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1990 Deville, Running rough and lack of power.


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I have a 1990 Deville 4.5L 4D sedan I picked up about a week ago, the car has been garaged most of its life and the mileage just rolled over 101,000. Before I picked up this car I know it had been sitting outside a garage for about 6-9 months, and was filled with bee's. Just before I picked up the car they replaced the distributor, spark plugs and plug wires, replaced the main gasket on the bottom of the transmission, changed the tranny oil, charged the battery, and topped off the other fluids. I have run a few oz of seafoam through the brake booster vacuum line to help clear out the cylinders and what not. The the car runs very rough still, it has a very rough idle from cold start and has very little power at low RPMS. Occasionally while at speed it seems to have power at low RPM's, not too often. It had about 5 gallons of 6 month old gas in it when I picked it up, I added some gas treatment to extend the shelf life of the gas, and filled it up with new gasoline. I think im currently getting about 8 mpg with the way its running, half town half freeway driving. The body and interior are in great shape, and for only 101k miles on it I feel like I can breathe some life into this car and bring it up shape.

I pulled the codes off the diagnostics on the console and got as follows:

..e.

E30

E32

E52

E98

..f.

F47

.f.f.

F47.

I looked up a code index and didnt really know what they all meant, maybe you could give me some pointers. I may be American, but this car is Foreign to me. on top of it running very rough It seems to have some electrical problems, The drivers windows doesnt move, and the other 3 windows will only roll down but they will not roll up without gently pulling on them and guiding them up while you hold the button down. It seems to have some electrical drain somewhere, like all the components are getting enough juice. Even the cigarette lighter can only seem to get the lighter to heat up half way. I have disconnected the stereo, as I was told that was draining the battery and it might kill the battery over night.

Im new to the forum and was hoping to get some pointers here, thanks!

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:welcomesmiley:

P030 (E030) ISC RPM out of range
P032 (E032) Open MAP Sensor Signal
P052 (E052) PCM Memory Reset
P098 (E098) High RPM P/N to D/R Shift Under ISC
A047 Low Refrigerant Charge

I would replace the battery. Be sure and get a 1,000 CCA premium battery. The battery is the worst part to try to economize on with an electronically controlled car.

You should also mark which codes are C (CURRENT) and which are H (HISTORY) next time. The E52 just means that the battery has been disconnected recently. The MAP sensor is unplugged, which can cause some or most of the problems you see. The MAP sensor is under the beauty cover in the center of the manifold on the back of the engine near the throttle body. The rough idle is because the idle speed stepping motor or the ISC sensor isn't working properly.

The E98 means that the car was shifted into gear while the engine was racing, apparently because the idle speed would not come down because the idle speed control (ISC) stepping motor was sticking, as the wording of the code interpretation says. That's a big no-no, as you know. If the transmission is OK, you can ignore it. But if the RPM won't come down, don't shift into Drive anyway, just wait and work the throttle, under the hood if necessary.

So, if you fix the MAP sensor and the ISC stepping motor, and have the Freon in the A/C looked at, you may be good to go. At any rate, you should do this and see how the driveability and the codes look.

Be sure and change the coolant and oil, check the power steering fluid, and such too.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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The open MAP sensor code is most likely causing the rough idle and poor fuel economy. It also sounds like something is going on with the idle speed control motor - poor contacts on the closed throttle switch portion of the ISC. There is a lot of information in the archives on the idle speed control motor.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Thank you very much for info, I'm getting the oil and radiator flushed today and fixing the map senor, battery replaced and alternator checked. As for the ISC stepping motor, ill have to figure that out after I get this done first, though the transmission is in good shape so im not sure how worried I should be about it. Ill report back, thank you for your help.

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  • 2 weeks later...

Update: I got the all the fluids changed and flushed, all the old gas burnt up at this point. But on my way to get the fluids flushed the car lost all power, and now only seems to just barley coast along. With a flat stretch the car can barley get up to 55 mph, and hills are pretty much out of the question. I'm not sure what happened, but im feeling like the engine is just flooded like crazy and can barley burn up the fuel that the system is putting in, based on the fact its just gulping down the gas at this point even while barley stepping on the gas.

Im still working on getting a new MAP sensor, its simple to locate and change and I tested the wires for power to make sure it was getting juice, but I have to wait about a week for that part to arrive. Assuming this wont solve half of the problems, im not sure where I should start with the ISC stepping motor. Should I just pull the thing off and inspect it?

Any other idea's would be helpful at this point, this poor motor has less power than a 1988 Toyota Tercel I use to own.

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Run the codes again, this time after driving the car and parking it but before turning off the key. Mark down which are CURRENT.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I would definately see what the MAP does. Waiting sucks unless you have another vehicle. Another possibility I am thinking of is a weak coilpack. That uses 1 for the system I assume, The question I have is do you have the coil pack in the top of the distributor? They seem to be a fairly common problem in that setup. I am rusty though because it has been awhile

GM FAN FOREVER

Nice, clean, luxury= fine automobile

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Weak/bad coils can do that as rockfangd says. I had two of them go out and the car would barely run. Didn't have the money to fix it immediately and fouled my cat. Anyhow, so yeah, replace the MAP. Other things to check....Fuel Pressure Regulator, Coolant Sensor, O2 Sensors, vacuum leaks (especially on the FPR), stuck open injector. Best of luck.

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I didn't ask this the first time, but I dont know how to tell which codes are history codes and current codes?

When you see the code listed, for some cars, it may be of the form

PCM E032 CURRENT

or

PCM E032 HISTORY

For others, it may be abbreviated,

PE032C

or

PE032H

Look for a C for CURRENT or an H for HISTORY after the code. If there is nothing after the code in your readout, it is a HISTORY code.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I didn't ask this the first time, but I dont know how to tell which codes are history codes and current codes?

When you see the code listed, for some cars, it may be of the form

PCM E032 CURRENT

or

PCM E032 HISTORY

For others, it may be abbreviated,

PE032C

or

PE032H

Look for a C for CURRENT or an H for HISTORY after the code. If there is nothing after the code in your readout, it is a HISTORY code.

This is not valid for a 1990 car. There is not a driver information center. That era displayed the codes on the fuel data center and if my memory is correct, only "current" codes were displayed.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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KHE - thanks, that was needed. I have no experience with pre-Northstar OBD I. I was reaching, based on posts I have seen in the past.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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  • 2 weeks later...

I cleared the codes and got the current codes. Current codes are E30 and F47...the car is in the same shape. I decided to unplug the map sensor to see if that would change anything, the car ran just as crappy. I plugged the map senor in, cleared the codes, and now its back to only showing E30 abd E47, this is after is of course after running to operating temp and driving around the block. So im not sure if it is the map sensor or not, more confused than before.

The car engine is really is great shape, the vacuum lines are in excellent shape no cracks or leaks that I can tell.. All else I can tell is that is running super rich and its getting horrible gas milage, probaby around 6-8 mpg. I wonder if one or several of my fuel injectors are leaking bad or something is allowing too much fuel into the chamber... only got 101k miles and was garaged most of its life.

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P030 (E030) ISC RPM out of range
P047 (E047) IPC - PCM Data Problem

The E030 code shows a problem with the stepping motor that controls the idle speed. It could be sticking or something in the ISC, throttle linkage, or even in the throttle body may need cleaning.

The P047 is more serious. It means that there is a problem with the car's network between the IPC (instrument panel cluster) and the PCM. Check for loose wiring under the dash, and pay particular attention to the purple wire, which is the color used for the network data line. Also check the wiring harness under the hood, particularly the two connectors on the PCM.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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hi muddx,have you solved your problems yet? I dont get onto this site as often as I would like. I still own a 90 seville which I think will be exactly the same mechanically as yours.The computor on these is the most user friendly I have ever seen- that is probably why they changed them .Information is displayed as you know on the ccdicpanel

and is very comprehensive.

You can check the isc motor very easily.Go to ecm overrides,press the hi button and go down to es03isc motor control.If you push the warmer button it will fully extend itself and if you push the cooler button it will fully retract.At full extension you should get a reading on the dash of 13.4 I think. You go into ecm data to get this while still in the override.Just push the off button to let you go into the data readout.See how you go with that .

They are great cars ,not much beats them for comfort on a trip.

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  • 2 years later...

I didn't ask this the first time, but I dont know how to tell which codes are history codes and current codes?

When you see the code listed, for some cars, it may be of the form

PCM E032 CURRENT

or

PCM E032 HISTORY

For others, it may be abbreviated,

PE032C

or

PE032H

Look for a C for CURRENT or an H for HISTORY after the code. If there is nothing after the code in your readout, it is a HISTORY code.

This is not valid for a 1990 car. There is not a driver information center. That era displayed the codes on the fuel data center and if my memory is correct, only "current" codes were displayed.

I believe you are incorrect I own a 1990 and a 1989 Eldorado and both show history and current on the codes.

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My question is - why did "they" replace the distributor? If the computer was not in set timing mode when it was installed and the BASE timing was set it is probably retarded severely, which could explain low MAP, low power and rich condition.

Where was the bee nest? Has any one checked the air filter housing for critter nests? Check the injector harness for rodent damage as well.

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 didn't ask this the first time, but I dont know how to tell which codes are history codes and current codes?

When you see the code listed, for some cars, it may be of the form

PCM E032 CURRENT

or

PCM E032 HISTORY

For others, it may be abbreviated,

PE032C

or

PE032H

Look for a C for CURRENT or an H for HISTORY after the code. If there is nothing after the code in your readout, it is a HISTORY code.

This is not valid for a 1990 car. There is not a driver information center. That era displayed the codes on the fuel data center and if my memory is correct, only "current" codes were displayed.

I believe you are incorrect I own a 1990 and a 1989 Eldorado and both show history and current on the codes.

The car in question is a Deville, not an Eldorado. The Devilles of that era displayed the codes on the fuel data center. There was a method to determine history codes from current codes but it has been so long since I worked on one of these cars, I can't remember.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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