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Discussion Starter · #1 ·
Hi, this is my first post and I'm new to Ram Forum. Before I get into the flexplate issue I wanted ya'll to hear what I've been doing to the truck over the past year.
You can skip that part and just look at the PROBLEM section if you choose to do so, unless you want to hear a good story.



Introduction of the rebuild:

I have a 1997 RAM 1500 5.9L 360 SPORT STANDARD CAB SHORTBED... Last year around October, I decided to rebuild the engine in my truck at almost 130,000 miles. The two previous owners really ran this truck rough. The guy I bought it from told me the first owner of this truck was a farmer in the Emporia, KS area.
This is my first rebuild EVER! I completely overhauled the engine + transmission with the help of a buddy. He has a big job, so he couldn't help me anymore after that. I worked on it BY MYSELF for many days and nights, on and off, over this past year. Of course, procrastination took it's toll and that's why it took over a full year to be finished.
I had it machined and it was bored .030 over I believe... I had him do a half rebuild for beginners sake because I did not have the proper tools to do some of the build. Basically he put in the crankshaft, camshaft, pistons etc.
With the machining, half rebuild, checking my heads for cracks, cleaning etc. the service cost was $600...
Of course, I had cracked heads, so it's time to order new parts. I ordered remanufactured heads, a full engine rebuild kit along with fresh new lifters, full gasket kit etc. It had a bad starter, so I bought a new one from AutoZone.
I paid much attention to detail when putting it together. Basically every bolt was torqued to spec, thread-locked when needed, sequences, everything. When I have sufficient funds, I'll probably replace the transmission. It's not bad, I just want the system to be fresh.
Then, all by myself, with my engine hoist I manuevered the engine + trans into the engine bay. I'll tell you, this SUCKED the most. Doing it alone is challenging and not recommended. I basically had to put a jack with wood blocks up to the transmission, so it will angle onto the cross member and sit inside the engine mount slots.
Lastly, I just banged out all the wiring, cooler lines, a/c lines, installed the a/c condensor, radiator, hoses, fan etc.

I cranked it for the first time the other day at she's alive!!! But here was the problem...





*PROBLEM*:
(1997 RAM 1500 5.9L 360 SPORT STANDARD CAB SHORTBED)
I don't think I bolted the flexplate to the torque converter correctly, so I think the engine is unbalanced. The reason is I just couldn't find any information on how to do it correctly and was going to figure it out through trial and error once it was put together and here I am....
SYMPTOMS: the idle fluctuates erratically between 500-1500 rpm and eventually shuts itself off. The first few seconds seem fine until it starts speeding up and down.
(I ran it 4 times, a few seconds each, to see the symptoms and stopped to prevent any damage)
NOTE: the flexplate uses weights and I believe the engine is externally balanced.


Any thoughts, questions, comments, and concerns will help a lot. Thanks guys!
 

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you can't unbalance the flexplate at the torque converter... the flex plate is weighted to be balanced to the harmonic balancer and the crank shaft. Uless some how you aren't centered on the Torque Converter, which is highly doubtful.

it sounds more or less like the PCM is trying to relearn the ignition curve. Also on first start up on a new engine you have to maintain a constant RPM of 1500 to 2000 rpms for about 15 miutes after the thermostat opens to break in the cam. failure to do so will result in premature cam wear and could cause symptoms you describe.
 

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Discussion Starter · #3 ·
you can't unbalance the flexplate at the torque converter... the flex plate is weighted to be balanced to the harmonic balancer and the crank shaft. Uless some how you aren't centered on the Torque Converter, which is highly doubtful.

it sounds more or less like the PCM is trying to relearn the ignition curve. Also on first start up on a new engine you have to maintain a constant RPM of 1500 to 2000 rpms for about 15 miutes after the thermostat opens to break in the cam. failure to do so will result in premature cam wear and could cause symptoms you describe.

Thanks for the advice. The original cam was used in the rebuild, does that matter at all?
 

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Discussion Starter · #5 ·
Not sure.. when I took it to the machine shop, I consulted with the guy and he said using the old cam is fine since it's still in good shape. He's very reputable around here so I took his word... Any cons to that? Did I make a rookie mistake??:wow:
 

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The 20 minute cam break in procedure is for flat tappet cams, not roller cams like the ones in the 5.9 Magnum. As long as the cam lobes are clean, and not pitted, it IS fine, as are the lifters, though, at some point those lifters may begin suffering plunger spring failure. With a mild cam like the stocker, they'll last a long time, so don't sweat it.
Agreed, it's not likely a balance issue. More likely the computer trying to re-learn the basics as has been stated. If it doesn't get better in short order, I'd be looking to the ignition and sensors.
Umm, wait. You had it bored .030 over? New oversize pistons? If so, was the new weight factored in? This could be a balance issue as well, but I do not think that's causing the issue you described.
 

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Discussion Starter · #7 ·
Update: the truck runs fine ONLY when I keep my foot on the gas pedal, but once I take it off it will shut itself off in the next few seconds. She's not putting out any trouble codes and i'm not hearing any out of the ordinary noises coming from the engine bay. I'm starting to think either ignition, or something to do with the intake.

Anything I should look into? Thanks guys!
 

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My truck did this to me today after disconnecting the battery to do some welding on the frame. took the battery cables loose again and cleaned the terminals.. fixed the problem right up
 

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Hey Kansas,
Sounds like you have a gross vacuum leak. Check the intake, make sure all your vacuum lines are in place. Listen for sucking sounds. Check the line going into the brake booster, those get knocked loose really easy.

If that checks out, make sure all your sensors are plugged in properly.

If that checks out, make sure your 02 sensors are intact and plugged in (these only work when the engine is warm though)

check your firing order on your wires. #1 cylinder is on the left side, up front. the one closest to the power steering pump. 1 8 4 3 6 5 7 2 is your firing order. left bank is 1 3 5 7 and right bank is 2 4 6 8 Your distributor cap is marked for #1
 

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Discussion Starter · #13 ·
Solution found

Hey everyone, I forgot to update ya'll, but I found the problem!

Basically, the flexplate/torque converter had nothing to do with it, the firing order was off. After doing some reading through the service manual, I had a hunch that I did not put the distributor and/or spark plug firing order on correctly. In that case, I took the distributor off, set the engine to TDC and reset the distributor to line up with the hash mark. Put everything nack together and it ran smooth as ever, no problems.


Thank you all for your feedback it really helps alot!
 
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