c5biscuit

I installed the FI Tech 4 fuel injection system on my 65 roadster. I love it, car runs great, runs smooth, idles smooth etc. However on three occasions it has not started. I drove it on short trips parked it came out an hour later and it would not start at all. We found there was no gas being feed into the injectors. Fuel pressure was good and getting plenty of spark, the also ran great on the drive. After checking the inline fuse, my mechanic said it was loose and pushed it in tight it fired off and ran great for a week and was driven daily. Then it happened again after a short drive the car would not start, would not even fire off at all. After several attempts including turning the key to the off position I finally got it to start. The car idled smooth and run good.

I spoke to FI Tech support and they said it had to be an ignition problem since I verified I was getting proper fuel pressure to the injectors and to check the blue wire to the negative side of the coil to make sure it was tight, it was and is. I even bought a new coil but again had the problem of it not starting after running great for a few drives. It has good spark and it cranks good but just no gas being shot into the injectors on occasion.

Initial installation included a new gas tank with an electric fuel pump in the tank and a return line. The fuel pump is working fine and supplying proper fuel pressure to the injectors, you can hear it click on when the key is turned on.

Any suggestions on what to check next. It is like the computer does not know the car is being started and does not open the fuel to the injectors.

K2

Just a thought.
If you still have stock ignition utilizing a resistor before the coil, it could be a faulty starter solenoid, or wiring from solenoid to resistor. When you turn ignition switch from run to start position, the power feed to coil is through the starter solenoid to the coil side of the resistor, bypassing the resistor and feeding 12 volts to coil. If the solenoid internal contact is burned, it may be intermittent or not closing the circuit and feeding power to coil when ignition switch is turned to the start position. Also check wire connections. When ignition switch is in run position power is fed directly to resistor and to coil so it will run fine until next time you try to start it. To test this next time it won't start, clip a jumper from a B+ source to coil and see if it will start. Don't leave jumper on too long or you risk frying coil.

cbernhardt

Fuel injectors can be checked with a tool known as a noid light, which plugs into the injector. If the light flashes that is an indication that the injector is getting power and is being pulsed by the computer.

c5biscuit

I have electronic ignition. Thank you for your reply.

c5biscuit

I will try find someone with the light and test it. Thanks

cbernhardt

Is the ECU powered by a connection directly from the battery or through the ignition switch? I don't know about the FITech but the Holley system requires a direct battery connection so that full power will be available to the ECU during starting.

c5biscuit

I will verify where it is powerd from.

c5biscuit

Checked the ECU, red wire, it does go directly to the battery but goes thru a breaker box that also powers my vintage AC system that is connected directly to the battery.

c5biscuit

FYI started it this morning. Started right up did take just a second to get up to idle speed. Let it run for a minute checked it and gas was flowing down the walls. Running good. I did leave the distributor/coil sheild off and will run it a few days in case it was causing any problems with connections.

Thanks for all input. Good stuff. If anyone has other views they are welcome.

Mossy66

How does the ecu get it's tach signal? I assume if it doesn't see rpm, it won't supply fuel. Is there anything else that would turn off the injectors like a rollover switch or oil pressure switch?

Gerry

c5biscuit

Per FITech support it gets the signal from the blue wire connected to the negative post on the coil. I have checked this connection and it appears good. Also it installed a new coil. He did say next time it happened to verify via the computer hand held dash board that the tach reading was not zero and not jumping around all over the place. This is what tells the computer to allow gas flow to injectors on start up. I will check it next time it won't.

Thanks for your input.

Larry21556

I just went through this situation with my very non original 63 vert. Took a run from 5000 ft elev to over 8900 ft. ran great. wouldn't start cold the next day. Went through every thing to no avail. Called FI (Bryce) his advice was to move the red bat wire from the fuse block to direct connection on battery and add ground strap on block. I was skeptical. Did it. Started right up no problems. Cold it needs a minimum of 10 cranking amps to fire the injectors, I was getting about 8 amps. still playing with tuning. They are incredibly vague with advice and manual is nearly useless. But the car runs better now. I would not hesitate to do the change again. It is that much better.

c5biscuit

My red wire is connected to a fuse blocke that powers my AC. That fuse block is mounted on the firewall on passenger side and then it is connected to the battery. I am thinking that if the compressor kicks onthat would cause a drop during start. I am going to tie the red wire directly to the battery also.

Thanks for the input.

rene-paul

Starting is the key word. Modern Fi is "generally" key on fuel pump on 3 seconds then off.
This provides positive fuel pressure to the injectors. Key to start and crank plus ignition follows.Positive oil pressure or rotational crank signal will complete the fuel pump "run" circuit. Now back to old style; mechanical fuel pumps provide fuel to the carb as long as the crankshaft is turning. Ignition during "start" is from the starter solenoid direct to coil.
IMHO you may be lacking sufficiet fuel pressure in the fuel rail during start as voltage and current is directed to the high amp draw starter; thus the possibilty of insufficient fuel pressure to the injectors due to electric fuel pump unable to run. Depending on fuel pressure bleed off and restart times this could appear intermittently..
Keep us informed.
Brgds,
Rene

c5biscuit

I am getting 52-55 lbs pressure to injectors and you can hear fuel pump kick in. Just on occasion the computer will not put fuel to the injectors to keep it running. I hot a new gas tank from tank including a gm fuel pump in the tank. When in just the on position you can hear the fuel pump kick on and see gas flowing down the wall. It will start then immediatly die like it run out of gas. Try to restart and nothing no gas supplied from fuel line in to the wall. Put a pressure gauge on the fuel line and there is adequate fuel pressure 52 lbs at the end of fuel line. Just no gas flowing down the wall. The vast majority of the time it fires right up and runs great but without any sign you can come out start the car and nothing.

I have traced all the wiring and it looks good and tight. The only thing I am going to change is run the red wire directly to the battery instead of fuse block. It was also suggested to ground it to the motor.

The car runs great. Just on occasion won't start. Even when the problem occurs the engine fires off goes instantly to @ 1,000 rpm then immediately shuts down. After that it will not fire off after multiple tries. After several tries it will fire off and I immediately give throttle to keep it idling and it then runs smooth. I can turn it off and do restart it will start right up. Then a few days later it will do same. I do drive the car anout every day.

Thank you for the input. It just frustrating not knowing when it will happen.

cbernhardt

Perhaps I do not understand exactly what you are saying, but when you turn the ignition switch to the ON position there is gas flowing down the walls of the throttle body into the intake? That does not sound right to me. If you just leave the switch in the ON position does the flow continue? If you leave the switch in the ON position does the fuel pump stop after a few seconds?

c5biscuit

[QUOTE=cbernhardt;1592442798]Perhaps I do not understand exactly what you are saying, but when you turn the ignition switch to the ON position there is gas flowing down the walls of the throttle body into the intake? That does not sound right to me. If you just leave the switch in the ON position does the flow continue? If you leave the switch in the ON position does the fuel pump stop after a few seconds?[/QUOTE

It is my understanding from my mechanic. When the engine won't start (this is occasionally) there is no gas flowing down walls of the injectors. But there is fuel pressure in the fuel line where it enters FI Tech injector. We indtalled this about a month ago. FITech 4. It is like the computer doesn't know it is being started. It may take several attempts to get it to start. When it does, it runs fine. One time we tried for over an hour to get it to start. Checked fuel pressure and it was good, fuel pump was fine, checked all wiring connections all were good. Finally checked in line fuses to make sure they were good mechanic said one was loose. Put them back in and it fired right off. However I have had 3 events out of perhaps 20 starts where it went back to just cranking but not starting. I would turn key off try start again after about 4 attempt of no firing it would finally start.


This is what is so frustrating. You never know when it won't start. I removed the shield around coil/distributor yesterday just in case there was an occasional ground from engine vibration.

c5biscuit

It is powered from a fuse block on the fire wall behind the batter. The fuse block is wired directly to the battery positive post. This fuse block powers my vintage air and the ECU.

Corkscrew

Fitech directions clearly state red power wire should be connected directly to the battery. Do that, then report back.

c5biscuit

I will relocate it thanks.