Fi-Tech double spritz on cold start

DorianL

DorianL

solid fixture here in the forum
Staff member
Hey all,

I have a Summit Racing branded Fi-Tech

www.summitracing.com

Summit Racing SUM-240505 Summit Racing™ MAX-efi 500 Fuel Injection Systems | Summit Racing

Free Shipping - Summit Racing™ MAX-efi 500 Fuel Injection Systems with qualifying orders of $109. Shop Fuel Injection Systems at Summit Racing.
www.summitracing.com www.summitracing.com

It works very well. The only thing that bothers me is the cold (and hot starts).

You should be able to get in the car, turn the key, and go.

The way it is now, when cold you need to “spritz” twice. For hot starts, spritzing once is enough.

By spritzing twice, I mean you need to turn key to on position. Wait three seconds as the fuel pump turns on for two seconds the fires a shot in the throttle body then shuts off.

For a hot start, you can the. crank and start. For a cold start, you have to repeat the process: turn the key off and back to run, spritz a second time, then crank.

According to the instructions, you should be able to crank and go. The instructions give no explanation on steps to take if that is not working.

Any thoughts?

I guess I should increase or decrease the priming shot.
 
your most likely correct, Id verify the fuel pressure is correct at the fuel rails, if it allows the system to drain the rails while the engine sits unused, or the fuel rails/injectors are not spraying fuel initially, on start-up, its likely your efi, is not providing fuel, until the air in the fuel lines is bled out, purged,
the symptom's sounds like, its a bit too lean on the initial start-up, and with a carb, a choke is generally applied and the accelerator pump shot covers the initial lean start, with efi, you'll likely need to have the initial fuel ratio boosted considerably for the first two-5 seconds, to compensate for the initial lack of fuel in the fuel rail feeding the throttle body
 
Last edited:
Interesting!!!!!

I think I might have found the issue.

The last time I researched this issue was about a year ago. I decided to give it the ol’ college try and googled again.

I found this video with a fellow experiencing the same issues.


I did an rpm check on cranking with the handheld: 0 rpm

I did a voltage test on the keyed ignition to the EFI and got 0 volts on cranking.

BINGO !

I don’t recall what I connected the EFI to as power source. I think the ACC. I’ll need to check. But, at first glance, it seems to be dropping power when cranking.

Which probably means that the EFI is not squirting while cranking. That would explain why it needs to spritzes to fire and hesitates a bit when it does.

I look forward to Wednesday when I can check where the power is sourced.
 
sure sounds like you might have found the root cause of the lean, on start issue!
adding a fuel pressure gauge to the throttle body inlet line is a good first test step
100187ERLerl-2.jpg

obviously a multi meter and fuel pressure gauge, and using NOID LIGHTS to see if the injector's,
fuel rail pressure and fuel pump are functional may help, testing is warranted.
image_6238.jpg



pressuregauge1.jpg


adding a fuel pressure gauge.

I wanted to install a mechanical fuel pressure gauge on my 91 L98 TPI. Sometimes the car don't start (driven infrequently) and I want to know at a glance if I got fuel pressure. I wanted the gauge to be visible from the drivers side, and not interfere with removing the valve covers. ended up...
garage.grumpysperformance.com

handy fuel system trouble shooting flow chart & info

IF youve purchased a vette thats been sitting awhile and it won,t start and run youll need to verify the fuel pump has electricity and its at least running, if it is at that point,drain the fuel tank, replace the fuel filter and fill the tank with fresh high test gas and two cans of fuel...
garage.grumpysperformance.com

TPI fuel pressure issue

I have a 1989 350 TPI engine in a street rod I built. I am having trouble with fuel pressure and did the diagnostics, which pointed to a faulty fuel pressure regulator. I replaced the fuel pressure regulator with an adjustable one from South Bay. I now have good fuel pressure while the car is...
garage.grumpysperformance.com
 
Last edited:
Ha !!!!!!

Well, I'll be !! This one had been nagging me for a couple of years, ever since I picked up the EFI in the summer of 2019 !

SOLVED !!! :rock: And it turned out to be the easiest fix ever... yeah, tell that to my nagging back as I twisted under the dash to reach the fuse box :sweating:

This car always seemed to be a bit hard to start. After a while, I simply adapted and figured out a workable routine of a spritz or two before cranking... it turns out this worked because the EFI was not sending fuel during cranking ! The motor was igniting the fuel accumulated from the primer shot(s) and not getting any cranking fuel. That also explains the rpm dip and near stall after initial combustion. If it didn't catch immediately, no matter how long you cranked, it would rarely fire up. I had gotten used to that and accepted it as being part of aftermarket EFI through throttle body.

So, indeed ! It was the line carrying power to the EFI, it would drop out when cranking. I traced the wired back to the accessory spade on the fuse box; it was plugged into the accessories port. The solution was simple: swap the connector over to the ignition spade; that was taken by the (after market) fog light (which is required here). Et voila !!!

I must have started the car a dozen times simply enjoying how well it fires up. Hmmm, this goes a long way to making me appreciate this ride much more.

It's funny how so much got solved in such a little time.

I suppose next weekend I will dig into the steering column to fix the horn, signal cancel and hazard light. The lack of signal cancel is the most annoying. I had fixed that, and the horn, not so long ago. AFAIK, the hazard lights never worked.
 
That is so cool, you found it !!!! That must feel mighty fine !

I had a similar problem with the TBucket.
 
yeah, its always a great feeling when you locate the source of a problem and can correct it easily while learning in the process.
 
You must log in or register to reply here.
Back
Top