Failed Emissions...bad

[CaddyFan777]

Good Morning,

Can't seem to get my 95 Eldo to pass emissions. Tests indicated High HC(300% higher than standards,High CO(200% higher than standards), NOx is 60% less than standards(Hooray),Co2 is about normal.

DTC are P137 History, I032 Current.

Bought the car with a cracked block, Have replaced engine and most of the sensors. Replaced plugs w/AC Delco 41-950,Replaced Plug Wires w/AC Delco 9748J, has a new FPR, upstream O2 sensors, new knock sensor,new map sensor,new intake air temp sensor,new TPS, approx $600 worth of new seals, gaskets,and Hoses.new egr valve. The car starts and runs smooth. No visible smoke or unusual smells. Thats the good news, now the bad news(which isn't even all that bad) The car lacks much get-up-and-go off the line. Acceleration at higher speeds isn't bad. I have a 96 DeVille as well with the same motor, It runs good so I have something to compare acceleration to. Fuel milage is all over the place since everything was reset and Ive been idling it in the garage checking on overheating(Which thanks to all of you and your posts, I know the temperature is just warm and not unusual) I've been going over past posts to try and find something similar. I'm sure there here, but all I found was the fuel pressure regulator. Im going to get my fuel pressure tester later today and check that too. I know what the codes mean, and they aren't much help with current problem.

One other thing to note, Parking brake doesn't release automatically, I don't hear any hissing like a vacuum leak.

At this point I am little lost for what to check next.

Any help or comments would be grealy appriciated.

You all have a great day and thanks again. Oh...one more thing, I broke my back recently,I'm in a brace now and crawling around the car can take me some time, thanks for your patience.

~Geo~

[joeb]

you took out a 95 motor and replaced it with what vintage? was the new motor the same VIN? sls or sts you know what i mean. why did you change so many sensors? i assume the car came with a motor and all sensors installed? why change them? i have changed several 02 sensors and a fuel regulator on my 96. every other sensor is original after 10yrs of owning it.

[CaddyFan777]

joeb,

I changed the motor myself and went out through the top, which is a very tight fit as I'm sure you know all to well. Since I had the motor out and had easy access to the sensors I just figured it would be better to do it then and not after I squished it all back under the hood. Preventative measures. As for the motor, I got it from a fairly reputable yard here in Denver. He made sure that I knew there were strict limitations on what I could put in there. Both are "Y" series,and as for the sensors that were on the original motor, I suppose it was overkill. I have a '96 DeVille as well and had to change the engine temp. sensor, that was a pain and that is what inspired my "overkill" I plan on keeping this one for a while, so I wanted to make future maint a minimum. My DeVille has been a good car. Not much to do to it.

Thanks for your time, I so appriciate it!!

~Geo~

[Ranger]

High hydrocarbons means incomplete fuel burning. Check for a leaky FPR. Other culprits could be EGR or PCV valves or a bad CAT.

[joeb]

just wanted to make sure your new motor was identical to the original. my 96 is obd2. i swapped my intake from a 95 and it was not the same. different molded hose barbs on the plenum. did you use new intake gaskets?

[CaddyFan777]

Thanks for the posts gentlemen,

I did replace the intake gaskets,and the intake I used was the one that came with the motor.When I got it, it appeared to be original, was stuck in place pretty good. As for the FPR, it was replaced new as well, I don't see or smell any fuel around it or in the Vacuum line. The "vacuum manifold"(that is the only name I can find for the rubber connector in the top of the Throttle body) has a small crack in it, but doesn't seem to leak. Personally I have been calling it the "Triple Knippulator". Can a drop in vacuum pressure to the FPR cause failure? Sorry, back was hurting bad yesterday and didn't get to check fuel rail pressure.The emissions test here in Colorado says the cat is passing, so I've not persued that further. I have replaced egr and pcv valves. something I can do to check the egr valve? I haven't done much testing on parts before, working on them for years, I usually just replace. But this has me flustered. Thanks again!

[CaddyFan777]

oh by the way and fyi I didn't replace camshaft or crank position sensors. I read alot of posts on the poor quality of AC Delco plugs. Should I just try replacing those with NGK's?

[Cadillac Jim]

There are several lines of AC/Delco spark plugs. The ones used in the Northstars are platinum 100,000 mile plugs which should go at least 60,000 miles under the worst conditions and don't give trouble. Just about anything else that anyone has tried has not worked out as well. So, stay with the recommended spark plug for your car, which I believe is GM part number 41950. These come with a boot lubricant and thread anti-sieze on them, and are pre-gapped. Unless I had experience and the boot lube and anti-size on hand, I would never put an old spark plug back if I took one out. The only warning I would have is to inspect the new plugs to make sure that they haven't been dropped before you got them.

I have a hard time understanding how your car could fail emissions so badly without something setting and OBD code and turning on the MIL (the "Check Engine" light). How are you reading your codes? There is a link in my signature block to a Caddyinfo page that describes the process of getting them all right from the HVAC and DIC. I do it about once a week to check up on things. In point of fact, even if the cat id dead and all the sensors are working OK, I don't think the readings would be that bad.

[sPECULATION]

There isn't a cat efficiency code that I see in the OBD I DTC list, so if everything is working except that the cat is bad or doesn't have the right input gases the car may not throw a code and still have high HC and CO. The NOx is low but the CO and HC aren't reduced by the cat. So, the cat is using the NOx and oxygen available to it. So, we are short of oxygen. If that model uses air injection, it isn't working.

[/sPECULATION]

[Ranger]

Air injection is only run at start up for 40 seconds or so to light off the CAT faster.

[Cadillac Jim]

I didn't know that the AIR shut down during warm-up. From the exhaust gas readings in the first post, it doesn't look like the CAT is being lit up. But there doesn't seem to be enough NOx to burn the HC and CO even if it did light up. This points to the engine tune, and implies that the DFI is running in open-loop mode. But, the ECM won't run a hot motor in open-loop mode unless a sensor output is bad or missing, and that will set a code and turn on the MIL.

I'm getting the feeling that there is something missing here. Please tell us how the codes are read out of the OBD I system, and all of the codes that are found.

Note that running with engine problems is the most common way to ruin a catalytic converter; ask your local muffler shop about that. You have just done major repairs to your engine, so from here it does look like you may have run your existing cat with engine problems. Until we have more information, which may not be forthcoming, the best thing that I can suggest that you drop the cat at the front flange and look in the front of the cat and see if you think it is still clean and working. If you have doubts that the cat is working, you can get a new one for about $200 installed if you go through Meinike, Midas, etc.

[CaddyFan777]

Good Morning,

Just wanted to let you know I'm still here and still trying to work on this, my back has been killing me for the last couple days and I haven't got to do much of anything.Pain killers aren't helping much. Have another dr's appt this morning and will be back with all/any codes the car will give me.

I did look at the cat when the engine was out and it does look clean. I ran a can of 44K through the gas tank to help clean the injectors. I will probably take it to emissions again and see what current readings are.

Sorry its taking me so long.

~Geo~

[Cadillac Jim]

Take your time. Your only deadlines are your own. Whenever anyone posts to this topic I get an email, and I have seen updates to two-year-old topics in minutes; in fact that exact thing happened this week. Your only real deadline is your inspection sticker expiration.

You pretty much eliminate obvious signs of cat disfunction from engine problems prior to your reconditioning of the motor. That doesn't mean that the cat is good but it takes an easy solution off the table. I would do more diagnosis before I spent $200, like hooking a temporary pipe to the exhaust in front of the cat and measuring the HC/CO/NOx/CO2, hooking it back up and driving around the block, then checking it again and comparing the readings.

At this point I suggest a good mechanic that has an OBD I capability that will let him read the internals of the PCM while the car is running. This will tell you (him/her, actually) exactly what is happening with the DFI, including all the sensor readings, the mixture, whether anything is maxed out, etc. When I had my last cat replaced, one of those guys took all the pressure out of the situation; he told me that the waveforms before and after my cat were too similar (I have an HO2 sensor behind my cat that measures cat efficiency). But, I don't believe that the 1995 model year Northstar or OBD I compliant cars in general have that extra oxygen sensor behind the cat.

[Seanmannino]

Geo -

I live in Denver and used to work for the emissions testing facility out in Commerce City and Northglenn after that one was closed. It is not recommended but if you are just trying to get the thing to pass so that you can get tags on it, run a half gallon of denatured alcohol through, before you take it to the E shop run it around for about 30 minutes and then head on in. Running this through the engine will not harm it, just cleaning things out... Once you have that done you can then resume the task of ensuring that your caddy is running properly.

[CaddyFan777]

Morning all,

First off need to thank you Sean, added 1/2 gal of Denatured Alcohol to 10 gals of gas, drove it for about 50 miles and took it in to emissions. Testing results are as follows, CO gpm dropped from 70.785 to 6.5 gpm, HC dropped from 1.96 gpm to 1.02 gpm and the car passed!! I was amaazed!

Reread my posts and realized that I had said that I had replaced plug wires before first two failures,that was not the case. Noticed a slight ticking sound,that was erratic,turned off garage lights, and saw the telltale little blue flashes against the block,that was when I replaced the plug wires.

The car doesn't seem to run much better after plug wire swap and is still lacking low end power.

Question: 1) Is it all that common for an intake manifold to crack and leak?

2) What is "WOT"?

3) Is it possible to test the EGR valve? It is new, but may not be working properly.

4) Is there a bulletin board on CaddyInfo? I have a 93 Fleetwood,but it has cancer and want to see about selling it as a parts car. I seem to be unable

to find any where to do that.

Thanks again for all of your help, Colorado DMV has the stupidist temp tag policies in HISTORY!!! At least for now I'm done paying late fees and one day trip permits(that is all they will issue)Now at least I can get it to the shop for emission testing without a trip to dmv just to move the thing. whew!

[BodybyFisher]

The intake can crack but if you have a vacuum leak I would check the seals, I dont think you would have passed if you had a cracked intake however

WOT=Wide Open Throttle, there is a specific procedure, search, WOT Procedure

If the EGR is not functioning you will set a code and not likely pass emissions

Did you changed your plugs?, that would cause poor power

[Cadillac Jim]

There is a "Cadillacs for Sale" board on Caddyinfo:

http://caddyinfo.ipbhost.com/index.php?showforum=5

[CaddyFan777]

Thanks Jim,

Looks like I'm just a moron, found the board as soon as I posted that. But thanks for the info just the same.

Have a great weekend

~geo~