i need help passing my truck. '87 dodge d150 318 w/ 2bbl (Holley 6280 or 2280) and 904 tranny. i failed on 3 of the parts, high speed hydrocarbons, highspeed CO, and lowspeed CO. i put a copy of the paperwork in my photo gallery. i just got done replacing my cap, rotor, and wires, and plugs are next. but if anyone knows what to do next please give me an idea. any help will be greatly appreciated. also if anyone know the differences between the two carbs i listed above, that would help. i know i need a carb kit for mine, but im on a budget and cant afford to be buying parts i dont need.

TYIA

 

A New Cat...

 

Make sure that your EGR is working

 

Change the oil too.

 

Ask around. I'm sure there's a testing station around that will pass anything.

 

i wanna do it legit "this time" i've done it in the past, but if i fix, that will also help my fuel mileage and performance.

 

New spark plugs help, a good tune up (oil & air filters, plugs, wires, rotor and cap) help too. Also before you get to the testing station, be sure that your truck is fully warmed up (as in drive it for at least 1/2 hour) as this will give the cat time to heat up and begin the catalytic process to clean up the exhaust.

 

High CO in both rpm ranges means that your mixture is too rich all thru the range. A carb kit is a goog place to start but those later carbs are a mama hoo hoo to set up correctly. Try putting a couple of bottles of rubbing alcohol in the tank and then run it around for 30 min. That is about all you can do chemical wise I think.

 

If it has a vacuum distributor, make sure it retards the timing correctly at idle. You might set the timing a little on the low side of the specs too.

 

Sea foam works wonders on stuff like that.

 

Try a bottle of HEET (methanol) in the tank.

MikeyB

 

i've already done the cap, rotor, and wires. i got a carb kit which a buddy of mine said he could do today. i will next put in plugs, change the oil and maybe put in a gallon or two of race gas and check timing.
thanks for all yall's help

 

UPDATE: got the carb rebuilt and put back on. runs better than ever. brakes are better than before too! tomorrow gonna go pay a ticket and with whatever money i have left ill change my oil and replace the plugs and retest. wish me luck

 

That must be one big ticket if your worried about changing oil and plugs.

 

Back in my gasser days I used to run the fuel down to empty and threw in a bottle of "Guaranteed To Pass". Worked every time.