Hi folks,

I just found my sis a low mileage 93 240, and she is trying to register it in DC.

We did these tune-up items before she failed inspection:

plugs (bosch copper)
wires (bosch) (w/dielectric grease)
rotor (bosch)
cap (bosch)
flame trap
oil separator
timing belt
front engine oil seals
cleaned throttle body
new throttle body gasket


Vacuum lines were in good shape it seemed, though now I wish I had put little zip ties on all of them.

Do these failing values suggest anything to anyone?

HC: reading: 1.7489; limit 1.200 FAIL
CO: reading: 15.5801; limit 20.000 PASS
NOX: reading: 2.8444; limit 2.500 FAIL

Gas cap test also failed.

One final piece of information is integral to this question. Someone I met while I was working on this car told me that I should advance the timing a little bit by rotating the distributor counter-clockwise to get it to start up better. He did it, and sure enough the car starts up in a flash, but I hope this didn't cause the car to fail emissions.

Thanks so much folks.

Hi Folks,

Thanks for all of your help and suggestions.

I've compiled answers to various questions in the tread:


OIL.

I put clean Castrol 10w30 and a Mahle filter in the car before she drove from my home in KY to DC.


AT OPERATING TEMP WHEN TESTED?

The car was also hot when she got it tested, having just been driven 20 mins to the shop and not shut off prior to testing.


HOW LOW IS LOW MILEAGE?

Mileage on the car is 120K. I had a 940 turbo with 270K that ran great, but I never had to get it emissions tested, and I'm not really familiar with emissions, as a Mississippi transplant to Kentucky (you can literally register and drive anything in Mississippi, and KY is only slightly tougher).


HAS O2 SENSOR BEEN CHANGED?

We will be getting the oxygen sensor changed before her next attempt. Will this likely reduce both NOX and CO?


ADJUSTABLE DISTRIBUTOR IN 93?

Unfortunately I don't have the car in front of me to see whether there is actually a slot in the distributor mount for it to be rotated. I do, however, remember that the "mechanic" loosened the distributor mounting bolt, and tapped the mount from the aft side, presumably (I couldn't actually see) rotating it in what would be a counter-clockwise direction, until the car started to stumble a little, then he rotated it back clockwise a little until it smoothed out.

Ken C, is there a possibility that some 93's have a slot for the distributor to be rotated and others don't? Because otherwise I don't see how the mechanic's tapping could noticeably affect the cars running.


DOES TURNING DISTRIBUTOR REDUCE AVAILABLE SPARK?

I am not sure if this is a good procedure, but just the other day I did this on an 88 240 that I have been working on. I swapped a motor from an 86 740 into the 88 240, and had to install the distributor and intermediate shaft, so once I got the car to start (another story), I turned the distributor a little counter-clockwise, and the car now idles and revs much better than with my initial placement of the distributor. In this case I improved the car's running, but I have no idea about how this affects emissions.


Assuming that it is possible to rotate the distributor in my sister's 93 240, can we assume that the ECU can then control the ignition timing for any reasonable placement of the distributor? Or as Charley suggests, could this actually be part of the emissions problem?

Thanks a lot for your input. I realize that I don't have ideal information for troubleshooting right now, like error codes, but it's just broke me trying to help my broke sister out in a piecemeal fashion.

Thanks so much

hello riyad,
for several years, my 86 240 was creeping closer to failing emissions according to my records.

i went through a laundry list as many do. i did replace the intake gasket which was needed, but the problem was the fuel injector seals--those rubber o-rings.

after i replaced 2 leaking ones, it ran much better and passed inspection.

be careful, injectors are kinda hard to put back on with new o-rings, and don't push down on your fuel rail, you'll bend it.

i sued a little tranny fluid to help slip them on the intake and fuel rail. you can do a search, too.

good luck,
regards,
byron golden
86 245
92 245
94 940

It also helps to have the engine at operating temperature so take it for a spin before testing.
Dan

How low is low mileage? It can make a difference. If it were me the first thing I would do is find out why the gas cap test failed. I believe the tank venting system is connected the a carbon canister which is connected to the intake system somewhere. If that hose is cracked or missing that could cause part of you problem.

Ron J

It should run a lot cleaner ... how about a new o2 sensor?

Did she change the oil. Clean oil makes big difference
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me http://home.lyse.net/brox/TonyPage4.html

Hi,


I just wanted to say that I really liked your post about the engine oil,


Goatman

First of all, the '93 has a distributor mount that doesn't let you rotate it -- the adjustment slot you would expect on an earlier model is blocked (hard to describe, but take my word for it -- I have two '93's).

The reason is that, sometime between '84 and '93 (probably late '80s), the control of spark timing was taken from the distributor's mechanical systems and given to the ECU's electronics. From that time on, the position of the distributor has NO effect on ignition timing whatsoever! There's nothing (no hall sensor, no advance weights or or springs, nothing) inside except the rotor and cap to send the spark to the right plug at the right time.

Spark timing, including advance (or retardation), is totalling a software issue in the ECU; position of the crankshaft is determined from a Crankshaft Position Sensor lying on the top of the bell housing over the flywheel.

Thus, there is no provision to "adjust" the timing by rotating the distributor body -- as long as the contacts between the rotor and cap's peripheral contacts touch, spark will occur at the plugs -- it's go or no go.

Adjusting the distributor will do nothing other than lower spark energy to the plugs. Timing is controlled by the ECU and the crank position sensor behind the head (no adjustment available). I would recommend reading the OBD I codes from the connector just behind the driver side front strut tower.

Read the codes and report back with the results.

jorrell
--
92 245 299.3K miles, IPD'd to the hilt, 06 XC70, 00 Eclipse custom Turbo setup...currently taking names and kicking reputations!

Assuming that the distributor is not supposed to be allowed to be adjusted, but in fact it can, I can see how this could be a problem. While turning the distributor doesn't change the timing, it does change the indexing of the cap and rotor. So, it is not impossible that moving it gave better indexing at cranking speed, but introduced unfavorable indexing at running speed. If the rotor contact is long enough, this should not be an issue, but maybe it is not long enough for the adjustment that was made.

Charley