354 Injector pump question?

[Bigbear]

OK, here's the deal. My Foton 354 has been dropping the back cylinder on and off for a couple months. White smoke starts to blow, loss of power, no diesel fuel, or very little coming through that line. Cannot bleed the line. Dealer sent me a new pump, same problem, same cylinder. Each time, the thing that seems to fix the problem is moving the compression release several times. I was told (by someone other than dealer) that the injector was bad and the check valve was not letting the pump work right. Can a bad injector have that effect on a pump? What are the chances of 2 pumps having the very same cylinder drop out from time to time? I still think the compression release is somehow to blame. It seems to me, if a pump went bad, it would stay bad.

Anyway, my dealer picked up the tractor Wed, I called today, and was told they were waiting on a new ?PUMP?. 2 pumps in less than 2 weeks, . What do you guys think about the problem? Thanks, BEAR /forums/images/graemlins/mad.gif

 

[RickB]

The injector on the rear cylinder is junk. Compression is pushing the fuel back in the pump. Operating the compression release allows fuel pressure to overcome lowered compression, filling the line and injector with fuel and "curing" the problem temporarily. The compression release is fine. The chances of a used, existing pump and a brand new injection pump sharing a common problem are just about nil. The first thing the shop should do is remove the injector line at the injector end, then crank or start the engine. They will probably find compression escaping from the injector pressure port.

 

[Bigbear]

That makes sense RickB, with what I was told about the workings of an injector. I noticed when I tore down the old pump (checking for dirt, etc) that it also has a check valve in each line. Does the injector send a backpressure pulse to the pump and close this check valve and thus allow fuel to charge the line again for the next firing order? (or close to that). I am starting to think, I should have just inspected the compression release parts and bought a new injector and tried to fix the problem myself.
Thanks for the input RickB /forums/images/graemlins/grin.gif

 

[Bigbear]

Almost a week now, still no tractor. Talked with dealer yesterday, he said 3rd new pump had arrived, now on vacation mechanic would come in to install. He did not call me back after we were cut off during conversation, they have many phones at dealership. Mechanic told him the issue with the hydraulics was due to low oil level to low, might have been, but it was touching the dip stick and had never done that before.
I want my Tractor BACK /forums/images/graemlins/mad.gif I am going to call him today and see if it's fixed, and then order a new hydraulic pump, and new injector, after the 3rd new injector pump, I think we can rule that out as the problem. /forums/images/graemlins/confused.gif

 

[camoman45]

Hey dad i'm a member now too! /forums/images/graemlins/smile.gif

 

[Bigbear]

Got the tractor back yesterday. Guess what, only needed a new injector. Wish we would have done that about 3 weeks ago. Oh well, I have her back now, and life is once again good. /forums/images/graemlins/grin.gif