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91 D150 -awesome!

4K views 68 replies 4 participants last post by  Saltillo Express 
#1 ·
After selling all my real dodge trucks over the years, I traded the 10 on a new Ram hemi last year. And hated it too. So yesterday -

I Picked up a 1991 D150 short bed with a 318 factory air automatic. Transmission is out of adjustment and it's running rich as hell. Factory AC, not working either. She is an absolute BEAUTY.

So happy to be back in a real truck. This thing is going be awesome! Looking forward to moving over to this section of the forum. 91 RULES!
 
#27 · (Edited)
EGR valve will cause bad ide and also smoke on start. Go invest in a vacuum gage. Also good for bleeding brakes. You will eventually need This done to. Lines always go bad behind fuel tank!
 
#29 ·
codes

41- generator field circuit open or shorted
35 - idle control switch input circuit opened
51- O2 sensor 1/1 sustained lean condition
51 -sustained lean condition exceeds range of adaptive fuel control bank 1

Not sure on the 41. Is that associated with the alternator? And the 35. Is that an idle air control module. On the throttle body? Maybe it's not plugged in? Or the module is bad. I but a brake wrench on that 02 sensor - it ain't coming out.

When you guys were saying - "get another manifold and do it like that" - You were RIGHT! OMG how do you get it out of there? I just hit with some PB blaster.

Feeling good - this thing is looking up. What do you guys think on the codes?
 
#31 · (Edited)
Run the codes again after resetting the computer. A loose belt shouldn't set that code, but best to rule that out. Test with belt tightened. Might be a bad alternator. The open idle circuit is another mystery. If it's starting up ok, it's probably working. Can you hear the little electro-mechanical noise it makes as soon as the engine is shut off? That's the controller re-setting the throttle arm for the next start up. If you don't hear it, well, there you go. Then there's the run lean condition. Typically, as the O2 sensor fails, the engine will run rich. If you're running lean, most likely a vacuum leak. You can isolate everything with caps (even the EGR) and see if things improve. It'll help you isolate where the leak is. Those vacuum lines can look fine, only to be cracked or missing chunks on the backside. Also, I hate to say it, because we are kinda stuck with it, but gasahol tends to lean things out. That may be causing the code 51. I know my '90 runs better on 100% gas. I tank up with the pure stuff every chance I get. The computer isn't as adaptive as the OBDII's and while the FSM states it can tolerate 10% ethanol-spiked gas, nobody told it, apparantly, because while it tolerates the stuff, it doesn't like it. Get another driver side manifold. you're gonna mess around and crack something. Then you'll need a replacement manifold anyway. Could be that the sensor is bad, but with the gasahol, it has blown some of the previously accumulated soot out, but it'll still start running rich at some point in the throttle advancement.
 
#32 ·
someone used a soft bolt to attach the O2 sensor. I could get to it underneath with a socket but it broke off. the manifold is coming off now no question. seems like that bolt should been more hardened given it was in the manifold. regardless, wrestling the manifold tomorrow.

Big Ram on the EGR - wouldn't that set a code? Or no? It's puking at start up. dark black smoke. but I have good compression on all 8.

I'm wondering about buying a bunch of sensors versus just swapping back to a little intake and carb. any comments or opinions?
 
#33 ·
Going to a carb requires a few other changes. You will need to re-route functions around the computer. Primarily, this means the alternator/regulator, fuel pump, ignition, and AirCond if you have that, plus fuel pressure regulator. It's definitely do-able, but it's not just an intake swap.
EGR will set code 32 if equipped with California emissions, code 34 if a 1987 model. Otherwise , no code.
Black smoke on startup sounds like no communication with O2 sensor, meaning it's shot. When it's toast, the computer basically goes to 80% full rich
 
#34 ·
I thought you guys abandoned me!!!!! :)

I rung off the O2 sensor bolt. It was a soft zinc bolt some idiot must have stuck in there. Anyway - I'm wrestling the manifold off tomorrow to take it to get that bolt tapped out etc.

What about the missing Idle Air Control Gen1Dak? I went to look and it ain't there!!! Do I have to have one plugged in to the harness - or can I run without it and just adjust the idle from the plates?

I knocked the trans linkage off the trans fighting with the O2 bolt. I gotta figure how to adjust that linkage now since it's gotta go back on.

Is there a link floating around for the service manual on this girl? I'd buy a six pack for a link to it.
 
#35 · (Edited)
This may seem like nit-picking, but there is no Idle Air Controller (IAC). That's for the Magnums. There is, however, an Idle Speed Control Actuator. Different mechanism for similar goals. I get what you're saying. Just a point for clarification. Anyway, I'm thinking the computer will not like not having the ISC. It contains the idle switch, and sets the throttle preset for next startup. It also sets engine speed on deceleration. Also, based on other computer inputs, sets hot and cold start throttle angle. You start trying to set it manually.....I dunnooooo. Thinkin' that ain't gonna fly. You're only gonna be right in one situation. Everywhere else will be various degrees of close, but not exact. On a carb'd engine that's not a big deal, but with injectors pulsing, no telling what sort of erratic issues you'd encounter.
 
#36 ·
yeah my bad I'm calling it that and it's not accurate. I tend to agree in that not having it plugged into the harness is a problem. Trying to get the manifold off it today to tap that stupid O2 sensor bolt out. Looks like I'm buying both the ISCA and the O2 Sensor. No golf this weekend.
 
#37 ·
Yes it could. As far IAC it's the plunger looking thing on the driver side below throttle cable. Best way to check is turn key on and see if plunger pops out 9 times out of 10 it's just bad and needs to be replaced. They don't get carbon coating like Gen 2's. Those take the place of spring choke and vacuum pull off.
 
#38 ·
Clark :) the ISCA is missing! As in - it ain't there! I kept looking around for it and finally realized - MIA. I wish I could find a download of the service manual on this puppy. The darned shift linkage came off and I'm not certain how to set it back up. Wish I could find a diagram of it. I'm just trying to move from beside the shop to "in" the shop. :)
 
#40 ·
I hope it's the TB I'm thinking of. Like the one I had on my 89 dakota it was external. It's been 20 years and a lot of brain cells have parishes sense then. But only the WEAK ONES! Or so I hope?
 
#41 ·
[me laughing] No man there was a story just yesterday that said the whole brain cells dying thing is a myth. Your right on it's external. And in this case - REALLY external as in - not there.

I got the linkage together and the old goat is moved into the barn. Back to wrestling the manifold off to get to the O2 sensor.
 
#42 ·
The bolt I broke was fastening some kind of exhaust recirculation deal into the back (firewall) side of the manifold. I thought THAT was the O2 sensor. It is not. The O2 sensor is on the front side of that same manifold. So weird that it is located so close to the combustion heat. Literally that's like "in the fire" of the exhaust.

Recirculation bolt, tapped and replaced. O2 sensor had to use heat but it's out too. Rolling to auto parts to get the new 02, and other parts to get this donkey bucking!
 
#43 ·
Well have fun with that. I have to get old goat ready for a trip to Illinois in morning. This will be the longest time on highway for her in a long time. This might get exciting! I'll need phone charged and AAA card ready!
 
#45 ·
Thanks for the offer. We made the trip. Put about 200+ on it and used about a half tank. Did really good and was fun. Also my friend that went with me sed it was quieter then his F150.
 
#47 ·
That's funny Gen1. Heck I didn't know, figured on a dinosaur hell it might have some weird metal tube around it, I didn't know. I was reeling from the fact IT'S IN THE MANIFOLD - WITH THE FIRE. :)

Mr. Griswald - that's 400 a tank. What's that about 15mpg or so? Not bad at all.

OK here's the update on the old donkey in the barn.

Trans
There was a little bit of dirt on the filter but not much at all. I watched the videos on the band adjustment till I was cross-eyed. Adjusted front and back bands. Honestly I'm not convinced they were that far out. New fluid and filter and pan gasket. Oh, it's a 904 by the way. Due the the pan gasket. Or some variant on the 904. Pan gasket was shot - that's where the fluid was going.

Earl
He got mad and left. :) Drain plug was metal on metal and was leaking. New drain plug. 5.5 quarts of Advanced Auto's finest & filter.

Plugs
NGK's were on special at $2 figured I'm working above my pay grade -what the heck. They're in.

O2 Sensor & Weird Exhaust Thing Bolt
You guys were 100% correct - you ain't getting that out with it on the truck. Had to heat it up to finally get it out. I think that location is problematic at best for an O2 sensor. Tapped out the bolt on the back and replaced them all with case hard, etc.

Next
Today I'm going to hook up the scanner and delete all the codes, because I am superstitious like that. And throw the fire to it and see what I've got. I'm still waiting on the Idle Auctuator but I have turned the plates up a tick or too. It idled a lot better backing it in, so (finger crossed).

Getting ready to rumble 170 ponies down here. :)
 
#48 ·
Sweet progress, was off a bit on miles driven yesterday. 135 miles. But still 10.28 mpg not bad for a 32 year old pig!
 
#50 ·
It is a carb and 360. Just tuned it. It's a Holley carburetor model H2-2210 (I think) about 230 cfm. The list is long on what I had to do to it to make it suck, bang and blow.
 
#51 ·
she started up fine and runs much better. there was about a half a quart of tranny fluid under the pan this morning. But I couldn't find a leak anywhere except the pan. So I re-torqued the pan bolts and no more leaks as of yet.

The engine is revving really good now but it's blowing out all the oil from the lean condition or whatever. So I shut it down. Why blow oil all over those new plugs? Gonna put the old ones back in and run it around for awhile - then put the new ones in later this week.

It still is not idling quite perfect and considering I'm going to get the AC going - I'm going spring for Idle Control Motor. $70 at Advance. $80 with the bracket. Of course the bracket is missing.

I'm still getting a 41 code. Gotta get some batteries for the voltmeter I guess. I tightened the alternator belt and no more noise but still getting that 41. I guess it's check battery and then alternator? Is there a voltage regulator - YES there is on the firewall. How the heck do you check that? And it's silver too - not orange. :(
 
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