Throttle body injection

Hi all, My head is spinning with confusion as to what to do.
I have a ‘94 Nautique 5.8 Pro Boss with Holley TBI which has always run great but now has an injector that wont spray. Had it cleaned and tested by the shop but it seems dead.
Surely there is an equivalent injector that will slot right in so i can replace the pair.
It just seems so senseless to have to upgrade the whole pod and install 4 new injectors or retro fit a Holley carby, distributor and mechanical fuel pump, all because of a single injector.
Any suggestions would be greatly appreciated as if i dont get the kids back on the water soon they’ll pack up and find a new dad with a boat they can ski behind.
Cheers

I would study your failing injector, pull it out and take a picture of the numbers on the injector itself.
I would bet that injector was used in another production engine from the 94 time period.
Several makes were selling cars with Throttle body injectors at that time.
PCM did not invent the wheel they bought those parts from someone.
I know others have searched with no luck but post a picture of the part and the part numbers shown on that injector. Maybe we can help you out.

PeterH wrote: Hi all, My head is spinning with confusion as to what to do. I have a ‘94 Nautique 5.8 Pro Boss with Holley TBI which has always run great but now has an injector that wont spray. Had it cleaned and tested by the shop but it seems dead. Surely there is an equivalent injector that will slot right in so i can replace the pair. It just seems so senseless to have to upgrade the whole pod and install 4 new injectors or retro fit a Holley carby, distributor and mechanical fuel pump, all because of a single injector. Any suggestions would be greatly appreciated as if i dont get the kids back on the water soon they’ll pack up and find a new dad with a boat they can ski behind. Cheers

Are you saying it's dead as tested by the shop or it was good at the shop and it's dead when installed in the boat like maybe it's a wiring issue?

I also have no qualm about carbs

But, have to inquire, have you swapped the injectors or harness to see if the issue moves?

If the injector has continuity but not getting driven with PWM from the controller, a new injector won't help.

Injector not ignition possibly failed

I did forget about that one. Whoops.

Thanks JQ, it's looking like the sensible thing to do as an expensive fix to a problem that will most likey rear it's ugly head again doesn't make much sense.
Hope I can get my head around the job.
Did you remove all the redundant parts such as the fuel pumps, electronic ignition set up etc.....stupid qu I guess, i'm sure you did.
Are there any sensors that need to be removed, plugged up etc that hook in to the control system of the engine, that all seems a little confusing to me having not done this before.
Cheers.

Guys one question I do have, how do I tell if my engine is a Windsor or a Cleveland and how do I tell if it is normal rotation or reverse rotation...?
I'm just an electrician so I don't feel too guilty asking dumb questions.
Cheers guys.

KENO wrote: See which way the belts and pulleys are turning when you're looking at the front of the engine. If they're turning toward the passengers side, it's normal rotation, if toward the drivers side then it's reverse rotation.

Ken,Turning towards the passenger or drivers side, is that the top or the bottom of the belts and pulleys?

Peter,
Maybe it's best that you tell us if they are turning clockwise or counterclockwise!

8122pbrainard wrote: KENO wrote: See which way the belts and pulleys are turning when you're looking at the front of the engine. If they're turning toward the passengers side, it's normal rotation, if toward the drivers side then it's reverse rotation. Ken,Turning towards the passenger or drivers side, is that the top or the bottom of the belts and pulleys? Peter, Maybe it's best that you tell us if they are turning clockwise or counterclockwise!

Now I could have written that but let's say his belts are turning clockwise, then he'll get told he has a LH rotating engine and maybe get all kinda confused since the engine is rotating to the right.

It's that old not confusing in the slightest question of figuring out marine engine rotation and terminology

Maybe we should say, lift the hood of your car and see which way the engine rotates and compare it to your boat engine. If they're the same then you have a standard rotation engine

You need to get your brain thawed out I think it's frozen

Hope you got the antifreeze today

Not even worth continuing this conversation Pete, I'm sure he can figure it out

Not sure if this was linked already, but the previous owner of my 1994 Supra comp did this upgrade due to a failed injector.

Tahoe_MB wrote: To keep the TBI you need the following: Holley injector pod upgrade kit (534-169) $170.95 Qty 4 Holley Fuel injectors(522-43) $117.95 ea You will need a fuel pressure guage as you will have to adjust fuel regulator (screw on back of TBI) to 20 lbs. This is max output of the high pressure pump. It is a very straightforward swap. Only other thing you need is a couple of o-rings to replace the 4 on the fuel spuds that interconnect the TBI to the TBI pod.

Hey all, so all due to a single injector failing, i've decided, based on many suggestions to go with the retrofit carby / distributor option.
It's a little more expensive than the injector pod upgrade and 4 new injectors ( if you can even locate them to purchase ), as time moves on, that upgrade is becoming more difficult to locate.
So the extra cost will be well worth it.
I was reluctant to go the carb/dissy retro initially as I felt it would be a step backwards in terms of technology / performance etc but as I have found in my research it seems the carb will be much more reliable, easier to tune and adjust the set up and in fact, may even perform as well if not better slightly than the TBI.
My 351w has the GT40 heads and relatively low hours so hopefully the bottom end is still in good shape.
With the decent heads I'm tempted to install a mild cam for improved low end response / torque and an Edelbrock performer intake manifold to compliment the new quick fuel 650 double pumper carby, I think that would be a great combination without overdoing things.
Wow, all that due to one single biddy injector......boys and toys huh !
I'll keep you posted as I get the work done.....I'm starting this week.
I'm sure I may have some questions as I go as you guys have way more experience than I do.
Thanks again for your advice and suggestions, it's a great forum.
If any of you are down under....look me up, we"ll hit the river.

I’m still learning about engine mods so excuse my ignorance...
I always thought roller rockers simply allowed for higher rpm without valve bouncing.
It just gets better......haha where does one stop ?
Maybe cam, intake manifold and roller rockers would be the best combination.
I need to be mindfull of the standard and 400 hour bottom end, i dont want to over do it.
It is a ski boat at the end of the day and im not looking at pulling big rpm, i just want something that pulls like a train out of the hole.
And as im putting a new carb and dissy on i just thought of the other components that might enhance the installation.
Id hate to think that i had this new set up with one compo ant that was holding back it’s potential.
Now you have me thinking :
Carb
Dissy
Intake manifold
Cam
Roller rockers
Is that too much ?

I wouldn't pull the camshaft out of a 400 hour engine. The factory cam specs aren't too bad just lacking in total lift. 1:7 roller rockers will get you around .480 total lift and reduce some friction and maybe valvetrain weight.

Maybe pickup an extra 25 hp or so with the intake/rockers.

Springs are really the determining factor for valve "Float", Camshaft ramp rates can also effect that but those are on the extreme end of specs for that type of issue.