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Injection Pump Efficiency

mfgguru

mfgguru

Makin' it better!
Messages
359
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7
Location
Winkler, MB, Canada
Well, this may have been asked before, but I can't find it. My IP is original on my truck. Now remember I am in Kilometers, so about 155 000 miles on it now. I am finding my fuel mileage horrible! It has been a gradual occurence I think. The new injectors didn't do much. I would like to know if my IP needs an upgrade prior to adding a reflash. I did notice a bit of a drop after adding the T/M but minimal. My thoughts would be over time the pressure may drop a bit resulting in poorer fuel atomization and therefor poorer energy yield from the same amount of fuel. Let me know what you think.
 
I think you would notice some much more distinct symptoms of a worn IP compared to a gradual loss of mpg, or kpg ( is that what you use? I think the higher numbers would make me feel better. :) ) Anyways, is there any chance you have a fuel weep anywhere? an air restriction? I had a clogged air filter lower my MPG from 18/19 to 10. I know you've probably gone thru this already, but I have to ask, fuel filter? Tire Pressure?
 
I usually calculate Mileage in MPG. KPG means nothing to me, even though that is our system. All good suggestions, but those are things I monitor regularly. I am also thinking my EMC may be doing funny things. It still surges occasionally.
 
Yeah, I guess I need to look into that. The obd1 guys have it easy with scanners, obdII software is not so cheap. Changing the topic a bit, is anyone running the GL-E upgrade? Sounds like a good option. What are the thoughts out there?
 
My fuel milage was around 14mpg. :rolleyes5: I hate to admit it because some are going to assume my IP was destroyed by the wvo, but I had several symptoms of a worn IP and just had it changed last week. I let everyone know if the milage changes, which I suspect it's going to. Here are a list of several early warning indications I got before that have since gone away.

1) I couldn't hold the throttle down and hold the rpm at a steady 2000. It wanted to either stay at idle or run up towards the red line.
2) Above 45mph the truck didn't want to hold a steady speed with either my foot or the cruise control. It either wanted to slow down or accelerate. The only time it would hold a constant speed was going up hill.
3) At start up the engine was extremely loud. It had what I thought was a normal diesel clatter. This is now much quieter at start on both cold and hot start ups.
4) Once the engine was at normal operating temperature and was shut down it wouldn't want to start. It would crank over and once it did start it would barely catch. On wvo it would start a little quicker but I believe this is because the wvo is a little thicker then the diesel.
5) All my settings are still factory. When I went WOT black smoke would roll. Again I thought this was normal. The new IP while still putting out black smoke at WOT it's not near as much.
6) On a mildly cold start (40 degrees F outside) I would get the common white smoke. With the new IP it's still there but not as much.

All this being said, I have read on here that the worn pump is providing more fuel then commanded which is what causes all these symptoms. If these are what you are seeing then I suspect you are dealing with the same thing as I.

Something else I found interesting that the guy swapping my IP's out told me about. When my old one was taken off the bolt that comes through the front had been worn and wobbled itself sround produceing a mushroomed head. This make sense to anyone? :confused:
 
I calculate my mileage evey week and I know this makes absolutley no sense but my lift pump stopped working due to wiring problem and I didn't realize it right away and the truck lost 3 MPG. You say your getting surging. it's worth a look before going for the big bucks.
 
mfgguru said:
Well, this may have been asked before, but I can't find it. My IP is original on my truck. Now remember I am in Kilometers, so about 155 000 miles on it now. I am finding my fuel mileage horrible! It has been a gradual occurence I think. The new injectors didn't do much. I would like to know if my IP needs an upgrade prior to adding a reflash. I did notice a bit of a drop after adding the T/M but minimal. My thoughts would be over time the pressure may drop a bit resulting in poorer fuel atomization and therefor poorer energy yield from the same amount of fuel. Let me know what you think.
Click to expand...


Hey Mike, what kind of mpg you seeing?

I'm always seeing 18-19 mpg just driving around town.

I'm a $20 guy at the pump lol. 20 bucks will get me 100km or so. Is this anywhere you are at?

BTW here in Altona, fuel is $1.27/L
 
i get as low as 13 pulling a trailer and as high as 24 on the highway. The 24 was calculated over a 1200 mile round trip. Not a single stop the entire 600 miles and i kept it at 2000-2200 rpm. EGT's were at 450 pre turbo and boost was 2-4 psi sustained. I toped the tank off and parked it for a while and filled up again so there wouldn't be any foam so i believe that my calculations are quite accurate. That was on my old IP with 60k on it.

I got a new injection system, thanks to GM's stupidity on the pmd, Mileage is pretty much the same. I've never gotten over 22 with the new ip but i've developed lead foot syndrom as of late :D and would need to take another long trip. I've put 18k on this one and havn't seen any changes really.....
 
Well, I guess I need to turn the T/M down a bit, I am running 4-5 psi sustained boost, probably a bit much. I am getting between 350 and 400 KMs per tank(1.6 km in a mile) just around town and home. Takes about 75 to 80 litres to fill(4.5l per gallon)CND. By my calculations, that is around 16 mpg. I rarely see over 20 on the hwy. The lift pump works. Remeber Ace that on obdII the OPS in on a different circuit. BTW ops is new too. I have adequate pressure to the IP via lift pump. Thanks guys. Keep it coming!
 
mfgguru said:
Well, I guess I need to turn the T/M down a bit, I am running 4-5 psi sustained boost, probably a bit much...
Click to expand...

Unless you are going to turn it down to a cracking pressure below 4 or 5 psi, then you won't see a change. Remember that the turbo master is regulating the turbine drive pressure limit. If you set it to crack at 10psi and you run 4 to 5 psi while cruising, you won't see a lower crusing boost by setting it to crack at 8 psi or even 6 psi.

What this means is that you are generating 4 or 5 psi boost's worth of turbine drive pressure at cruise. The only way to reduce boost pressure at cruise is to reduce the turbine drive pressure at cruise. This could be done a multitude of different ways, both good and bad.

My question is what is your EGT at cruise? Please note that Deere Freak's EGT at cruise was 450F (pre-turbo) while his boost was 2 to 4 psi. This is similar to how my truck performs cruising at 60MPH: 450F and 2.8 PSI of boost. At 70MPH, I see 520F and 4PSI of boost and my truck (K3500 SRW CC long bed) consistently returns 18MPG on the Interstate. The EGT can be a good indicator of where you turbine drive pressure is, as higher EGT equates to higher load and subsequently higher turbine drive pressures.

Don't believe me? Instrument your turbine drive pressure like I did...

Regards,
 
Well, I guess I need an egt gauge. I have been putting it off due to other bills and a lack of funds. I would like to think that my truck is similar to Gold"s and Deere's but how the heck to do I know if I don't have the tools. Time to "git 'er dooonnee!"
 
mfgguru said:
Well, I guess I need an egt gauge. I have been putting it off due to other bills and a lack of funds. I would like to think that my truck is similar to Gold"s and Deere's but how the heck to do I know if I don't have the tools. Time to "git 'er dooonnee!"
Click to expand...

I got mine from Autozone for $130. Everything was in it except the labor :D I also got a pillar mount while i was at it, seems to be the most popular way to show off your guages. I think that was $30 or something like that.....
 
Wow, that is really reasonable. That is competitive with most BAY prices. When I come down to Fargo for some Black Friday shopping, I'll have to check it out. Thanks.
 
Goldsburg said:
The EGT can be a good indicator of where you turbine drive pressure is, as higher EGT equates to higher load and subsequently higher turbine drive pressures.

Don't believe me? Instrument your turbine drive pressure like I did...

Regards,
Click to expand...

Hey Gary I've got it did:

FYI last Sunday's run back to Ga I avgd 21.37 mpg and that was with a lot of 85-90 mph driving, the ATT is a beautiful thing most times running 2 psi boost 5 psi backpressure, 450 EGT, this afternoon coming back, I just got in back to Ms haven't refilled to know return mpg, but playing around some @ 100mph 6 psi boost once settled in at rpm 750 EGT 9 psi back pressure.

I'm netting 2-4 mpg gains consistently depending how I drive, can't wait to put one on the Burb that is getting that with the GM-8 already, I'm guessing 24-26 is a possibility
 
Turbine Doc said:
Hey Gary I've got it did:

FYI last Sunday's run back to Ga I avgd 21.37 mpg and that was with a lot of 85-90 mph driving, the ATT is a beautiful thing most times running 2 psi boost 5 psi backpressure, 450 EGT, this afternoon coming back, I just got in back to Ms haven't refilled to know return mpg, but playing around some @ 100mph 6 psi boost once settled in at rpm 750 EGT 9 psi back pressure.

I'm netting 2-4 mpg gains consistently depending how I drive, can't wait to put one on the Burb that is getting that with the GM-8 already, I'm guessing 24-26 is a possibility
Click to expand...

Hey Tim -

Notice how in your own numbers (my observations are the same with my truck) that as the EGT climbs the boost and turbine drive pressures get closer together? That would sure prove to me that "heat" has an important part to play in driving the turbine moreso than pressure alone. When I am at WOT on my truck I can usually see 9psi sustained with just ~11psi of turbine drive pressure. Of course this is with a GM-4, in OD (5th on my truck), and nearly 1100 degF pre-turbo...:eek:

Regards,
 
With my ATT yes, not so with my GM-8 my drive pressure was 2x and almost 3x when high boosting, but I had the WG fully gagged shut so it could never open and EGT was 900-950 pre-turbo there also depending how hard I was into it, check with NVMTNLION his pre turbo EGT was like yors mine much lower, we both ran HP-4 program but him with a GM-4 turbo (bad as it turns out) I sent him my old GM-8 and his EGTs were lowered about 200F, so we don't know if bad turbo or slight flow differences gm4 vs GM8 contributing to higher EGT.
 
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