Injectors aren't firing, possible ECU failure
Quote from SodaPop on July 14, 2021, 7:08 pmElectronics dont like heat and it greatly shortens it's life. I am a IT Tech and I can tell you heat causes components to fail prematurely. Especially graphic processors. Also electronics require stable grounds and voltage. The heat shield gasket is a cheap insurance and makes a big difference in ecu temps. Just my 2 cents...
by heat shield gasket - do you mean just the spacer or the whole plate thing ?
here’s an example I found-
https://www.summitracing.com/parts/hly-108-70
(Are you referring to the bottom left or the one on the right?)
Carburetor heat insulator gasket is what I used. They are also referred to as a spacer ( non metal spacer). The brand I used I dont remember as I threw out the packaging and it was recommended by my mechanic. But the one in the link below would work fine. The same company has thicker versions too, if your hood clearance allows.
my hood clearance is quite low unfortunately... i did use this actually which seems similar, and it didn't save my ECU :\
https://www.jegs.com/i/Edelbrock/350/9266/10002/-1
UPDATE:
the new ECU arrived, it has some differences comparing it to the old one (images attached). some of the differences i've noticed are heavier gauge wiring for the fuel pump and an additional brown wire that wasn't on the old ECU. no idea where it leads no.
anyhow, installation was quick and easy, car started up like nothing, everything worked great. did a test run and everything seemed peachy.
a day later i drove 25 minutes and parked it. it was a hot day 29C (~84F) and after a hour i returned to the car to start but.... nothing. the fuel pump didn't prime so i checked everything related to it (checked out fine) but then I noticed that no data is shown on the handheld. like the ECU is dead. checked all relevant fuses, waited several minutes - and then it started working again.
f*ck me. i drove home, everything seemed fine. after i parked, waited again for about a hour - and again, it didn't start, no data from the ECU. so it seems heat kills it - like it has a breaker.
I do have a heat insulator (like on the link in the previous post - Edelbrock 9266), but after the car seats for a time, the heat rises to the FiTech unit. i measured temps and after shutdown they were : 80C (176F) intake and 53C (127F) on the ECU plate.
after one hour of "soaking": 77C (170F) intake and 79C (174F) on the ECU plate.
I again contacted Fitech support..... but as of now, I have no faith in my car and I can't reliably use it and it sucks ass.
can anyone test how hot their ECU plate gets? that might help me understand if its a specific issue i'm having (if y'all running the same temps), or something that happens due too a hotter than normal situation...
here's a video the demonstrates the issue:
EDIT:
here's another vid, another hour passed, now the fuel pump prime keeps resetting, so it seems the ECU isn't loading fully or something is messed up there. at the end it's more audible - the pump works->stops->works->stop until key off.
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It might be the hand held that may be causing the issues. Try this: Disconnect the 2 connectors of the wire harness that go to the handheld at the throttle body end so as to disconnect the hand held and wiring completely from the throttle body. The hand held or wiring may be shorting out 5volts, which is critical for IC Chips on the ECU. Start the car and dont drive it. Just let it idle until it gets hot (170+) and than turn off the engine and let it sit for 5 minutes or so. Than try to start it.
The gasket you are using is correct. Do you have a good ground wire from the fitech directly to the battery?
Secondly are you controlling timing with with Fitech. Are you using a electric fan to cool the engine? I use a electric fan that is controlled by a Northern Radiator PWM ( Pulse Width Modulation) fan controller, which is fantastic, and it runs my fan for a few minutes after I shut off the car to help cool things down.
Also put a volt meter on the white wire to make sure you are getting clean voltage when cranking as it seems the voltage is dropping causing the ECU to shut off and on
Last thing. Install a relay to provide power to your fuel pump instead of Fitch providing power. Just use the fitech to trigger the relay. Just wondering if the pump is drawing to much power. I dont think so, but maybe. Like alot of repairs, it's trial and error. There is always just exchanging the whole throttle body with Fitech.
Lastly how old is the battery in the car? I know I had issues with my Fitech starting when the battery was old and replacing the car battery resolved it. Trying to give you a few ideals
replying on all of your comments and seggustions:
- I disconnected the handheld from the ECU side - no change. doesn't start, ECU keeps resetting.
- I don't have a ground wire, but checked resistence from the unit bolt to the battery- it's 0ohm.
- I do have electric fans - they trigger a relay for a PWM module I retrofitted from another car (mazda 6)
- White wire voltage is around 10V while cranking. the ECU is resetting even with just the key on (without cranking)
- Fuel pump is already wired with a relay. did this several months back to off load the ECU as preventative maintenance (that went well #FACEPALM)
- The FiTech unit is outside of warranty - they sent me an ECU at no charge as good will gesture. also I'm from Israel. shipment is long and not cheap.
- Battery is new - after the previous ECU died, so did the battery. new BOSCH battery that is fully charged.
and also a small update - sometimes after disconnecting and reconnecting the battery - the ECU stops resetting and it loads "fine". but a fault appears : P0560 Main Relay. when trying to start the engine - no fuel is sprayed.
I will go through all the wiring, will try wires straight to the battery. but I'm afraid this ECU is dead as well...
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Try this. Disconnect wires from the alternator and see if it helps. Also with power off disconnect the + side from the battery and put a amp meter to see if there is any current draw. This seems to be a electrical issue that heat triggers or something is drawing alot of current causing the voltage to drop when ignition is on or cranking and I think the error you are getting is because of the low voltage triggering on the main relay of the ECU. If I remember correct FiTech told me, volts have to be above 11v to start correctly. I checked today and my voltage when cranking on white wire is 11.9v cranking and 12.6 on. You could also start unplugging fuses to see if a accessory is causes the problem. Lastly with jumper cables attached to another car running, try to start and see what the voltage is on the white wire. I hope any of this helps in some way.