Lethalweapon100
Senior Member
Hi all. Im back. It seems the little sensor in the seat detected that my wallet was getting a bit too fat and it decided to thin it out for me. 1997 Ram 2500 5.9 V8.
So lets step back a few days - 4 or 5 days ago the alternator in my truck gave up the ghost. It was a 136 amp alternator, which I didn't know, so i installed a 90A one. Parts guy told me it would work and that it was base equipment. I installed it, and then the battery died. So I put in a new battery, drove around with the little 90A alt, and then upgraded to the 136A one because i wasn't satisfied with the voltage the 90A one was making. 136A kept voltage above 14V at all times just like the old one, quite an improvement.
I haven't had any problems other than that until today.
I was driving to work on the highway doing about 72 MPH, when suddenly, the engine began to produce what i thought was a knock. It sounded like a very firm POP sound, and the engine lost a lot of power. Engine was about 2250 RPM when this happened, going up a slight incline, not really on the gas but not off it either. Check engine light flashed a few times and then lit up solid. I limped to work, and did some diagnosing.
I should mention i work in a Chrysler dealership in the shop after hours doing minor projects and janitorial work, im only in highschool. I get to work, and thank god, 2 master techs im pretty good friends with were still there. One of which with lots of experience working on these trucks.
We plugged it into the code reader, and a stored multiple cylinder misfire code came up, as well as an active Cyl 8 misfire. I think the mult cyl misfire code was from when I accidentally swapped 2 plug wires after changing them 20,000 miles ago. We ran a test on the computer to show which cylinders were misfiring as it was running, cyl 4 misfired twice and cyl 8 misfired almost 200 times in a span of 30 seconds. So, misfired on every time it was supposed to normally fire.
We changed the cyl 8 plug wire to no avail, and cleaned the spark plug (parts dpt didnt have a new one). Reset the PCM and started it up, and loaded up the engine. No misfire. I thought I was golden.
About halfway home on the highway, it did it again. Power drops way off, CEL comes on. I figured it was the plug, although clean, acting up for some reason. I replaced plugs on cyl 8 and 4 just to be safe. I disconnected both terminals and touched them together to reset the PCM. Truck started fine and idled rough as if it was still misfiring. Heres where it gets kind of odd.
I put the brake to the floor and stepped on the gas to load it up (no burnouts I swear) and the truck didn't have nearly as much pull as it usually did. Usually it can almost force past the brakes. This time, not even close.
A quick run down the road revealed nothing out of the ordinary. Once I was on the main road (40 MPHish) I noticed a large power decrease. It was pinging loud and a lot, but no POP like from before. No CEL yet.
I ran the truck up a 15% grade for about 1000 yards throughout 3rd gear and 4th gear/OD. It popped a few times like it did before, but no CEL still. Def lacked a lot of power.
Back on flat road, i give it probably 3/4-full throttle from a dead stop. 1st gear pulls fine up to 4250 RPM, 2nd gear does the same, I felt almost no noticeable power lack at all. 3rd gear, the engine hits 3000 RPM, and power very suddenly drops way way down. More so than it had before. It hits 4th gear/OD, and the engine still has no power, makes the classic POP from before (and does it a lot). Finally the check engine light flashes for a solid 30 seconds before it turns solid and remains on. At this point the engine is popping like a SOB under moderate/heavy throttle, a characteristic only occuring with the CEL on, at least for this scenario.
Im not really sure what ill test first, i think ill just kind of go through everything. Probably with the fuel injector. The cap and rotor got changed with the plugs 20K ago, and like I said, the old cyl 8 plug looked horrid when i pulled it out earlier tonight.
What else should I go through?
Sent from my SM-G920P using Tapatalk
So lets step back a few days - 4 or 5 days ago the alternator in my truck gave up the ghost. It was a 136 amp alternator, which I didn't know, so i installed a 90A one. Parts guy told me it would work and that it was base equipment. I installed it, and then the battery died. So I put in a new battery, drove around with the little 90A alt, and then upgraded to the 136A one because i wasn't satisfied with the voltage the 90A one was making. 136A kept voltage above 14V at all times just like the old one, quite an improvement.
I haven't had any problems other than that until today.
I was driving to work on the highway doing about 72 MPH, when suddenly, the engine began to produce what i thought was a knock. It sounded like a very firm POP sound, and the engine lost a lot of power. Engine was about 2250 RPM when this happened, going up a slight incline, not really on the gas but not off it either. Check engine light flashed a few times and then lit up solid. I limped to work, and did some diagnosing.
I should mention i work in a Chrysler dealership in the shop after hours doing minor projects and janitorial work, im only in highschool. I get to work, and thank god, 2 master techs im pretty good friends with were still there. One of which with lots of experience working on these trucks.
We plugged it into the code reader, and a stored multiple cylinder misfire code came up, as well as an active Cyl 8 misfire. I think the mult cyl misfire code was from when I accidentally swapped 2 plug wires after changing them 20,000 miles ago. We ran a test on the computer to show which cylinders were misfiring as it was running, cyl 4 misfired twice and cyl 8 misfired almost 200 times in a span of 30 seconds. So, misfired on every time it was supposed to normally fire.
We changed the cyl 8 plug wire to no avail, and cleaned the spark plug (parts dpt didnt have a new one). Reset the PCM and started it up, and loaded up the engine. No misfire. I thought I was golden.
About halfway home on the highway, it did it again. Power drops way off, CEL comes on. I figured it was the plug, although clean, acting up for some reason. I replaced plugs on cyl 8 and 4 just to be safe. I disconnected both terminals and touched them together to reset the PCM. Truck started fine and idled rough as if it was still misfiring. Heres where it gets kind of odd.
I put the brake to the floor and stepped on the gas to load it up (no burnouts I swear) and the truck didn't have nearly as much pull as it usually did. Usually it can almost force past the brakes. This time, not even close.
A quick run down the road revealed nothing out of the ordinary. Once I was on the main road (40 MPHish) I noticed a large power decrease. It was pinging loud and a lot, but no POP like from before. No CEL yet.
I ran the truck up a 15% grade for about 1000 yards throughout 3rd gear and 4th gear/OD. It popped a few times like it did before, but no CEL still. Def lacked a lot of power.
Back on flat road, i give it probably 3/4-full throttle from a dead stop. 1st gear pulls fine up to 4250 RPM, 2nd gear does the same, I felt almost no noticeable power lack at all. 3rd gear, the engine hits 3000 RPM, and power very suddenly drops way way down. More so than it had before. It hits 4th gear/OD, and the engine still has no power, makes the classic POP from before (and does it a lot). Finally the check engine light flashes for a solid 30 seconds before it turns solid and remains on. At this point the engine is popping like a SOB under moderate/heavy throttle, a characteristic only occuring with the CEL on, at least for this scenario.
Im not really sure what ill test first, i think ill just kind of go through everything. Probably with the fuel injector. The cap and rotor got changed with the plugs 20K ago, and like I said, the old cyl 8 plug looked horrid when i pulled it out earlier tonight.
What else should I go through?
Sent from my SM-G920P using Tapatalk
