injector knock?
 

I have a 99 ppump 24v didn't know if I should post here or what. rebuilt the engine awhile back we couldn't get a sheet on timing so we set the timing where we thought it was best, at idle you cant really hear the knocking or rattle but as you accelerate you can hear it and you can hear it best going under a bridge or next to jersey barriers or a tractor trailer on highway, the injectors were in the truck when I got it and it didn't have the knock like it does now after we rebuilt the engine its not a rod knock or bearing. I was going to pull out the injectors to have them pop tested but was wondering what the bar should be set at for the p7100. the pump has work done and flows around 600cc of fuel and injectors are 7x16 sac "billet bodies".

Also really only does it when in gear with a load on the engine

you seriously spent all this money and guessed on pump timing???
has the timing tab been changed in the pump or is it set to stock timing?
you didnt pin time it or set it with a gauge? im baffled in your thinking.
if you have a god awful amount of timing it will be hard starting hase white and rattle ALOT unless you are WAY up in the RPMS.

i set my injectors between 160 and 180 bar depending on the application

kinda rare for these style injectors to fuel knock as they are mechanical and have to really really F-up to start dumping fuel instead of a solenoid issue like the newer stuff. they normally leak or have poor chatter or spray pattern causing misses and excess smoke/loss of power issues. stuck open injectors will make you tow the truck home, like OMG what is wrong with the truck shut the key off kinda stuff.

i vote properly set your timing and enjoy. around 20* for a hot street truck.

Not pin timed. Not hard to start it hazes white while idling and cruising down the highway. It didn't do this before I rebuilt the engine. I was going to pull out the injectors cause it cost 7 dollars to bar test them which is cheap. At idle like I said not to chattery and can't hear a knock even when I bring up the rpm in park or neutral when u put it into gear and have a load on the engine and start on the throttle is when you have the problem. And wen under a bridge or whatever sounds more like comming from the passenger side of the rig

We set it with a dial indicator

thats fine , i do too. what did you set it to? are these injectors new? you said billet bodies i can only assume they dont have bunches of miles on them

I would say .. Your timing is way too high .. You need to time it right .. 20* should be a good starting point ..:tu:

injectors are not new, have had them for awhile.. like I said we do not know where the timing is atm because we could not find a chart for the pump this pump, we set it to where it sounded best at an idle going to reset tomorrow. Ive been told if it hazes on the highway its way to high.

ya theres your problem. set to .000's of an inch and you guessed

yeah too much timing will cause you to actually hear each injector/cumbustion event .. :td:

.. Unless you are going to spin it to like 5K ..

P-Pump Timing Chart - Competition Diesel.Com - Bringing The BEST Together

This thread will give you all the Info you need .. :tu::c:.. Keep us posted :pca1:

why such a monster injector for a street truck? 7x.016's are huge


I hope you ment 260-280 bar :c:

lol oops. and i didnt catch the 7 x 16 thing, glimpst at it and figured 5x16. maybe he had a brain fart aswell. lol

That's what was in the truck before I rebuilt it.. when you start making some boost it starts to disapate

do you know them to be that size or are you going off what the kid told you when you bought it? because those are huge injectors. like really really big.

I think I would be more concerned with the timing rather than the injector at the moment .. could wash a cylinder though with that much fuel .. and the injection event comming in WAY to early .. all can lead to engine damage ..:td:

timing is set to 24 degrees when we checked it yesterday. and yes have had injectors looked at awhile ago when I rebuilt the engine.

Take it back to 18-20* and see how that sounds ... I think with your injector size and the static timing you have put in your actual timing is going to be closer to 28-32*..

Larger injectors put in more fuel in less crankshaft duration, = Advanced timing ..

I would push the timing back and I would think you would notice a difference in the way it runs and sounds .. :tu:

when we ran it arund 18 before it didn't have a lot of low end. and I forgot to mention this motor that I built I had the deck shaved and the head shaved so the clearances are even tighter.

But when it was at 18 degrees it wasent as chattery

the reason is wasnt chattery is due to the injection event .. your only dealing with static timing when you set your IP @ the gear ..

When you are able to time the Actual injection event .. you will be able to get a better timing set up .. 1-2* can and will make a big difference .. I would play with it a bit .. go to about 19-20* ... see where that takes ya .. and you will have to make adjustments to the AFC .. :pca1:

yeah il have to mess around with it later on in the winter

Make sure the eninge is all warmed up before trying to make any good passes .. pop a HG like I did... :argh::td: