Dim check engine light

s300 and SManager software questions & answers
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Ichiro718
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Joined: Sun Oct 23, 2022 9:16 am

Dim check engine light

Post by Ichiro718 »

So got the car started last night, i go out today to continue ignition tuning and fuel pump relay was clicking and check engine was dim..

Cleaned thermostat housing(which was already cleaned)
Battery has juice.
Good grounds

ECU related? Capacitors dont appear to be leaking but there is a strange smell. Not a burnt smell but a smell nonetheless. PC picks up Hondata(says online) what should I look for?
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Spunkster
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Re: Dim check engine light

Post by Spunkster »

What is the battery voltage at the ECU when cranking when you check it with a multimeter?

Have the capacitors been replaced in the ECU?
Ichiro718
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Re: Dim check engine light

Post by Ichiro718 »

When you say battery voltage at the ECU,do you mean the main wire that feeds the ECU?what wire is that?

I have no replaced any capacitors, but that was probably going to be my next move.

, i will upload pics of the board, but there's no burnt sections or the usual signs that a capacitor is leaking. I did look up that they release hydrogen gas or some type of crazy gas and they only have a life of 10k hours or something to that nature.

The smell was different from when i first installed the hondata. It's not burnt, but it's like pungent smell. Thought it was flux paste but i smelled that and no smell.
Ichiro718
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Re: Dim check engine light

Post by Ichiro718 »

Here's pics and here's a video i uploaded to YouTube.

https://youtu.be/_aKUXdzdJoA
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Ichiro718
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Re: Dim check engine light

Post by Ichiro718 »

Here's more pics. Notice on the board by the capacitors, where it passes through, it's almost yellowish, and silver like other pieces

I also plugged in my si computer and fuel pump primes normally but cel is still dim, but not as dim.
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Spunkster
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Re: Dim check engine light

Post by Spunkster »

The capacitors should be replaced no matter what. Especially if they smell fishy when powered on.

What you are describing sounds like low battery voltage...especially if you hear a relay clicking when trying to crank.

Measure with a multimeter at Pins A25(12v) and A26(ground).
Ichiro718
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Re: Dim check engine light

Post by Ichiro718 »

So i should go ahead and order the whole set? Yeah ok I'll do that.

A25 is supposed to be a 12v switched? I think i have that powering the guage or something like that, no?

Battery is in the trunk. That's 12.5, the junction in the engine bay is 12.5. g101 is giving ground. Verified that. .
Will report my findings. Anything else?
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Spunkster
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Re: Dim check engine light

Post by Spunkster »

What is the battery voltage measured at the ECU pins when cranking?
Ichiro718
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Re: Dim check engine light

Post by Ichiro718 »

I will relay that to you once i do that. Had no time today. Here is the link for the capacitors

ECU Capacitor Repair Kit (fits OBDI Honda Civic) https://a.co/d/asd9HCS
Ichiro718
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Re: Dim check engine light

Post by Ichiro718 »

Swapping out the capacitors as we speak, i found this one 100 220uf looking crusty, along with the solder.
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Ichiro718
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Re: Dim check engine light

Post by Ichiro718 »

Charged up battery, still nothing. Fuel pump primed but cranked it nothing. Check engine is still dim. Will hook up to the PC and see what things are doing. Seeing if I'm getting fuel or spark or what have you.
Ichiro718
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Re: Dim check engine light

Post by Ichiro718 »

To give an update. I got another ECU that was tested and known to be good. Same issue! So first thing i did was unplug sensors to see what's up. Speed sensor wiring checked out ok, but was getting weird issues, like the plastic inside the plug was giving me 12v reading😆But when i would unplug the VTEC solenoid plug(1 wire), fuel pump would shut off, and check engine light would go away.(didn't know they were on the same leg)

. I cleaned up all the grounds and put it back. Once i got to g101, as i would loosen, it would spark up. What i did was turn the key on, and it would do its usual stuff(fuel pump staying on barely-20ish psi and no spark) i would move the harness by the ground, and fuel pump would prime normal speed, reaching 40+psi. I did this about 5 times, then would verify with my test light. As i wiggled the harness by the ground, I'd lose ground.

I took the harness out of the car, and i opened up the harness and i found 2 ground wire from g101 was broken at the connector for the VTEC pressure switch. Now I'm going over every inch of the harness for any more broken wires.
Ichiro718
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Joined: Sun Oct 23, 2022 9:16 am

Re: Dim check engine light

Post by Ichiro718 »

I found the issue!! The thermostat housing was tight, but the thermostat cover wasn't tight! There was some play! I tightened it up and installed everything and she started up with no problem!!
DaX
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Re: Dim check engine light

Post by DaX »

Excellent news. Thanks for sharing the solution and closing the loop.
Ichiro718
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Joined: Sun Oct 23, 2022 9:16 am

Re: Dim check engine light

Post by Ichiro718 »

Yep yep! Now just dealing with another issue
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