News:

Due to a technical issue, some recently uploaded pictures have been lost. We are investigating why this happened but the issue has been resolved so that future uploads should be safe.  You can also Modify your post (MORE...) and re-upload the pictures in your post.

Main Menu

500 efi blues

Started by stevehansford@comcast.net, August 16, 2017, 10:37:59 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

stevehansford@comcast.net

Have been working on 500 efi Eldorado for five years now. This car has 2 new fuel pumps, clean tank, new fuel injectors,new fuel pressure regulator, new timing chain and sprockets, new intake manifold gasket, new laser cut throttle body gasket, new tps, temp sensors at 950-1000 ohms, working hi idle sensor, passed leak down & compression test, new plugs, cap, rotor, etc. We had the ECU refurbished by Mr. Bruce Roe in the spring. He also provided us info on this system we didn't know existed. Thank you again Mr. Roe. The system pressure tested at 39 lbs. So, here is the issue--engine starts immediately, hi idles perfectly, slows to normal, then starts to surge with rough idle. Putting the car in gear results in a stall, but restarts without issue. Pulling the vacuum tube off the fuel pressure regulator results in a perfect idle without issue. Have been told to scrap this system and go carb, but I can be a stupid pigheaded man. If anyone has any suggestions or a test we missed - anything would be greatly appreciated. Almost forgot the Delco refurbished distributor. Would anyone have the ohm number the speed sensor should test out at? Thank you in advance for any info you could send our way. Regards,  Steve Hansford # 30486

The Tassie Devil(le)

Surging sounds like the system is running lean, and the engine is hunting for fuel.

Bruce. >:D

PS.   Congratulations on persevering with it, as when it is right, you will be so pleased.
'72 Eldorado Convertible (LHD)
'70 Ranchero Squire (RHD)
'74 Chris Craft Gull Wing (SH)
'02 VX Series II Holden Commodore SS Sedan
(Past President Modified Chapter)

Past Cars of significance - to me
1935 Ford 3 Window Coupe
1936 Ford 5 Window Coupe
1937 Chevrolet Sports Coupe
1955 Chevrolet Convertible
1959 Ford Fairlane Ranch Wagon
1960 Cadillac CDV
1972 Cadillac Eldorado Coupe

Phil Weber

Faulty EGR operation can cause rough idle and surging also. 

Phil


stevehansford@comcast.net

Thank you for responding. We will have another look  at the egr and lean fuel condition (again). Regards,   Steve 30486

TJ Hopland

Seems like I remember Bruce mentioning he has found a few distributors that were assembled incorrectly so the injection signal was out of phase.    Seems like the kind of thing that would be worse at idle. 

I think I would be thinking back to basics.   How do the spark plugs look?    All the same?   If not look at the runner layout that may give some clues to where a problem could be.   Still have the AC compressor in place?   There is at least one bolt that goes into one of the intake runners.   Seen that problem more than one time on these Cad motors.   

How is the exhaust system?   Does this have an EFE valve?   Cat?   Original muffler?  Res?    I have seen photos of mufflers from that era that had major internal failures but still looked pretty decent on the outside.    Cats have major issues with running rich or lean for extended periods of time. 

Have you at least temporarily disconnected all the various vacuum devices to make sure there isn't something leaking and causing a lean condition?   I just worked on a car that the brake booster was leaking.  You could not hear it while it was running but when you shut it off there was just a slight hiss.  At first we thought it was the AC so I didn't think anything of it.   Assuming this is a 76 so no vacuum booster but there are plenty of other vacuum items that could add up.   
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

stevehansford@comcast.net

Thank you for all these suggestions. Never thought of some of these items. We are out in the garage today. Will look at all these issues. Thanks again.  Regards,  Steve30486

bcroe

OK, my notes say this was an intermittent (really hate those)
ECU; a fault was found, but just maybe it wasn't the only one.
If it is failing very lean, its going to have to go around again. 
The best approach is put in a different ECU and see if the fault
goes away.  Maybe time to send you the TEST ECU, which I
modified to allow temporary mixture adjustments on site. 

For some hard cases (including my car) I have started recommending
putting in a Wide Band OX sensor gauge, and an electric fuel
pressure gauge.  I built a WBOX in 2000 before they were
available, but today consumer versions are quite affordable. 
It will immediately display issues with mixture; works on carbs
too.  Can be shoved in the tailpipe if no air leaks.  Get the kind
with a moving scale, cause quick transitions will just be a
blur of segments on a digital display.  One is

APSX V2 Anti-Glare D2 Digital Wideband O2 AFR Gauge & Sensor Kit

Taking the hose off causes a really rich idle, sounds like a really
lean condition.  Speed sensor phasing reversed will hurt idle,
but perhaps not this severely.  Can be checked in the field, by
taking off the Speed Sensor magnet cover and HEI cap, or by
pushing the crank around with ohm meter on speed sensors;
would expect that problem on a rebuilt, not a factory HEI

There have been a couple intermittent 70s ECUs here that took
many months to finally reveal their problem, so they could be
fixed.  Bruce Roe

stevehansford@comcast.net

Thank you again Mr. Roe for your always helpful  advice. If the test ecu is available we would be very interested in plugging it in to see what happens . Then we could start the hunt for a working replacement and backup. Will go back look at speed sensor today. Thanks again.       
Regards,
Steve Hansford #30486                                         

fellenzer

Very interesting read. I hope you win and get the EFI working properly. I have a 1976 Eldorado convertible, 500 with carb, 102K on the clock. Just bought a 1976 Fleetwood with 500 EFI, 28K on the clock. The Eldorado runs/performs great, no complaints, very smooth. I have to say that I am absolutely shocked at the performance difference with the EFI on the Fleetwood. This one purrs like a kitten. I'd never driven a 500 EFI before. The power in this barge is amazing! Keep working at it. You will be very pleased in the long run.
Michael Fellenzer, #30007
Indianapolis, IN
1976 Eldorado Convertible
1976 Fleetwood Sixty Special Brougham (EFI, ACRS)
1976 Coupe deVille (Astro/Cabriolet)
1984 Seville
1989 Fleetwood Coupe
1989 Sedan deVille
1992 Fleetwood
1992 Coupe deVille
1992 Sedan deVille
1993 Sixty Special (Ultra)
1994 Fleetwood Brougham
2015 SRX

Phil Weber

#9
I have a scanned copy of this EFI manual for the 1975 and 1976 models . If anybody would like a copy let me know.

Phillipweber@optusnet.com.au

Phil

bcroe

#10
Quote from: Phil WeberI have a scanned copy of this EFI manual for the
1975 and 1976 models . If anybody would like a copy let me know.     
Phillipweber@optusnet.com.au      Phil   

That is the book I most recommend for the 75-79 Cad EFI.  Part No. 1099984
Cat No. S-1453.  Several are on Evil Bay right now.  My preference is to get the
actual book. 

I got out the test ECU; is the post office open during the eclipse?  Bruce Roe

stevehansford@comcast.net

I have the diagnostic manual and have followed the decision trees down to the final option of replacing the ecu. Guess I should have gone the last step.
Mr. Roe , I will gladly pay for all the shipping and any service charge for the use of the test unit . I think the Post Office is open it's only an eclipse.
Would you be willing to test  our unit again to see if  another anomaly would show up? Also, we had a question about the model # 160339 ecu. When looking for a replacement  that model is listed as a  "California" model. This vehicle was delivered new in Ohio. We wondered if that made any difference and if any other model #'s would work just as well. Thanks again to everyone. Haven't thrown a wrench yet,but we have severely tested our frustration tolerance.
Regards,
Steve #30486

stevehansford@comcast.net

Sorry, that CA model # is 1608339.
Regards,
Steve 30486

stevehansford@comcast.net

sorry, again.  1608339 is the 49 state application.  Was wondering if 1608340e cal,1608822 c cal/e fed,or 1608823 e cal would be acceptable substitutes?
Thanks in advance.
Steve 30486

bcroe

#14
I sent you my special test ECU via USPS, which should resolve if indeed
your ECU has developed another problem. 

There are several numbers for the 500 ECUs; Cal or Fed, new or repaired. 
On my test set they all measure the same; I consider them completely
interchangeable.  I think they used all those numbers to make the EPA happy;
in fact that EFI measured far cleaner than any of my cars with a carb on the
same engine.  It was even cleaner than its (cheaper) 1980 replacement,
the throttle body 368, so a few of the old system were sent to Cal that year. 

Bruce

stevehansford@comcast.net

Thank you very much again Mr. Roe. You are  an invaluable resource of info on these engines. Searching for a replacement ( or 2) if ours has a gremlin
Regards,
Steve 30486

V63

I would verify that the fuel is fresh and not stale!

It's also good practice to add 2oz of marvel mystery oil per 5 gallons of fuel if your state adds alcohol.

Fuel pump failure will result if you do not.

I have a few of these systems for parts.

bcroe

Quote from: V63I have a few of these systems for parts.   

Some of the owners using them would like to find spare ECUs, if you have
them.  Esp, for 500s.  I just fix them.  Bruce Roe

stevehansford@comcast.net

" Blues update"  Mr. Roe sent us his test ecu for an experiment against ours.
This car has never run  like this in the 5 years we have owned it. Near Perfect!
Unbelievable. Starts, runs, and shifts like it should. No stalling. Good power. Hot starts - not a problem.
Why our ecu runs to lean is the mystery. Have to find another one.
Thank you Mr. Roe for letting us use your test unit and all your valuable information.
Thanks to everyone for your suggestions to this problem child of a car.
Hopefully we can get to the finish line, finally.

Regards,
Steve30486