New BR 2.3RPM Build No Start Tried Everything Need GURU !! lol
Sep 4, 2017, 05:37 PM
#1
New BR 2.3RPM Build No Start Tried Everything Need GURU !! lol
Ok so its going to be a long story so we can get everyone on the same page.
As you can see from my signature Ive owned the car since before my joining date and for the past couple years Ive had it at a shop having a new build underway.
So once they got the car back together they have been having no luck getting it to fire. So after giving them enough money with no results i decided to pull car out of shop and go at it myself.
Along with the new motor and parts along the way they had to find me a new oem wiring harness and a new PCM.
So upon getting it back they told me they could only connect to ecu if they jumped the MFI relay to ground.
Now we just went with keeping it grounded to go through every possibility we could in order to just see if it would fire.
When the car turns over we get fuel but no spark is the issue.
I replaced all sensors so far including :
Crank Sensor
Cam Sensor
Coolant temp Sensor
GM Intake Air Temp Sensor for SD
Coils
Wires
We have also switched between my old PCM that was said to be bad and my new ecu and only difference being stronger cranking with the new PCM.
Made sure IMMOBILISER was disabled. But to be sure I again put in old ecu with original key and turned it back on with all the correct values. Still nothing.
I printed about 2000 worth of pages of manuals and my friend and I have been tracing all the grounds and connections making sure we had no bad wires or grounds.
Now with everything we replaced and still havent gotten it to fire we went back to that jumped MFI relay and removed the ground wire.
But in doing so now we dont get any relays to click there not getting triggered from the ecu. We checked pin #38 which should be MFI relay trigger (red WIre) and we got continuity.
A question we did have is are we supposed to have constant power there even with the key in off position ? Because we get full battery voltage and the black n yellow wires on the same MFI relay.
Because I do have a draw some where that is causing my battery to die unless i un do ground every night.
Hopefully you guys can make heads or tails of all that. my brain is full of all this it hurts. lol.
As you can see from my signature Ive owned the car since before my joining date and for the past couple years Ive had it at a shop having a new build underway.
So once they got the car back together they have been having no luck getting it to fire. So after giving them enough money with no results i decided to pull car out of shop and go at it myself.
Along with the new motor and parts along the way they had to find me a new oem wiring harness and a new PCM.
So upon getting it back they told me they could only connect to ecu if they jumped the MFI relay to ground.
Now we just went with keeping it grounded to go through every possibility we could in order to just see if it would fire.
When the car turns over we get fuel but no spark is the issue.
I replaced all sensors so far including :
Crank Sensor
Cam Sensor
Coolant temp Sensor
GM Intake Air Temp Sensor for SD
Coils
Wires
We have also switched between my old PCM that was said to be bad and my new ecu and only difference being stronger cranking with the new PCM.
Made sure IMMOBILISER was disabled. But to be sure I again put in old ecu with original key and turned it back on with all the correct values. Still nothing.
I printed about 2000 worth of pages of manuals and my friend and I have been tracing all the grounds and connections making sure we had no bad wires or grounds.
Now with everything we replaced and still havent gotten it to fire we went back to that jumped MFI relay and removed the ground wire.
But in doing so now we dont get any relays to click there not getting triggered from the ecu. We checked pin #38 which should be MFI relay trigger (red WIre) and we got continuity.
A question we did have is are we supposed to have constant power there even with the key in off position ? Because we get full battery voltage and the black n yellow wires on the same MFI relay.
Because I do have a draw some where that is causing my battery to die unless i un do ground every night.
Hopefully you guys can make heads or tails of all that. my brain is full of all this it hurts. lol.
Sep 5, 2017, 12:56 AM
#2
Check all the relays and check for burnt fuses. If everything is good make sure coils are getting power. Check power to all sensors. Check grounds. Just start to I g out all the connections. Make sure everything g is plugged in. Tone out all the ecu connections to the engine compartment. I redid my whole harness from tail lights to the headlights and it is very simple but there are a lot of joint connections.
Sep 5, 2017, 11:52 AM
#3
EvoM Guru
iTrader: (1)
WTF? You dropped off a running car at the shop, and they took your money after they couldn't get it to start??
Are you sure the reluctor wheel for the exhaust cam is installed correctly? It can be flipped 180* and the car won't start.
Are you sure the reluctor wheel for the exhaust cam is installed correctly? It can be flipped 180* and the car won't start.
Sep 5, 2017, 04:02 PM
#5
Not to get into right now but no I dropped off a car with no motor in it to them. It was a running car with no issues before motor came out.
After they finished putting it together its been nothing but diagnosing the no start.
So Im going to the shop now to make a check list of everything ive checked with my friend. We are both tech's. I don't however do it for a living, he does.
I have checked the reluctor wheel and it was correct position but we are going to quadruple check tonight.
As for the crank trigger plate being backwards im not sure. shop said they checked it and cleaned it so took for granted it was on correct. Have to make sure tonight once again.
We have checked for power and ground at the coils. Just seems to be no signal.
Im going to post my rom and if anyone has the time to check out that I have it set up right would be great just to be sure.
The car is going to need to be set up for speed density. I have no maf or maf connector for one and two im running the black in hopes for high hp also. So dont want no maf cone getting sucked in.
I have the omni 4 bar map sensor installed. GM intake air temp sensor, and have the GM BCS.
Car has the Forced Performance 4R's in it along with Precision 780's still.
If you anyone does check it out have a look at the immobiliser values and make sure it looks good too.
After they finished putting it together its been nothing but diagnosing the no start.
So Im going to the shop now to make a check list of everything ive checked with my friend. We are both tech's. I don't however do it for a living, he does.
I have checked the reluctor wheel and it was correct position but we are going to quadruple check tonight.
As for the crank trigger plate being backwards im not sure. shop said they checked it and cleaned it so took for granted it was on correct. Have to make sure tonight once again.
We have checked for power and ground at the coils. Just seems to be no signal.
Im going to post my rom and if anyone has the time to check out that I have it set up right would be great just to be sure.
The car is going to need to be set up for speed density. I have no maf or maf connector for one and two im running the black in hopes for high hp also. So dont want no maf cone getting sucked in.
I have the omni 4 bar map sensor installed. GM intake air temp sensor, and have the GM BCS.
Car has the Forced Performance 4R's in it along with Precision 780's still.
If you anyone does check it out have a look at the immobiliser values and make sure it looks good too.
Sep 5, 2017, 08:11 PM
#6
Tested all that other stuff once again and clear every where. re-did some corroded wires at some connectors just to be sure. Still no start though.
Ok question of the night for you guys...
If you remember I am having to ground out ecu mfi signal at the relay in order to get ecu to send fuel and be able to read and write to ecu.
I tested the wire and I am getting 12v power through the ecu ground pin 38 without even a key in.
So based on some reading it says pin 62 sends signal to mfi relay pin 38 and I am also getting 12v constant there with no key in.
Also not getting power at my switched 12v power supply pins 12 and 25 without grounding out that mfi relay wire to ecu.
Now we have the idea I have a bad ground we think but we can not find anything. So if anyone has any ideas let me know.
Ok question of the night for you guys...
If you remember I am having to ground out ecu mfi signal at the relay in order to get ecu to send fuel and be able to read and write to ecu.
I tested the wire and I am getting 12v power through the ecu ground pin 38 without even a key in.
So based on some reading it says pin 62 sends signal to mfi relay pin 38 and I am also getting 12v constant there with no key in.
Also not getting power at my switched 12v power supply pins 12 and 25 without grounding out that mfi relay wire to ecu.
Now we have the idea I have a bad ground we think but we can not find anything. So if anyone has any ideas let me know.
Sep 6, 2017, 07:38 AM
#7
EvoM Guru
iTrader: (1)
I've never had to dive that deep into the wiring on these cars. Only ever had to fix mechanical issues, or just a sensor. But it definitely sounds like you have something crossed somewhere, or a missing ground.
Are you sure you have the correct harness and you didn't get like a JDM harness or something silly like that? It should be pretty straight forward to swap a harness out.
Are you sure you have the correct harness and you didn't get like a JDM harness or something silly like that? It should be pretty straight forward to swap a harness out.
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Sep 12, 2017, 08:26 AM
#8
Does this car run yet ? Because there is so much missing. Like why would it need a complete wiring harness? And why is it missing the MAF connector?
It doesnt have a MAF , has it been tuned for SD. You have a 4 bar map installed, did you set it up?If you answered no to either of those. Do that first, it will not start without those being setup.
It doesnt have a MAF , has it been tuned for SD. You have a 4 bar map installed, did you set it up?If you answered no to either of those. Do that first, it will not start without those being setup.
Sep 12, 2017, 11:04 AM
#9
EvoM Community Team Leader
so as far as you know, the wiring and ECU where fine when you dropped the car off. Then they tell you they had to replace the main harness and ECU, but still cant get the car to start. Now electrical stuff still isnt working.
From what it sounds like they screwed up and fried your original harness and/or ECU and probably did the same thing to the replacement. Fets are probably toasted on the ECU main board which is why you are having to manually trigger relays, because the ECU cant. Its going to take a massive effort going through OEM wiring diagrams and making sure everything is right at the main harness before even plugging it into an ECU so you don't just keep frying them. If that is what is going on anyway. Electrical is a Super PITA to diagnose when you have physical access to the hardware, let alone over the interwebs with limited information.
My advice would be to reduce the problem space, if you can, try plugging one of the ECU's into another evo and see if it works, if you don't have access to another evo for testing, send it to someone who can bench test it. While thats going on you can start going one by one and verifying every single pin in the harness is going to the correct place, using a multi meter.
From what it sounds like they screwed up and fried your original harness and/or ECU and probably did the same thing to the replacement. Fets are probably toasted on the ECU main board which is why you are having to manually trigger relays, because the ECU cant. Its going to take a massive effort going through OEM wiring diagrams and making sure everything is right at the main harness before even plugging it into an ECU so you don't just keep frying them. If that is what is going on anyway. Electrical is a Super PITA to diagnose when you have physical access to the hardware, let alone over the interwebs with limited information.
My advice would be to reduce the problem space, if you can, try plugging one of the ECU's into another evo and see if it works, if you don't have access to another evo for testing, send it to someone who can bench test it. While thats going on you can start going one by one and verifying every single pin in the harness is going to the correct place, using a multi meter.
Last edited by Biggiesacks; Sep 12, 2017 at 11:12 AM.
Sep 13, 2017, 09:40 PM
#10
Pin 38 gets grounded by ECU to activate main relay. You will see voltage there with key out because it is a battery feed, and you are reading the voltage through the relay coil.
Ensure that pin 80 has power. Pin 82 should have power with key on.
Check those items first.
Electrical diagnosis has to be methodical.
Ensure that pin 80 has power. Pin 82 should have power with key on.
Check those items first.
Electrical diagnosis has to be methodical.
Sep 16, 2017, 03:02 AM
#11
Yeah we came to a conclusion that both ecu's i had were fried.
Both of them not throwing a ground to the mfi relay or the ignition. We have continuity between the two and the ecu just not getting a signal.
We ran through the shop manual diagnosing several of the different issues and we kept coming up to a blown ecu.
I found a new used on here and got it in other day but Im trying to go through the rom now and make sure all the right things are in it and changed.
Like for instance I have to start off trying to get it to start on speed density because the harness the shop bought had no maf plug or maf sensor kicking around for that matter. If i did i would just try and keep it as stock as possible but its not really an option anymore.
Both of them not throwing a ground to the mfi relay or the ignition. We have continuity between the two and the ecu just not getting a signal.
We ran through the shop manual diagnosing several of the different issues and we kept coming up to a blown ecu.
I found a new used on here and got it in other day but Im trying to go through the rom now and make sure all the right things are in it and changed.
Like for instance I have to start off trying to get it to start on speed density because the harness the shop bought had no maf plug or maf sensor kicking around for that matter. If i did i would just try and keep it as stock as possible but its not really an option anymore.
Sep 16, 2017, 06:41 PM
#12
So still no luck getting it to fire. My friend and I are going nuts trying to figure it out. Wish I didn't have to start off trying to get it to fire on speed density but have no choice until i can either buy a used maf and just try to hot wire it in for now. Been running low on funds buying all these new sensors and what not else to be sure its not that.
As of right now its for what ever reason not telling the coils to fire. Could be my programming in ecuflash but won't know until i can get someone to back up my work. So we just chasing our tails until then i feel.
As of right now its for what ever reason not telling the coils to fire. Could be my programming in ecuflash but won't know until i can get someone to back up my work. So we just chasing our tails until then i feel.
Sep 17, 2017, 04:03 AM
#13
I wish I had people around to test the ecu's I have it would rule them out. At the moment I have two ecu's sitting that we believe are fried.
Got a new ecu in like i said and we did make some progress because we are not having to ground out the MFI relay anymore.
We get power to the coils still but no spark. tried with a timing light to see and also just put another plug into boot and left on valve cover.
We have continuity between grounds and ecu. 5v reference wires have continuity.
I feel as if its my work in the ROM holding us back. I don't have to many option with no maf plug or maf. Other than buy a used one and hot wire it in.
Ive gone through all the steps to set up the omni 4 bar map sensor and wiring in the gm iat sensor to maf wires.
I have no codes present after cranking car. I also get iat and map readings using a snap-on scan tool. Not sure what the map or baro should read though when no running.
Trying to get my Evoscan software to log so we can see what the car is trying to do but haven't had any luck with it yet. been so long with everything i have to re-learn it all.
Got a new ecu in like i said and we did make some progress because we are not having to ground out the MFI relay anymore.
We get power to the coils still but no spark. tried with a timing light to see and also just put another plug into boot and left on valve cover.
We have continuity between grounds and ecu. 5v reference wires have continuity.
I feel as if its my work in the ROM holding us back. I don't have to many option with no maf plug or maf. Other than buy a used one and hot wire it in.
Ive gone through all the steps to set up the omni 4 bar map sensor and wiring in the gm iat sensor to maf wires.
I have no codes present after cranking car. I also get iat and map readings using a snap-on scan tool. Not sure what the map or baro should read though when no running.
Trying to get my Evoscan software to log so we can see what the car is trying to do but haven't had any luck with it yet. been so long with everything i have to re-learn it all.
Sep 17, 2017, 05:29 AM
#15
Yeah we are getting fuel. Smell it and take plugs out there wet. Just no combustion or signs of burn on plugs.
Have a new crank sensor in and checked the plate and its clean and in correct. Indent in i believe it was.
Checking the car on a solus right now because i cant get evo scan to connect. But we are getting rpms which was about 160+rpms i believe it was.
Have a new crank sensor in and checked the plate and its clean and in correct. Indent in i believe it was.
Checking the car on a solus right now because i cant get evo scan to connect. But we are getting rpms which was about 160+rpms i believe it was.