1997 3.4 to newer 3.4 motor swap

i recently did a motor swap on my 97 Tacoma with a newer 3.4 that takes the brown 2 hole injectors. cranks fine but acts like its running lean, getting out of first and second gear is ok but third and forth gear it shudders pretty bad but when i hold the gas pedal at a certain point to maintain speed you can feel the power its supposed to have kick in for a second and back out like its pulsating. ive done new injectors, swapped coil packs and wires and plugs going from the coil packs to the other three cylinders, cleaned those plugs and cleaned throttle body. if anybody has an idea i greatly appreciate it i am lost as to what to try next.

also noticed that 97 and 99 fuel pump are different

 

So did you swap ECUs or keep your 97 ecu and wiring harness?

I had a friend who owns a 2000 Tacoma have similar symptoms you're describing (his just started happening to his original motor with around 380k miles though, no motor swap involved). One day we tried new brown injectors (used OEM ones though), and also replaced the IAC valve (used new OEM Toyota for that). That resolved his issue entirely, but we'll never know if the injectors or the IAC was the culprit as we did both at the same time.

 

Codes ??? Check eng light

 

only codes are misfire on cylinder 1,2,3,4,5,6 and misfire on all cylinders, im going to look more into the iac valves and which one i should get for which year.

 

I wouldn't spend too much time worrying about the IAC... It's not going to throw misfire codes on all cylinders under load. I'd be considering checking the fuel pressure... What brand and source injectors did you go with? Lots of fake parts on ebay and Amazon.

 

These injectors you RR’d…..
What kind?

reason I ask is I RR’d mine with fleabay ones…..got host of issues/codes never had
Before. Sent my original OE ones to Motorwest…..very pleased with results
(No codes after RM’d injectors installed)

this code covers all cyl misfires(random)

 

injectors are rebuilt oem injectors and didnt make a difference when installed. i realized there wasnt even a thermostat installed so i did that today and obviously it runs at normal temp and now doesnt throw any codes and doesnt have the misfires nearly as bad, but still low power. im probably going to end up throwing a new fuel pump because thats the last i can think of after cleaning throttle body and maf sensor. when i hold it about 4000 rpms thats when you can feel it go and in out quickly but slightly.

 

Anyway to get fuel pressure readings?

 

Did you ever run a compression test on the new-to-you (used) motor?

 

Did it sit a while, nothing worse than gummed up fuel tank, I rebuilt my fuel tank hanger w/ new pump when I resurrected my truck with new to me engine because it was giving me fuel problems.

 

sat for maybe a month and id assume compression is fine because you can feel the power its supposed to have kick in intermittently when holding the gas while driving. thats what has me thinking fuel delivery problem but i dont have a fuel pressure tester. it has 360k miles and 1997 and 1998 takes different fuel pumps… so possibly does the newer 3.4 need more pressure, while also keeping in mind the 1997 pump in there allready possibly not delivering what its supposed to.

 

A month is nothing, so sitting should not be an issue. I'm not sure about your fuel pressure specs I have a 2001 pressure is suppose to be around 21psi. Not sure if that's 3.4l across the board or some variances by YM.

 

Bc extensive work/mods needed to get FP readings on my 2rz(only can imagine the same on 5vz)

I broke down and bought LCE gauge
46lbs when running
Stays to 35lbs after shut down after 30mins

 

If you have the part numbers for bothh injectors look them up to see what they are rated to flow

https://motorwestperformance.com/fuel-injector-flow-rates-and-specs/

 

so its back to throwing misfire codes and running bad like how it was and also turning over but not starting. so im thinking either fuel pump or also i notice one of my headlights flickering while it was idling, i shut the motor off and wiggled the wires for the headlights to see if it was a bad connection somewhere but no flickering. so maybe a electrical issue? im going to put 12 volts straight to the fuel pump today to see what i get.

 

Always start with the simple things- make sure the battery terminals are corrosion free. Inspect the cable fittings, and cables themselves- they can corrode on the ends and extend into the cable itself. Check the grounds- there is one on the firewall, one on the intake manifold, one on the passenger fender, and one below the oil filter. There might be a few more in the cab under the kick panels, around the aux ecms...

unfortunately measuring fuel pressure can be tricky- there are a few threads on this forum with details on that. Here is one of them: Guide To Hooking up Fuel Pressure Tester on 1st Gen | Tacoma World

 

Double check your grounding point on the upper intake by the diagnose plug... probably have a broken wire internally or it is loose.

 

Crack that banjo fitting where the fuel line goes to the fuel rail from the tank. That's how I proved to myself my engine i just installed was fuel starved. I was pissed did every thing right all it did was crank no start. Twas no fuel spew from line. IIRC there is a little bracket that secures it you have to pull couple bolts than you can check it. It sat awhile so needed fuel pump and.hanger TLC.

 

Mine was bad, to say the least, you possibly could just have bad fuel pump

 

so I've replaced the fuel pump and fuel filter and it does seem to run better but still has the misfires and misfire codes. will check pictures i took of the engine bay before the swap and make sure all grounds etc are bolted. since the swap was done the speedometer hasn't worked and is throwing a code for "vehicle speed sensor" I'm not sure if this effects anything.