Hi, I have been trying to get my fiance's 93 850 non-turbo to pass emissions test and on its 2nd attempt we are still failing. Now since I am not familiar with Volvo's I am short on ideas to fix this. The first test resulted in clean HC, clean CO, but NOX was at 2045ppm (435limit), so my first thought was EGR, I go to clean it out only to find that there is NO EGR to be found?! I see there is no EGR whatsoever on this car (Canadian model BTW), I know where its suppose to be, there is a mount there, but its not even tapped for one to be bolted onto it. So all I could think of was a new cat converter, so I replaced it as well I fixed 1 vacuum hose that goes from the intake mani to i dunno where, and put in some 91 octane gas in hopes that it might help lower combustion temps so i could pass. 2nd attemp FAIL, but this time NOX was 945ppm, still needs to be 435, so tonight I checked for intake mani leaks, none, but found 2 vacuum hoses that were off and they seemed to go to something under the battery, not the charchol canister, something else, fixed them, also disconnected the battery to refresh the ECU. The car also has new cap/rotor/plugs, car has 351,000km on it and has been well maintained throughout its life. I know I have to lower combustion temps, but i am out of ideas on how to correct this.
Please can someone help me out here, any words of advice will be much appreciated.

Thanks Ryan

 

Hello Ryan,

Greetings from Chicagoland.

You seem to have done pretty much everything I can think of, except oxygen sensors. There are two on 850, and if one or both are failing, the mixture might get richer than it should be, thus dirtier exhaust.

Did you wait at least 5 minutes after disconnecting the battery? There is a relay for the ECU that keeps power to the ECU for about 5 minutes even after the battery is disconnected.

Now, the car has new cap + rotor + plugs, what about the ignition wires? I believe they are new as well, since the car seems to have been maintained well.

I also hope that all parts that have been replaced are OEM or of better quality.

Good luck,


JPN

 

I only see one O2 sensor and its pre cat, after the cat there is nothing that I can see. As for the O2 we believe its newer, say a year old. THe wires were not replaced, but they are in good condition, I have no missing during acceleration so I doubt that is an issue, plus if it was misfiring the HC and CO would be higher.

I'm going to see if I can get my hands on a scan tool of some sort to check for codes.

 

You can check codes without a scanner since your car is pre OBDII. There is a box near the washer fill tube. You can pull DTCs from there. Instructions are around on this forum or on troublecodes.net or volvospeed in the repairs section.

 

I didn't know retrieving codes what that easy, thats the first thing I will do after work.

..went in for 3rd test, failed worse that both others combined and all i did was run some combustion chamber cleaner, fuel system cleaner and fix 2 more vacuum hoses.

 

Also check fuel pressure and make sure there is no codes in the system.

 

I got some codes, O2 sensor, MAS, ignition RPM signal erratic. I then cleared the codes, went for a drive and no more CEL or codes.

The car is at the local emission specialist today for a diagnosis, I gave up and we are leaving it up to them to sort it out.

 

I bet the o2 sensor is your biggest culprit. - AB

 

O2 is about 2months old.

 

How old is the Mass flow? It could very well be bad.

The RPM signal erratic might be the cam sensor going bad. But wouldn't affect the emissions.

 

Sounds like the EGR, the guy who is diagnosing the car said there is an EGR under the engine that is only visible from underneath, no wonder I couldn't find the EGR and that its likely the culprit...no ****.

I can't believe I got fooled by a car, I know a lot about cars and only once before took a car to a shop because I could not fix it, I can rebuild an engine, swap a turbo, clutch, drive shaft, t-case, suspension, you name I have done it, but I couldn't find a bloody EGR valve...so much money could have been saved it only I knew. [:@][]

 

Hello Ryan,

I hope the car passes the emissions test this time.

The EGR should be visible from the top too, it's right under the throttle area plastic cover. It is somewhat hidden at the far right (looking at the engine) of the intake manifold, but you can see it. However, in some cases people seem to take it off and block it for some reason. I recently found that even my 850 has an EGR hose blocked with a bolt. I don't know what kind of benefit you can get by disabling the EGR valve.

I wouldn't feel bad about not being able to find the EGR valve. Modern cars are very complex and years of experience alone is no longer sufficient, especially for emissions control systems, electrical/electronic controls. To troubleshoot these systems require good amount of reading, understanding and training, as well as having proper diagnosis equipment & service manual. Many technicians' knowledge is expired, though many of them don't want to admit it. Also, each mfg designs these systems differently, so an access to up-to-date info is critical.

In my prejudice, Volvo's are usually over-engineered because even a negligible fault (sensor signal out-of-spec, etc...) can disable a system (ABS is a good example). Digital system is susceptible to signal noise/missing signals, as compared to analog. Volvo's come with too may diagnostic systems with a number of codes, which I think is way too much and not very accurate sometimes.

Anyway, enough burbling. I wish the car passes the test.

Best wishes,


JPN

 

JPN, I know where the EGR location is suppose to be just behind the TB, but our car does not have it there, the mechanic says its down in the back of the engine near the manifold, thats why I could not find it.

On another note we have the car back from diagnosis, the result is a missing intake manifold gasket! yikes, so its suching in extra air causing a lean situation. To prove that its leaking they blew propane onto the intake mani and the engine changed tone and idled higher. So this week I'll be tearing it apart to change it.

 

I see, someone else on this board had the same problem, the EGR missing and blocked by a plate. I wonder why some people remove EGR valve.

A missing intake gasket, I wonder how it happened. Anyway, I'm glad you've found the culprit.

I wish the car passes the emissions test after you do the gasket.

Regards,


JPN

 

hey you're right JPN that was me haha

some people remove the EGR for preformance reasons, It is only there for emmissions reasions and who really want's exhause gassed going back in thier intake anyway!

I eliminated the EGR from my Mitsubishi 3000GT 5 years ago and it really didn't matter to me because I lived in a place that did not have emmissions testing, but that changed and I moved to Guelph Ontario, different city different province and guess what? I needed an emmissions test.... with out the EGR and 2 of the 3 cat converters it still passed.

Also unknown to me at the time I bought my fist volvoo, an 850 Turbo and it did not havbe an EGR it had been previously removed. It passed Emmissions testing, although it was close on hydrocarbons, but added to that fact is that there was oil burning on the surface of the engine and that's not far from the air intake.

Ryan, have you done the usual "tricks" before you did your E-Test?

-Mike

 

FYI, the intake gasket is an easy job, ya might as well get the throttle body gasket while you're at it.

Cheap at fcpgroton.com

 

Hello Mike,

Now I remember it was your 850 that was missing the EGR valve. As long as the car passes the emissions test and drives ok, I guess it doesn't matter. As a matter of fact, my 850 has a hose from EGR valve and the hose is blocked with a bolt, which I noticed recently.

However, I am a "as is from the factory" phobia and I plan to fix it. I wouldn't want the exhaust going back to intake either, but it does help reduce the emissions by reducing the combustion chamber temp and giving some of unburned A/F mixture another chance to get burned. Well, whatever helps the environment even a little bit...

Replacing the throttle body gasket is definitely a good idea.

We had about 30cm of snow the other day, I wonder if you had some in your area too. I used "winter mode" on the tranny but I noticed regular mode worked better.

BTW, did you fix the rear-end of your 850? I hope you did.

Cheers,


JPN

 

Not too much snow up this way, a little "dusting" of it but no big amounts to have to deal with. I'm from St. John's on the east coast(actually as east as it gets in North America haha) and out there it's nothing to get 4 concecutive days with 40cm each day, I still say I have yet to see a "real" snowfall in Ontario. I do think I'm going to put my 15" steelies with winter rubber on the car soo as making the drive up HWY 6 from Hamilton to guelph on sunday night the road was a little snow covered, although it was no big sdeal i should do it before I get stuck! and no I didn't do anything with the reae end as of yet, it is only cosmetic scrapes anyway I'm not overly concerned!

-Mike

 

I went to remove the intake mani only to see that the gasket is perfectly fine, there is no way its leaking. I did notice that the right side of the fuel rail was loose as the bolt was backed off about 3 threads which could have caused the far right side injectors to leak air, so I replaced the injector seals while I had them off.
Now while I was messing around the car i did notice I do have an EGR!! its below the intake mani, I could not get a good look at it since the car needed to be jacked up to see, but its just right of center and is not anything like the Normal EGR location, weird **** I tell you. But I did notice through the small view I could get of the EGR that there is a vacuum hose missing, the nipple on the diagram has no hose, so it doesn't take an expert to tell you that no vacuum means no workie. So tonight I'll take it up and try to fix it, looks like its going to be a bitch to get at.

BTW i did change the TB gasket.

 

Forget what I said in my last post, it wasn't an EGR, but rather some sort of intake port flapper. Hard to describe, but there was a vacuum operated diaphram under the intake mani that opened and closed the lower part of the intake runner. The intake runners are 2 channeled, the lower channels all have these black plastic flappers that open and close via the diaphram. It seems at full vacuum they close and with less vacuum like when accelerating they open up. The problem with this on my car is that arm from the diagram and its small linkage was seized leaving it open all the time, so i unseized it and now it works fine.

I took some pics on my camera phone, but I cannot upload them.

Either way when I had the intake mani off there is no way there is an EGR on this car, my guess is that this flapper system closes off air during cruise maybe letting it run cooler, i dunno.

I assume this might have caused the etest failure so I'll have it tested tonight or tomorrow.