Well… I think my ECU died

Dzrtrat1111

Dzrtrat1111

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The is a continuation and end result of my last post “high idle hot start”  I replaced the IAC with no change in hot start idle but said screw it, I’m going.

Came out to the dunes early Thursday morning and the wind was howling 40+. The sand was perfect Friday morning and went for a ride with my group. Within 10 minutes I noticed my car was running hotter than normal so stoped at the hill to check it out and found only one fan was working. Went to back to camp to chase the problem. My electrical guy is in my group and started chasing it. Found the fan and relay was good but an issue with the trigger wire. While working on the fix and the fuel pump stops working. Find the ECU, is now not triggering the fuel pump. So, we wire the pump to a switch to get me through the trip. Get that done and now no spark and the engine won’t start. 
 

I’m thinking the ECU is toast, so here I sit enjoying the Sun and camping, thinking I should convert to a Holley. 
 

for reference: LS 376/525 GM crate engine

CBM harness and Mefi 4b tuned by CBM. 

** Also, the beginning of last season the ECU stopped triggering the fans, so I wired them to relays and push buttons breakers, controlled by a temp sender in the head and had no issues since**

 
Dzrtrat1111 said:
The is a continuation and end result of my last post “high idle hot start”  I replaced the IAC with no change in hot start idle but said screw it, I’m going.

Came out to the dunes early Thursday morning and the wind was howling 40+. The sand was perfect Friday morning and went for a ride with my group. Within 10 minutes I noticed my car was running hotter than normal so stoped at the hill to check it out and found only one fan was working. Went to back to camp to chase the problem. My electrical guy is in my group and started chasing it. Found the fan and relay was good but an issue with the trigger wire. While working on the fix and the fuel pump stops working. Find the ECU, is now not triggering the fuel pump. So, we wire the pump to a switch to get me through the trip. Get that done and now no spark and the engine won’t start. 
 

I’m thinking the ECU is toast, so here I sit enjoying the Sun and camping, thinking I should convert to a Holley. 
 

for reference: LS 376/525 GM crate engine

CBM harness and Mefi 4b tuned by CBM. 

** Also, the beginning of last season the ECU stopped triggering the fans, so I wired them to relays and push buttons breakers, controlled by a temp sender in the head and had no issues since**
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I do have a mefi 4b computer that was set up for a LS 376/525 GM crate engine. I turbocharged my car and ended up going with a holley terminator.

 
You can find a decent used Mefi 4B and have CBM put your same tune on it. Or bite the bullet and get a Holley ECU and harness. I finally upgraded my old Mefi 4A to the Holley and it's been trouble free all season. 

 
I have a cbm tuned mefi 4 that I just pulled outta my car. It’s sitting in my garage. I was going to sell it but hell, you can have the damn thing if you want it, at least to get you through the rest of the season without having to do the Holley. I changed over to Holley a month ago and I’m still having problems, namely because I haven’t taken it to anyone to finish it. LRS is right, you can take the number off your Mefi 4 and cbm should have the “key” tune for it and can reflash it. 

who’s your wiring guy, btw…

 
BONES said:
I have a cbm tuned mefi 4 that I just pulled outta my car. It’s sitting in my garage. I was going to sell it but hell, you can have the damn thing if you want it, at least to get you through the rest of the season without having to do the Holley. I changed over to Holley a month ago and I’m still having problems, namely because I haven’t taken it to anyone to finish it. LRS is right, you can take the number off your Mefi 4 and cbm should have the “key” tune for it and can reflash it. 

who’s your wiring guy, btw…
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Free is amazingly generous but I will gladly bring you a bottle of you favorite alcohol and could return it to you at the end of the season if you want to sell it. 
 

My wiring guy is a long time friend who is now is AZ. He doesn’t own a wiring business but used to work for a company called Directed Electric and has done several SEMA cars. 

 
i did the the holly as well i did the HP not the terminator 4 or 5 years ago was before the terminator was out. has been flawless was super easy to install but i did have help from some friends here that do alot of street racing the biggest thing was getting injector data to put in the holly. i haven't been able to get the car on a dyno since i did the holly all the dynos here are too narrow for the car.  i still could add some more timing and grab some more HP but it run real good where its at and very conservative the only problem i have had is the dash isn't water proof last trip out over christmas it rained and water got in from the screen the glue has started to dry out over the years. i took it apart and dried it out still works fine. i also have my old 4b you could boworro its just been sitting in the trailer for the last 4 years only problem is that its in glamis and im in nj will be out on the 10th 

 
Dzrtrat1111 said:
Grounds were the first thing we checked. 
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Sucks that you're having issues. The reason I suggested grounds is from your comment that you separated the fan electrical system from the ECU but you stated that the fan problem was the first issue you noticed on this trip. I guess I didn't understand from your post what the fans had to do with the ECU. 

 
My car was doing the same thing and it ended up being the ground inside the ECU. Couldn't tell till I pulled the ECU out and realized it was broken in there and cracked at the bottom. I replaced the unit through CBM and it has run great since.

 
Shout out to @BONES, Thank You!! Met up with him this morning and he GAVE me an ECU. I have to say that I am thankful that this forum and community is full of people willing to help out those they have never met. 

Now just need to get a tune flashed on to and get back out there. 

 
My pleasure. I’ve been helped out a bunch by everyone on here, I wanted to make sure I kept it going. 
I agree, it’s a pretty rad community to be apart of. 

 
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