KeepKool

This might not be the most appropriate forum to post to but I'm desperate and need some input to get my rig back on the road again so any feedback is welcome .

So here's my situation . Bought a 89 3.0 5spd runner knowing I was doing it to drop a 3.4 into it and after a few , more than a few rookie mistakes I had put together a great rig that had preformed well and never left me stranded . This was my first venture into anything like this but with lot's of homework and some help from ORS and the folks at Toyotasonly I had my rig together about four years now and love love love it .

Now my dilemma . I was pulling onto the freeway after work one day and hit the gas as of course ya just have to do sometimes and my 3.4 stumbled and would not recover . Every time I hit the throttle it will just stall out . Dosn't die but won't accelerate either . Fuel delivery problem right ? Well to date I have replaced fuel pump and filter , wires , plugs , air filter just because , Idle air , tested the mass air by unplugging it and engine immediately dies which I read means it's good , checked rail pressure as best I can and it read about 45 lbs , does not backfire or run rough at all and actually still starts right up so thinking not a injector deal , tested both crank and cam shaft sensors and both react the way they should ...... took it into a shop and spent around $400 for them to diagnose and what they came up with i'm not at all convinced is the problem . Had it in the shop twice , first time I was told bad ecu so tracked down and installed another ecu from a automatic trans truck but the folks at Toyota's only swaps who helped me with my harness assured me would work just fine , just have a cell light because the ecu is looking for a at which isn't there but hey , I wanted my truck running again so another $125 bucks later swapped the unit in and exact same problem both ecu's . Oh ya , the donner was a 99 3.4 M/T Tacoma , took the rig back to same shop and this time they tell me both cam shafts have jumped a tooth ?? When I did the swap I checked everything out and replaced anything that was at all questionable and put in a new belt so shouldn't magicly jump teeth on both sides and not really sure how they came up with that because I was told they loosened the timing belt cover and could see that way but you have to pull the main pully off the crank to see the timing alignment marks from what I remember unless I'm totally wrong here .......

So here I am after a month of evening and weekend head scratching and still not getting it sooooooo what the am I missing ?? I want my baby back , I will admit I have named her Carrie after the Movie because there were some issues getting her going but she's been going strong now for about four years so what the heck ? She has been my daily driver and stuck with a pos for the time being for transpo which is embarrassing if nothing else ; )

old87yota

I am not totally up to speed with the 5VZ-FE swaps, but I will try to move things along.

What ECU is in there now? Is it also from a 1999 vehicle?

Are you able to read codes from the ECU? The check engine light could be on for multiple reasons and may give you a clue as to what is going on.

You should be able to read live sensor data with a scan tool and by looking at sensor data (like fuel trims) and if something does not look right, it can give you direction as to where the problem lies.

It never hurts to check the mechanical timing of the engine as it sounds like you don't trust the shop that looked at your vehicle.

Also, it may help others here that know more about 5VZ-FE swaps to give more detail about the swap.

Kolton5543

To check the timing, they probably just set the crank at TDC using the harmonic balancer marks. This would be fine so long the balancer hasn't spun. Chances are, it didn't skip a tooth on each cam but more likely on the crank which would make both cams off. The best way to check it would be to pull the lower cover and make sure the crank pulley lines up. Mine had identical symptoms when I did the swap. It would start and idle but stall as soon the throttle was open. Would stall when the sensor was unplugged too. It ended up being a cooked MAF sensor.

KeepKool

Thanks to all for the feedback , everything helps even if just to jog my memory .

The ECU is from the 99 , I have been able to read codes live and otherwise and see nothing there that is amiss unless I'm missing something . I will need to drain the radiator and remove the the crank pulley as the mark is buried behind it from what I see but if it's what I need to do of course I well do it .

I have checked the MAF by simply unplugging it and from what I read if it dies the runs again after hooking it back up it's working correctly , is this accurate ?

KeepKool

ECU and all components are from the 99 and have been reading codes live as well and see nothing there amiss unless I'm missing something .

I have checked the MAF sensor by simply unplugging it to see if engine dies and it does . Is this the correct way to check or is there a more in depth way of doing things ?

KeepKool

Sorry guys , I did the first reply and didn't see it post so did it again , my bad .

Smaay

i had something like this happen in my Supra. The short rubber hose from the pump to the fuel line (inside the tank) split, so there was enough fuel to idle but as soon as i gave it some gas, it stalled out. check that

KeepKool

I will definitely look at the pump next and see what I can see

akwheeler

I wouldn't just go straight to pulling the fuel tank to check the pump, check the fuel pressure.

Bad Karma

Watch this video (there's 2 parts), sounds like what you are describing. Spoiler alert, it's the timing belt cog on the crankshaft, the keyway gets hogged out and causes all kinds of mayhem...

Innocent Fool

Did it ever run properly after you did the swap?

Mine ran great after I did the swap but then started stumbling when accelerating.
Got worse and eventually could barely get up to road speed

Being as this was a swap I went deep into troubleshooting.
Checked belt timing, Fuel Pressure, and harness wiring

Mine turned out to be a bad MAF sensor.
It seemed to test out OK but ran better when it was replaced

asg1290

How old are your o2 sensors? I had some issues with my swap, hesitating, bucking under acceleration, swapped the front o2 sensor with a new denso one and was back in business.