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454XL fuel delivery issue

390Express

Regular Contributor
It’s not any of the three filters, or the pump, or the regulator, or the anti-siphon valve. I’ve been through all of it, and pretty fed up at this point.

Anyone know if I can drill and tap an O2 sensor on the area of the crusader exhaust riser that looks like a freeze plug? (it’s just an embossed flat, I don’t think it has anything to do with a freeze plug)

I have the 1996 low psi TBI system. I think my issue is stemming from either my ECU (had to buy a new one), or my TBI head/injectors (also had to buy new ones). I believe I have already swapped my ECU to no avail, so I’m leaning toward the injectors.

The primary issue that I’m having is, I have the 14 psi system, and no one can tell me which injectors to use. I believe I have a set of the 28psi injectors installed, and at 14 psi provided, they’re not getting enough pressure to provide adequate fuel. I can rev to 4k in neutral, but I cannot sustain any RPM in neutral or under a load.

I’d be more than happy to get a stiffer spring and run a 28 psi system (the pump can handle it), but at this point, I’m leaning toward gutting all of this garbage and going with a Fast, Fi-tech, or Holley efi. The only issue there is, I’ll have to install an O2, at least temporarily.

Any advice would be greatly appreciated.
 
The ECU is programmed for a given set of injectors...and the injectors are designed for a given pressure for operation and it all has to be matched....

there are a few injector shops that still deal with the TBI setups...they are probably the better source of info...my guess is much of the GM data is obsolete at this point.

you can always get the ECU reprogrammed....I think the MEFIBurn sowftware is just a little more than a custom tune but haven't checked in a while...I would think the correct injectors would be even cheaper....and I'd think a new fuel pump and a carb would be a lot cheaper than a new injection system. FWIW, the old holley marine systems used to run open loop, with no O2 sensor to tweak the injector curve....
 
The ECU is programmed for a given set of injectors...and the injectors are designed for a given pressure for operation and it all has to be matched....

there are a few injector shops that still deal with the TBI setups...they are probably the better source of info...my guess is much of the GM data is obsolete at this point.

you can always get the ECU reprogrammed....I think the MEFIBurn sowftware is just a little more than a custom tune but haven't checked in a while...I would think the correct injectors would be even cheaper....and I'd think a new fuel pump and a carb would be a lot cheaper than a new injection system. FWIW, the old holley marine systems used to run open loop, with no O2 sensor to tweak the injector curve....

I talked to the Holley tech, which seems to currently be the easiest system to deal with. The best system they have right now is the Holley Sniper. It needs to be ran at least temporarily in "Learn" mode in a closed loop, then you can open the loop and eliminate the O2 sensor, but there is no way to custom program even a base tune, and have the system be closed loop, 100% of the time.

I did talk to Fi-tech and FAST, no one runs a pure closed loop/no O2 system, that does not require "learning" mode with an O2. I could possibly jerry rig something out of rubber hose, that would get me by for a couple of hours of "play" time. (take a 3" od tube and a 4" od tube, and jerry rig an 02 bung in there, with rubber cement, and mess with it on the lake for a couple hours, until it "learned" itself.

I wish Crusader or an after market co sold a riser with a cast in 02 bung. I'd pay $500 for the same, as long as it was compatible with my current manifold/riser extensions, and required no further modification.

I'm just sick of dealing with this TBI mess, that no one seems to know anything about. I do have a quadrajet carb, but I'd have to re-plumb the fuel system to accommodate the same. (install a bypass regulator, and re-plumb the return line) The other alternatives are to 1) try an 18 psi spring, and if that doesn't work try the 25/28psi spring... The higher psi systems are supposed to be more efficient anyhow, 2) to reprogram the ECU/buy MEFI burn, or 3) get new injectors, but I have not found anyone that can tell me what the stock flow rating of the 14 psi Crusader system should be @ 14 psi.

I have very little interest in programming the ECU. I paid $900 for my ECU programmed from ASM, and their customer service sucks. Had I known better at the time, I would have bought a blank ECU and MEFI Burn, and did it myself. I don't mind buying MEFI burn, but the system is antiquated, no one really uses a MEFI 1-4 anymore, and their customer service is going downhill. At $595 for MEFI burn, and $800 for a Holley Sniper, I'd rather just get the damn Holley system, and stop messing with this junk TBI nonsense.

If they dropped the price, I'd consider it, but it's been the same cost for a decade, with no improvement, and reduced capability/application. Kind of annoying to pay 80% of the cost for an entire new, upgraded EFI system (fuel pump, 02 sensor, controller, all wiring etc), for a CD and a cable.
 
sad but true....its a by-product of a short-lived system the was abandoned by the OEM soon after introduction....

FWIW, there is nothing Crusader specific about the TBI unit - it is GM all the way...so that may make it easier to find some reference data...if you have the old injector(s), there should be a GM part number on it and that should get you all the flow data you need.

I have seen a few internet posts over the years about adding an O2 bung to an existing elbow...the bad part is the sesnors usually don't tolerate any water...

I think another viable option would be to add the O2 sensor in the exhaust port at the inlet to the exhaust manifold....no water jacket to worry about...shortcoming is that you tune to that cylinder....may make sense for establishing a learning curve...
 
The gm tbi system is very simple and robust in my opinion but usually gets blamed for all kinds of problems that aren't usually fuel related.I would strongly recommend a compression test cylinder balance test and make sure you have strong spark and test fuel pressure with a gage before going any further.Diagnose the problem and not replace random parts. There is a company that is called affordable fuel injection that you can find on the web.They still sell there own tbi version for hot rods and marine. They also made a plate to go between the riser and manifold to install a o2 sensor. Wouldn't hurt to give them a call but I do not know if they will just sell you the parts. Good luck and hope this helps.
 
Forgot to add you can also buy a o2 sensor adapter plate from hardin marine.I have also seen them on ebay but have heard the quality is poor.
 
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