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93 DeVille
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9 Posts
Discussion Starter · #1 ·
Hello,

I just bought a 1993 Deville 4-door today, has 168,300 miles on it do not know it's history or have a service manual.

There is some issues I found that I need to correct so if anyone has the answers would help me focus in to the root causes.

1. Random - the air pump for the leveling system comes on for a short time, maybe about 1 minute, maybe every 1/2 hour or so. This of course will drag battery down.
I put a battery tender on as this will not be a daily driver but that pump coming on forces the tender to be in charge mode most of the time

General cause of this ? - slow leak ?
If so what normally begins to leak ?
If the fuse is pulled for this does it have any negative effect in driving or cause some controller a problem ?
Best way to find the leak ?

2. Using a OBD-I scanner I find both BLMS way up about 160 which says way lean about 20%.
Also the 2 02 sensors reporting a best a maximum of 0.240 mVolts, far from a perfect 0.450 mVolts. Both head have same values for BLM, INTs, O2s and injector pulse width so problem is common to both.

Common cause ? - is there a valve on fuel rail to put a test pressure gauge on, of so where is it ?
Where is the fuel filter located and is it easy to replace ?

3. Once that is resolved I will cook up a custom tune. Where is the ECM located and how to get it out so I can replace the Eprom with a custom tune ?

4. inside car smells like oil fumes ? - common root problem and if so what tends to be the cause ?
Maybe it is a water/antifreeze leak burning off engine ? - no leaks seen on ground, the surge tank was empty

Thanks
 

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1993 Coupe Deville, 2009 XLR-V 1 of 6 Crystal Red
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2,484 Posts
First step, find a FSM by Helms on ebay. Your best investment if you plan to keep this car.

1. Get a spray bottle with soapy water and spray on lines, fittings, rear strut shocks, and around compressor. Most likely it will be the boot on the shock, but reports of compressor and lines leaking also.

2. You don't need an external scanner for this car, it is already built in. Read the sticky at the top of the page. The FSM is very detailed on this.

3. You'd be wasting time doing that. There is no documented evidence that this has been done successfully. It is a luxury car, not a performance street rod.

4. Most likely the heater core. Surge tank empty? Not good, how low is the radiator? Check to see if the heater hoses have been bypassed at the firewall. How bad are the valve covers leaking. It's possible the fumes you are smelling are from the oil seepage on the exhaust manifold burning off. Common problem at this mileage. While you are under the hood, check for leaking trans cooler lines and engine oil cooler lines.
 

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93 DeVille
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9 Posts
Discussion Starter · #3 ·
Thanks for the reply

Guess I will have to jack car up and play the game to find what causes the air pump random on and pressure issue
I have nothing to compare to as to heights but it seems back sits lower then front and that is with nothing in trunk or back seats.

It is not a full OBD-I scanner DIC has but a simple DTC code reader which cannot diag exactly the engine and trannie is where there is about 50 parameters (PIDS) that can be scanned or recorded while driving and how I was able to find that the ECM is adjusting for 15-20% too lean with low 02 sensors readings backing up the BLMS so high


I do custom tuning as a business and there can be performance gains as older ECMs being slow and less feedback does not adjust to elevation being there is no MAF and is speed density, or for fact today's gas has at least 10% ethanol and higher now that the feds have approved E15.
Tune is for correcting how a 170,000 mile engine is functioning.

Passenger floor is dry and heater not even turned on but I assume it can be both oil and water leaks but suspect it is within the engine bay.

Thanks
 

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99STS,2004 Jeep Liberty Renegade,98 Deville RIP
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on an obd1 car, your scantool should be reporting a over .45 and under .45 for each o2 sensor about 14 times a minute, this would indicate a proper running car, as far as the block learn mode, it seems to working in lockstep, i think in this case you have two very lazy o2 sensors and should be replaced. i would also clear the fuel trim and reset it and see where it takes you. also does your scantool report the car in closed loop or open loop?
 

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93 DeVille
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9 Posts
Discussion Starter · #6 ·
This forum is not allowing me to post images so cannot show all the PID data but the BLMs and INTs were reset and go back up on relearn.

ECM is going into closed loop and fuel learn is toggling on/off as it should along with MAP, water and MAT temps normal

It is reporting 2 O2s but other post says there is only one so anyone have a image of exhaust makeup to where 02(s) are ?
Yes ECM would bias 0.450 mVolt for part throttle but best seen is about half of that.

For now have disconnected the wiring to the leveling pump as it was coming on about every 5 minutes for on time about 20 seconds even with key off. At least saves battery until I can track leak down.

Problem as to idle above 1,000 RPMs found, whoever owned the car, who knows but there was a lot of gravel stone on top of engine and a rock was preventing throttle linkage by TB not to close.

TB clean, so is aircleaner and no leak.
Measured fuel rail pressure and reports as per stock is 35 PSI at idle, about 44 PSI under throttle.
 

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2011 Crown Vic LX, 2009 Chevy Malibu 2LT
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Those numbers aren't necessarily telling you that the O2 sensor is defective, they may be telling you that the engine is running very lean - so lean that it's beyond full control of the pcm (128 is baseline, 160 is the max block learn, your test shows the PCM is bouncing off of that limit and is still unable to bring up the O2 voltage). You sure there's no large vacuum leaks? Check for anything that could lean to a lean condition: large vacuum leaks including the intake manifold gaskets, poor fuel pressure, leaking exhaust manifold, etc. ) O2's on pfi engines are quite reliable, though failure isn't out of the question.
 

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93 DeVille
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Discussion Starter · #11 ·
If the AFR was as lean as BLM and O2 reports engine should have knock or other issues and it does not

I found the O2 is close to rear exhaust manifold by firewall



If intake type of leak like when at idle when TB butterfly is almost closed there should be loss of vacuum where MAP at idle is right on and steady at 35 KPA



Guess I can use my smoker and see if there is any air/exhaust leak but if O2 is being fooled exhaust leak would have to be upstream of O2 which is already close to engine manifold

Slanting to fuel injector issue as rail pressure is correct or high percentage of ethanol
 

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93 DeVille
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Discussion Starter · #12 ·
Problem is focused down to the exhaust donut where the pipe couples to back exhaust facing firewall

The 02 sensor is right there, over time with engine and exhaust flex leak occurs and pulling in air which then fools the O2 sensor

 

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Hey, 93Caddie, it is a year later. I wondered if you ever pulled the ECM and reprogrammed the memcal? Do you have tables for the 16132240 ECM (the 91-93)? I put the 93 4.9l in my Fiero with the ECM and am interested in tuning it. Have you looked at TunerPro? I'd be interested in comparing notes.
 

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Deville
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288 Posts
Cool software what are you using? and is it PC or MAC ?

Any ways easy to remove ECM. Just pull down the Right side lower hush panel and take off one 10mm nut , lower ECM a bit remove conectors.

There's a cover on cpu for Memcal 2 different styles remove cover to see yours
 

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Deville
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onecool said:
Cool software what are you using? and is it PC or MAC ?

Any ways easy to remove ECM. Just pull down the Right side lower hush panel and take off one 10mm nut , lower ECM a bit remove conectors.

There's a cover on ECU for Memcal 2 different styles remove cover to see yours
okokok
 

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'93 SedanDeville 60 Special
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561 Posts
Hey, 93Caddie, it is a year later. I wondered if you ever pulled the ECM and reprogrammed the memcal? Do you have tables for the 16132240 ECM (the 91-93)? I put the 93 4.9l in my Fiero with the ECM and am interested in tuning it. Have you looked at TunerPro? I'd be interested in comparing notes.
Yes after seeing engine issues with the OBD-I scanner I did a smoke test and found the exhaust coupler near 02 sensor leaking, replaced the gasket and replaced the 1 O2 sensor.

After ECM relearn was done with those issues fixed did a testrun with OBD-I scanner in record mode and analyzing that I did a custom tune.
1 issue as finding new 32K E-proms to burn a new tune into but found some but getting harder to find vendors selling E-proms.

Engine ran much better with fixes and custom tune, fuel mileage much better and engine performance gain was good.

I have owned Tunercat since mid 1990s so I use that for all tuning I do of GM cars/trucks from 1984 to present.

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The scanner I use and also sell runs off your MSwindows based laptop.
Works for most nameplates for all years from 1984 to present.

Kinda a pain in ase but ECM is located behind the kick panel on passenger side, has a couple of bolts to mount to firewall
Once those are off ECM can be pulled down and then the Eprom cover taken off and E-prom unplugged to replace with another E-prom that tune is burned into.

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Cool software what are you using? and is it PC or MAC ?

Any ways easy to remove ECM. Just pull down the Right side lower hush panel and take off one 10mm nut , lower ECM a bit remove conectors.

There's a cover on cpu for Memcal 2 different styles remove cover to see yours
The scanner I use and also sell runs off your MSwindows based laptop.
Works for most nameplates for all years from 1984 to present.

Kinda a pain in ase but ECM is located behind the kick panel on passenger side, has a couple of bolts to mount to firewall
Once those are off ECM can be pulled down and then the Eprom cover taken off and E-prom unplugged to replace with another E-prom that tune is burned into.
 

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1993 Deville Sedan
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128 Posts
could you qualify what sort of specific changes you made to the e-prom and their effects??

curious to their effects; i'm personally interested in gas mileage
you would need a scanner, an e-rom, and a means to burn it (as well as know what changes you are making) if i'm correct


Yes after seeing engine issues with the OBD-I scanner I did a smoke test and found the exhaust coupler near 02 sensor leaking, replaced the gasket and replaced the 1 O2 sensor.

After ECM relearn was done with those issues fixed did a testrun with OBD-I scanner in record mode and analyzing that I did a custom tune.
1 issue as finding new 32K E-proms to burn a new tune into but found some but getting harder to find vendors selling E-proms.

Engine ran much better with fixes and custom tune, fuel mileage much better and engine performance gain was good.

I have owned Tunercat since mid 1990s so I use that for all tuning I do of GM cars/trucks from 1984 to present.

----------

The scanner I use and also sell runs off your MSwindows based laptop.
Works for most nameplates for all years from 1984 to present.

Kinda a pain in ase but ECM is located behind the kick panel on passenger side, has a couple of bolts to mount to firewall
Once those are off ECM can be pulled down and then the Eprom cover taken off and E-prom unplugged to replace with another E-prom that tune is burned into.

----------



The scanner I use and also sell runs off your MSwindows based laptop.
Works for most nameplates for all years from 1984 to present.

Kinda a pain in ase but ECM is located behind the kick panel on passenger side, has a couple of bolts to mount to firewall
Once those are off ECM can be pulled down and then the Eprom cover taken off and E-prom unplugged to replace with another E-prom that tune is burned into.
 

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1993 Coupe Deville, 2009 XLR-V 1 of 6 Crystal Red
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2,484 Posts
Yes after seeing engine issues with the OBD-I scanner I did a smoke test and found the exhaust coupler near 02 sensor leaking, replaced the gasket and replaced the 1 O2 sensor.
What brand and model scanner do you use or is the software for a laptop that is in the kit?

After ECM relearn was done with those issues fixed did a testrun with OBD-I scanner in record mode and analyzing that I did a custom tune. 1 issue as finding new 32K E-proms to burn a new tune into but found some but getting harder to find vendors selling E-proms.
Digi-key doesn't have them?

Engine ran much better with fixes and custom tune, fuel mileage much better and engine performance gain was good. I have owned Tunercat since mid 1990s so I use that for all tuning I do of GM cars/trucks from 1984 to present. The scanner I use and also sell runs off your MSwindows based laptop. Works for most nameplates for all years from 1984 to present. Kinda a pain in ase but ECM is located behind the kick panel on passenger side, has a couple of bolts to mount to firewall Once those are off ECM can be pulled down and then the Eprom cover taken off and E-prom unplugged to replace with another E-prom that tune is burned into.
So the Tunercat Kit with my laptop makes a scanner? And this works on a OBD 1 Cadillac?

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i'm personally interested in gas mileage
you would need a scanner, an e-rom, and a means to burn it (as well as know what changes you are making) if i'm correct
Yeah that:yeah:
 
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