Injectors or something else?

[SilverMoose]

Hey guys, it’s been a while since posting but I have been checking in.  Life is really getting in my way.  I hope everyone is well.

 

Now on to my issue.  For the past few weeks my load (from OBDlink) at idle in gear has been very high.  It’s higher now than when I’ve had my AC on previously.  When at idle and in park it bounces between 0% and 4%.  It’s when I put it in gear that it jumps up to above 15% (typically 18%-20%).  I’ve also notice that my fuel rate has jumped to levels higher than when my AC was on (somewhere between 0.7 and 0.9 gal/hr).  When I do have my AC on the load is well above 20% (around 24% +/-).  Previously, with my AC on my max fuel rate was right at 0.7 gal/hr and without Ac around 0.4 gal/hr.  With 140K mile, I know that I am due for new injectors and wonder if this could be a reason for this?  I have searched the posts here and most information says that idle will increase and load drop with old worn out injectors.  RPM’s are fine.  800 idle in park, 750 idle in gear.  I am planning to get new injectors in the next few weeks.  I have noticed some slight hiccups during idle lately but very random and not frequent.  Once I am moving everything seems to be normal.  There are no error codes.

 

 

I also added the MAP sensor gauge to OBDlink to see if maybe this could be part of my problem.  The reading I get on that key on engine off is around 59inhg +/-.  I would think that should be around 29inhg +/- but haven’t been able to find any definite information about this online.  I am thinking about taking it out and testing it using a USB power source to see what the output voltage is with no boost.

 

The truck seems to be running fine and I my mileage could be a slightly lower.  I’m early on a tank and can’t be sure until my next fill.  I’m trying to see if I notice any performance degradation but conforming this could just be my imagination working overtime.  There are no boost leaks.  I did a WOT run and the boost jumped right up to 19psi where the wastegate opened.  The MAP sensor read 75inhg +/- at WOT.  I borrowed a boost leak tester from a friend and I test with that this weekend.

 

I hate to say this but the only other thing I could think of is possibly something is not right in the trans.  Hoping that is not the case though.  I use the Chris O Meter and went for a drive to check the trans temp and it appears to be normal.  Running temp was around 160.

 

Anyway, I’m kind of stumped and would appreciate any advice.

 

Thanks in advance.

 

L8tr

d

[Me78569]

late trucks don't report map values in in/hg like you are expecting.  those numbers look normal for boost at idle vs WOT.  

 

i wouldn't sweat it too much if you are already planning on getting new injectors.  Just see what it is like after the injectors.

 

doubt the trans is having issues.

[SilverMoose]

@Me78569 thanks for the input.  Now for the question...  I would like to wake the moose up a little.  RV275 or some 50hp sticks?  RV's are VCO I believe but what about SAC (for the 50's)?  I don't hot rod it too much but a little extra go may be nice but don't want to hurt the trans but realize it will probably need a rebuild some day.  I was thinking about keeping the stock injectors.  That way when I finally rebuild the trans I can rebuild them larger and add quad.

 

Thanks again.

[Me78569]

I almost dont see the point of doing small injectors if you are planning on more down the road.

 

I guess id do rv275's

[Evan]

I agree. Glad I went with 100s when my stockers were done

[SilverMoose]

I figure if I need new ones, I might as well upgrade a little over stock.  Do I need to, no but a little extra night be nice. Who knows maybe the trains will last another 200k.  How's that for wishful thinking.

 

l8tr

d