timing surge

[Black dawg]

hello, last week I put a reman pump on my truck. on the way home from the shop, above 2200 rpm the timing would surge, motor getting real loud and then normal again. The next day it didnt do it so I figured it must have had some air stuck in it. Then yesterday, 6 days later it started doing it again. Timing is set to spec, have good fuel pressure and volume, still does it with cold advance wire unhooked, checked for air intrusion and return restriction. Pump shop doesnt think the pump is the problem. < am I missing something?> the motor doesnt gain speed or power when this happens, it just rattles harder. thanks for any help

 

[Agnem]

Welcome to the site. Timing changes are caused by fluxuations in the fuel presure inside of the pump, either because the presure changes coming in, or it changes going out. Air of course, will change the presure suddenly, but so will a restricition in the return line, or a problem with the lift pump. If it's not air, and it's not a presure problem on the supply or return side, then it is the pump. While not practicle to impliment, ideally it would be great if you could monitor the incoming fuel presure while you drive. If the problem continues, and you've exhausted all your options on verifying that the return isn't restricted, and the fuel supply is good, you may have to swap the pump to prove or disprove that it IS in fact the pump. Disconnect the cold idle advance solenoid to rule that one out.

 

[OkieGringo]

At what level is the fuel gauge showing when this happens? Around 1/4?

 

[Black dawg]

thanks for the replys, it does this on both tanks ,fuel level doesnt matter. It did not do this at all before this pump.

 

[Agnem]

If the pump is indeed all that was changed, and your return lines and what not were not disturbed, it's sounding an awfull lot like the pump to me.

 

[Black dawg]

Sooooo,










it was the injection pump.
Hate it when people come in and ask questions and never share any outcome.

 

[Clb]

20 years ago...
Wholly xxxx Batman..

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[Black dawg]

Was looking for some info that I posted long ago and found this.
After reading through many others, seems to have been pretty common for me to leave them open like that......
...

 

[Danielle]

Haha I'm also one that finds myself digging through a lot of 20 year old threads with no outcome.

 

[Black dawg]

Still drive that truck almost every day. Engine has had 1 valve cover gasket replaced in that time, other than that and fuel system stuff, and water pump, un touched. Burns much oil, takes a special sequence to get it to start cold, but other than that its like new....lol.