Bad temp reading. Running rich. 1990 Dodge B250 5.9L
Hi everyone. First post but I have been using this forum constantly since installing my 600hp system in November.
I installed the Fitech on my Dodge Ram camper van to increase efficiency, power, and reliability for long trips. The van had multiple chronic problems before, mostly related to the ECU.
Since installing we've had several problems with the fitech. On our first drive we had low power and a glowing red hot catalytic converter. We cut the cat out but it's still running very rich and have little to no power.
We think it's because the coolant temperature sensor isn't reading properly. We replaced it with a brand new one when we installed the fitech but the temp never reads above 120F, even after 30+ mins of idle and driving.
Logs are attached from the last time it was started.
Here's what we did before/after installing the fitech system:
- new battery
- new spark plugs
- new distributor
- new coil
- new fuel pump & lines
- new catalytic converter
- isolated and protected the blue tach wire (to coil)
- new intake manifold (to fit fitech)
- changed oil and trans fluid (and filters)
Any help appreciated. Thanks!
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I cant seem to see the log files but just from a guy with miniscule EFI experience I would offer my 30 years of hotrod experience. I would get a cheap second temp gauge and run it just temporarily to verify temps against. If you are running it in the intake many intakes have a opening on each side making it easy to compare the numbers.
Without doing that Id say you definitely have a temperature issue if its maxing out at 120F, even after 30+ mins of idle and driving. Some things I would consider would be.
- Make sure you have a thermostat in the new intake.
- Make sure the thermostat is installed correctly in the new intake.
- If you can try and put the sending unit in the cylinder head vs the intake. The heads usually give the hotter reading.
- Consider changing your sensor to the highly suggested AC Delco 213-928 if you haven't already.
- See if your software has CTS adjustment menu you may be able to tune it if you get it close. If you don't have the CTS adjustment you may try and get the Software Updates for Throttle Body systems.
Maybe something will help.
Yeah, I had noticed a pretty significant differential between the temp in the heads vs. temp in the intake. Then I put on this bad boy, and now they read the same in my 700 Hp N/A small block 454 with 4.185 bore and 4.125 stroke. This sucker needs some cooling.
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It is strange how things work different in various situations. When I was a young fellow [many years ago] I used to circuit race using a 2.5 litre straight 6 engine revving to 8,000 rpm, no thermostat, we had to fit a restrictor in the top hose to slow the water down or it would overheat, consensus was that it flowed too quick through the radiator cores to get cool.
Yeah, it's a tuning thing. Every engine has it's own needs for sure.
Thanks for the help!
I installed the ACDelco temp sensor recommended above and the temp is now reading as it should (~200 when warm). I also replaced the NGK spark plugs I had installed with Champions and it is running infinitely better. I added a fuel pressure gauge in-line and I'm getting 50-60psi consistently.
All this said, there are still times when the AFR goes down to ~10 at idle when warm.
What else might cause the engine to run so rich?
Quote from lucasfraser on January 23, 2021, 3:46 pmThanks for the help!
I installed the ACDelco temp sensor recommended above and the temp is now reading as it should (~200 when warm). I also replaced the NGK spark plugs I had installed with Champions and it is running infinitely better. I added a fuel pressure gauge in-line and I'm getting 50-60psi consistently.
All this said, there are still times when the AFR goes down to ~10 at idle when warm.
What else might cause the engine to run so rich?
I would really closely check the O2 sensor. If the unit is trying to add fuel excessively, in many cases I have read, had air leaks near the O2 sensor giving a false reading. The fresh air leaking in on the sensor tells it it is lean so it tries to correct or compensate by adding fuel.
- Make absolutely sure it is located per the instructions. There are several specific criteria listed that depending on how you mounted your it must follow.
- Absolutely make sure that where the bung is installed it has a air tight seal. Black soot marks are easily seen where there are leaks. If its welded in it needs to be a good weld all the way around with no pin holes. If its clamped on make sure its positioned to seal on the round exhaust pipe and clamped tight.
With me, running extremely rich at idle was a small vacuum leak, O2 sensor picked up unburned oxygen and compensated with extra fuel, spray around inlet did not pick it up, took a smoke test to locate, base gasket blown from a backfire.