OK, finally got the 89 240 DL sussed out (short in the crankshaft position sensor leads).

However, the diagnostics show that the Jetronic is now throwing a 113 error code (faulty fuel injector).


Here are the symptoms:

1.) When the engine is cold, it will start and immediately stall.

2.) If you depress the gas pedal a bit, it will start and run rough, and some gas pedal must be applied to prevent stalling. After about 30 seconds, the engine runs just fine and this problem goes away, that is, until you let the engine get cold and try to start again.

3.) Fuel consumption is normal at about 29-32 miles per gallon.

4.) If you clear out the error code, it does not reset until you have driven about 10 miles.


All the injectors are clicking away in the diagnostic mode (I haven't checked the total resistance on the circuit or the the resistance of each injector - 4 ohms and 16 ohms, respectively - yet. I have not checked the ground connections for the injectors yet.

My question is, could this error code be caused by one of the following and not one or more of the injectors?:

Faulty cold start valve
Faulty engine temperature sensor
Faulty Lambda-sond
Faulty O2 sensor
Crudded up injectors that need to be cleaned

I have the LH 2.4 Jetronic manual and all it indicates is that the 113 is thrown by an improper electrical resistance reading in the injector circuit (one or more injector has packed in).

I'm thinking crudded up injectors, but the miles per gallon rate is outstanding, even excellent, at 29-32 MPG.

I'm also thinking a bad ground or connector at one or more of the injectors that goes away as the operating temperatures increase.


Anyone ever run into this problem?

 

This exact problem, no.
The OBD1 system is iffy... lots of errors, etc.
I'd look at the Coolant Temp. Sensor based on the symptoms you mention...

 

The code is thrown by improper electrical resistance in the injector circuitry. It could be caused by a faulty injector but not likely any of the other items you mentioned. First, check all of the grounds to the engine. There is one from the firewall to the valve cover. There should be another directly from the battery over to a bolt on the engine near the driver side engine mount. There should also be two on the injector rail itself to the intake manifold. Make sure these are all good and clean. Also check the connections to each injector. It also wouldn't hurt to check the resistance on the wire from the ECU to each injector.

Being that it idles poor when cold and better when warm could be a sticking injector but I have never in my experience with these cars had an issue with an injector failing.

 

Considering the recent history of this car (RE: Mystery Problem), check to see if they are the correct injectors. From reading your post when you purchased the car, it sounds like it was well maintained. I would not expect the injectors to be in bad condition, unless they are not... Does it look like they have been removed recently? It is not out of the realm of possibilities. While you are there, grab your multi-meter, and do a resistance test on the injectors. Test cold and hot.

BTW, what did happen with that shop? You left us with a real cliffhanger.

 

Well, we finally got the car back from the shop. They discovered it was exactly what I thought it was initially (either bad wire/short in the crank shaft position sensor - which would explain why there was spark but no signal to the injectors).

The mechanic kept claiming the 113 error code indicated that yet another Jetronic unit was 'bad' because he said "the 113 error code is for a bad injector unit which is the Jetronic unit" which, of course, it is not. The 113 code simply indicates that there is an impedance level error (improper resistance) on the circuit involving the injectors.

When we first got the car back, it was being snotty when trying to start it cold (would start, stall, you had to give it gas, etc., to get it started). So, I checked the injectors one by one and they were fine (proper resistance, operating properly, proper injectors, etc).

So, my wife comes up with a brilliant idea: she said, what if the injectors are fouled and the fouled injectors are causing heat in the drivers in the injectors and the resistance goes up? Let's throw some injector cleaner in the fuel, take it out on the highway for half an hour to blow out the cobwebs and see if there's any improvement.

Well, there was a massive improvement. The car starts beautifully cold, hot or warm. The car is getting 30 MPG off the highway in local driving at this point.

But the funny part is that if you clear out the codes, about 15 minutes after the car reaches operating temperatures it throws a 113 code and the check engine light comes on. In fact, you get three incidences of the 113 code stored in the memory (it can only hold three codes for each level of diagnostics).

At first I thought this might indicate a Lambda-sond/O2 sensor issue, but all the components test out just fine as do the circuits. So, this seems to be an intermittent increase in the resistance of the injectors/injector circuit.

If it was the Lambda-sond/O2, such an error would show up as another code and would occur long before the engine was at normal operating temperatures.

I looked at the programming of these particular Jetronic units and there is also a very good possibility that it is a bogus error code caused by a transient voltage or resistance problem, most likely a crappy ground point. All it takes to irritate these computers is for one ground to be faulty and it results in a 'sneak circuit' occurring causing a voltage to go up on the injector circuit thus changing the resistance on that circuit momentarily.

I'll check each connector and ground for the injectors.

Or, as an engineer with Volvo in Sweden said, it could be just a spöke i maskinen.

But for now, the car is running perfectly, except for that damned 113 code that crops up largely at random.

 

https://www.volvoclub.org.uk/faq/Eng...InjectionFault says its a 'fuel trim (lambda control) too lean or rich', and is likely due to O2 sensor wiring

 

Glad to hear it is getting better. Actually, I was asking about the possibility of your car being cannibalized while at the shop. You were relating a story (in your other post) where you met someone who also used that shop, and were told that their car was repaired with parts from a car in the lot. You were beginning to speculate on a worse case scenario regarding the disposition of your car at that shop. It was a real cliffhanger of a story.

 

The LH2.4 ECU has no circuitry to monitor the current used to batch fire the injectors. What it has, is an idea of how much it can increase or decrease injector open duration before coming to the conclusion closed loop feedback does not exist. When this happens the mixture is set safely rich and the 113 DTC is set, and no further attempts are made to pay attention to the oxygen sensor input. 113 can have many causes, but because of that "injector" verbiage in some manuals, many, many people have dumped money into new injectors with disappointing results. The injector driver transistor in LH2.4 is a simple bipolar open collector switch. The only thing LH2.4 knows about the injectors is how long the switch is closed.

 

very few of these cars have a motronic 1.8 system that /does/ monitor the injectors, and 113 is the code for that, I don't think these ever made it to the USA.

on lh2.4, 113 is o2 sensor related, suggesting the engine is running too lean or too rich, out of range. while a bad o2 sensor (or wiring) can trigger it, air leaks, and other such things can, too.

 

I obtained a manual for this particular Jetronic unit (Bosch 0 280 000 556 in particular, which covers a number of interchangeable Jetronic Units). The 113 code just indicates that the resistance of the entire injector circuit is out of range (4 ohms +/- 1 ohm) which could be caused by a bad injector or bad ground or bad wiring harness.

Now, here's the funny part. I checked the cumulative resistance and the individual injectors and the resistance is right where it should be in part and whole.

And I forgot to mention this part earlier when I did the initial diagnostics when I got the car back from the mechanic because the check engine light was suddenly on again:

I went to erase the error code and low and behold, the mechanic left the diagnostic connection in the #2 receptacle on the little diagnostic interface (which is an amazingly idiotic design).

I thought to myself, surely such an oversight by the mechanic would not cause a bogus code to be thrown.

So, just for the joy of it (not) I went through the entire procedure to see what codes were stored and it was three instances of 113. See where this is going?

So, I checked with a Volvo dealer about this and the response was, 'oh, yeah, by the way, if you leave the diagnostic plug in a receptacle and forget about it and run the car, the Jetronic will act a little funky'. No kidding, like throw bogus codes because depending upon the receptacle, you will disable or limp out any number of sensors.

So, after I removed the diagnostic connection wire and stowed it properly, drove the car until the Jetronic threw a 113 code again. Then, I simply erased the stored codes via the diagnostic interface under the hood and it hasn't thrown a code since.

Apparently, the mechanic leaving the diagnostic centre connected like it was being tested was causing the error code for some odd reason.

 

556 is the standard early LH 2.4 ECU for cars with EGR (California, etc).

all the tables I find online say 1-1-3 is a fuel trim error, basically that the o2 sensor reading doesn't jive with the ECU's expectations. See https://www.volvoclub.org.uk/faq/Eng...InjectionFault for example. the injector current error is only on the motronic 1.8 ECU which was used on Volvo 260/760's with the V6...

 

Manual for a Jetronic unit? Do show and tell!

The circuit has no knowledge of the resistance of its load. Like Pierce said, this is a Motronic feature not relevant to Jetronic cars.

Leaving the pin in is harmless.

Folks working for Volvo dealers will say anything to get you started?

No, it had no effect. If you want to reset the codes reliably, lift the 25A fuse momentarily. Removing power from the ECU immediately clears its stored DTCs and adaptive trim.