Weird electrical problem. No power to ECU.

Fourth Generation Honda Prelude topics

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AudioFunk
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Weird electrical problem. No power to ECU.

Postby AudioFunk » Tue Sep 03, 2013 2:58 am

This will be kind of long, but I have been trying to figure out what is wrong with my car. Firstly, I got a 1994 Prelude Si H23A1. I was driving to work one day and my tach needle started to bounce. It got to the point were the engine would jerk and gave off some noises. I took it to a mechanic close by and he said my car had bad bearings. He said it could also be an electrical problem to why my tach needle started to bounce. After further research It became clear it was my Ignition Control Module. I bought a new dizzy and found a new mechanic. Btw I had another local "Mechanic" check out my problem and said it was my TPS. I let him change it. At the time I thought my timing was bad so I told him to check it. He moved the engine and moved the distributor around and the car would not start at all. He messed up the timing to the point it didn't start. I kicked him out and got a new mechanic who actually fixed my timing and the car started. I got a new distributor from autozone and told my new mechanic to put it on. He put it on and it didn't start. He thought he put it wrong but he came to the conclusion it was a faulty dizzy. This is where my problem starts. I was sitting in the drivers seat and I guess he was testing the dizzy. I noticed my check engine light getting dim and the clock was dim (Clock stopped working a few weeks before) No D4 light or CEL light came on when turned to the on position. No fuel pump prime, No main relay clicks. Woke up at 6AM to go to work. Tried to start the car but still no CEL or D4. Came back from work around 3PM and I turned the key to the on position and boom, CEL and D4 light came on. I also heard alot of clicks coming from the main relay. I got a new dizzy and put it on myself. Car started. Took it for a test drive no more engine jerking and no more bouncing tach. That night I found a blown fuse in the box in the engine bay and it was the one for the clock and radio. I thought that was the source of my ECU not getting power at times. My friend was trying to get my stereo to work and I think he blew the fuse, but the clocked stopped working a while back and it didn't do this before. I got a new fuse and put it on. Started the car and went to go fill up. As I reversed out of my driveway and into Drive it just shut off. Check engine light was on. Started the car and 2 blocks later it shut off again. I went home after it shut off for the second time. It died on me 2 days later when I took it to work at 6 AM. 3 times. After the 3rd time it didn't do it again. Now before it shuts off the rpm needle and speedometer needle both go to 0 at the same time. The car kinda bogs then dies. Oil and Battery light stay on. It didnt do this before with the old distributor on. Idk if it's the dizzy or power to the ecu cuts off when driving. Also, after installing the new dizzy my car idles very low when in drive or reverse when warmed up. Sometimes it does this. The needle will go down to almost 400 rpm car would shake like its about to stall then the rpm would climb then go down etc. Anyways I got a video of the problem. You can hear a cracking sound coming from the wire that comes out of the distributor after I turn the key to the on position. Maybe theres a short somewhere there? When I turn the key and see no CEL or D4 light I have to do this so it gets power and the fuel pump would prime to start the car. Maybe I can finally get some answers. Thank you all in advance for taking the time in reading this and helping me out. http://www.youtube.com/watch?v=eSPEyHOF ... fpHP5Oc3cQ

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spiffyguido
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Re: Weird electrical problem. No power to ECU.

Postby spiffyguido » Tue Sep 03, 2013 2:38 pm

From what you've described, it sounds to me like you certainly have some electrical problems, most likely a short. I would double check a lot of your wiring very carefully and look for a potential source of the problem. If you gauges are acting funny it could be that your chassis is being energized by a positive lead somewhere in your system. You should check carefully any wires you added while working on your stereo and while changing out the dizzy. Shorts of this nature can be rather simple in nature...perhaps a frayed wire that is contacting the body of the car somewhere. Check the wires around your battery, alternator, dizzy, coil and main harnesses in particular.

AudioFunk
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Re: Weird electrical problem. No power to ECU.

Postby AudioFunk » Sun Sep 08, 2013 2:51 am

spiffyguido wrote:From what you've described, it sounds to me like you certainly have some electrical problems, most likely a short. I would double check a lot of your wiring very carefully and look for a potential source of the problem. If you gauges are acting funny it could be that your chassis is being energized by a positive lead somewhere in your system. You should check carefully any wires you added while working on your stereo and while changing out the dizzy. Shorts of this nature can be rather simple in nature...perhaps a frayed wire that is contacting the body of the car somewhere. Check the wires around your battery, alternator, dizzy, coil and main harnesses in particular.

In the video you can hear like a crackling noise coming from the engine bay once I turn the key. I know It's weird but I can't describe it. It sounds like It's coming from the main wiring cause when I move it it always primes my fuel pump, which means it gets power to my ECU. There's a short somewhere there. I wonder if the comnection that connects to the dizzy can be dirty? I remember seeing some dirt in there. I know It's not related to the radio cause it didn't so it before. It all started after I took off my old dizzy and put in a new one that was faulty. I was driving today and my tach needle bounced at high RPM's. It did that when my old dizzy went out. I'm tired of these re-manufactured dizzy's. Imma re-check all the wiring tomorrow and hopefully it doesn't go out again cause imma be without a car lol cause I know autozone won't have another dizzy since my local store had to send me farther for one and they only had 2. 1 was faulty and the other one is failing on me lol. I think my rpm just dropping rapidly is due to that dizzy. Idk but can a bad dizzy or ICM cause a bad idle? When my Lude warms up or after 10 min or so of driving to work when I get there I it would idle low as hell like maybe 300 RPM lmao. The car would shake like It's about to die. It didn't do this before when I had the old dizzy. It also revs up when I brake, again, started to happen after I installed that dizzy. I got home and was about to park in the street, put in in Reverse and bam, she stalls. Wont stall in Park or Neutral. It seems like it gets more air, but after warmed up in D4 or R it would idle low and possibly stall, It won't do it all the time. If I'm sitting at a red light it would idle like at 900 or 800 RPM and all of a sudden I would feel like a mini jerk and the idle would get a lil lower. Misfire perhaps? My valves need to be adjusted also. Idk if that could cause my symptoms. Anyways, check out theat video I posted. And thanks for your help. Imma solve this soon

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spiffyguido
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Re: Weird electrical problem. No power to ECU.

Postby spiffyguido » Mon Sep 09, 2013 7:44 am

I watched the video, and yes I can hear the crackling. As I said, it seems highly likely that you have a short, which you seem pretty confident is originating due to the change in the distributor. This is certainly a possible explanation and a great place to start looking as this is something that you recently changed.

Your idle problem could be due to many things. Start by getting that short fixed and then try to fix the idle. There are great steps in the service manual (see top of screen) on how to adjust the idle according to Honda's specs. You'll also want to check for any ECU codes to give you clues about any sensors that might be malfunctioning and interrupting ordinary idle management.

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Re: Weird electrical problem. No power to ECU.

Postby AudioFunk » Tue Sep 10, 2013 2:42 pm

My old distributor took a crap on me again. I went out and got a new one today. I can still hear that crackling, but she runs. I need to get that short fixed. It's possible the short is burning out the distributors. Imma take it in next week.

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Re: Weird electrical problem. No power to ECU.

Postby spiffyguido » Thu Sep 12, 2013 10:00 am

Yes, it's possible the short could be damaging the dizzy.

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Re: Weird electrical problem. No power to ECU.

Postby AudioFunk » Tue Sep 17, 2013 6:15 pm

spiffyguido wrote:Yes, it's possible the short could be damaging the dizzy.


Update. I changed the distributor with a new one and nothing. I actually tried 3 different ones and still showing same symptoms. The car would start and the tach would bounce then the car would die. I while back before my first dizzy went I had a mechanic do a compression test and i dont think he unplugged the dizzy. You think my coil is bad?

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Re: Weird electrical problem. No power to ECU.

Postby AudioFunk » Wed Sep 18, 2013 2:39 pm

Guys, I got closer to the problem. While the key was turned on the D4 light or CEL didn't come on. So I went to my engine bay and heard the crackling noise. I moved the main ground on the thermostat housing and boom I would hear fuel pressure. That ground is bad or dirty. It explains my ECU not getting power since It's clearly not being grounded correctly. How can I clean it?

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Re: Weird electrical problem. No power to ECU.

Postby AudioFunk » Wed Sep 18, 2013 3:38 pm

Problem solved. It was the main ground under the thermostat housing. It was loose. Didn't know it cause cause all sorts of problems. Thank you all for your help.

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Re: Weird electrical problem. No power to ECU.

Postby spiffyguido » Thu Sep 19, 2013 12:28 pm

Excellent. It had to be something simple like that....it always is.

Glad you got it fixed.

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Re: Weird electrical problem. No power to ECU.

Postby AudioFunk » Thu Sep 19, 2013 1:33 pm

spiffyguido wrote:Excellent. It had to be something simple like that....it always is.

Glad you got it fixed.

Yeah, I'm glad it was. I knew something was fishy after 5 different distributors I put on and still same symptoms. It had to be something else. Now I need to find a way to get my idle smooth and I'll be set (:




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