door lock to arm; manual door key unlock to disarm); arming sequence seems to work fine, but the security light flashes when door opens after unlocking the door with the key. The ignition key turns easily to all positions. At start, the accelerator pedal bumps on the floor, starter does not engage, and chimes sound. From manual, does not appear that ignition keys had the resistance chip of later GM cars; however, don't have original keys (square or round heads). Battery is fully charged, accessories work in "run" position; however, starting circuit appears to be overridden by security system. Car was running when loaded onto transport; security light flashing ever since as door is opened. Any and all ideas on how to troubleshoot (no schematics here) and/or resolve problem (bypass system temporarily or repair) will be greatly appreciated. Thanks!

Dr Dan Goad
Austin TX

76eldo

Try unlocking the door from the driver's side inside unlock switch.  Also try removing battery power for 30 seconds.

Brian
Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

Johnny

Are you aware of the special care that the engine requires?

Dan85Eldo

Brian,

Tks! I did swap out the battery for one fully charged and then replaced the car's battery after recharging (holds the charge). Your idea on the power unlock is a good one. I noticed that the driver's side door lock switch works to lock the doors, but does not unlock--may be a switch contact. I hadn't thought about the connection with the security system, but the circuit wiring may require a good connection; I'll check it out. The passenger's side switch works to lock and unlock, so I can at least trade them out and see if that helps. I'll try it by arming the system with the power lock, close the door, and then use the power door unlock. Thanks for the tip!

Dan85Eldo

Quote from: Johnny on May 26, 2008, 07:13:02 AM
Are you aware of the special care that the engine requires?

Johnny,

The only thing I know about the HT4100 is from friends who said the engine had problems early on. I am hoping that by '85, they had the problems resolved, although the engine size, even with fuel injection, seems a bit small for the GVW. I would appreciate any links or other information sources that will help me properly care for the engine--IF it ever starts again!

76eldo

Go here and start reading posts, and use the search feature to lear more about your car:

http://autos.groups.yahoo.com/group/HT4100exchange/

Brian
Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

Rusty Shepherd CLC 6397

#6
You say that when you turn the key to the start position the accelerator bumps to the floor.  That is definitely not normal and I would want to find out what is causing that and stop it before you proceed with getting the car started.  It seems likely to me that while that condition exists the engine would start with full throttle and may stay that way causing excessive engine speed that could only be reduced by turning the ignition off and even that may not work if the fuel injection computer doesn't stop the fuel flow when the ignition is turned off and since it shows signs of significant malfunction, it may not.  Even if the throttle returns to fast idle or idle after starting, you've still started a somewhat fragile aluminum engine from cold with way too much throttle/RPM's.

76eldo

It's probably not "bumping to the floor", but the idle speed control motor (ISC) is probably tapping the linkage which you feel in the pedal.

That's another issue, the ISC motor being bad or out of adjustment will give you the tapping, and idle may be too high, or going up and down, searching for a spot.

Get it started first.  Unless something is drastically wrong, there is no way the electronics of the car can pull the throttle down to the floor.

Brian
Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

Dan85Eldo

Hey Rusty,

YIKES! I assumed that the thumping accelerator pedal was some type of warning to would-be thieves, i.e. part of the security system. It did seem odd, but then again, I don't know anything about this car or its vintage counterparts. It is the weirdest thing--never heard or saw an accelerator pedal act like that on any car! I've heard the HT4100 was not a great success; I was hoping that by '85 (last year for that model car), Cadillac had worked out the bugs. On the other hand, I had a flawless 80 Eldorado diesel and never had a problem with it--wish I'd kept it! Thanks for some sage advice!

Quote from: Rusty Shepherd CLC 6397 on May 26, 2008, 06:23:00 PM
You say that when you turn the key to the start position the accelerator bumps to the floor.  That is definitely not normal and I would want to find out what is causing that and stop it before you proceed with getting the car started.  It seems likely to me that while that condition exists the engine would start with full throttle and may stay that way causing excessive engine speed that could only be reduced by turning the ignition off and even that may not work if the fuel injection computer doesn't stop the fuel flow when the ignition is turned off and since it shows signs of significant malfunction, it may not.  Even if the throttle returns to fast idle or idle after starting, you've still started a somewhat fragile aluminum engine from cold with way too much throttle/RPM's.

Dan85Eldo

Okay, Brian, good to know that the thumping accelerator issue is not related to the security system. It's the weirdest thing--never saw or heard anything like it. Only happens when the ignition is in the "start" position. Do you happen to know if this car should have a resistance chip on the ignition key? The (only) key I have is a plain GM square-headed ignition key that works only in the ignition, but at least it does allow the switch to go from ACC all the way through the detents to the start position.  I think I'm in for quite an education with this car; perhaps I can help others along their path once I've solve a few of these puzzles. thanks!

Quote from: 76eldo on May 26, 2008, 08:43:53 PM
It's probably not "bumping to the floor", but the idle speed control motor (ISC) is probably tapping the linkage which you feel in the pedal.

That's another issue, the ISC motor being bad or out of adjustment will give you the tapping, and idle may be too high, or going up and down, searching for a spot.

Get it started first.  Unless something is drastically wrong, there is no way the electronics of the car can pull the throttle down to the floor.

Brian

Dan85Eldo

Good point! That hadn't even crossed my mind; I remember some of the older Fords had that problem. I can try holding the lever in park and/or shifting to neutral; I believe it should start in either position. That would be embarrassing after all I've read and tried...but you could be right!!

Quote from: South_paw on May 26, 2008, 09:36:04 PM
Seeing that the car ran on the transporter, I would check the to make sure the gear selector is properly engaged in park. Mess around with the shifter a little & try to crank it over.   

HTH,
Lou

Guidematic

 Normal operation.

The security system tell tale will flash whenever any door is opened and the system is not armed. When you lock the doors using either one of the front door lock buttons the system will arm and the light will illuminate steady until the doors are all closed. The light will stay illuminated for a few seconds afterward, and then go out.

To test the system, lower the driver's windo, then arm the system. Then reach in and unlock the door using the mechanical lock, then open the door. Then the horn should sound on and off and the lights flash. Use the key to unlock the door and it should all stop.

To me it sounds as if the system is not even being armed.

The suggestion to move the shift lever is a good one. The neutral safety switch may be out of adjustment and give the symtoms described.

However, it is all to easy to go to the most complex system in the car and blame that, simply because you don't understand it. Don't forgret your basics. Eliminate that first. Maybe the starter itself is defective. Look into the basic starting system first.

GM did not start using the PASS key security system until 1991 or 1992, and it's a completely differant system that you have in the Eldorado. That's the one with the resistor pellet in the key.

And it's physically impossible for the ISC motor to apply full throttle on the throttle body. What you are feeling is simply the ISC motor hunting for idle. Nothing more. It may do this so long as the engine is not running, then when you do get it running it should settle down. This sort of thing was common on the early DFI engines.

As far as the upkeep and maintenance of the HT4100, you can find a lot on the HT4100 exchange. And yes, most all of the early issues had been dealt with by 1985, but they could still give some grief. I have an '85 Eldo that needs an engine. I am currently building one for it, and enlarging it to 4.5 litres. I also have an '88 Eldo Biarritz with the 4.5 and it is an excellent engine.

Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69

76eldo

85's did not have the chip (VATS) system.

Brian
Brian Rachlin
Huntingdon Valley, Pa
I prefer email's not PM's rachlin@comcast.net

1960 62 Series Conv with Factory Tri Power
1970 DeVille Conv
1970 Eldo
1970 Caribu (?) "The Cadmino"
1973 Eldorado Conv Pace Car
1976 Eldorado Conv
1980 Eldorado H & E Conv
1993 Allante with Hardtop (X2)
2008 DTS
2012 CTS Coupe
2017 XT
1956 Thunderbird
1966 Olds Toronado

35-709

Dr. Goad,
You might also like to check out the HT 4100 Chapter of the Cadillac & LaSalle Club at  http://www.ht4100.com/
:)
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Dan85Eldo

Mike,

Thanks much for all. I'll follow your advice and report back. I'm really amazed--and appreciative--of the guys on this site!

Dan85Eldo

Geoff,

Thanks! It's a great site with lots of useful information. I'm sure I'll be "fluent" in HT4100 before this is all said and done!

35-709

#16
"I'm sure I'll be "fluent" in HT4100 before this is all said and done!"

:D :D :D  You got that right!
Good luck!
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Rusty Shepherd CLC 6397

Dan, You say "Yikes!" and that is pretty much the reaction almost everyone who knows HT4100's would have about them.  Cadillac did make incremental improvements to a very flawed design from 1982 through the end in 1987, but the final ones still suffered from most of the problems of the '82's.  Some people through a combination of luck and very rigorous and frequent cooling system and oiling system maintenance and never having an overheating condition (which were almost always fatal to HT4100's) got good service out of them, but they were very much in the minority. Only when the 4.5 came out for 1988 did all the problems end even though the engine was basically the same design as the 4100 including aluminum block and cast iron heads. Thorough re-engineering and testing eliminated all the bugs of the original and the performance was significantly improved as well. Giving the devil his due, when HT4100's are in good shape, they are very smooth and quiet and reasonably fuel-efficient. They are somewhat sluggish, especially in the heavier RWD cars and pre-86 Eldorados and Sevilles, but really little, if any, more so than 302 Lincolns and 307 Cadillacs, Electras, and Ninety-Eights.

Dan85Eldo

Rusty,

Got it. I've made a practice of changing oil & filter on all my vehicles every 3K miles or at least twice a year--so far, so good! I haven't been as "faithful" with flushing the coolant system, although I do check the level and boiling point periodically to ensure the engine is protected. How often would you recommend flushing the coolant system?

Guidematic

 Everey 2 years. Regardless of mileage. Also make sure you get the GM cooling system supplement, Part # 3634621. Use 2 tablets.

Mike
1970 Fleetwood Brougham 68169
1985 Eldorado Coupe 6EL57
1988 Eldorado Biarritz 6EL57
1990 Brougham d'Elegance 6DW69
1994 Fleetwood Brougham 6DW69