horrible mpg and weird idle drop

[KNBlazer]

This is a video of a tapping/knocking noise I only hear it when its cold I'm not shure what it is any ideas?

https://www.dropbox.com/s/suhihikwl9ownlj/VIDEO0043.mp4?dl=0

Lifter noise? Common among Chevy's ... google it ... Rule of thumb, or at least from what I've gathered, as long as it goes away, it's not bad.... I recently rented a 15 passenger Chevy van and there was a tapping, clicking noise, 3k miles on the odometer, it apparently was either, lifter or injector related...

 

[Gerbil21]

Well I hear it more from the pasanger side if that helps. Could it be the cat? I'm going to replace it soon either way also the sound goes away with higher rpm.

 

[Gerbil21]

One other thing did you read the post above the video, I would like to know if that's normal for cruise control

 

[KNBlazer]

something I would strongly urge you to do, otherwise you'll just be throwing money at it and if you haven't already done it, is to perform a compression test... you could have a bad valve... I had 4 bad valves, gas mileage though was typically between 14.5 and 15 mpg... the tapping sound if it goes away after the truck is warmed up, I wouldn't put much thought into it... my newly rebuilt engine is doing it... my old engine would sometimes do it as well... but only when cold or when it been parked for an hour or so...

 

[Gerbil21]

something I would strongly urge you to do, otherwise you'll just be throwing money at it and if you haven't already done it, is to perform a compression test... you could have a bad valve... I had 4 bad valves, gas mileage though was typically between 14.5 and 15 mpg... the tapping sound if it goes away after the truck is warmed up, I wouldn't put much thought into it... my newly rebuilt engine is doing it... my old engine would sometimes do it as well... but only when cold or when it been parked for an hour or so...

Check post #120(compression test results) there is a video after it too, and check post #159 (inside cylinder, and valve pics)

 

[gmcman]

The compression built kinda slow though, did you do a dry then wet test or only dry?

 

[Gerbil21]

Only dry

 

[Gerbil21]

So is cruise control supposes to operate like that? Also I should be installing all parts Wednesday if it dosent rain so let's see how much the cat helps. Also I might take off the spark plugs again and look in with camera again

 

[gmcman]

If you have the cruise set and the set speed isn't satisfied it will keep adding throttle and sometimes will downshift.

 

[Gerbil21]

Yea but does it floor it to get up to speed when its only about 20 under how is it for you?

 

[gmcman]

It will take off pretty good sometimes but usually not WOT, but strong.

 

[Gerbil21]

I got to make a video then because sometimes it will hit 5k easy

 

[Gerbil21]

OK well if anyone is following this thread so far I got a shift kit from ctpowertrain and a weld on cat converter I also got mopar combustion chamber cleaner to use before I change the cat.

So far I'm having a 1-2 shift problem

 

[Gerbil21]

OK so to gmcman what could cause a harsh shift only on 1-2 hot or cold

On the ortb forum he had two springs and only replaced the inner spring I decided to follow the transgo instructions and put 3 I did notice the bottom two springs stick together because there close in size

 

[gmcman]

OK so to gmcman what could cause a harsh shift only on 1-2 hot or cold

High spring pressure in the 1-2 accumulator.

Also drilling a passage larger than recommended. ..only takes a few thousandths.

Since you enlarged the hole more than you should, that will increase the firmness.

Did you install a vette servo as well?

I would maybe remove a spring or go back to the stock plate. If your are having harsh shifts you need to undo some of what you did.

 

[Gerbil21]

High spring pressure in the 1-2 accumulator.

Also drilling a passage larger than recommended. ..only takes a few thousandths.

Since you enlarged the hole more than you should, that will increase the firmness.

Did you install a vette servo as well?

I would maybe remove a spring or go back to the stock plate. If your are having harsh shifts you need to undo some of what you did.

I edited my post above

Also the bigger hole wasn't for 1-2 and still had a lot more room for a bigger size.

Also there was no modification to the servo and yea I might just remove the inner spring that was very stiff

 

[Gerbil21]

OK well i just used the mopar combustion chamber cleaner.

It smoked a bit and had a
rotten-ish exhaust smell nothing like a dead cat even thought. So Im going to leave it for a hour instead of 5-10min. And drive it hard on the highway

 

[Gerbil21]

OK well sorry I never gave a update but it did nothing we started it and it fired right up like nothing. Never smoked

The only thing i can think of is that we had to rev it up a bit high to prevent dying and we let it idle a bit after the can finished only about 10 seconds.

I will see if I get another can. Should I get another mopar can or the gm tec spray

 

[Gerbil21]

OK I know its been a while but this Tuesday we should be changing the transmission servo and have smooth shifts again and finally get rid of our harsh 1-2 shift.

Also a update on mpg
I will be getting another can of Mopar CCC of should I get gm tec spray? Hopefully that will help some, also I still need to get the cat welded on.

As for mpg I reset avg. MPG. On the dic and drove out the parking lot after waiting a bit to leave when I got to the first light I got to 1.7mpg. I reset it again and After driving down the block to the next light I got to 5.7mpg and it stood like that for a few blocks then I got up to 8mpg while doing 25mph stuck behind a a minivan. After getting home which was a few miles away driving at 30-35 (no way anyone's doing the new 25mph speed limit, ...except for that minivan) it got up to low 9mpg.

So far after new o2, spark plugs, all fluids, and fuel treatment I still get horrible mpg [emoji34]

 

[Gerbil21]

OK one other question if I use the x66p can I put a hose on the evap fitting on the throttle body while at op. Temp and pour it in there? I don't like the thought of spraying it on the throttle plate since it gets blow away with the fan and the throttle doesn't open much. So its just spilling on a hot engine.

 

[Gerbil21]

OK just a update on the mpg so far I'm getting 9.8mpg

Also can I pour the x66p thought the evap fitting on the throttle body?

 

[Gerbil21]

OK well I'm finally getting the cat put in $60 I will see what the MPG go to right now it's at 9.8 with a good bit of highway driving

 

[Gerbil21]

OK well mpg is at 10.6 cruising and around the low 10's in more stop and go the car feels much better, I kind of expected a bit more mpg but idk maybe the rear o2? Also I'm going to try pulling the PCM fuses and let it reset

 

[Gerbil21]

On well so far calculating the mpg gets me 11.8mpg with 32miles of mixed driving with a few miles of highway and a cold start using 2.7 gallons of fuel (according to dic)

 

[gmcman]

What you need to do is top off your tank, and run it until the light comes on. Do this twice and report the mileage per tank and gallons used to refill tank.

Try to avoid jack rabbit starts and prolonged idle times.

If you let the car warmup for a long period of time....say 30 min each day, that will kill MPG's

 

[Gerbil21]

Last time I got gas it was close to full but I will go back and fill up. I never liked the idea of the light coming on but I'll do it.

Also I'm not shure I can Drive it super smooth since I am in NYC and you constantly have to move quick time to time weather its a entrance ramp or something else but I'll see

 

[Gerbil21]

Last time I got gas it was close to full but I will go back and fill up. I never liked the idea of the light coming on but I'll do it.

Also I'm not shure I can Drive it super smooth since I am in NYC and you constantly have to move quick time to time weather its a entrance ramp or something else but I'll see

Also I usually let it warm up for 5-10min. Depending. I know warm ups kill mpg big time but I still drive it easy till it warmed up

 

[Gerbil21]

Do you think you can make a video of your avg mpg while idling and resetting while driving at 30 or so?

 

[Gerbil21]

OK I just noticed it takes literally 10 seconds for the mpg to go down one decimal point while idling also I'll make a vid since I'm driving right now

Also I forgot to mention the temp sits at 170-180 when it's not at 210 I think this t stat is no good I got to see what my brothers 05 TB gets we just put the same t Stat in his

 

[Gerbil21]

The old cat, it looks darker but the flash makes it look more white

 

[Gerbil21]

The other side once again a bit darker but the flash makes it whiter this side was the darkest

 

[Gerbil21]

These small pieces came out. No big chunks ever came out also I'm still able to see light out of it even with it pointed down so it was definitely not clogged

 

[gmcman]

Not to kick a dead horse but this is why a back pressure test is important. Coupled with a downstream O2 sensor report you can determine if the cat is working or not.

I guess being in the big Apple you may need more fuel reserve than at the fuel light....ha. But I can't imagine NY City would return favorable fuel mileage......I would base it off the tankful.

 

[Gerbil21]

I know I should of had done the back pressure test but the o2 was reporting it as bad and the mpg was worse also with a intentionally put 160* t stat I figured it was definitely in need of replacement

And I'll see what I can do about a full tank I'll probably use the dic to see gallons used

 

[Gerbil21]

OK well I got a full tank of gas and I reset the dic the highest I got was 12.3 after going on the highway here are some logs, the one with highway speeds is the last one I did with the full tank of gas. Also with a full tank it shows range of 210 miles

https://www.dropbox.com/s/jh7legc7ous9jmq/Powertrain%202014_11_21%2010_31_49.xls?dl=0

https://www.dropbox.com/s/mos2y4hnhp300sz/Powertrain%202014_11_21%2010_13_02.xls?dl=0

https://www.dropbox.com/s/6uszbxviw9jvj79/Powertrain%202014_11_21%2009_58_50.xls?dl=0

 

[gmcman]

Man....looks like you are stationary longer than you are driving. 185 deg coolant temp kinda worries me.....granted its cold outside but it struggles to get there and when it does it plateaus.

12 MPG under those conditions seems normal, I would start suspecting the thermostat and if you change that, change the ECM at the same time.

How old is the stat?

 

[Gerbil21]

Yup dam NYC, every car here should have start stop engines.

Also yes I've noticed that it only gets to 210 when its stopped for a while or constant highway driving.

That is 12mpg driving from the gas station straight to the highway (3 blocks) and then bit of highway and 30mph coasting after, I think it should be a bit higher but if I got winter blend fuel then it's understandable

Also the t stat is a few months old with about 3k on it

Also ecm? Did you mean temp sensor?

 

[gmcman]

change the ECM at the same time.

That was supposed to be "ECT" not "ECM".

 

[Gerbil21]

That was supposed to be "ECT" not "ECM".

Well I did clean the temp sensor it was more shiny that a new one, and as far as I can tell it seems to work but if I do change the t stat again I'll replace it too

Also I used advance auto brand- stant t stat I think I should get motorad I've heard good things about them

 

[Gerbil21]

OK well I looked over the logs and noticed the log for the highway never recorded so I will have to see if I can get another highway log