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supermoto154
01-24-2013, 11:46 AM
Hey guys,
I tried searching the forum for topics the same as mine before posting. I have a 2002 freight liner that the engine pulses under acceleration. I have replaced my fuel filter and the fuel lines because I had a small air leak, also it looks like my #2 injector could be leaking. Where do I start? Thanks!!

Aqua Puttana
01-24-2013, 12:10 PM
Were the fuel lines and filter changed and then the problems surfaced, or were they replaced as an attempt to correct the symptoms?

There have been threads where uneven power traced to leaks in the turbo system. A small leak can open during the higher boost pressures of acceleration and close back up (or leak less) when the pressures are lower.

A misadjusted or faulty brake switch can also contribute to momentary power loss.

In this case you say you have a questionable injector. What revealed that?

Without a possible injector problem indicated, I would advise to do a close inspection of the turbo boost system for leaks. That is still worthwhile.

Assuming accurate information about the injector, don't ignore the injector.

Just information, not a diagnosis. vic

Hey guys,
I tried searching the forum for topics the same as mine before posting. I have a 2002 freight liner that the engine pulses under acceleration. I have replaced my fuel filter and the fuel lines because I had a small air leak, also it looks like my #2 injector could be leaking. Where do I start? Thanks!!

supermoto154
01-24-2013, 12:17 PM
Fuel lines were replaced because of hard starting, I was getting air in the line. While I was working I inspected injectors, it looks as if #2 has the black death ? All around it. My van runs fine, I just have a small pulse when getting on the highway. I suppose I need to replace the injector and that could fix or keep any further problems. I replaced my turbo about a year ago also.. Thanks for the help!

Aqua Puttana
01-24-2013, 12:41 PM
Fuel lines were replaced because of hard starting, I was getting air in the line. While I was working I inspected injectors, it looks as if #2 has the black death ? All around it. My van runs fine, I just have a small pulse when getting on the highway. I suppose I need to replace the injector and that could fix or keep any further problems. I replaced my turbo about a year ago also.. Thanks for the help!
Early or small volume injector seat copper seal leakage will not generally affect performance. If it is leaking to the point of hearing a chuffing noise then maybe that could contribute.

The injector showing black death indicates that the mechanical seal has failed. It generally has nothing to do with injector preformance. Unless testing points to an injector problem, an injector with a leaking seal can be removed, the seal restored to good condition, and the injector re-installed.

Look to other issues causing your power issues. The black death likely has nothing to do with it.

vic

talkinghorse43
01-24-2013, 02:52 PM
Fuel lines were replaced because of hard starting, I was getting air in the line. While I was working I inspected injectors, it looks as if #2 has the black death ? All around it. My van runs fine, I just have a small pulse when getting on the highway. I suppose I need to replace the injector and that could fix or keep any further problems. I replaced my turbo about a year ago also.. Thanks for the help!

When pulsing, what does the tach show? Do rpms go down during a pulse, or up? If down, then I suspect a fuel supply problem (could even be a partially plugged fuel filter). If up, then maybe a tranny problem.

autostaretx
01-24-2013, 03:25 PM
Does a dealer-level scanner (DAD, CarSoft, DRB-III, AutoEnginuity, SnapOn) reveal any stored codes?
That level of scanner can test for cylinder-by-cylinder misfirings

--dick

jackbombay
01-24-2013, 03:49 PM
How quick is the power cycling up and down? 1 cycle per second? 2 cycles per second? Has it caused limp mode yet?

Boater
01-24-2013, 04:53 PM
Could the pulsing be no 2 injector not firing at all?

supermoto154
01-24-2013, 06:58 PM
The engine pulse occurs every 1-2 seconds under hard accel. I havent pulled any codes yet. My biggest problem now is i have air leak that i cant find, so cold day starts are not fun. Ive checked orings and regreased. Ive also replaced filter and fuel lines....?

jackbombay
01-24-2013, 07:18 PM
The engine pulse occurs every 1-2 seconds under hard accel.

Can you hear the turbo whistle changing in volume in unison with the pulses?

If so I bet you have a bad boost control solenoid, I just changed mine out....

I was getting limp mode if I put the pedal down, and it seems you are not getting limp mode?

talkinghorse43
01-25-2013, 01:42 AM
The engine pulse occurs every 1-2 seconds under hard accel. I havent pulled any codes yet. My biggest problem now is i have air leak that i cant find, so cold day starts are not fun. Ive checked orings and regreased. Ive also replaced filter and fuel lines....?

Assuming you mean here that you have an air leak into the fuel system? If yes, then that might cause the pulse because it could be limiting the rail pressure at high demand and result in too low pressure on acceleration - similar to what a partially plugged filter would. I have Autoengenuity, so I would record rail pressure while pulsing to check this hypothesis.