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Installed a Holley TBI yesterday...have a question

I doubt that it was vapor lock. I hear that vapor lock is almost non-existent with Fuel Injected vehicles because fuel runs through the lines to fast for it to boil up. I did have vapor lock before I switched to TBI and I moved the rubber fuel lines to the outside of the frame away from the dual exhaust and this fixed the problem. Your problem sounds like the ignition module might be going out. I am assuming that you have HEI ignition. This happened to a buddy of mine on his 91 chevy with TBI. The engine would just shut off and no fuel would be delivered. I few minutes later it would turn right back on. I would have the ignition module checked.
 
I am going to look into the ignition module, I assume since I was carb'ed before it did not cause this sort of problem. What are some other symptoms that it is bad? This is inside the dist cap, correct? Anyone have a pic? I need to have this TBI reliable as I am going on a weekend wheeling trip at the end of this month.


Thanks for any input guys:)
 
I am assuming that you have HEI ignition. This happened to a buddy of mine on his 91 chevy with TBI. The engine would just shut off and no fuel would be delivered. I few minutes later it would turn right back on. I would have the ignition module checked.
Click to expand...

This is something I am not familiar with. This would mean that the fuel injector solonoid electrical system was passing through the ignion electrical system, in order for the injectors to work. Would this be a correct assumption?
 
It is wired through the distributor.....The thing is the system is setup to where you turn the key on and then pump the gas once, this shoots a burst of fuel into the TB. This is to aid in initial fire up. It would not even do this when I had the problem?

It fires up fine now, I just don't want to be in BFE and have it do this again.....:dope:
 
If this is anything like the GM system, you'd need to see if the injectors were TRYING to fire, or if (more likely) the injectors aren't being commanded to fire.

Problem is, that's something you need to check when it's happening. If it's an electrical component like the module or coil, more than likely it's going to start happening more and more frequently, or catastrophically fail. (that makes it easy to fix at least.:))

Whats this pumping gas thing before starting? How does the ECM know to fire the injectors (once?) based on the throttle position and key in run? TPS?
 
I don't know, I will have to look at the manual to figure that one out. My bud had it on his rig before and said it was to fill the intsake to assist startup.....
 
Of course I'm only basing this on my GM knowledge, but with that there is no reason to pump the gas, injector pulsewidth on startup is different in order to "choke" the engine with the right amount of fuel based on engine temp.

A lot of people with EFI that wheel in remote places carry a spare module and coil (at least) just in case, not a bad idea IMO, even with GM parts.

No one that wheels is going to be carrying all their electronic diagnostic stuff with them, if the thing dies in the middle of nowhere, and won't fire the injectors, the module is a VERY good bet as to what the problem is once you rule out the stuff you can (fuel pump running, etc) and still a decent bet if you don't/can't even check to see if the injectors are firing.

Personally I think a noid light along with those spares mentioned would be almost everything you need for minimal-spare-parts trail running. (add a fuel pump and call it good)

Noid light tells you if you're not getting fuel, (pulse but no spray=no fuel pressure for whatever reason, no pulse means the ECM isn't commanding the injectors to fire) and you can check spark very easily.

You can still probably name 20 other things (dare I say "many"?? lol) that would cause an engine to just die, but we all understand that running 100 miles from the nearest auto parts store, no cell phone reception, and no roads and a dead vehicle are not a fun combo. Minimal spares and diagnostic stuff is better than nothing, and won't take up too much space. Besides, if you carry what this stuff, and it happens again, you can do the basic tests, then swap parts (all easy/fast to do) until it either runs, or you are in the same situation you started in. :) At least you can't make things worse!

If I was carrying spares and really out in the middle of nowhere often, I might even take the precaution of testing my spares out before even using them as spares. Either that, or take your used ones that work 99% of the time, and replace those with the new ones. Personally I'd rather keep known good newer stuff as spares than ones that might decide to fail when you most need them.
 
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