88 Park Avenue codes

[88PA]

Well the old girl began running rough last week so I got the codes which dont make since to me, maybe they will to you. 14, 41, 42. 14-coolant sensor don't seem to have anything to do with the other two codes. 41, we ran without a cam sensor for a couple years before I did the old JB weld trick which has held for a year and half now, ran just fine. 42, I replaced the ig. module last year but the way it's running right now is nothing like it ran when the I.M. went out. IDK, I cleared the codes and am going to run for a few minutes to see if the same codes pop up. It's running extremly rich and rough, won't idle at all. Acually, it hasn't been idling very well for quite a while now.

Any Ideas???

[maxwedge]

The coolant sensor can make it run rich, attend to that first.

[88PA]

Oh yea, I guess if the ECM thinks the engine is hot it would adjust the mixture accordingly. Hadn't thought of that. The Coolant sensor is only about 10 bucks at autozone so that'll be my first thing. Where is the coolant sensor anyway? Thanks, Don

[88PA]

Well, it's throwing totally new codes now....27,28 & 42. One thing I failed to mention is that when it's acting up the speedometer will drop to zero and the checkengine light flashes intermittenly like there is a loose connection. I checked all the connections and cleaned the sensor that's right after the air filter and I also took the filter out incase it was clogged. It is running much better now but will cut out from time to time so I feel it has a short somewhere, I hate chasing wiring problems.

Any idea....coments? Thanks for any expertise you can offer.....

[Blue Bowtie]

27 & 28 are either gear switch or throttle switch circuit problems. The 4T60 (440-T4) used a pressure switch in the trans valve body to determine when the transmission was in either 3 or OD ranges as control inputs in the TCC circuit. This connects to the ECM via the transmission harness.

42 is a fault in the EST system - Back to the ICM and sensors, it would appear. Don't overlook the detonation sensor, and make sure the EST bypass wire is intact (if your V6 has a bypass).

[88PA]

I checked fuel pressure and it's fine at 42 PSI, I just discovered that autozone can check my ICM so I'm going to do that today. Question, can I check the MAF with a fluke meter? There should be a known resistance readable between terminals A&B (across the little resisters). This MAF is as little as 160 bucks and as much as 359 bucks! I'm not sure the entire car is worth that!

[Blue Bowtie]

If you Fluke has a frequency counter (some do) you should be able to check the MAF. Otherwise you'll need to read the ECM's data on the MAF and see if it is in a reasonable range or dropping off.

Why do you want to check the MAF anyway? Your codes and symptoms don't indicate and MAF problem.

[88PA]

Originally Posted by Blue Bowtie

If you Fluke has a frequency counter (some do) you should be able to check the MAF.
Why do you want to check the MAF anyway? Your codes and symptoms don't indicate and MAF problem.

Well, I've checked fuel pressure, MAF, ICM, and put a new O2 sensor in and it's still running rich and won't idle. It will accelerate really great just wont run at lower RPMs and coughs out black smoke. I want to check the Speed sensor but I cant find it...haha...book says it should have two wires that I can check frequency but the only sensor I can find has about six wires leading into it and without a schematic it's impossible to know which to test. I hate it but I thinks it's time to break down and limp it to a garage that has the diagnostic tools to find the problem.

[maxwedge]

Speed sensor will not cause this,, disconnect the maf see what happens, did you replace the coolant sensor, it has 2 wire hook coonector, not the single wire one.

[maxwedge]

Speed sensor will not cause this,, disconnect the maf see what happens, did you replace the coolant sensor, it has 2 wire hook connector, not the single wire one.

[88PA]

Originally Posted by maxwedge

Speed sensor will not cause this,, disconnect the maf see what happens, did you replace the coolant sensor, it has 2 wire hook connector, not the single wire one.

Oh yea, I forgot to say that I replaced the coolant sensor too. Disconnecting any of the sensors doesn't seem to make a difference and I assume this is because it's in limp or bypass mode and I also assume this means it's by-passing most if not all the sensors, lots of assumptions I know, LOL. The reason I wanted to check the speed sensor is because the speedometer falls to 0 then back to speed then to 0 and so on......it's not rythmatic but very intermitten. I checked continuity on the MAF and it was 520 Meg ohm....a new one in the box from Autozone is the same reading. Got me stumped, this will be the first time i EVER took a car to a garage!

[maxwedge]

The pcm could cause this and the other conditions, there really is no very little limp mode programming in 88, Try tapping the pcm firmly ,with say a screw driver handle, see what happens. I assume you have checked for good vacuum to the map sensor, this can cause an overrich condition also.

[Blue Bowtie]

Have you checked for fuel in the vacuum line of the pressure regulator? Just a thought.

[88PA]

The PCM is under the dash to the right of the column....right? I will try the ol tap tap tap before I take it in Thursday. Thing is, if I drive like I'm in a car chase it runs well, lots of power and good acceleration, it's when I back off on the throttle that it sputters and dies, and if I can coax an idle out of it, black smoke just rolls out the pipe.

[bmorebuick88]

interesting stuff in this thread guys. thanks for the info.
i've had a code reading 15 since i bought the car three years ago, and im pretty sure it was on befoer that because the last person had the check engine light covered up with electrical tape. its for low coolant temp. i figured it was the thermostat and changed that, but the check engine light and that code is still there. any ideas?