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sircurb
Novice
Jan 8, 2008, 10:23 AM
Post #1 of 13
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1991 dodge w150
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my 318 ci engine runs poorly, it has been checked by shops and dealer. when I would turn the engine off in the past I would here what sounded like a modular motor resetting in the engine compartment. THis sound no longer occurs and there are no codes.
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azrael
Novice
Jan 10, 2008, 1:44 PM
Post #2 of 13
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Re: 1991 dodge w150
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I'm no expert, but I've seen my fair share of chrystler issues and do not mind sharing the knowledge. I need more info to better asses this problem. When you say it is running poorly please describe how, what noises, etc... also an Idea of mileage and past tune up info may help avoid un-necessary inquiries.
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way2old
Veteran
/ Moderator
Jan 10, 2008, 5:10 PM
Post #3 of 13
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Re: 1991 dodge w150
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What you were hearing is the cold start motor(idle speed motor) pre-setting for the next start. Look at the little motor that is hooked to your throttle linkage and see if it moves when you turn key on and push the accelerator down. The plunger should try to fin the linkage to complete a ground. If it does not move, replace the motor on the side of throttle body. Being way2old is why I need help from younger minds
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sircurb
Novice
Jan 11, 2008, 6:32 AM
Post #4 of 13
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Re: 1991 dodge w150
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The cold idle motor has been replaced along with oxygen sensor,egr valve, map sensor, coolant temp sensor, fuel reg, idle position sensor. The fuel pump has been tested. A number of vacuum test have been done. The three selonoids(egr, canister etc.) have been tested. The fuel injecters (tbi) have been replaced and the computer has been replaced. Discription of problem; rough idle- fuel in oil- poor mileage- periodic loss of power- periodic drop in rpm when coming to a stop. The truck never idles right but at times it will run strong otherwise.
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Double J
Veteran
/ Moderator
Jan 11, 2008, 11:29 AM
Post #5 of 13
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Re: 1991 dodge w150
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Just curious...how many miles on the engine/vehicle??? you stated you had it in to shops/dealer.....what have they said... Has the compression been checked??? spark plugs /spark plug wires changed??? Jim
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sircurb
Novice
Jan 11, 2008, 6:29 PM
Post #6 of 13
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Re: 1991 dodge w150
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THe truck has 130,000 miles, I didn,t do a compression test but I can. The engine has all the power it had when I bought it, thats why I didn't think compression test. it is definitly running rich because it blows black smoke when I stomp on it. I had the truck tuned up, the dealer replaced the computer and the injecters. One shop replaced the fuel reg, another did the oxygen and map senser, another did the coolant temp senser. I replaced the cold start idle motor but I still don't here the gear sound that I use to here.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 12, 2008, 4:19 AM
Post #7 of 13
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Re: 1991 dodge w150
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Idea! Timing Chain jumping?? I bet you can get in thru a cover plate where a mechanical fuel pump would have been and feel the slack....Also, will this just up and behave if you pull out PCV and plug it for a moment? Have some ideas if so, T
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sircurb
Novice
Jan 12, 2008, 7:48 AM
Post #8 of 13
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Re: 1991 dodge w150
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I'll try it and let you know
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sircurb
Novice
Jan 12, 2008, 11:15 AM
Post #9 of 13
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Re: 1991 dodge w150
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I was always told that the idle is not set by the cold idle control. Once the engine has warmed the cold idle should have very little to do with operation of the engine. I have unbolted the cold idle motor from the tbi (still wired), the engine is warm. The truck is just barely running and the rpm"s are fluctuating by about 100 rpm. I checked the idle positioning sensor, it is fine. I believe the cold idle motor is not working(it is new) but with the engine warm it should not matter much. I pulled and plugged the pcv valve , I didn't notice a difference. I am thinking timing chain or distibutor, I will have to borrow a timing light.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 12, 2008, 12:00 PM
Post #10 of 13
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Re: 1991 dodge w150
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All kinds of engine functions are linked to manifold vacuum If the chain was able to jump and sometimes be right you might have a moment or longer time with it running ok and with full power. I wouldn't believe it but I've had one do that and somehow find the correct spot and go months and then bad and back again? This just with V8 American engines in general not specific to yours. More specific to yours is (been a while) that the intake is heated with exhaust heat and a couple sludged up even on cared for cars and did this crap and the vacuum wasn't steady (it won't be with the idle going up and down anyway) but was discovered by unplugging and then with thumb of finger stop the vacuum leak like the pcv and the dang engine would at least be steady about being wrong. Hey - I can't say with this one but I do recall those screwing me up and they were fixed by removing intake manifold and cleaning all the fudge up. In those there was a lot and I was surprised at what I found. Those were cars (late 70s) and I just had a hunch that the trucks used a lot of old technology while still using the 318 while they were done with them in cars by 91. If you know the timing chain is original I'm somewhat worried about that. If you have a distributor you can set the crank pulley so timing is on a mark you can tell degrees. Take dist cap off and by flex handle and socket turn crank bolt slowly back and forth and see how many degrees it turns before rotor in distributor turns. I think if you see more than like 4 or 5 degrees the chain is suspect. Could be elsewhere along the way to turn the distributor but that was one clue without taking it apart. Just a thought?? T
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sircurb
Novice
Jan 12, 2008, 5:38 PM
Post #11 of 13
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Re: 1991 dodge w150
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If I remove the dist. cap and turn the crank shaft as you say the rotor should move almost instantly, if not the timing chain may be stretched or the distributor shaft could be damaged (the gears). Does this sound about right?
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jan 12, 2008, 6:21 PM
Post #12 of 13
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Re: 1991 dodge w150
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The chain test: Turn crank such that it is tight and turning the rotor. Go the other way an note how many degrees it takes to move the rotor. There just plain will be some motion and loss to dist gear lash and hard to notice by eye when it starts moving. Hope I'm not wasting your time with that. This is older with some miles. We (speaking for myself) tend to think real timing chains vs the rubber ones never go bad but they do. For a decade I replaced near every chain on cars that needed just water pumps as you are already that much closer. That for cars/vehicles with 100k or more and known original chains. A few were running like new and the chains (sproket with nylon gear teeth) were so gone such that I was surprised it ran and others looked brand new?? You don't know for sure until you are looking right at the thing. One thing noted is I never had to re-replace the non nylon chain set ever again, T Ps: When I speak of replacements I always mean both gears and the chain. Not just what looks most worn if you are there.
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sircurb
Novice
Jan 13, 2008, 6:24 PM
Post #13 of 13
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Re: 1991 dodge w150
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I can and will do the chain test, I do not have a garage and the temp here in phila. can get pretty cold. As soon as this coming weekend I will do the test and let you know what I find. Thanks!
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