Engine/Transmission (1998.5 - 2002) 99 With bad fuel mileage

[Highfinance97]

When i bought this truck it wouldnt start so I installed a HPFP and a injection pump from II.



The truck runs great except it gets 12 MPG on the highway.

I installed a open filter intake and removed the muffler. so that might have helped a bit.

I took out the AIT sensor and cleaned and tested it and it seems to be working properly



Any ideas???





Michael

 

[SAndreasen]

When i bought this truck it wouldnt start so I installed a HPFP and a injection pump from II.



The truck runs great except it gets 12 MPG on the highway.

I installed a open filter intake and removed the muffler. so that might have helped a bit.

I took out the AIT sensor and cleaned and tested it and it seems to be working properly



Any ideas???





Michael

have you checked your fuel filter? and made sure you have good fuel flow to the filter ?

 

[SAndreasen]

When i bought this truck it wouldnt start so I installed a HPFP and a injection pump from II.



The truck runs great except it gets 12 MPG on the highway.

I installed a open filter intake and removed the muffler. so that might have helped a bit.

I took out the AIT sensor and cleaned and tested it and it seems to be working properly



Any ideas???





Michael

also check and see if you have any blown intercooler boots or loose clamps on intercooler and turbo

 

[hdtrukn]

Swap out the injectors for a set of RV275's.

How do I know, almost the same truck since new. Bad mileage from day one.

I got around 15mpg, swapped in 275's and went up to 21mpg.

Not saying 275's will give you that increase just saying stock set was terrrible.

Just my 2 cents.

Scott

 

[Highfinance97]

have you checked your fuel filter? and made sure you have good fuel flow to the filter ?

Brand new

also check and see if you have any blown intercooler boots or loose clamps on intercooler and turbo

Will have to check





hdtrukn

Are those injectors bigger than stock or just a differant spray pattern??





Michael

 

[ProspectorTim]

Your '99 auto was probably rated at 215 hp from the factory (see sticker on the driver's side of the timing case) 275's should give you about 60 hp (275-215=60).

Juice w/ attitude plus injectors ... If you don't have transmission problems already, you will real soon! FWIW, your poor fuel economy my be due to a torque converter that is already slipping.

 

[Highfinance97]

I went on a long trip this weekend and i did get better fuel mileage (15-16MPG)



I was thinking about putting a juice W/add. in, When i can find $600 dollars for it I will:-laf



As for the trans now its "OK" It might be slipping a bit but nothing noticable yet. Instead of doing a trans What about A aftermarket tourque converter or a pressure lock?? will they help or just buy my time???







Michael

 

[DFerverda]

clean and check your map sensor also. If it is dirty or bad it can screw up the mileage also. I would try the injector's first... . the transmission will go all in good time.
Dirk