Cadillac Owners Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter #1
I have a few irritating problems with my 1990 Deville (103,400 miles) such as:
  • Idles High/Rough/Erratic
  • When accelerating to higher speeds the car jerks violently (freeway driving)
  • When accelerating up to a higher speeds the car begins to jerk (stop and go driving)
One of the diagnostic code thrown is E098 - High RPM P/N to D/R in ISC Range. Can anyone help me figure what parts are going bad? :banghead:
 

·
Registered
Joined
·
16 Posts
Discussion Starter #3
This is another set of problems that just occurred :ill: It keeps getting worse and worse with this old girl. But, I love her to death so I'll do what ever is best to keep her running as good as she looks.

:cool2:
 

·
Registered
1990 Sedan Deville, 2000 Chevy Tahoe
Joined
·
29 Posts
I have a 90 Sedan Deville and as far as the idle issue, mine was a combination of vaccume leaks (3) a bad ISC? ( the black thing with the bolt that touches the throttle!!) and adjustment to the two upper throttle cables and lower cruise control cable. The way we knew it was with the cables is we could lower the idle by pushing down on the throttle with a screwdriver and this would depress the ISC and the car would idle down. But driving or hitting the gas would not bring down the idle. As far as missing on the highway ... I know NOTHING!!
 

·
Registered
Joined
·
77 Posts
The jerking during acceleration symptom could be caused by bad plugs, wires, or a bad distributor cap/rotor.

I had similar symptoms on my '96 Seville a year ago and 4 of the 8 plugs were missing the platinum pad on the ground electrode. A new set of 41-950 plugs cured the problem.
 

·
Registered
Joined
·
16 Posts
Discussion Starter #6
The "jerking" during acceleration was actually due to my transmission fluid being low. I took the car in this morning for a transmission service. This afternoon the mechanic called to tell me the transmission fluid was low and "burnt" and changing the filter/fluid likely won't fix the "jerking"/shifting problem due to the "burnt" fluid. Their trying to talk me into replacing the transmission, is this necessarry??

I'm ordering a ISC Motor online today and I'll check for vaccume leaks when I get my car back from the shop.

Thanks for your help guys!!
 

·
Registered
Joined
·
16 Posts
Discussion Starter #7
Ok, after all the headaches and stress a full tune-up with platinum plugs cured 99% of the problems. I no longer get the diagnostic code but my car doesnt pass smog :helpless:. I'm being told I need a new cam sensor which will have my car running smooth again. After replacing the ISC Motor, Cat Converter, Transmission Service, and full Tune-Up my car is still undriveable due to this sensor being bad. Can anyone tell me the procedure to chage out one of these sensors? I was quoted an estimate of $220.00 and speaking with the parts department at GM they told me the "cam sensor" isn't listed in their parts catalog :hmm:. Is this mechanic giving me some b.s. :suspect:? Well if anyone could help me discover which sensor is being called "cam sensor" when it is actually a Oxygen Sensor or TPS in the GM catalog I'd appreciate it. Does a 1990 Cadillac Deville even have a Cam Sensor???? And, If they did have a Cam Sensor wouldn't GM be able to tell me the status of this mystery part?? :hmm: :hmm: :hmm: :hmm:
 

·
Registered
Joined
·
305 Posts
Your mechanic could referr to the crankshaft position sensor. It does two things: It monitors engine rpm and helps the computer determine relative position of the crankshaft so the PCM can control spark timing and fuel delivery in the proper sequence. The PCM also uses the crank sensor's input to regulate idle speed, which it does by sending a signal to an idle speed control motor or idle air bypass motor. On some engines, an additional camshaft position sensor is used to provide additional input to the PCM about valve timing.
 

·
Registered
1992 Town Car Cartier & 2014 Accord LX MTX
Joined
·
34,087 Posts
has anyone considered a fuel injector? When my #5 injector went out, it ran very very rough.
 

·
Registered
Joined
·
16 Posts
Discussion Starter #10
During my last tune-up I was told my #8 fuel injector needed to be replaced. So I went ahead and replaced all 8 injectors with Five-O Bosch injectors (fiveomotorsports.com). Also, during this recent tune-up the mechanic did mention my injectors may be missing. They ran tests on the injectors at no-cost and cleaned them out. After all this they told me my injectors all passed and it's my cam sensor that is bad and needs replacing. The fuel/air mixture isn't correct causing my car to run very very very rough and miss.

Could the crankshaft postion sensor be referred to as the cam sensor in my case?? After calling GM they told me my year cadillac (1990 Deville) doesn't have that part listed.
 

·
Registered
1992 Town Car Cartier & 2014 Accord LX MTX
Joined
·
34,087 Posts
Wow you replaced all eight? That must have been expensive!
 

·
Registered
Joined
·
16 Posts
Discussion Starter #12
Check out fiveomotorsport.com! I was able to get 8 brand new Bosch fuel injectors for my 1990 Deville and it only cost me $278.60 (includes shipping). And I spent about 2hours putting them in myself so I saved alot of money. I was quoted by a mechanic 1200.00 which includes 1 injector plus 250.00 for each remaining injector (1200 + 250*7 = :bomb: ).
 

·
Registered
2018 Mazda 6 (Venus) 1964 Impala (Betty) 1991 Miata (Dolly)
Joined
·
14,333 Posts
NoRtHErN_CaDdY_bOy said:
After all this they told me my injectors all passed and it's my cam sensor that is bad and needs replacing. The fuel/air mixture isn't correct causing my car to run very very very rough and miss.

Could the crankshaft postion sensor be referred to as the cam sensor in my case?? After calling GM they told me my year cadillac (1990 Deville) doesn't have that part listed.
The camshaft position sensor is also known as the hall effect switch. I got one for my '91 4.9 from GM Parts Network for about $75 with shipping. GM Parts Direct has it as well for about the same price.

The cam sensor is under the distributor cap, and the mounting bolts are hard to reach (you'll need an open-end 1/4" wrench), but if you can change your fuel injectors, you can change this sensor. You might also replace your ignition control module, which is also under the distributor cap, while you're at it. It's a $30 part at most auto parts stores. My DeVille was stumbling and stalling constantly, even after replacing the fuel injectors (also from Five O Motorsport) and the cam sensor (I was getting the E41 code). Only after replacing the ignition module did my car start running right again.

Good luck.
 
1 - 13 of 13 Posts
Top