How to tell if 318 isn't running right

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d250

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My 1991 d250 318 v8 seems to have something off. I just drove it on the highway and went up to 85 mph and my dad seems to think its only running on 7 cylinders. I did spark plugs, wires, cap and rotor I also did an o2 sensor.
The truck also seems to have no power when shifting between 1 and second gear. Can someone please help me?


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d250

d250

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d250

d250

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i don't know. never driven a vehicle that was only running on 7 cylinders.



I'm not sure! I know it's not that fast or powerful. How does yours feel power wise?
 

crazzywolfie

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neither are super fast or powerful off the line but usually once they hit about 2-3000rpm area they start moving pretty good.
 

Jimmy68

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you can get a spark tester to make sure every plug is getting spark. then all you would have to do is pull every plug and make sure they are all working properly.
Inline Ignition Spark Checker

Save the cash. Just pull a plug and hold it while dad cranks the engine. Keep doing it till you get no spark.
 
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d250

d250

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neither are super fast or powerful off the line but usually once they hit about 2-3000rpm area they start moving pretty good.



It seems to be running ok now but I just drove it parked it turned it off and left when I started it up in was popping out of the exhaust I pressed on the gas and it felt like a backfire type thing that came out of the throttle body.
 

crazzywolfie

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you can actually use one of your old spark plugs as a spark tester. figure out which plug is not getting a proper spark first. if all plugs are getting spark i would try tossing your old plugs back in. it hasn't happened very often but i have had a couple new plugs that fail.
 
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d250

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you can actually use one of your old spark plugs as a spark tester. figure out which plug is not getting a proper spark first. if all plugs are getting spark i would try tossing your old plugs back in. it hasn't happened very often but i have had a couple new plugs that fail.



It might be out of timing. Do you know how to adjust that?
 

crazzywolfie

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you can't adjust the timing on a 91. that is computer controlled. you can only adjust the fuel sync using the distributor but you may want to check your plugs and for spark first since it sounds like you are having an issue that is not consistent.
 

Pntyrmvr

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Sticking valves.


"Talk is cheap. Whiskey costs money."
 
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d250

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you can't adjust the timing on a 91. that is computer controlled. you can only adjust the fuel sync using the distributor but you may want to check your plugs and for spark first since it sounds like you are having an issue that is not consistent.



An update on the truck! It's running on all 8 cylinders but it still seems to be running rich. Today it stalled for the first time. I had the a/c on full speed and once i put it down to the lowest sped the truck died. I started it back up and it was popping and backfiring out of the exhaust more than before. I can't figure it out.
 

crazzywolfie

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does it have an o2 sensor? i think i remember you saying there was a hole in the exhaust for it but someone had just removed it all together
 
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d250

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does it have an o2 sensor? i think i remember you saying there was a hole in the exhaust for it but someone had just removed it all together



Yes I did the o2 sensor on the manifold. The pipe going to the cat seems to be some type of emissions system. The truck has a maintenance and brake light on but no check engine light. The oil pressure gauge also reads very low almost all the way to the left. I don't know if this could affect how it's running. It still makes a popping noise out of the exhaust. I've been running high octane 93 if that affects anything.
 
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d250

d250

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does it have an o2 sensor? i think i remember you saying there was a hole in the exhaust for it but someone had just removed it all together



Also is there a way to reset the computer like turning it on and off like 10 times. I'm not sure what you said about the cap and rotor. You can adjust that right please explain.
 

preachp

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Do you have a vacuum advance? If so check for a vacuum leak.

Hope you get 'er sorted,

preachp
 

crazzywolfie

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Yes I did the o2 sensor on the manifold. The pipe going to the cat seems to be some type of emissions system. The truck has a maintenance and brake light on but no check engine light. The oil pressure gauge also reads very low almost all the way to the left. I don't know if this could affect how it's running. It still makes a popping noise out of the exhaust. I've been running high octane 93 if that affects anything.
ya. i am pretty sure the pump on the engine pumps air into the cat which helps your cat burn off any excess emissions.

brake light being on most likely means there is some issue with the RWAL system. you can unplug the computer that is hiding behind the glove box and it should shut the light off.
Also is there a way to reset the computer like turning it on and off like 10 times. I'm not sure what you said about the cap and rotor. You can adjust that right please explain.
only way to really to really reset the computer is to disconnect the battery and try starting the truck with it disconnected.

adjusting the distributor effects when fuel injectors fire. you can try adjusting it to get things to run better. it will most likely need it anyways to compensate for slack in the time chain. just make sure to mark the base just in case you make things worse
Do you have a vacuum advance? If so check for a vacuum leak.

Hope you get 'er sorted,

preachp
it shouldn't have a vacuum advance. it is fuel injected
 
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d250

d250

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ya. i am pretty sure the pump on the engine pumps air into the cat which helps your cat burn off any excess emissions.



brake light being on most likely means there is some issue with the RWAL system. you can unplug the computer that is hiding behind the glove box and it should shut the light off.



only way to really to really reset the computer is to disconnect the battery and try starting the truck with it disconnected.



adjusting the distributor effects when fuel injectors fire. you can try adjusting it to get things to run better. it will most likely need it anyways to compensate for slack in the time chain. just make sure to mark the base just in case you make things worse



it shouldn't have a vacuum advance. it is fuel injected



Ok I'll try to JB weld the pipe back on the cat as I don't have a welder. I'll see if that helps. As far as the distributor goes what do I do just turn in when the trucks running?
 
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