240 with rough idle codes 113, 232, 221. Where to start?

2fixmybrick · Post by **2fixmybrick** » 15 Mar 2012, 12:46

Hello, I could use some advice. My '89 240 is somewhat new to me. When I first got the car the CE light was on and it failed emissions test (NOX was too high). I checked the code then and got back "113" for the injectors. The car ran ok then just a bit stinky as it seemed rich. Starting at the easy stuff I put some fuel injector cleaner in and switched to mid grade gas. Now all of a sudden the car idles rough, still rich smelling and I have new codes (232, 221, and the ever present 113). I took the injectors out and back flushed them (didn't do a spray pattern test or leak test, was unsure how to) and replaced the plugs which were carbon'ed up (all equal). It ran ok for a day but is now rough again.

I'm afraid to run it much longer for fear of ruining the cat converter and I just don't know where to start. I have read that the O2 sensor can cause troubles (???) MAF sensor? How to test fuel injectors? ECU? blah, blah.

Any advice is appreciated, thanks.

Post by **billofdurham** » 15 Mar 2012, 13:46

You say 1-1-3 is ever present. Did you clear it after you added the injector cleaner? If the code is left in the system the ECU will compensate for it regardless of the repairs done.

The three codes all point to an incorrect fuel trim. My first point of attack with codes of this kind is to clear them and run the car to see if they return. If you do that and the codes do return you will need to start checking other things.

Mass Air Flow (MAF) sensor. The MAF can be cleaned with a spray cleaner available at any good parts shop.

Intake/exhaust leak.

Fuel pressure. Difficult to check without the right kit.

Engine Coolant Temperature sensor. The attached shows the readings you should obtain with an ohmmeter:

240 Coolant temperature sensor test..pdf: (177.66 KiB) Downloaded 971 times

To test the injectors fully you would need to have access to the correct equipment. That would be low on my list because of the cost involved.

The oxygen sensor can be tested but, again, it would be low on my list for testing.

Start with the easy stuff first and keep us updated so we can guide you further.

Bill.

2fixmybrick · Post by **2fixmybrick** » 15 Mar 2012, 15:30

Thanks Bill, Yes I did clear the codes after cleaning the injectors. What I meant by the 113 code being ever present is that it was there before I did any other work. I had cleared the codes before and the 113 would come back very soon after. It ran ok then but wouldn't pass emissions. I should also mention that the ground wire on the fuel rail was badly corroded, I really thought that would be the fix. But no. Now it runs rough and I have the aforementioned new codes. I bought some MAF cleaner today so I'll try that and change the oil (very gassy) and let ya know. Thanks, Al.

Amys 940 · Post by **Amys 940** » 15 Mar 2012, 22:54

You mentioned that the car failed emissions and was running high Oxides of nitrogen. Any idea what the carbon monoxide and hydrocarbon numbers looked like? The only reason I ask is because high oxides of nitrogen usually form when combustion temps are extremely high (usually indicating a lean run if the nox gases are the only thing that's high). We used to find that non functioning egr systems would be at fault. Again, I stress, that this only applies if NxO is the ONLY unusually high or failing number. If carbon monoxide and hydrocarbons are also thru the roof, you have some other problems (and probably a failed cat converter to boot). If all of your gas numbers are out of whack, I'd start with the MAF too. Clean it up good.

If the rough running is at idle only, I just found by personal experience, that cleaning the idle air valve is a good idea. My searching idle when cold disappeared after I did this.

Keep us updated!

Amys 940 · Post by **Amys 940** » 16 Mar 2012, 04:33

Forgot that Bill is also correct with the ECT recommendation. If your ECT is reporting a low coolant temp to the computer it will consistently dump gas into the cylinders to compensate.

Your car may have run better for a day because you had fresh plugs in there that became fouled out over a short period of time due to the still-existing problem.

2fixmybrick · Post by **2fixmybrick** » 21 Mar 2012, 18:25

Thanks all for the advice! I had not yet reported back because I wanted to give it a few days and see how it went. Up until a day ago I thought all was well. I cleaned the MAF sensor with the proper cleaner, changed the oil, reset the codes, disconnected the battery to be sure, fired it up and it was smooth, not rich smelling, not stumbling, etc. It was great!

So it ran like that for two days of city and highway driving then today it started the rough idle, black smoke idleing, CEL, and using gas like crazy (I really think I can see the gas gauge going down!)

I did not check the resistance of the temp sender (thanks Bill) because honestly I didnt know which one it was. There's a single wire sender that I thought was for the gauge in the water jacket. Is this the sensor in question or is there another?

To "Amys 940" yes the NO reading was the only high number. HC was was 100 on the last test, CO was 0.36...
I should say that the plugs were quite black though unless the computer would compensate that much?

Also, I keep seeing a problem on some forums regarding a cold start relay with these buggers, can that apply here? also a blade fuse under the hood?

Sorry, I seem to have more questions than answers. I am worried about the Cat converter too. If it was plugged wouldnt it run bad always or get super hot?

Thank you in advance,
Al

IL740gl90 · Post by **IL740gl90** » 21 Mar 2012, 22:37

Check your fuel pressure regulator - pull off the vacuum tube and smell for gas or feel if it is wet - if it is you need a new one and check your throttle position switch right off the intake manifold. Vibrations may have made it loose. Start the car and then see if your tps is movable to touch if it is when in the proper spot your engine will get smooth running so tighten it down., the return of rough running could be plugs or wires or distrib cap as well but I thinkk tps and fuel pressr regulator - fpr and tps those two go on our older chariots

2fixmybrick · Post by **2fixmybrick** » 22 Mar 2012, 04:53

Forgot to mention that the same codes are back. 113, 232, and 221 if it helps.

2fixmybrick · Post by **2fixmybrick** » 11 May 2012, 10:43

Hello all, after driving for a month I would just like to say thank you to those that provided help. The problems I had seemed to be from a bad fuel pressure regulator and subsequent failure of the o2 sensor. After replacing the fpr the problem would go away for a while then the ce light would come on again. I finally replaced the o2 sensor which it seems was damaged by the constant rich condition. With the new O2 sensor all is well. I may even go get an emissions test (hope that doesn't jinx me lol).

Anyways, a big thank you for the assistance!

Post by **billofdurham** » 11 May 2012, 13:39

A job well done. Thank you for the update.

Bill.