Hello, I just rebuilt the carberator on my d150 /6 because of poor performance. It has a new distributer, new cap n rotor, new fuel pump, new fuel lines, new fuel filter, new spark plugs, new wires. everything aside from the coil is new. What it does is it will get to 3rd gear and loose all power. I press the gas in 3rd and it will sound like it is just sucking air in the intake. Butterfly is open too, so i am trying to figure out what it is. Origonally the problem was the fuel line had a hole in it, but I fixed that and it ran good for about a month and then started acting up again, after replacing all of those things mentioned earlier it still stalls out. Runs better than it did as far as the idle goes but once it gets a load on the engine it just looses power and stalls out. I've checked the vaccume routing and everything thats still connected is routed right. Checked timing with timing advance vaccume plugged, and it is dead on. I am hoping that its not a burnt exhaust valve or something internal like that.

I checked the fuel pressure with a low pressure gauge and it read between 4.5 and 5 lbs. My suspission is that its either a weak coil or plugged egr valve. I should just disconnect the EGR valve because i no longer am running the smog pump.. The EGR valve has been pulled off and replaced too so I know that actually isnt the problem, but i still want disconnect it. I am going to check the resistance between the coil and the current out of the coil tomorrow to make sure its running right.

Hopefully someone has some input.

_________________
-- Mister Perkins --

Pictures of my truck
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Typically, the fuel pump should be putting out a minimum of 5 psi. This may or may not be your issue, I am sure others will provide more convincing evidence.

Where is your initial timing set at?


~THOR~

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1984 D100 Shorty Custom
Certified Auto Appraiser - RevItUp Classic Appraisals
President - Cherry City Bombers CC
Part of Tyrde-Browne Racing

Is your exhaust is flowing freely? A blocked catalytic converter or a bent pipe can do that.

Danny

Another vote for clogged converter. My `84 D100 would run fine around town; it was never "zippy" but once I got the carb rebuilt it ran acceptably well. But on the interstate, it would buck and surge going up hills. Finally, it just quit running. I had a muffler shop do a simple backpressure test and the after cat was nearly solid!

Worth a look.

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If it was easy, everybody would be doing it.

catylitic converter isnt plugged. Has anyone here ever had problems with the ECM going bad? I was reading a book at my shop about the ECM and it says that it has two modes.. start mode and run mode. When the computer fails it will go from run mode to start mode, and if that fails it says to replace the computer. I am guessing that my problem is more electrical than anything so thats why im leaning towards the ECM being bad. I was thinking of putting eletronic ignition on it but I'm not too sure how to hook it up and where to get it. Any more info is greatly appreciated.

_________________
-- Mister Perkins --

Pictures of my truck
http://www.cardomain.com/ride/3257131p

Okay, well I'm not sure what the problem is. I've been reading a book that my shop had and going through the whole electronic system testing the wiring harness, sensors, coil resistance, pick up resistance, and everything is okay. My dodge has 198,000 miles on it. All the fuel lines are re-done. The truck will run great idleing. Once I start driving the truck though it shuts down. I pull the wing nut off of the carb, pulled air filter.. butterfly valve open. pushed the throttle and smoke came out of the center of the carb. re-set choke and tried to start it again and nothing. sprayed a little starting fluid in the carb and cranked it. Started right up.. but only for a second. Wait about 5-10 minutes, crank it and it starts right up.. Runs fine idleing once again, but once i start driving it.. it shuts down. The only thing that I can think is that maybe the crank shaft lobe is wore down and isnt letting the mechanical pump work properly. I tried heating up the ECM with a heat gun for about 20 minutes because my suspission was the ECM was bad, but it started right up. So I would like to replace the mechanical pump with a low pressure electronic pump. Does anyone think that this is what my problem with the truck is?

Everything I have done to my truck:

:: Rebuilt carb
:: New Fuel Lines
:: New Coil / Relocated Coil (180ohm resistance)
:: New Distributer, cap, rotor (cant remember resistance)
:: New spark plugs
:: New spark plug wires
:: Removed smog pump and plugged lines
:: Removed charcol canaster
:: Disconnected EGR valve
:: New Thermostat
:: Timed truck with vaccume advance plugged
:: New Fuel Pump
:: New Fuel Filter


Oh .. I ran an OBD I scan tool and it showed code 91 which is vaccume transducer circuit. ECU problem? please post comments

_________________
-- Mister Perkins --

Pictures of my truck
http://www.cardomain.com/ride/3257131p

Without the air pump the converter can plug rather quickly. It's not designed to operate without the air injection.

If your making five pounds of fuel pressure I doubt its the pump. Is there visible damage to the pump lobe?

How about the fuel pickup in the tank? If there's loose rust and junk in there, you can temporarily starve for fuel.

A classic coil failure is to run till hot, then die. Possible, though unlikely.

The smog pump doesn't really cost anything in power. If your still running with the ECM and associated sensors, you may have serious problems with any emission equipment removed. The EGR allows greater cruise ignition advance when working properly. That will equate to better cruise economy. Without it you are more prone to pinging also.
If your going to continue running with that ignition system, it will work much better in complete form. Not that the ecm controlled systems work that well to begin with. If your someplace that you have to smog the truck, you'll need to reinstall all that stuff.

two cents

CJ

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Part of Tyrde-Browne Racing

no visible wear that I could see right off hand on the lobe. but I couldnt really get a good look. I felt it though and the center of the lobe felt dipped in. I am planning on doing an HEI conversion once i get my hands on a distributer. I think I might just hollow the cat out. I know its not plugged, but I dont want to risk getting it plugged without the smog hooked up. No emissions in Warren, PA so I am okay. Plus I am a mechanic so I do my own inspections =). I am just not very familiar with carburated engines. I can go over a fuel injected engine with my eyes closed, but when it comes to carbs and vaccume I get lost. Thats why I bought the truck too.. to familiarize myself with carburated engines. The other mechanic here knows all about carburated engines so it makes it kinda nice if I have a question, but we both were kinda stumped. He was the one who gave me the idea to run a heat gun on the ECM. he told me I could remove all of that stuff and the engine would still run. The thing is, even before I removed smog, egr, and charcol canaster, it was running the same. So I know me removing these things had nothing to do with the problem. I really dont want to keep throwing parts at it because I'm getting no where. It has high miles, so I am planning on doing a cam swap and replacing the timing chain, boring the block and adding a stroker kit and overside pistons/rings as long as theres no core shift.. but I'de like to pin point the problem before doing anything like that.

Edit:
The only thing fuel wise I have not replaced is the fuel sending unit. Does anyone know where I can pick one of those up? Parts stores dont list the sending unit. Maybe a website that someone knows does though.

Edit 2:
Did a little research and I found a sending unit. Just to make sure, doesnt the d150 have 5/16 fuel line sending unit? I found one with 3/8 , 3.7L /6 is listed but just making sure..
http://www.amazon.com/gp/product/B00199 ... ative=9325

_________________
-- Mister Perkins --

Pictures of my truck
http://www.cardomain.com/ride/3257131p

Don't know on the sending unit, but your charcoal canister acts as a filter for your fuel tank vent, and keeps gasoline stink out of the cab from the carb vent. I left mine on, though I don't have a carb vent to hook onto on the Carter AFB or any of my Holleys.

Hows your float level in the carb? Did you rebuild it, or buy a rebuilt? The only rebuilt I ever had that was worth anything was a Carter YF rebuilt by Holley. Everything else either didn't run right, or burned in place. Most rebuilts are junk. The initial set up of rebuilt carbs are rarely right.
If you still have your original, good deal. There are BBD's that are set up for Jeeps and other manufacturers and engines that will be difficult to get right on the slant. Don't get one of those as a novice carburetor mechanic. They'll sour you on carburetors real quick. Too many things need to be done to get them to work, and they may not work correctly even at that. Too many patches need to be made to them to run right.
I'm not a BBD expert. Perhaps you can post the carburetor number here and somebody can make sure it's the right one for the application.

CJ

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Part of Tyrde-Browne Racing

I bet that is it.

The carb i bought a rebuild kit for it.

_________________
-- Mister Perkins --

Pictures of my truck
http://www.cardomain.com/ride/3257131p

if you flop the egr valve over it will seal off....i didnt and it took out pistons 4 & 5 in a new rebuild

dheck your pickup right where it comes out of tank ....i 've had several of them rust thru...suck air

Good deal. Everything is back to spec on the OE Carb, and you had your carburetor savvy friend look things over?

Have you solved your 91 code yet? Fix the circuit/transducer, and/or address the ECM like Ed suggested. Hantayo's suggestion is a good one. If your going to run without the EGR, you aren't gong to have much luck with the computer. It won't run things right without it.

If your going to continue running the ECM, fix the stuff plugged into it. If not, then we have a different barrel of apples.
Don't try to mix and match equipment from different design philosophies. It isn't going to work well.

Stick with it! You can get it working!

CJ

I thought the EGR valve had something to do with the smog pump? I know its not connected to it. Its connected to the vaccume amplifier, but for some reason I thought it had something to do with the smog. Has anyone ever had problems with the Vaccume Amplifier going bad? I wonder if maybe I'm not getting enough vaccume or something too. I dont know. I bought this truck for $500.00 from a guy who couldnt get it to run right. I dropped the tank, cracked rubber hose on the feed side, replaced it.. ran great for a month. Now I've put some bucks into it replacing old with new, tuning, etc.. and it doesnt even run barely. I'de like to be able to park my integra and start driving the old mopar again.

My co-worker watched me rebuild it and told me what to take off and clean. Took everything out of it cleaned the jets out, ajdusted the floats, replaced the accelerator pump gasket, etc... I got a NAPA rebuild kit.. not sure if its a good brand or not. My co-worker said it would be alright. Well he actually first told me to get a new engine with a 4-barrel setup, but I told him I wanted to keep the slant six. We have a 350 chevy small block and a 454 big block out back of the shop I can drop in, but I really want to keep it original. As far as the pickup goes on the tank, I've had the truck on the rack about 5 times and 3 of those times I had the tank out and inspected the sending unit. As far as I could see it had no holes in it. The only thing I know is wrong with it is where the lines come out they were rusted and broke off where the original bends were. So I clamped hose clamps on the knubs that were sticking out. My co-worker said that my sock on my sending unit could collapse and close off the feed side causing me to run out of fuel. Which would make sense because it will idle fine but then once it starts rolling it shuts down. Oh, another question I have.. Would code 91 show up if I had the vaccume transistor disconnected? Maybe I should try resetting the ECM and see if it shows back up on the scan tool. I ran an oscilliscope on the spark plugs and coils and everything seems fine as far as I can see. I matched the wave forms up with a book that ken had and they were the same. So I am almost possitive I am having a fuel problem. Oh, no one ever answered my question about the smoke coming out of the carb. Would that mean that it was out of fuel? Or maybe the intake valves are leaking causing the unburnt exhaust to escape through the valves. Well when I get a chance to lift it up I am planning on dropping the tank again and pulling the sending unit out and trying to see if it will run better with the sock off. Input appreciated =)

_________________
-- Mister Perkins --

Pictures of my truck
http://www.cardomain.com/ride/3257131p

When my truck is hot and I pump the gas it givesme that smoke also, so my guess would be the it was the fuel hitting a warm manifold and evaporating.