Contacting Members

Tiny
CADDYFAN
  • MEMBER
  • 1990 CADILLAC DEVILLE
  • V8
  • FWD
  • AUTOMATIC
  • 82,000 MILES
Reviewing the archives for someone with similar problems that I'm having on a 1990 Caddy, I came upon a question asked by a member describing the exact same problem. The question dated Feb. 05, 2010 was answered with several possibilities. Since that was over a year ago, and the member may have worked through the issues by now, is there any way to contact them to find out exactly what they did to fixt the problem?
Do you
have the same problem?
Yes
No
Wednesday, May 18th, 2011 AT 5:21 PM

12 Replies

Tiny
JDL
  • EXPERT
The person that asked the question, if their name is highlited, you can click on the name and send them a private email.
Was this
answer
helpful?
Yes
No
Wednesday, May 18th, 2011 AT 5:50 PM
Tiny
CADIEMAN
  • MEMBER
Just ask it?
Was this
answer
helpful?
Yes
No
Wednesday, May 18th, 2011 AT 6:28 PM
Tiny
CADDYFAN
  • MEMBER
Unfortunately the name of the member is not highlighted -- too bad. His question describes the condition of my car exactly, though I'm not too worried about the tapping of ISC motor. He writes:

"1990 Cadillac El Dorado Idle Speed Control
Engine Performance problem
1990 Cadillac El Dorado V8 Two Wheel Drive Automatic 135000 miles

When ignition turned on, idle speed control motor pulses about 3 times. I can feel it at the gas pedal. Engine starts rough from cold with low idle speed and no power to drive off. Soon warms up, power is good, but engine still misfires on light throttle. When ignition turned off, engine warm, idle speed control motor pulses about 17 times.

Throttle position switch gives correct voltages, have changed idle speed motor and spark plugs. No vacuum leaks found. Any other ideas?"

I would add a rough idle as part of the symptoms. When stopped, in gear, the intensity increases and often the "Service Engine Soon" light comes on.

I've been chasing this since I started driving it (inherited from my father). In the last 8000 miles I have replaced: distributor cap, rotor, plugs, wires, PCV, fuel filter, TPS, ISC, ECM, and applied a BG fuel induction cleaning kit to clean throttle body, fuel injectors, fuel rail, and fuel tank. I'm beginning to suspect the injectors, and plan on checking for shorts next. Any other suggestions?
Was this
answer
helpful?
Yes
No
Thursday, May 19th, 2011 AT 2:15 PM
Tiny
CADDYFAN
  • MEMBER
BTW, when the "Service Engine Light" comes on, it triggers an E30 code - ISC RPM Out of Range (the only code).

Also, Linder Technical Services describes these 1990 4.5 vin "3" Cadillac Mul-Tec injectors as one of their "dirty dozen" problematic injectors. Not sure the best approach to use if it turns out one or more are shorted -- very expensive.

Finally, (after checking for GM Bulletins) I need to investigate the ground at the block, and make sure that is not part of the problem. GM wrote several Bulletins, and eventually added a bracket at the starter to fix the problem.
Was this
answer
helpful?
Yes
No
Thursday, May 19th, 2011 AT 2:42 PM
Tiny
JDL
  • EXPERT
I can give you the flow chart for the E030. I'm not supposed to copy and paste, for reasoms I don't want to go into, here goeds.

Key on enter diagnostics. Is code EO55 stored as current or history?
Was this
answer
helpful?
Yes
No
Thursday, May 19th, 2011 AT 5:43 PM
Tiny
CADIEMAN
  • MEMBER
This tps switch is adjustable and must set by using volt meter.I have been lookin for the sensor setting procedure but havent fond it yet. Gl
Was this
answer
helpful?
Yes
No
Thursday, May 19th, 2011 AT 8:07 PM
Tiny
CADIEMAN
  • MEMBER
U need to adjust the sensor to 5 volts and tight the sensor. Gl
Was this
answer
helpful?
Yes
No
Thursday, May 19th, 2011 AT 8:15 PM
Tiny
JDL
  • EXPERT
There is a lot of manual diagnostics, you can do on this vehicle, have you done all that? That is where I'd have to start.
Was this
answer
helpful?
Yes
No
Thursday, May 19th, 2011 AT 8:39 PM
Tiny
CADDYFAN
  • MEMBER
Thanks guys. I have the Service Manual (thanks to Faxon Auto Literature), and have worked through the flow charts (E055 is not set). The TPS has been set at 5 volts. You're right about the diagnostics. Even though the system is OBD I, it is fairly sophisticated with a lot of information available from the PCM/BCM through the on-board Electronic Climate Control (ECC) panel and the Fuel Data Center (FDC) panel. I just haven't been able to put all the pieces together yet.
Was this
answer
helpful?
Yes
No
Thursday, May 19th, 2011 AT 9:30 PM
Tiny
JDL
  • EXPERT
I don't know where to go from here.
Was this
answer
helpful?
Yes
No
Friday, May 20th, 2011 AT 3:47 PM
Tiny
CADIEMAN
  • MEMBER
If u follow the flow chart e30 it will tell u what the problem is.I wood get a new tps install it set to 5v to see if its good. What does the flow chart say is bad. Just because a part is new doesnt mean its a good part. Ive seen new dealer parts that are new be bad.
Was this
answer
helpful?
Yes
No
Friday, May 20th, 2011 AT 4:26 PM
Tiny
CADIEMAN
  • MEMBER
You need to test voltage readings to tps sensor. This has to be where your problem is. Before buying a new tps check for proper voltage at the tps connector.1 is 12v 1 is 5v serial data line. Not sure on other 1. If u dont have the data line from the ecm u will have to pull the ecm and check the wire and if there is no 5v signal coming out you need a ecm. If the line reads 5v at the ecm but not at the tps harness. Then that wire is open somewhere from the ecm and tps. Youll need to check all the connectors the wire go through between the 2 componants. The flow sheet takes u through all these voltages read it. You have replaced all the componaits. The only thing u havent replaced is the harness. Gl
Was this
answer
helpful?
Yes
No
Saturday, May 21st, 2011 AT 12:20 AM

Please login or register to post a reply.

Recommended Guides