I just picked up my first volvo. It's a 1981 Volvo 242 glt. Ok so upon starting the car, you have to feed it fuel to keep it alive. It will not idle on its own. At low rpm it has a hard miss that causes the engine to shake (bad engine mounts also). If I bring rpm up to around 3k it runs better but still has a sporadic miss. I checked plugs and they are gapped accordingly and seem to be burning evenly. Distributor cap is brand new as well. The idle motor looked to be unplugged from its electrical clip so clipped it in and no change at all. Boost doesn't build till around 3k either. But all charge piping is sealed tightly. There is however a terrible exhaust leak on either A. The exhaust manifold, B. The turbo mounting flange, C. Turbo outlet gasket or D all of the above. Also noticed the spot for the o2 sensor is plugged off. Did the 81 come with an o2? Also any advice or ideas? I so far plan to check the dwell, fuel pressure, and CPR.

 

I believe thats an old K-Jet system. it may or may not have the 'constant idle system', that was used on some late K-jets. I thought by 1981 they all had "Lambda" (O2 sensors) but I don't have any cars that old so I don't know, nor do I have wiring diagrams for 1980-1983 (those years are missing from my library).

I had a K-jet mercedes that had all kinds of rough idle problems, many of which traced to fouled injectors combined with bad injector seals.

 

I am going to do a fuel pressure test and an intake pressure test to see what is or isn't going on in those systems when I get paid(need to buy the tools for said tasks). I also found that cylinder 3 spark plug wire was dead. Have to wait till the weekend to get new plug wires.


I have been searching to see about if the car needs to have an O2 sensor or not. I cannot find an empty plug anywhere in the engine bay at all that resembles the plug for an O2 that would come this car.


I need to read more about the k-jet system and how to care for it along with do's and do not's.

 

K-Jetronics (sometimes called CIS for Continuous Injection System except that Volvo thinks CIS is Constant Idle System...) works off differential pressures, each segment of the fuel distributor has a upper and lower chamber, with a pressure diaphragm between them.

there's scans of a bunch of VOlvo 'greenbooks' here, 200 Series » Section 2 ? Engine | K-Jet.org on early 240 CI systems, in particular this book seems to be apprporiate here, http://www.k-jet.org/files/greenbook..._ci_system.pdf

 

the B230 Turbos are super finicky

Mine had very similar issues with a bad MAF sensor
start the car with it unplugged and see if there is ANY change to idle and how it revs

in your case the exhaust leak will calls a whole mess of issues, that will need to be fixed first (will also account for the difficulty getting boost)
also a side note, try not to go into a boost condition when the engine is missing on a cylinder, that would potentially cause issues

K-Jet is not my territory tho, this information is from personal experience with a 93' 940 turbo

 

Yea I took it into boost once just to see if and when it would build. I can already tell this car is going to teach me a lot not only about volvos, but myself and the boundaries of my patience and will. It will hopefully be a fun, frustrating journey with some rewards mixed in.

 

the B230FT turbos are LH2.2 (up to 1989) or 2.4 (1990+), and *completely* different than the B21FT from 1981. No MAF (Mass Air Flow) on KE-Jet, thats purely a LH thing.

 

O2 sensor is in the manifold. Leaks passed downstream of the sensor will not effect it.

You need to check the throttle switch is adjust correctly. Click as soon as it moves.

Then check the air flow meter plater. It should be it the center. The housing.

The fuel adjust screw adjust the ether player at idle. You might have to check that.

Idle motor working? Boost builds at 3000 in that car.

 

I put in bold all my replies in the quote.

 

ugh, if you don't know what the air meter is on a CIS system, you should find someone familiar with CIS/KE-Jet to work on this, maybe a older VW (rabbit/golf, jetta from the 80s) mechanic, or Porsche, or even Mercedes, they all used CIS nearly a decade after Volvo dropped it.

CIS/KE-Jet is very intricate and doesn't take well to hamfishted wrenching. It works very well when its working.

With a turbo, any exhaust leaks in the manifold should be dealt with immediately as they are going to make a mess of the boost, and that engine will never perform right. intake manifold leaks are a common cause of fuel delivery problems too.

 

I have been watching video after video about the CIS/K-Jetronic system and how to clean, adjust and replace parts of the system. I have the gaskets for the manifold ordered. I am going to replace most vacuum lines and thinking about testing and cleaning the injectors along with replacing o rings and holders if needed to eliminate any vacuum leaks in that area. But not before I do enough research, I dont want to go in there still having a bunch of questions and second guesses.

 

testing and cleaning CIS injectors requires a 'pop tester' which puts pressurized cleaning fluid through them at like 40 PSI or something, as they won't even open below that.

the critical test is that the spray pattern from all 4 injectors is equal and symmetric, and under the same pressure they flow the same amount of fluid.

a diesel injection shop has the equipment to do this.

if they are clogged up, cleaning only works some of the time, more often than not, they need replacing. the volvo 1276037 injectors do appear to be available, for instance, Volvo KJet Fuel Injector BOSCH 100264 1276037 0437502015 0437502023 (you need 4), also 4 each upper o-ring and lower oring, here's a kit of 4, Volvo Fuel Injector Seal Kit 104082 2D0300K

 

Payday is the 30th, so then I will be able to get the pop tester needed, along with a few other things. And yea from what I have read and watched, it is around 40 PSI. Thank you for the links, I greatly appreciate those, as well as your time and insight. I hope that I can learn this system well and keep it efficient for a few more years. Hopefully I can get it to the point of idling on its own, and not dying every time I need to come to a stop, soon.

 

get the engine running relatively smoothly with the hood up, and use a unlit propane to flood areas around the intake manifold with said propane. if the engine speed or tone changes when the propane is flooded around the injectors, then its almost certainly the seals.