BodybyFisher

1995 Eldorado - Racing Idle - ISC Motor

73 posts in this topic

OldCadTech and BodybyFisher, I ordered the standard motor products SA4 (not economy type-SA4T) before I saw OldCadTech's comment on the Walker unit.

They ran about the same price and the Standard Products comes with the plunger installed by the looks of the picture, same as Walker.

The bracket does not matter since I have two for the Eldo application. Its the same Std. Prod. ISC  offered by rockauto but this one had free shipping. The application list was correct for the 92 Eldo Touring 4.9 engine.

 

Anyway, I determined that both jumper harnesses were good. So that eliminated the harness variable and possible lack of 12v power. I have not touched the idle-air adjustment at all and coincidentally, about three days ago, the car ran excellent over several run and park- starts and stops- all day. This was with the original ISC motor (not the junkyard one) and all other original settings and TPS unit. That was a fluke, because the next day(s) it was stuck at high idle,including today. This leads me to think that I should not touch the idle air screw. I can disconnect the battery and reconnect in order to force a zero setting and do an idle learn as needed after installing the new ISC.

 

I also did the 'palm rap' test twice before I removed the ISC for testing the harnesses etc.. The PCM passed as it absolutely did not cause any variance or interruption of the (high) idle.

Using the ignition on (engine off) and ignition off procedure, The junkyard ISC  motor did run and ratcheted-plunger did not move-only jiggled, after the ignition was shut off. This was true under both jumper harnesses.

The original ISC unit was dead under both jumper harness tests. Later I did a post-mortem on the original ISC and found nothing wrong inside- same as the first time I opened her up for a clean and lube. I then placed a 9 volt battery onto the motor electrical leads and it was stone dead. I did not try that with the junkyard ISC because it was in the garage. (lazy me).

So, I hope to be successful after installing the new Standard Products ISC.

Only thing I am aware of is to make sure the plunger is exactly the same length as the other two ISC units I have that measured the same. That would be my standard measurement.

Any tips would be appreciated so I don't make some silly oversight. I also am  assuming the original TPS unit is OK as it stands. I have spares and have read about how to install and leave loose in order to set, but I don't quite understand the underlying mechanics with this thing in order to get brave with it. That TPS comes off easy enough but its installing and correctly calibrating that might get CRAZY !

Thank you !

Arriving May 23 - May 25

 

Standard Motor Products SA4 Idle Speed Control

Sold by: bestdealautoparts

$50.48

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Put the plunger at the same length and you should do good.  Once it's in you can check the gap.  

Given that these cars are getting older, I like to clean the connectors with electrical contact cleaner.

You did a great diagnosis job, I am sure it will run terrific.  

I am sorry I didn't get to help you more, I am going through major life changes and my focus is elsewhere.  That is why I lured @OldCadTech into this his expertise is a valuable asset to caddyinfo and I want to thank him. :grouphug:

Can't wait to see the results


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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BodybyFisher, you are very humble and I truly appreciate your  valuable help ! You have been extremely helpful and there is no need to apologize. Short of being present and physically doing this repair, you have contributed expertly, patiently and professionally to this equally humble recipient of CaddyInfo help.

 

Yes, I am equally grateful to OldCadTech ! My fingers and toes are crossed !!!

 

I will update much later..

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13 hours ago, the gold2 said:

BodybyFisher, you are very humble and I truly appreciate your  valuable help ! You have been extremely helpful and there is no need to apologize. Short of being present and physically doing this repair, you have contributed expertly, patiently and professionally to this equally humble recipient of CaddyInfo help.

 

Yes, I am equally grateful to OldCadTech ! My fingers and toes are crossed !!!

 

I will update much later..

Just trying to help a fellow caddy lover,.thank you, impressive work sir.

You know I have joined a few Cadillac groups on Facebook and it's a raw free for all.  Members insulting other members for their suggestions people in "Cadillac lovers" groups dumping on Cadillac, it is the wild west.  Over The last 2 weeks I have tried to explain that everybody has different experiences but no suggestion should be criticized, and that it's brainstorming.  I'll be paring down my group memberships, it's frustrating 

This thread is an example of everybody contributing to a final goal, Logan, brought up the ECM tap test and his experience.  Brainstorming is powerful

 


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I hope you all can see this you may not be able to, look at the ridiculous replies to this guys question 

https://m.facebook.com/groups/218482641508701?view=permalink&id=1570291949661090&fs=1

 


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I have found Sonnax to have good info and tech reports

http://www.sonnax.com/units/221-4t80-e

 


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Thanks BodybyFisher, I bookmarked sonnax.

 

That facebook forum is really wild. Basically when I pose questions on forums, I like to explain my process and follow up because it contributes to the archives. Often times folks can just research and find some good info bits inside threads that prove positive in correcting their issue. That in turn reduces the number of repetitive threads.

I normally do research first in order to find solutions and/or get a frame of reference (education) before asking questions. Otherwise help from experts may fall on infertile ground !

 

Once again thank you for your valuable contributions to Caddyinfo !

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Thank you, that Sonnax link was meant for another thread, but good that you.saved it, it's a good resource.

What do you do for a living?


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Property manager, basically I wear many hats ! Science background from Univ. days.

Thanks.

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26 minutes ago, the gold2 said:

Property manager, basically I wear many hats ! Science background from Univ. days.

Thanks.

Our fields overlap, I was an MAI commercial real estate appraiser for 25 years, appraised apartments, office buildings, malls, retail, land, industrial and other types.  I taught cash flow analysis software at NUT.  <<< example it should be NYU

I am really disliking the continuous spell checking on my new galaxy S7, it insists it knows better.

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Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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@BodybyFisher I'm thinking those auto-corrects should be eliminated from every phone. THEY SUCK :excl: :P

 

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THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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I'm sorta, kinda in property management......


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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Interesting coincidences ! I am a small time operator. Nut'in fancy. I do grunt work, paper work, legal work, rental work, work-work,fix it work  etc...

 

I got the new ISC this afternoon. Looks like I might have to fit in the 'pintel' from one of the other ISC only because the new pintel is very long...

 

The new ISC's plunger reaches to the top of the old ISC's pintel threading as seen in the picture. Otherwise the dimensions of the new ISC are exact. It even came with an unexpected correct mounting plate, different from the sales picture. The old ISC is pictured with the mounting plate attached.

isc new comparison.jpg

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That's not right, measure and use your own pindle...


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I agree with @BodybyFisher , also needs to be retracted and gap set when installing. 


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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Alright guys, thanks. I won't be able to begin work until maybe Sunday or next week.

I will update.

 

P.S. I agree that auto correct is a real pain. I have it on my tablet and it causes some weird shenanigans!

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May 24th 2017 update.  Murphy's Law !!

 

Here is the sequence of events.

 

I disconnected the battery and installed the new ISC that had the pintel length set exactly as the original factory setting was.

I reconnected battery and ignition on (engine off) entered diagnostics to ECM override ES03 (ISC motor) and then pressed the cooler button on the dashboard hvac control.

Climate control went from '50 to '00' as per FSManual 6E-C2-15.

The ISC plunger did not retract by itself but after I retracted the throttle lever and pushed gently with my finger, the ISC plunger retracted nicely.

I then disconnected the harness.

At this point I measured the gap between the pintel and throttle lever to be wider than 0.03". More like approximately 0.90" (mind you this is the exact same pintel length as the factory set old ISC.)

The second throttle lever was indeed resting on the Idle-air screw, as per FSM.

I set the gap at 0.03" (see pictures)

 

I then buttoned up the air filter assembly etc. and began the Idle Learn procedure as outlined by OldCadTech. What I did not do was set the idle air screw to 525 rpm. Why? Because nobody has touched that screw and not long ago, the old ISC motor came to life and the car operated beautifully. Spot on idle, no codes, no sailing.

So as commented earlier, I assumed the idle is set to factory criteria.

So after reaching the stage of the Idle learn that the engine is turned on, it started up at around 2K briefly and lowered to about 1100 rpm. I let the car reach operating temperature after 13 minutes (65 deg. F outside). No codes were thrown. The idle did NOT go down to anywhere close to 525 or 900 in Park.

I shut engine off. Started it up again and it began idling at around 1300 and soon threw the Check engine dummy light.

 

So, I decided to rest the pintel back to the same length as the factory set old ISC after disconnecting the battery.

Reconnect battery and Went through the idle learn routine. No difference. It still idled high at around 1100 and threw the dummy light and same old ISC code (no other codes).

I decided to disconnect the battery and try the relearn again. No difference. It still threw the dummy light and ISC code.

I then decided to enter diagnostics- ignition on (engine off) and selected ECM override ES03, hit cooler button and tried to retract the ISC as before.

It would not budge.

I tried this routine from scratch again and could not retract it like the first time. It would not budge. Basically it is between full extension and retraction and the throttle lever sits on the pintel head with engine off. Presumably normal.

This begs an academic question. How critical is the gap between pintel and throttle lever? Does the PCM, TPS and ISC figure it out as long as when fully retracted the pintel does not touch the lever? (note the FSM just directs to not allow the pintel to touch the lever at full ISC retraction but does not declare a gap measurement).

Secondly, am I correct to assume that the factory set idle air screw should not be tampered with since it worked fine not long ago and has not been tampered with ever?

So what do you folks think?

I personally am inclined to swap out the PCM with a good spare and see what happens.

 

What is strange is that after installing the new ISC I was able to retract the plunger and I could feel the pulsing of the ISC at my finger tip. Afterward, there was no pulsing and the plunger would not retract under the same  ES03 conditions.

 

I also tried entering the diagnosis tree routine FSM 6E-A-69, E007 (and E006) ECM output. This showed a cycling between "Hi and Lo" but I could not see the ISC physically moving nor could I finger the pintel to move during this test.

 

Afterward, lastly, I tried the idle relearn as per factory manual and still no luck.

 

So I am back to the silly drawing board.

 

Help? opinions?

 

PS the retaining nut at the base of the new pintel just keeps the pintel snug and does not interfere with the retraction stage.

 

Thank you !

 

 

DSCN6208.JPG

DSCN6209.JPG

Edited by the gold2

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First thing I would do is take the nut off. Main reason is the nut will move even when the ISC is operating as designed. You are jamming that nut down against the smallest part of the plunger also. If the ISC needed a jam nut, there would have been one on the original design and on the replacement parts as well. Secondly, I would use the old pintle or at least I would remove them both and see if they are physically the same length. Was the pintle loose or wobbly, making you think it needed additional support? Do the pintles screw in easily or is there enough resistance to keep it from turning? There should be enough rotational resistance to hold the pintle and it should require a tool to move it.

The idle learn and the minimum air setting are designed to allow a threshold to compensate for throttle plate build-up and throttle shaft wear. The ECM is responding to inputs and for some reason "thinks" that no load idle speed needs to be at 1300 rpm. Did you have A/C on or move the steering wheel during any of the tests, if so, turn the A/C off. There MUST NOT be any load on the engine during the relearn.

I can't stress it enough the minimum air idle speed is an important setting. The engine MUST stay running. The idle learn MUST be followed exactly, including the cycling through of the onboard diagnostics OR the idle learn will FAIL. The ECM could be at fault and since you have a USED replacement I would swap it out only to see what happens. I always hesitate to recommend using old parts to test with though, simply because of too many false positives and/or false negatives. I've been caught too many times in that scenario.

 


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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10 hours ago, OldCadTech said:

Secondly, I would use the old pintle or at least I would remove them both and see if they are physically the same length. Was the pintle loose or wobbly, making you think it needed additional support? Do the pintles screw in easily or is there enough resistance to keep it from turning? There should be enough rotational resistance to hold the pintle and it should require a tool to move it.

Hello OldCadTech, you are correct about the jam nut. I figured as such that if it were needed it would have been part of the original set up.

Curiously the internal threading of the plungers seem to be a sort of heli coil. It appears to have a tighter fit deeper into the plunger.

The pintel that came with the new unit was too long. A friend who is very good with detail, used a mechanical caliper to precisely measure the original pintel length and dimensions as it appeared on the factory setting on the old unit and cut the longer pintel to size allowing enough thread to enter the plunger exactly as the original had.. That exact length did allow for some rotational tightness inside the plunger (without a jam nut). The gap at the factory setting later turned out to be  more than 0.03" with the ISC fully retracted.

(We removed the original pintel from the old unit as well using a heat gun on the pintel head. It was on there tight. Maybe with loktite.)

I unscrewed the new pintel to reach the 0.03 gap, and it was then kind of loose inside the pintel. Ergo the jam nut.

The original pintel was also  tried for fit and it screwed in very finger tight just shy of any gap at all during that first  ISC full retraction. I would have had to use a tool to tighten it another 3-4 threads and I did not want to commit to that because it is a very tight rotational fit at that point and,  at that point,  I would have to hold the plunger shaft body with a protected  plier while tightening the pintel so as not to put alot of tension on the plunger and internal gears. (my reasoning).

 

The unusual thing is that, subsequently,  I could not get the new ISC to retract using the method outlined previously. THAT boggles me.

 

I followed the idle learn procedure methodically and the AC was not on nor did I touch the steering wheel or throttle pedal. I ran it 13 minutes in Park after the final routine and operating temp was reached (190F).

Edited by the gold2

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In the photo above the feeler gauges, a couple of posts back, it appears the plunger is retracted.You should be fine as long as the pintles are the same length.

I'm not too concerned with the gap measurement, but the pintle should require a considerable amount of force to turn. it is very difficult to relay in writing the torque amount because there is not a torque specification for it but yes, you would have to hold it very tightly or do it while it is mounted on the t-body.

Once again, :fighting0030: :paint2: if you have the ISC off the t-body start the engine and make sure the engine will idle. Cadillac tech support ALWAYS wanted 525 RPM as the magical number but as long as it idled "somewhere" close to that, it worked in the real world. If I remember correctly you stated that the vehicle has 144000 miles on it. It is possible the throttle shaft is wobbly causing TPS inaccuracy.

I too am perplexed as to why the initial installation worked but once the key was cycled it came back with the code and high idle. BUT, you must verify everything is operating as designed. With the ISC removed look at your TPS again, what is the throttle angle at closed throttle?


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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Hi OldCadTech, guess what ! Possible progress !  BTW the mileage is only like 53K miles Not in the hundred thousands...1992 Eldorado TC 4.9 liter engine.

OK, so yesterday I disconnected the battery and let it sit overnight and some...I also pulled 'ON' the headlamp switch for a minute to discharge some capacitor I read about in this forum or other Caddy forum...

So, late this afternoon I decided to have at it again with the idle learn.

I reconnected the battery.

This time I started up the engine momentarily in order to allow me to turn OFF the AC- for certain !  (as we know, the AC goes on automatically after the battery is reconnected).

Curiously this time upon first engine on, the idle did not surge way high to 2K and stay at 1500 but gradually went down to about 1100...BUT I shut the engine off quickly.

 

I waited over a minute and began your idle learn procedure using 40 second intervals rather than 20 second minimums.

Upon engine 'ON' ,it behaved nicely and shot up to about 2 K RPM for a second and shot down to around 1100 and slowly settled around 1K rpm as the engine idled for 14 minutes in PARK.

 

I shut engine off and waited about 2 minutes and then turned the engine ON again. It behaved similarly and was doing well. I took it for a short spin around the block several times and it was not sailing and the RPM would dunk drop and settle the idle to around 900 RPM after coming to a stop in DRIVE. (I recognized this as normal and good)

Later I parked and shut off engine and waited a couple minutes. Turned it on and it behaved well. In Park at operating temperature it idles at 1K steady. In Drive at op temp and at a standstill it is at around 900 RPM.

Its been so long since I drove it that this seems about correct with what I recall from this car' idle and RPM behavior....

 

The pintel remained as before with the jam nut and the length set same as the original factory stetting.

 

I will see what tomorrow brings since I have been down this road before with a full day of good behavior with the old ISC followed by Check engine light etc...

 

I was thinking of using a tiny spot of white laquer paint at the back of the jam nut in order to keep it fixed so it does not vibrate loose.

 

If all goes well for an extended period of time, I may brave installing the original pintel once I get the 'penny tool' and feel confident that the problem is resolved.

 

We shall see what tomorrow brings !!

 

Picture of the original pintel. You can see the cleaner threads that were inside the plunger and the darker 9 external threads making up the standardized (for me) length of the pintel.

DSCN6210.JPG

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900-1000 RPM is great!

Be sure to test the ISC with the A/C on. Set the A/C to 60 and manually select low fan. Let it idle and watch the ISC. It should increase idle just before the A/C compressor engagement and reduce idle just prior to A/C clutch disengagement.

Hmmm, sorry, don't know where I got the extra mileage at :blush:

That's all good news, hope it stays "fixed" ...

Edited by OldCadTech

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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For future reference the procedure for draining transient voltage is to disconnect both battery cables from the battery and briefly touch both cable ends together.

The battery being disconnected for over 30 minutes will do the same as touching the cable ends together. 


THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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