fin_diesel
11-19-2010, 13:08
I'm totally confused with my 6.2L N/As. It would be great it someone could show me the light. Long story with bad euro english:o:
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Background:
I have a couple of Chevrolet Caprice STWs running with 6.2 motors. Both of them are updated with new and remanufactured injection pumps. I'm calling those cars as STW1 and STW2.
I have a timing light with pulse sensor. I'm using it to check dynamic timing.
Military manuals are saying that timing for late 6.2L and 6.5L pumps should be 5 deg / 1300rpm. This is timing I'm looking for.
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First STW1: It has just rebuilt motor (about 1000 miles behind). And the new injection pump is: DB2831 5149 94-96 HMMWV(Military) 6.5L N/A, 1.2CSt(170hp). Pump is set to timing marks on line and got the following results with timing light: 1300 rpm / 5 deg. This is exactly what Military spec says and car is running and working nicely.
Then I find a pump quick test intructions from inet:
- pressing lower should retard timing 3 to 5 degrees => PASS
- activating cold advance solenoid should advance timing 3 to 5 degrees => PASS
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So, everything seems to be fine with this STW1 but then STW2:
its motor is rebuilt about 20000 miles ago. And the remanufactured injection pump is: DB2831-4911 10183901 1992-93 HD C/K & P - Turbo (200 hp). Pump is set to timing marks on line and got the following results with timing light: 1300 rpm / -2 deg. It's running very badly and no black smoke.
Pump quick test:
- pressing lower should retard timing 3 to 5 degrees => FAIL, no changes
- activating cold advance solenoid should advance timing 3 to 5 degrees => no changes seen by eye but maybe little change by ear(or I'm just imaging it ).
=> Anyway, there is a change with timing value between idle(0deg) to 1300(-2deg) rpm, so advance piston is moving a little at least.
It seems that timing is too retarded.
---
And then the open items:
-Should I advance the timing to 5 deg / 1300 rpm with timing light ?
-Is there something wrong with the pump itself because advance is changing so little in degrees ? Or could it be explained with retarded timing ?
-Is this 5 deg / 1300rpm value valid for this 6.5TD pump also?
Hopefully someone understood what I'm looking for. And even better if you can give some hints what to do. I bought them via dealer without direct contact to vendor but there is one year warranty available.
---
Background:
I have a couple of Chevrolet Caprice STWs running with 6.2 motors. Both of them are updated with new and remanufactured injection pumps. I'm calling those cars as STW1 and STW2.
I have a timing light with pulse sensor. I'm using it to check dynamic timing.
Military manuals are saying that timing for late 6.2L and 6.5L pumps should be 5 deg / 1300rpm. This is timing I'm looking for.
---
First STW1: It has just rebuilt motor (about 1000 miles behind). And the new injection pump is: DB2831 5149 94-96 HMMWV(Military) 6.5L N/A, 1.2CSt(170hp). Pump is set to timing marks on line and got the following results with timing light: 1300 rpm / 5 deg. This is exactly what Military spec says and car is running and working nicely.
Then I find a pump quick test intructions from inet:
- pressing lower should retard timing 3 to 5 degrees => PASS
- activating cold advance solenoid should advance timing 3 to 5 degrees => PASS
---
So, everything seems to be fine with this STW1 but then STW2:
its motor is rebuilt about 20000 miles ago. And the remanufactured injection pump is: DB2831-4911 10183901 1992-93 HD C/K & P - Turbo (200 hp). Pump is set to timing marks on line and got the following results with timing light: 1300 rpm / -2 deg. It's running very badly and no black smoke.
Pump quick test:
- pressing lower should retard timing 3 to 5 degrees => FAIL, no changes
- activating cold advance solenoid should advance timing 3 to 5 degrees => no changes seen by eye but maybe little change by ear(or I'm just imaging it ).
=> Anyway, there is a change with timing value between idle(0deg) to 1300(-2deg) rpm, so advance piston is moving a little at least.
It seems that timing is too retarded.
---
And then the open items:
-Should I advance the timing to 5 deg / 1300 rpm with timing light ?
-Is there something wrong with the pump itself because advance is changing so little in degrees ? Or could it be explained with retarded timing ?
-Is this 5 deg / 1300rpm value valid for this 6.5TD pump also?
Hopefully someone understood what I'm looking for. And even better if you can give some hints what to do. I bought them via dealer without direct contact to vendor but there is one year warranty available.