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1979 seville no start a well worn path...help

Started by pacificnwrider, January 20, 2013, 02:29:33 PM

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pacificnwrider

I see many posts about this and unfortunately I'm yet another sojourner on this path.  I want to apologize in advance for causing any of you to re-state this information.  My recently acquired 79 Seville with the EFI won't run. 

PO states(with supporting documentation) its got a mechanic installed GM crate 350 with steel timing set).  PO also states(again with supporting documentation) the car sat for a long time, he took it to his mechanic, had the tank dropped, both pumps replaced, fuel lines cleaned.  States he drove it around for a few weeks during which time it wasn't running great.  He then states it was running rough at his house one day, backfired, and stopped running; at which time he parked it...that was fall of 2012. 

It starts and sputters and coughs...does this for a couple seconds, then dies.  If I go to try to start it again it more or less, just cranks...if I give it 20 minutes or so and try and start it again, it will do the 2 second sputter.  running rich? I replaced both of the coolant temp sensors, no change.  It's in time...Can I test the map sensor in the ECU? What should I try next?  I am really hoping to get it running with the EFI, but I'm pretty discouraged this morning, ugh.  I know you guys have been over this but I'd really love some help yet again

TJ Hopland

Don't give up on the EFI yet.   Bruce Roe is a regular poster here and does repair work on these ECU's so Im sure he will be along soon with some more things to check.    I know a little about these and one of the things I know is they are not much like modern systems.

Have you got a chance to hook up a fuel pressure gauge?   I wonder if its the issue where the power circuit for the fuel pumps has been damaged on the ECU so you are not getting full or consistent power to the pumps?   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

pacificnwrider

Thanks for the encouragement TJ, I've gleaned a ton of good information from yours, as well as Bruce's posts in my parusal here.  This EFI seems like a pretty straight forward system...it almost feels like it's running far too rich; as it sputters longest after sitting a bit...I think it may have something to do with the ECU...but these are presumptions on my part....

bcroe

Sounds like the ECU is running the injectors high duty cycle; usually a bad IC in the
ECU.  Fortunately a simple fix. 

Could also be a badly leaking injector.  Put the pressure gauge on the fuel rail, turn
on the key and see 39 psi.  Turn it off again, the pressure should hold for a few
seconds if no leaking injectors. 

Bruce Roe

pacificnwrider

Thanks Bruce! Thanks TJ! So I bought a complete set of FJ2 injectors which are stated to fit this vehicles application.  Is this correct?

76eldo

Bruce,

You seem to really know your stuff with these early injected cars and the specific CPU issues and the fuel pump relays.

Have you ever thought of making or designing a plug in replacement for these CPU's?

It seems that anyone that has one of these cars would (or should) be willing to purchase a replacement solution.  Seems like the cars that are not experiencing trouble yet will have problems at some point.

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

TJ Hopland

There was a guy several years ago that made a few components to make a Megasquirt kit plug in.   Last time it came up most of the links to him and his info had disappeared.  Seems he had several 79-85 and had done tons of swaps.  I think he also had a lot of good info on the 4100.   If I am remembering the correct guy he started as a teen and looked to be college in his later posts.  Guessing life got in the way of the fun of tinkering with these cars.   I had some of his stuff saved on another machine, I should look and see if I still have it.  It was really good info with lots of good photos.   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

76eldo

The person you are referring to is Cory Heisterkamp.  He moved his website here:

http://www.radar58.com/eldo/index.html

It's still the same site with all of the info from the old site.

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

waterzap

I am almost 90% sure its the ECU. There are three weak points on these cars. The two temp sensors, and the ECU. The temp sensors only work when the car is cold. Once the car is hot, you dont need them anymore.

You can test the MAP sensor. It should have a specific voltage output. I will have a look to see my notes. I think they are still on Bruce's web page.

First thing though, do you hear the pumps come on when you turn the key to start? The pumps should come on for a few seconds, then switch off when you dont start the car.

I have an extra ECU in my trunk. First thing you need to do is go on ebay and see if you can find a rebuilt one. There are a couple available, around $300. I will check my notes, but I am almost certain that any year 350 will work on another year. Up to 1980. 1979 and 1980 had different brackets, and probably better internals than the other computers, but I believe they are all interchangable.

Then use Bruce's diagram and rewire a relay into the ECU wiring. VERY IMPORTANT. It protects the ECU. If you dont put the relay in, the pumps pull too much current through the ECU when they go bad. It WILL kill the relays in the ECU. You need a spare ECU though.

Another thing you can try, which is easy. Replace the ignition parts. My car ran much better when I replaced the ignition coil, cap and rotor. You can still get a rebuilt distributor on Rock Auto for not much. Who knows if you will be able to find one in a few years.

I had SO many problems when I got my 76 Seville. With Bruce's help and lots and lots of time and effort, the car now runs GREAT. I bought all the 70's EFI books I could find. Also the EFI testers are helpful. You are going to have to become your own best expert in these systems. No one else knows how to fix these cars.

Took the Seville on the highway tonight. 65, 70 easy, and not pushing the car. Runs like a champ. Keep at it, these cars run beautifully once you have all the bugs worked out. My 76 Seville runs rings around my 78 Eldorado. Faster, starts easier, and twice the mileage. The ones with original FI is getting rarer by the day.

I am not thinking of a replacement solution quite yet. Replaced my whole injection system. Have a few spare sensors, and two good computers. I can probably buy 10 computers for the price of a replacement system. If the computers only last 15 years each (which is possible with the limited mileage), I still can get 30 years out of this car :-)

IM me if you need more help.
Leesburg, AL

bcroe

Quote from: 76eldo on January 21, 2013, 02:05:15 PM
Bruce,  You seem to really know your stuff with these early injected cars and the specific
CPU issues and the fuel pump relays.

Have you ever thought of making or designing a plug in replacement for these CPU's?
It seems that anyone that has one of these cars would (or should) be willing to purchase a replacement solution.  Seems like the cars that are not experiencing trouble yet will have problems at some point.
Brian 
Brian, to modernize these systems with lots of closed loops would require a lot more than a new
plug in ECU.  Just about everything would have to be changed, at major cost in time & dollars. 

Instead I have concentrated on improving the reliability of 70s EFI, while maintaining standard
parts & procedures.  Replacements have been found for some problem parts.  The cost in time &
dollars is minimal.  I could detail this out, but it would be a long & boring post.  Bruce Roe

Gene Beaird

Quote from: bcroe on January 21, 2013, 11:53:29 PM
<SNIP>Replacements have been found for some problem parts.  The cost in time &
dollars is minimal.  I could detail this out, but it would be a long & boring post.  Bruce Roe

Oh no it wouldn't!!  Do tell, do tell!!   ;D
Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

76eldo

Bruce,

So do you have rebuilt ECU's ready to exchange when people need them?

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

bcroe

Quote from: 76eldoBruce,   So do you have rebuilt ECU's ready
to exchange when people need them?  Brian

Brian, I don't have that many 70s ECUs; donations are accepted. 
Not a business here, just a club tech trying to help other owners.  I
try to repair owners' ECUs, often a simple IC gets it shipped back the
same day for next to nothing.  Some need critical or UNOBTAINIUM
parts, might need a sacrificial ECU to get it.  Connector (damaged by
fuel pump current) or big ceramic (76/77 only) fall into that category. 

Owners are encouraged to grab ECUs in the yards or where ever, 3
bad ones can be made into 2 good ones.  Once these are gone, there
will never be any more.  Bruce Roe

bcroe

Quote from: Gene BeairdOh no it wouldn't!!  Do tell, do tell!!
OK, here it is. 

I own a 79 Eldo, had a few problems, so I reverse engineered its EFI.  The early
70s analog computer design is completely different from digital versions after
1980.  But it looks a lot like the stuff I was designing in the 70s. 

I have rewired my 79, so I can plug in about any ECU, as well as the original. 
I have run it with sequential port injection (as opposed to batch) using another
ECU.  The engine has 2 sets of sensors, 70s and 80s. 

The question is, what advantages might be gotten by modernizing the EFI? 
1. Increased reliability;
2. Multi dimensional fuel map;
3. Multi dimensional spark advance map;
4. Knock sensor feedback;
5. Closed loop idle speed air motor;
6. Closed loop OXygen sensor;
7. Possibly lower emissions;
8. Just slightly smoother idle and MPG.

Things not advantageous
1. Creating a system nobody else can understand , since there
        is no official documentation;
2. Create a system for which there are no standard replacement parts;
3. Create a system that becomes a long term tuning project;
4. Create a system that is illegal for emission testing;
5. Create a system that will disable the car for a considerable amount
      of time during the changeover
6. Create an expensive project for little gain. 

There are plenty of after market ECUs sold to people that have considered
the above.  Some use a Megasquirt.  But:

A multi dimensional fuel map will require a lot of fine tuning to actually
be advantageous, using instruments like a wide band OX sensor. 

A multi dimensional spark map requires a new distributor, a properly
chosen & mounted knock sensor, and a lot of fine tuning. 

An idle air motor would require major mechanical changes to the
throttle body setup. 

An OXygen sensor requires proper modification to the exhaust system. 

Any of the above require a bunch of new wiring. 

I think MOST 70s Cad EFI owners don't want a huge project, they don't
their cars out of service a long time, they don't to become tuners, they
just want to drive their cars.  The 70s EFI is marginally better than a
carb, so I have concentrated on improving the RELIABILITY of the
original system. 

The 100 odd 70s EFI failures I have fixed mostly fall into 3 catagories. 
I try to quickly fix them, and possibly improve reliability. 

The fuel pump circuit damages the ECU with excessive current.  This can
be cured by adding an external fuel pump relay (like all EFI after 1980). 

The failing MAP sensor (in the ECU) can be replaced by a newer part. 
An 80s can be adapted, or a custom replacement is now being tested. 
Either is fairly expensive. 

Failing ICs can be easily replaced; keeping a spare ECU keeps the car
going in the mean time. 

The leaking idle air motor can be fully closed by adding a shim. 

I contacted the original temp sensor mfgr about making more parts,
which he did (and does).  Probably I wasn't the only one requesting
this.  This expensive part has a nearly linear curve suitable for an
analog computer; modern sensors have a log curve. 

Old wiring & plumbing have issues which can be cleaned up.  But a new
ECU won't cure these.  Oh, and change the timing chain set.  Bruce Roe

Gene Beaird

Thanks, Bruce.  Nice to read and learn from your experience.  I still need to install the external relay for the fuel pumps, but I did grab two temp sensors when they recently got restocked at MTS. 

Gene Beaird,
1968 Calais
1979 Seville
Pearland, Texas
CLC Member No. 29873

pacificnwrider

The no start saga continues.  Thank you Bruce for your efforts! Thanks to Bruce and his diagnostic and other expertice, the ECU has a clean bill of health.  I'm wondering where to go next? fuel pressure regulator?
Just by point of review, the car will sputter and cough(even though its running horrible for the few seconds it runs, it sounds in time); then won't start after that for about 20 minutes.  Wait 20 minutes and it will start, sputter and cough for another 3 to 5 seconds then die. 
I can smell gas in the exhaust. 
Any tips would be greatly appreciated. 

bigdave

Does your car have a catalytic converter and what is its condition? Reading your symptoms its sounds like yours may be plugged.
'65 Eldorado
'67 Calais
'81 Coupe deVille
'03 CTS

TJ Hopland

My experience with cats is the engine will usually idle fine it just wont make any power.   The first time I ran into that I discovered it by looking under the hood outside at night.  Exhaust manifolds were glowing as was the down pipe and cat.  Never would have noticed in the light.

Have you checked for spark when it won't start?  My experience with HEI's is they wont be intermittent very many times usually you just get one warning before they are just dead but who knows.  Another common failure on vacuum controlled HEI's was the pickup coil wires would eventually crack from the flexing when the vacuum operates.  This could possibly fit if there is something that disables the vacuum when the engine is cold so its not moving but as soon as the vacuum is applied it tries to operate and looses contact.  It starts again till the vac comes up?

Does a 79 have the electronic spark control system?  I remember that was a feature on 78 sevilles but I don't know if it was used again.  I think it was just a modification thing vs. total control but its been a few years since I thought or read about it.  Seems like it was a module mounted on the firewall if its got it.   There was a additional round connector that came out of the distributor base in addition to the ones that went to the cap and the ones down on the stalk that go to the ECU.  Maybe something is wacky with that system so the timing is going way off at times.  Its supposed to be a 3 mode thing - normal or +.   Maybe its really messed up and someone has the base timing off to compensate then it kicks in and messes things up?   I think it had a coolant signal, crank signal, and vacuum signal (from the economy sensor).   
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

pacificnwrider

Quote from: bigdave on January 27, 2013, 10:06:30 PM
Does your car have a catalytic converter and what is its condition? Reading your symptoms its sounds like yours may be plugged.

I'll put that on the list of things to check.  My plan has been to delete the cat anyway, no enforcement where I live here  anyway.

pacificnwrider

Quote from: TJ Hopland on January 27, 2013, 11:34:42 PM
Have you checked for spark when it won't start?  My experience with HEI's is they wont be intermittent very many times usually you just get one warning before they are just dead but who knows.  Another common failure on vacuum controlled HEI's was the pickup coil wires would eventually crack from the flexing when the vacuum operates.  This could possibly fit if there is something that disables the vacuum when the engine is cold so its not moving but as soon as the vacuum is applied it tries to operate and looses contact.  It starts again till the vac comes up?

Does a 79 have the electronic spark control system?  I remember that was a feature on 78 sevilles but I don't know if it was used again.  I think it was just a modification thing vs. total control but its been a few years since I thought or read about it.  Seems like it was a module mounted on the firewall if its got it.   There was a additional round connector that came out of the distributor base in addition to the ones that went to the cap and the ones down on the stalk that go to the ECU.  Maybe something is wacky with that system so the timing is going way off at times.  Its supposed to be a 3 mode thing - normal or +.   Maybe its really messed up and someone has the base timing off to compensate then it kicks in and messes things up?   I think it had a coolant signal, crank signal, and vacuum signal (from the economy sensor).   

The HEI does incorporate the Electronic Spark Control in this model.  My understanding from Bruce is that can fail too.  Hoping to get one of these to "test" whether its functional or not.  Please keep watching this post, I'll continue to update based upon my troubleshooting.