Help pls, Mondial QV running very rich

What model year? '83 (K-Jet) or '84+ (K-Jet with Lambda)?

Does it run poorly when cold and warm or just when warm?

 

You might want to confirm that the cold start injector (a.k.a., auxilary starting assembly) is not stuck "open" either electrically or mechanically -- i.e., it shouldn't have +12V on it always -- you could just unplug the electrical connector when running to see if things change or not, and, if you run the fuel pump manually (by jumping the fuel pump relay with the engine not running), no fuel should come out of the business end -- just some easy things to confirm/deny (you'll be lucky if this is the problem).

How do you know that "the warm up regulator shuts down" -- have you made actual measurements of the fuel control pressure?

The good news is that the dumb K-Jet system really doesn't have much electrical that can go wrong, but that's also the bad news -- if the supply and control pressures are working OK, and the cold start injector is working correctly, that essentially only leaves the FD.

 

There's a FD for a mercedes v8 on ebay right now for a buy it now of I think $250. I dont know if they are caliberated for a 3 liter though.

Dave

 

8039202955 It has about 18 hrs left

Dave

 

dont know, the 208 is a Dino. Is the Dino a 6cyl or 8cyl? I believe the pic on ebay looks like an 8cyl.

Dave

 

One thing to check for is that the ECU is getting power - there is a fused relay (on my 88 at least) and when the fuse blows out all kinds of crazy mixture problems become really apparent.

On that CIS system, the way to confirm if the FI is running really rich is to measure the fuel pressure. There is a fairly narrow band of correct fuel pressure in the manual and with a fuel pressure guage you'll be able to check this. Fuel pressure (as adjusted by the arm attached to the air flow plate) is the means by which mixture is regulated on the CIS cars. Good luck and persist!

 

The 208's were the 2 litre 308 gt4 / gtb /gts for the Italian market, the 208 turbos were introduced to improve the performance of the 2 litre cars (which as they were post 1976/7 were always badged as Ferrari's!)

You may want to cross refernce this FD with Bosch to see if the application is still valid.

You may also want to take the car to a Bosch service centre.....a relativley quick and cheap way to diagnose any FI problems if you dont already have the kit to test fuel pressure etc.

 

Check the simple stuff first.

Sticky cold start injector (blue plug, take it physically out of the plenum and provide some catch basin, seal the resultant vacuum leak), fuel pressure and control pressure.

IIRC, no electronic gizmos in '83 (I owned Birdman's '83 QV coupe) but in 1984, the control relay for the added frequency valve (which WOULD cause this very problem) was in the lower right hand portion of the trunk under a panel under the carpet, would get wet all the time and fritz out.

CS injector
system pressure
control pressure

These checks will isolate the fuel pump, warm-up regulator or fuel distributor. The FD's don't give much trouble and the standard drill is to take them out, clean up the plunger and the bore to fix them...

-Peter

 

Yes, diagnosing an ailing K-Jet for your symptom pretty much requires the pressure measurements (if it isn't the cold start injector misbehaving). Actually, I think you can do better than this on price via one of the discount tool websites, but here's one example:

http://www.jcwhitney.com/autoparts/ItemBrowse/c-10101/s-10101/p-100000160266/mediaCode-ZX/appId-100000160266/Pr-p_CATENTRY_ID:100000160266

Try some internet searches on something like "Bosch CIS injection pressure gauge" or "CIS pressure gauge", etc. -- should get you some other suppliers.

 

I am not sure if that year was supposed to have a Lambda circuit or not.
Does it have an Oxy sensor on the exhaust? If it does, tht is to tell the lambda the input it needs on the mixtures burn quality by analysing the gasses. No sensor, no lambda.
The Bosch is a simple, yet highly complicated unit. Complicated in that there is very little input on how to work with the system. Mnuals, such as the Probst book are good to a point, but do not tell a lot of the story.
The simplest way I can describe the fuel metering adjustablity is it relies on a balance of systems and their pressures to work well.
The system pressure, adjusted by shims is one part, and the air doors 3mm adjustment is another.
Adjusting the air doors relationship to the pintle (that rod that moves in and out of the fuel distributor), by turning that set screw can be of some good, but one must be carefull as you can cause running problems if it goes too far. Difficulty starting is one problem that can be seen.
You may wish to check the manifold vacuum hose to the Control Pressure Regulator (often called the WUR). This is the smaller of the two hoses that go to the unit. If there is a leak, as often happens on a bend when the hose gets old and brittle, The regulator reads that as a low manifold vacuum, such as would be seen if the throttle were opened quickly, and it will fatten up the mixture to avoid a bog.
Relax, it is a good system, just greatly understood. Just about every car manufacturer over there, and a few in Japan have all run it at one time or another, so it must be good!
On the control pressures, a good friend of mine had a gauge put on the fuel distributor of his Mondy to read them. A small, liquid filled one can be fitted in with a bit of work, and it is damn handy. You can watch the system go from cold pressue as it starts to warm presure any time. Sure takes the guess work out of it.
I can send you information on the pressures if you want.

 

Hi Doc,
Could you send me the info on the pressure test kit your buying? I have a Mondi 8 that I'll be keeping for a few years so could use the info.

Thanx.
Mike

 

Doc:
I believe the sensors you refer to are just thermocouples rather than O2 sensors. They measure temperature, and as you say connect to the “too hot” warning lights.

 

If you can get it the Mond 8/ Mond QV Workshop manual # 281/83 is an exellent manual to own for anyone working on V8 cars.
It has a very good section on the engine mangement system with a great section on CIS injection that gives a great deal of info on theory of operation. It is also good on diagnosis info. It is my most used book when working on V8's of the 80's no matter what chassis they are in.

 

That would be the AAV, or Auxiliar Air Valve. It's job is to provide short term extra air to get the cold higher idle. You are still getting the fuel for that air however, so it will be fat as hell (running excessively rich).

 

Doc -- This would only affect cold-running (so if warm-running is bad too, as you indicted earlier, that must be something else), but the Cold Start Air Valve is controlled by the same electrics running that warning light in the dash. Gives the same kind of problem that Kermit mentioned for the AAV -- when cold, the fuel system is adding extra fuel expecting the Cold Start Air Valve to be open, so, if it isn't, the A/F ratio is rich.

Not sure about the logic, but, if you remove the small vacuum line going to the Cold Start Air Valve (page 70 in your OM), and feel it with your finger, it should change state from cold to warm -- i.e., in one state = "no vacuum present" and in the other state = "vacuum present". Also, just plugging and unplugging that vacuum line from the Cold Start Air Valve, during both cold and warm running, and noting what happens (or doesn't happen) to the engine running can be informative. (Just some suggestions to rule the CSAV in or out).

 

Forget about the diagnosis plug. It was for the Jofatron, we called it the Jokeatron. Useless POS. Only did partial primary ignition diagnosis anyway.

 

Ferrari built 208 Turbo versions of the 308 2V & 4V for the Italian market. Anything over 2L or so had a horrendous tax at athe time. They're pretty rare.

The 208 air intake system was radically different from that of the other injected 3x8s, due to the turbos & their plumbing.

That's only a partial distributor, It's missing the entire airflow sensing plate & it's housing. All that's there is the fuel valving/distribution part of the distributor.