Hey guys!
I bought a 1st gen diesel because I was told that they get up to 20-22 mpg. Mine is only getting 10-13.9. I had the valves adjusted and all but 3 were extremely tight. Seems like it runs good but the milage is poor. I changed all of the filters and added a 4 inch exhaust. I have a cold air intake (asa)on backorder from piers. Any ideas what else to check? The engine only has 94,000 original miles so I haven't checked the injectors yet. I can find my way around a gasser pretty well but I'm a little challenged when it comes to diesels. I even tried driving like a granny for a full tank and the best I got was 13.9 I think there is something wrong. Any ideas would be helpful. Thanks in advance.


Jeff

 

What year? auto? Fill out your profile and that will help with answers.

 

Sorry Apache I haven't figured out how to do the profile yet. I'm also on the central coast. I have a 93 1st gen. with a getrag. Not sure of the gears but I think that they are 3:54 because that's what the plate attached to the axle cover says.

 

is it a 3500 dulley. if so that's normal

 

click on user cp buttom to edit your profile above.

jiMMy

 

Single axle.. not a dually... sorry I didn't give all the info

 

I have 2 first gen 93s. My 2wd with 112k gets 20 and the 350 4x4with 177k gets 15 or so. How does it seem to run otherwise? lots of smoke? ever go up the cuesta grade? how does it pull? my 2wd had the pump done a while back and it runs great 80+ up the grade no problem the other might pull 70 at best. I think the injector timing has a lot to do with my differences. are you sure on your mileage checks due to foaming diesel fill ups?. If you like you can PM me and we can talk. I will give the name of the shop I had my pump done at in Santa Maria. Maybe you can offer some help also. You should be doing much better it would seem.

 

I had a 93 and got 21 MPG US pretty repeatably.

I am suspecting timing or someone has tinkered with the pump.

J-eh

 

I'd have to say it's probably retarded timing. I've been getting a consistent 17 mpg in local traffic. I've seen as good as 19 mpg on the highway at 70.

 

****, i just toped off my tank for the first time since owning this truck, and did the math and only got 13.7mpg i went 101 miles and the tank took 7.6 gal.

im thinking the timing needs to be advanced on mine some too. ill be towing through the hills tomorrow so ill get towing 6k lbs numbers too.

wife is buying me a turbo for my bday and some POD's hopefully this helps out too.


also i was getting about 60mph in OD doing 2k rpms

jIMMy

 

Its amazing how the timing degrades as the miles rack up. My 93 when I bought it had worn its way down to 1° BTDC. Just putting it back to the stock 10° made a huge difference.

J-eh

 

I've read threads about adjusting the timing and they all seem to show the poor mans 1/8 inch method but also mention that the real method requires special equipment. What equipment? I called a local diesel shop and the guy told me it was a 6 hour job to check my timing. Is he smoking crack or is this true? Anyone know where I can get a manual ?

 

When I took my truck in for timing I cost me about $170 with taxes. Took them about 1 hour to do.. They used the "pulse" method where they have a sensor they clamp to the injector tubing that senses the pressure pulse of the injector. This runs a timing lite and they adjust the timing that way.

If it takes 6 hours to set timing, I would hate to see what they charge for a valve set. Might try another shop man.

The poor mans method is fine if you know you are at 10° and want to advance 5°. That 1/8 trick wouldn't have worked for me, just to get it back to stock was probably 3/16 or more plus any movement to go over 10°.


J-eh

 

I thought that a 6 hour timing job sounded WAY out of line. Thanks for the info. :0)

 

After calling a few shops most say the pump needs to come out to make it easy, they also said can be done by just loosening the nuts and twisting sometimes. theres your 6 hours I would guess.