5.9 magnum runs like crap

BLKDODGE04 · Oct 16, 2017

I have a 98 dakota that has had a 5.9 magnum swapped in it from a 97 ram truck. Was originally a v6, always been a 5 speed. Gauge cluster don't work. If truck idles for a period of time it will start to stall and eventually die, you can hear the intake sucking in air. I changed plenum gaskets and cleaned everything good. Seems to do this more at an idle but maybe just seem to notice it more idk. Sometimes it seems like it is lacking power going down the road but it runs like a striped ass ape when it runs right. Any ideas what could cause this intermittent miss? I changed cap and rotor also and plug wires. Also pickup inside distributor, can't remember what its called.

Shadow_Death · Oct 16, 2017

I'm just guessing here but maybe check the IAC to see if it's dirty. Also check the port that it goes into. Mine was gunked up really good and required that I cleaned it.

See album here.

The most this will cost you is time,a can of TB cleaner, a old toothbrush, and some rags. I used B12 Carb and Throttlebody cleaner on mine. The truck woke right up after that.

dapepper9 · Oct 17, 2017

What do you have for pcm and harness?

BLKDODGE04 · Oct 17, 2017

Pcm and harness all from same truck as motor as far as I know

BLKDODGE04 · Oct 17, 2017

I took IAC out and cleaned it, it was pretty bad, so was port it goes in to. Didn't seem to change much. Sometimes it will idle great and other times it will idle like ****. Seems like a hit or miss problem

BLKDODGE04 · Oct 17, 2017

How critical are o2 sensors with these motors? I know some motors will run just fine with them unhooked and others will do funny things. Mine are currently unhooked.

SYKRAMMAN · Oct 17, 2017

Have you had the pcm scanned lately?

BLKDODGE04 · Oct 17, 2017

I took IAC out and cleaned it, it was pretty bad, so was port it goes in to. Didn't seem to change much. Sometimes it will idle great and other times it will idle like ****. Seems like a hit or miss problem

BLKDODGE04 · Oct 17, 2017

Yes I had it scanned, all I could really tell was it was running rich

SYKRAMMAN · Oct 17, 2017

How old is the 1/1 o2 sensor?

Yeret · Oct 17, 2017

Plug the O2 sensors back in, especially the upstream one. These are critical for the ECU to properly adjust and maintain fuel/air mixture. Unplug 'em and the ECU can only rely on MAP and TPS readings to try and adjust the mixture, which will result in the engine running excessively rich. O2 sensors are there for a reason.

BLKDODGE04 · Oct 17, 2017

O2 sensor wiring harness has been cut, can someone take a pic of the wiring on their sensor and how it is color coded? I tried looking online but couldn't find much or at least not the right wiring diagram.

SYKRAMMAN · Oct 17, 2017

Where is it cut at? If it's just the plug end then your good cause when you buy a splice in o2 sensor it comes with a wiring diagram.

BLKDODGE04 · Oct 17, 2017

Yeah its cut on o2 sensor side, just pigtail is cut off. I just need to know what color to run to what color. If I remember correctly new o2 has 2 white a grey and a black. Truck side is all different colors. Think there's a black with blue stripe which is ground I think. Then there's an orange with green stripe I believe, I'd have to look for sure. Just need to know which wire goes to what.

BLKDODGE04 · Oct 17, 2017

Anyone got a picture?

svdsinner · Oct 18, 2017

Have you checked the catalytic converter? Blown intake gaskets often destroy them, and without O2 sensors, you would get no warning.

Sent from my SM-G950U using Tapatalk

Big_Al · Nov 13, 2017

BLKDODGE04 said:
Pcm and harness all from same truck as motor as far as I know

That is likely the issue with the gauges. FWIW....Al

Was with my swap using a 97 5.9 ECM in a 99 Ram.

5.9 magnum runs like crap

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