1983 Volvo 245 turbo cylinder wash out

[JJtaylor]

Looking for some advice on this project of mine..

Car had been sitting since 1999, I have re-done the entire fuel system (as well as basic tune up, timing belt, head gasket, intake/exhaust etc) from the gas tank to the injectors, as well as rebuilt the fuel distribution unit, set the base mixture with the Allen screw and It fired right up, I was able to adjust idle to about 950-1100 where it would surge, no obvious vacuum leaks. It will run for about 30 minutes fairly well and then wash the cylinders out. I have done this 2 or 3 times now, and with fresh oil it runs for awhile and same thing. System pressure is 75 psi, dwell seems to be in spec, timing is between 10 and 12 degrees but hard to tell with surging idle/miss from running rich.

My next thoughts are to possibly lower the system pressure from 75 to 65-70 and see if that prevents wash out.

Am I on the right track? Let me know if I am leaving anything out.

Thank you!

 

[302ftw?]

What about control pressure? In my case, I found my intank pump is not working, which may be affecting both system and control pressure.

 

[2manyturbos]

Looking for some advice on this project of mine..

Car had been sitting since 1999, I have re-done the entire fuel system (as well as basic tune up, timing belt, head gasket, intake/exhaust etc) from the gas tank to the injectors, as well as rebuilt the fuel distribution unit, set the base mixture with the Allen screw and It fired right up, I was able to adjust idle to about 950-1100 where it would surge, no obvious vacuum leaks. It will run for about 30 minutes fairly well and then wash the cylinders out. I have done this 2 or 3 times now, and with fresh oil it runs for awhile and same thing. System pressure is 75 psi, dwell seems to be in spec, timing is between 10 and 12 degrees but hard to tell with surging idle/miss from running rich.

My next thoughts are to possibly lower the system pressure from 75 to 65-70 and see if that prevents wash out.

Am I on the right track? Let me know if I am leaving anything out.

Thank you!

No. The system pressure is not 75 psi. That is the pressure to the system. That is exactly what you should have going from the pump to the fuel distributor. The warm up regulator controls the system pressure. You need to have a much better set of fuel pressure gages to really know what is going on with K-jet. The Green book shows how to measure pressures in the system.

 

[dl242gt]

The B21FT uses Kjet Lambda. So after you have verified the system, control, and rest pressures. Next you move to the lambda control system which is used to enrich the fuel mixture for cold starting as well as for boost. You'll need a dwell meter, and a voltmeter to test that stuff. Also for cold running there is an enrichment setup on the control pressure regulator. Check over the vacuum hoses and make sure there aren't any split ones.

On the engine block on the left toward the rear is a single wire sensor. This grounds on a cold engine making the mixture very rich. As the block warms the sensor opens the circuit. If your wiring is flaking and bad there it could shorting causing too much fuel. There are two sensors there. The two wire one is for the engine coolant temp for the Continuous Idle System.

 

[JJtaylor]

The B21FT uses Kjet Lambda. So after you have verified the system, control, and rest pressures. Next you move to the lambda control system which is used to enrich the fuel mixture for cold starting as well as for boost. You'll need a dwell meter, and a voltmeter to test that stuff. Also for cold running there is an enrichment setup on the control pressure regulator. Check over the vacuum hoses and make sure there aren't any split ones.

On the engine block on the left toward the rear is a single wire sensor. This grounds on a cold engine making the mixture very rich. As the block warms the sensor opens the circuit. If your wiring is flaking and bad there it could shorting causing too much fuel. There are two sensors there. The two wire one is for the engine coolant temp for the Continuous Idle System.

I should have mentioned I replaced the engine harness with a new one, double checked the wiring on the intake side near the back everything seems clean & connected. I tried using the dwell meter, I forget the numbers but they were within spec with O2 connected & disconnected per the manual. What I did not see was any sweeping of the needle or changes when I turned the mixture screw?

My primary concern is to set myself up to not wash out the cylinders in 30 minutes. I have accepted it may happen again as I diagnose. Thank you for the advice!

 

[dl242gt]

If the O2 sensor is bad it won't sweep. If the adjustment of the mixture screw is too far out of range then the engine won't cycle when warmed up.

The default basic adjustment to get the engine in range is to back off the screw till the engine won't start. Then using about a a quarter to a half turn at a time turn clockwise to richen till it starts. Then maybe a quarter turn richer from that point. Then I would warm the engine up completely and see what the dwell is. You should be hearing a buzzing sound as the frequency valve adjusts the mixture. Then you will also see the sweep on the dwell meter if it's in range. Aim for the lower side of the 41-44 degrees of dwell with a warmed up engine idling. If you take too long to measure the o2 sensor can get cooled off. Then rev the engine for about 30-45 seconds and check the idle dwell again. Very slight changes will change the dwell a lot.
Another very important Kjet test is injector spray pattern. You can put each injector in a clear jar and fire up the pumps jumpering fuse 5 to fuse 7. Then lift the airflow plate and look at the pattern. Compare to the book pictures. It should be an atomized spray. Not a stream. That will also wash down cylinders and run rough if the pattern is poor. Don't mind the screaming sound it's normal.