I have a 1987 Dodge D150 shortbox and it has a /6 with a 4spd OD in it and its a decent truck and all but i have major problems...I bought this truck for $250.00 bucks and i put about $1500 into it to get it roadworthey and when i did i found out a major power problem. It originally had a 1bbl card on it and i replaced it 3 times thinking that it was the problem but of course not...The truck has a sparkcontrol system and i replaced that to for another 200bucks! again no difference...So not only does it suck powerwise its horrible on gas...I checked the compression and the lowest one is 150psi and the highest is 170psi....this thing gets 16 on the hwy and whoknows what in the city..My buddy is telling me he knows someone that gets 25 on the hwy and has tuns of power...In my truck 1st gear its got ok power,2nd its pretty good, 3rd its getting pretty bad and in 4th which is OD i actually can lose speed when its to the floor! I think these engines are awsome and i'd never traid for a V8 but i have a 318 and a 2bbl intake so i was going to take the 2bbl off the 318 and put the 2bbl intake & carb on the slant. I was wondering if anyone else has had this problem before and if ne one has plez help me...also i was wondering what the maximum RPM i should rev this stock engine is?? and what the redline is...Thanx all!

justin_redneck@hotmail.com

I had one identical to what you have. Mine had 3.91 rear gears and was ok on power but wasn't a powerhouse. It did OK as long as it was unloaded. Mine got around 19 mpg highway when I got it and down to 17 mpg when I took the Michelin highway tread tires off and put mud and snow tires on. The top speed of the truck was 82MPH in 3rd or 4th gear, it didn't matter. I wouldn't run the engine over 4500 rpm because I doubt you could even get it to run that fast in gear. You should get better MPG if you have a lower numerical gear in the rearend but the power is going to get worse. You should also make sure that you set the timing correctly. Even though it has a computer controlled ignition system you can still adjust the timing. I would add about 4 degrees advance to the factory timing spec. and back it off slightly if you hear pinging. I hope this helps.

I have a 1987 D150 with slant 6.
Mine was a fleet truck from a county park system. They had about 9 of those trucks all identical. Talking to the maintenence people they told me they had catalytic converter problems with all of them. The 1987 trucks have two coverters. One by the engine alongside the starter motor, the other under the cab of the truck. Mine seemed to have a power problem too. The cat under the cab was replaced with an aftermarket unit before I got the truck. The one by the eingine was original but the heat shield was coming loose. I removed the cat and pipe assembly one day to find the core in the front cat was broken and melted and the stainless steel shell was cracked open from excessive heat. I used a steel rod as a punch to knock out what was left of the core in the front converter, welded the crack and put it back together. Now I had good power again. Later on I replaced the front converter with a pipe for a 1981 truck without the front converter. Made for a neater engine compartment.

I'd check those catalytic converters for being plugged up on our truck.

Oh yea, also you need to determine if the ESA computer is working and going into the warm engine mode after the engine warms up. Mine has a glitch in it and it will get stuck in "limp" mode every now and then, usually it does this when I have to crank the engine more than once. I think a voltage spike from turning the key from run to start more than once is causing this. It's easy for me to tell when this happens becaue I notice the driveability problem and also the auto trans lockup torque converter does not lock up. You have a manual transmission so you may not notice the problem as easily. To cure the problem I shut off the engine, wait a few seconds, then restart and all is well.

cfield@ll.net

Here's a similar /6 vehicle to compare yours to:
My daily driver, bought new, is a 1987 van with no mods, federal emissions, one cat, ESA, Holley 1945 1 bbl, 4speedOD, 3.91 axle, 205/75/15 tires, cheapest possible gas, 190K miles.

Passes emissions testing (HC 22 PPM at idle, 12 PPM at 2500 RPM, limit 220 PPM), compression 160-175-175-170-175-175, intake vacuum 21 idle, 22 at 2500 RPM EGR off, 18 EGR on. Some blowby, such that you can't see light through the air filter after about 8K miles. Idle timing 12 BTDC, very slight pinging under light load, plugs stay clean.

Carb has been rebuilt and all vacuum hoses replaced. Otherwise just normal maintenance.

Performance Issues? Well, yes.
This winter, commuting to work 17 miles each way city/interstate and WOT climbing up to Snoqualmie Pass on the weekends I am getting 14-15 MPG. When new it was 16-18 MPG. Could probably do better with a lighter foot.
Not much power below 1700 RPM or above 3500. 4th gear is fine for cruising at 75 MPH until it hits a steep grade or stiff headwind. Then it slows to about 55-60 and then in 3rd I can get back to 65-70. Passing is definitely a carefully planned operation. Acceleration is much better than an old VW bus, but wouldn't want to race anything else.

Recommendations:
1. Buy a vacuum gauge/pump and run all the tests described in its directions. Might diagnose a clogged exhaust, bad valve/ignition timing, etc.
2. Advance the timing to the limit of pinging and check that the ESA is giving you the proper advance at spec'ed RPM and vacuum.
3. Don't run oversize tires, shouldn't be taller than stock. You need all the RPMs you can get.
4. The two barrel carb/intake would add more power and is what I might add some day.

Good Luck! Remember, to paraphrase NBC's Bob Costas, slant six power is just like victory to those Winter Olympic atheletes who are from unlikely places (Bermuda, Thailand, etc.).
It is a journey, not a destination.
Fred



powellf@earthlink.net

I have an 85 shortbox with the Ram Miser option. Had similar problems - took it to two dealers and one independent garage and noone could figure out the power loss problem. It was the failure of the pre-converter by the engine and it's internal honeycombed material had separated and plugged the main converter. Put on a pipe from an earlier model and replaced the converter - and it came back to life. Check your exhaust pipe after a hard drive - if it is glowing a bit then you have a plugged unit if it is so equipped. Vacuum test should tell you also.
Cheers-Spiff.

spiffship@eudoramail.com

Classic plugged cat problem. dump both cats, and check the muffler for chunks. After it is cleared, set the tinming and have a good day.