Some of you know I just completed my engine swap. I pulled a 89 2.8l v6 out and put in a 91 305tpi in. Harnesses and ecm and all. Car runs but what im noticing is when under acceleration or overdrive my car sputters, surges and backfires. Makes driving harsh and embarrassing. Im using original v6 pump cause I was told it was ample capable. V6 was MPFI. I set timing to 0 and this helps soften the back fire from 6 degrees advanced where I had it. Tps is at. 54 and smooth in its action. Im wondering if I have a fuel issue. I noticed some injectors are replaced with ones called tomco rotary disk. All other injectors are black with a green ring around them (original???) FPR is original. What should my pressure be. Im gonna pick up a gauge so I can check. Also under the distributor cap and rotor I noticed the magnetic pick up? (Part that rotates within a metal ring, kinda star shaped) was pretty rusty. It seems to run great sitting still. It might pop if you burp the throttle off idle (might). Ignition coil is brand new. Wires, cap, rotor, plugs new. Any thought? ???

 

Wanna add, no codes or light. And 02 sensor is unheated in header. (Gotta change) could knock sensor cause any of this? I do have a new one ready to install.

 

play with the timing and see if it fixes it,also timing chain could be really shot

 

All internals of engine are new. Cam, gears, chain, rods, pistons. Block was bored. Noticed it runs better when cold. Im thinking possibly ICM OR injectors.

 

also could be the egr,did you use the same cam?or different,may require different timing

 

possible large exhaust leak? I had some awful backfires under load when I lost 4 of my 6 header collector bolts... LOL. But the car ran fine.

 

The factory injectors are notoriously unreliable. I bet they are leaking.
The fuel pressure for a TPI is supposed to be 42-47 psi.
The factory timing setting is 6* BTC.

Hope this helps.

 

Cam is the hotter of the two stock ones offered. I just bought a egr block off plate. Gonna remove it. Will it throw a code? Gonna check fuel pressure and injector resistance. 12-16 ohms seem right to you guys?

 

it will throw code 32,you will need to get it deleted off the ecm,

 

I deleted all EGR type crap and have no codes, stock chip.

Check plug wires at night with a spray bottle of water.
spray a fine mist of water on plug wires while engine is running.

 

its suposed to throw a code,idk in ur case

 

If the computer moniters the sensor it will thro a code.
If its just a controlled component it wont. AIR,EGR, EGR temp
If the wire shorts or the controlled part shorts itll thro a light.
So not all components will thro a code if unhooked.

 

Well....I think I figured it out. I need a fuel pump. Gauge shows 30 psi. Doesn't leak down. Guess the v6 pump can't take it...swappers beware!

 

Update!!!! CAR RUNS PERFECT!!!! Wasn't fuel pump. Had to purge air from fuel gauge set. Didn't know that. (Fancy snap-on tools) 44 psi car off. 38 psi running. Holds pressure to 30 psi overnight.

So what was the problem you ask?
Spark plug wires to cylinder 5 and 7 were backwards. DOH!!!!
I feel so dumb you guys. I checked wires probably 6 times and missed. Still gonna block off egr valve.