I have a 1994 Dodge Ram 250 conversion van. I've removed the air filter and all that, but for the life of me I can't find the screws to adjust the air/fuel mix. It's a Holley carburetor.
I think the problem is that the van is burning rich, it failed emissions due to high CO during idling.
All comments appreciated, also if anyone knows a good online resource for free schematics or anything, that could help too.
2007-06-05 01:55:00 · 6 answers · asked by frolicgfx 1 in Cars & Transportation ➔ Maintenance & Repairs
it should be fuel injected
2007-06-05 01:58:37 · answer #1 · answered by dumbo 3 · 1⤊ 0⤋
are you sure it is carburated and you are not looking at the throttle body??? I am not a ram 250 expert, but it's rare to see a 94 with a carb as opposed to fuel injection.
Anyway before you go fiddling with screws, have someone download error codes from your OBD system. It would be a good idea to do a tune up too as that can resolve most emmision problems.
New O2 sensor usually last about 60K miles
New plugs and wires usually about 60K miles
new ERG vavle usually about 60K miles
New PCV valve every 15-20K miles
fresh oil and filters every 3-5K miles
new vacuum lines every 3rd year
MAF sensors (mass airflow, sometimes called by another name) I would test this part rather than replace.
Not only will you pass inspection, it will run smoother and get better mileage too.
The last possilbily to fail your emmision test is the Catylatic Convertor.
Buy yourself a Haynes repair manual and do the work yourself if you are mechanically inclined. These types of repairs are easy for a DIY mechanic.
Even if this is a carburated system, I find it is rare to have to reset the mixture screws after initial dial in. If you change that and nothing else, you are masking the real problem....that one of the sensors is telling your fuel system that it needs more gas than it really needs for the amount of air.
2007-06-05 02:21:30 · answer #2 · answered by DH1 4 · 1⤊ 0⤋
Your vehicle is equipped with a digital fuel to air/idle speed management system preventing you from manually adjusting these items.
The management system collects data from many sensors...mass air flow sensor, temp sensor, oil pressure sensor, speed sensor, etc to determine the best mix possible. The only way to alter the settings is to interface with the diagnostic port.
I do not recommend changing these values, your van has underlying issues causing it to fail emissions. A good tune up would probably eliminate the failure. A clogged fuel filter is typically the primary cause for this type of failure, the engine is overcompensating for a lack of fuel delivery.
2007-06-05 02:27:09 · answer #3 · answered by mrharris32 4 · 1⤊ 0⤋
Could be a bad power valve also from a backfire--will blow them out---how does it run otherwise? bogs on acceleration? Get your carb number off the air horn and call Holley tech support number for instructions on setting mixture screws--shouldn't have to tamper with factory presets unless someone else did already and they need to be put back to original settings.
Couple of sites on Holley tuning here---http://www.holley.com/data/Products/Technical/199R9881.pdf
http://www.bob2000.com/carb.htm
http://www.holley.com/
2007-06-05 03:10:51 · answer #4 · answered by paul h 7 · 0⤊ 1⤋
it should be locacted in front of the carb. follow the fuel line past the fuel filter to where it enters the carb. rull of thum to adjust is close all the way and open 1 1/4 turn until engine is idle smooth.
2007-06-05 01:59:31 · answer #5 · answered by RAUL R 2 · 0⤊ 2⤋
it has no adjustment if it a throttle body type carburetor . its controlled by computer mogul. you need to run diagnostic and it should tell you which censer you need to replace.
most likely the oxygen control censer is bad.
2007-06-05 02:02:59 · answer #6 · answered by milldoc 3 · 2⤊ 0⤋