I've got a project that a little different than most, I just installed Tuned Port Injection on my Rock Crawler and all of my searching for answers brings me back to this page. So I hope yall don't mind it's not a Camaro or Firebird, but it is a TPI Small Block.

What i've got is a 383 stroker, World Products 2.02/1.60 heads and all Comp Cams Valve train, MSD Digital 6 AL, Airtex E8445 in-line fuel pump. I just swapped out from a TBI to a TPI. It's been a challenge to say the least, I purchased a "complete" or almost complete unit from Craigslist. And it was almost complete, a full intake manifold, Accel yellow top 24lb/hr injectors (all marked with a 24 on them), all sensors, a 7727 ecm, and a stand-alone aftermarket wire harness. Long story short, the harness wasn't marked very well since it's an aftermarket it doesn't use factory wire colors. So that being said, it was a challenge to start as it was firing only on the passenger side(even cyl,2468), and nothing on the drivers side (odd, 1357). Eventually I got the drivers side firing and got it started. It starts right up now and idles pretty decent, but the throttle is sluggish, and runs somewhat rich. Also, when I rev it up to like 2000-2500, rpm and let it return to idle i get a back fire out of the drivers side exhaust pipe with a small flame.

So here's my question, with this being a "batch fire" system as i'm reading is it possible to get the injector wires on the wrong side injectors and still run(kinda like it's outta time)? Also my other concern is possibly a stuck injector, and can an additive mixed with fuel like SeaFoam be run thru them while running and get them to free up if stuck? Any input that can be offered is greatly appreciated, as i'm almost at a loss on where to go or what to check next.

 

You are leaving out a lot of information, cam specs , idle vacuum, base timing who tuned the calibrator , if your going in CL ?

 

Ok sorry about that I wasn't sure how much or what info was needed. So here goes.

The camshaft is a
Comp Cams TPI grind 12-256-4
lift .449/.456
duration 256/268 and @.050 212/218
center line 108
lobe separation 112.
1.5 ratio roller rockers

17 inches of manifold vacuum at idle/ idle is approx. 1000 rpm (give or take a little bit)

with a timing advance light 10 btdc with e.s.c disconnected

Tru Dyno Sports LLC in Conover NC did the tune on the chip/prom

I don't have a handheld scan tool so I couldn't tell you if it's going to CL or not

One of the things ive noticed is the exhaust sounds different (the pitch has changed from a low rumble to a higher pitch), from the TBI that I had to the TPI that i'm working with. I haven't changed heads, cam, exhaust, or anything other than intake and fuel injection (injectors, wiring, ecm, ect.). This leads to a few questions, is it possible for a intake/.F.I. change to change the exhaust sound?

Is it possible for the injector harness to be swapped side to side on the injectors and still run fair with it being a "Batch Fire" but maybe a slight delay in the fuel delivery causing a sluggish throttle and not be a crisp throttle?

Is it possible for an injector/injectors to be sluggish and there be a delay in the fuel delivery causing a "late burn" or back fire like I found last night when going from throttle back to idle but only on one side of the motor?

It idles well, starts up with no hesitation, I have no codes or C.E.light on, which leads me to believe it's in the fuel delivery system and the ecm isn't seeing it. But that's just a guess on my part. If theres anything else you need i'll be happy to do the best I can to get the info your looking for.

Thanks again for the input

 

Have you primed up the fuel system and see how long it takes for the pressure to bleed off ? If it bleeds off in ten minuets or less start pulling plugs looking for wet ones and the fpr reference line. Tpi is batch you can't good up side to side there is only one injector driver in the ecm.

 

Bleeds off? From full pressure for what? in 10 minutes or less. I haven't started it since last night so I may go pull the plugs now and see if anything stands out or looks unusual. I'll try to find a fuel pressure gauge tomorrow and go that route and see what I find with that.

 

Correct see if the pressure is dropping fast after a prime. A lean condition cylinder miss or exhaust leak by the o2 faulty map, bad cts , tps will all cause a rich running condition.