: codes 44+45 1988 Brougham w. 307

08-15-07, 08:57 AM

Car runs great if itīs cold but doesnīt accelerate if it gets warm.
So we checked:
the choke device: ok.
Throtle linkage: ok
vakuum hoses by brake claener with engine running: ok; no leaks.

The codes were the 44 and 45; lean AND rich o2 sensor.

so we took the emmission reading machine (donīt exactly know how it is called)
an it told us that the co2 is toooo low (0,000something) and the o2 Sensor
reading is 1,4something to 1,5something since it has to be around 1,0 !:bigroll:

Today i bought a new o2 sensor and we will install it next week.

Am i on the right way and will this fix the problem?
As i wrote before; car runs great until it enters closed loop.
Idling is perfect cold AND warm.

08-15-07, 01:29 PM
o2 sensor readings are an indicator of what is coming out the pipe - unless the o2 sensor itself is messed up (always possible) it is telling you of other issues upstream.

Replacing the sensor is a good first step to ensure that you are starting with a clean/new sensor. As far as symptoms going onto closed loop, have you checked the function of the EGR valve, the TPS sensor reading, and the mixture control solenoid voltage? There are of course specific steps needed to check these items, especially the TPS and MCS. Also worth checking are the air pump diverter valve and the vapor cannister solenoid valve. That is assuming that the carb itself is in good shape, the ignition system is functioning properly. and that the catalytic converter is not plugged up. Did you check the NOx readings? High NOx readings usually indicate a bad or clogged EGR system. There are also miles of vacuum lines under the hood - did you verify that they are all in good shape?

But this is just guessing - all this stuff points to doing a step by step methodical troubleshooting to be able to rule out what is not the problem. I highly recommend getting the factory shop service manual - of course the best would be for an 88, but one from 86-89 would still be much better than nothing or a generic Haynes/Chiltons. I got a factory service manual for my 86 FWB for $20 off of ebay and it is like gold in helping to diagnose problems - they have step by step troubleshooting procedures and the correct adjustment specs. If you are going to keep the car, get the service manual, you will be glad you did.

08-20-07, 10:09 AM

I just ordered an ī88 Cadillac Brougham service manual.
It will be delivered within 6-14 business days. We will see...

Yesterday we wanted to run the DIACOM.
But the cable couldnīt get any data ? It worked fine on the ī88 GTA.
I found out that the aldl ports pins differ...

My brougham:

(-) ( ) (-) (-) (-) (-)
( ) ( ) ( ) ( ) ( ) ( )

My friendīs 88 Pontiac Trans Am GTA:

( ) (-) ( ) (-) (-) (-)
(-) ( ) ( ) ( ) ( ) (-)

Iīm confused; why does my caddy not have the diagnostic pins E and/or M ??

Another question:
How can i easily check the mixture control device for proper function?
I guess it does not work well when engine reaches closed loop...

thanx for any advice

08-20-07, 09:07 PM
I don't know about the data port problem - you should be at least able to jumper the top 2 right terminals and read the CEL flashes to get any codes.
(-) ( ) (-) (-) (-) (-)
( ) ( ) ( ) ( ) ( ) ( )

Your manual will outline how to check the mix control solenoid. There is a green or blue terminal in the wiring harness in front of the carb that looks like it should be connected to something, it's just sitting there. You connect the + lead of a dwell meter to that terminal and connect - lead to a metal ground. Dwell meter is set and/or read on the 6 cyl scale. With the engine running, you will see the dwell vary from somewhere like 30 to 50 degrees, but will do it very rapidly so that the net effect is the dwell reading in the middle, with the needle wavering. That means that (1) the solenoid is cycling as it should (varied readings) and (2) the range is within spec. I believe that the mix solenoid works in open or closed loop, as does the TPS.

Getting the manual is a good thing - it will walk you thru go/no-go troubleshooting procedures for all this stuff.

08-21-07, 12:55 AM
Replace the O2 Sensor. That's a good first step.

Is your cold air intake installed?

08-21-07, 07:06 AM

thanx for your advice testing the mcs.
I got the codes 44+45 by jumpering the a + b pins.

But the aldl cable from the laptop needs the pins e and/or m for communication with the car´s ecm.
Why does my caddy don´t have them? Does caddy use other pins to allow the aldl cable communicate
with the ecm?