ECU car not starting?
ECU car not starting?
Without switching out the ECU what other way can I determine why the FI spider won't start?
Ok... here 's the detail... I was driving fine for about a mile when the car just died... new battery, all cables seem fine, all ground pods sanded and prepped (good grounds), ignition switch seems fine, I'm not getting spark from coil, when I turn the key on the switch am I supposed to hear the fuel pump running because it's not. If I remove the wires to the fuel pump and use 12v supply... I can hear it turn on... does this mean it works fine? I'm stumped on this one... all the fuses are fine, checked the two in-line fuses and the double relay (they work... I took them apart and the diodes as well as the relay works).
The cold start valve and the Air Flow unity works since I hear the buzzing sound on the air flow flap.
Anybody have this problem... Anything else I'm missing?
Thanks...
Ok... here 's the detail... I was driving fine for about a mile when the car just died... new battery, all cables seem fine, all ground pods sanded and prepped (good grounds), ignition switch seems fine, I'm not getting spark from coil, when I turn the key on the switch am I supposed to hear the fuel pump running because it's not. If I remove the wires to the fuel pump and use 12v supply... I can hear it turn on... does this mean it works fine? I'm stumped on this one... all the fuses are fine, checked the two in-line fuses and the double relay (they work... I took them apart and the diodes as well as the relay works).
The cold start valve and the Air Flow unity works since I hear the buzzing sound on the air flow flap.
Anybody have this problem... Anything else I'm missing?
Thanks...
Re: ECU car not starting?
if you're not getting spark, focus on the ignition system not the FI. Two common ignition problems are a failed pickup in the dist and a failed module under the coil
Re: ECU car not starting?
Thanks Mark, looks like I might have to try out the FI diagnostics above and check entire the system to see if anything else is amiss, might be something simple I'm missing, go through every step outlined before I rule anything out.
Nick
Nick
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Re: ECU car not starting?
I had an ignition pickup fail as the car warmed up. New pickup did the trick.
Re: ECU car not starting?
Yeah, Mark eluded to the ignition module, but the car was running fine, I really think it might be the fuel pump, does the fuel under pressure to the cold start valve activate some type of sensor that activates the ignition module or is the ignition module activation per the ignition key regardless of whether fuel is in the line?
Nick
Nick
Re: ECU car not starting?
I think that its the thermo-airflow throttle aux. double relay valve pump sensor switch module. Make sure you check that one out.
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Re: ECU car not starting?
Hot damn Pope! I think you nailed it!
Ron
Ron
Re: ECU car not starting?
the ign module gets power from the ign switch, and has nothing to do with the FI
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Re: ECU car not starting?
Your first post said you're not getting spark. That's not related to the fuel pump in any way. The brown with white wire takes 12v to the dual relay, when you're key is on, or in start position, that 12v goes out the green with black wire from the dual relay to the fuel pump. As Mark stated, the coil gets it's 12v from the ignition switch through the pink wire. If you're getting 12v on the + term. (pink wire) at the coil and not getting a spark out of the coil to the dist. it's most likely the module under the coil or a break in the wires going to the pick up under the dist. cap. There are two windings in a coil, it is possible you have a bad coil also.
Ron
Ron
Re: ECU car not starting?
OK... I'm getting 12 volts to the coil or at least to the terminal at the module, I'm also getting 12v to the pump, as measured with voltmeter/light. Could be the coil but I checked the windings with the ohmeter and there is no shorts, but if it's the module how would you know, has anyone ever checked it to know what the reading is, can it be checked like a diode/transistor, I mean it's got to be some heavy duty voltage regulator/transistor type device right?
What I was referring to previously was if the fuel injection system had to be pressurized for the igintion module to get voltage (some type of switch in the fuel system), but I guess it doesn't according to Mark.
Nick
What I was referring to previously was if the fuel injection system had to be pressurized for the igintion module to get voltage (some type of switch in the fuel system), but I guess it doesn't according to Mark.
Nick
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Re: ECU car not starting?
Mark is right. (Go figure.) There is no switch in the fuel system, only a pressure regulator. The sensors in the FI system don't communicate with anything but the ECU, which uses this information to determine the duration of the injector pulse and if the cold start valve needs to open. The module acts to break the primary circuit, the function that points served when they opened. If it fails, the primary circuit never gets to the secondary windings to get boosted to the 40,000 volts or so that leave the coil going to the spark plug through the dizzy.
Ron
Ron
Re: ECU car not starting?
Thanks Ron, looks like I'll be on the market for a new module, but I'll replace the fuel pump as a good measure in case it's not running right, who knows maybe I'll need that pump one day during a long distance trip... where did I read that before?
Nick
Nick
Last edited by radiopilot on Fri Jan 23, 2009 8:52 pm, edited 1 time in total.
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- Patron 2022
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Re: ECU car not starting?
Are you sure it's not the pick up wires? They need to be good to get the signal to the module.
Ron
Ron
Re: ECU car not starting?
Pickup wire looks good, no obvious burn marks but don't know if it's attached correctly at the dizzy side, what should I check for other than if it's disconnected, can it be removed easily at the dizzy side? When cleaning all the ground pods I also removed all the connections at the module and cleaned them too, I used the dremel wire tool to clean the crusted oxidation off the terminals, then cleaned connectors so they made good contacts.
Nick
Nick
- launieg
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Re: ECU car not starting?
Just a thought. Did you remove the module from the heat sink? It needs to be grounded to the heat sink via the lithium grease that comes with the module (or get some from a computer shop).
Launie
'81 Spider Rolling Restoration
'81 Spider Rolling Restoration