I have a 1992 Toyota PU and it has a very bad throttle delay, I put a new tps sensor, knock sensor, cleaned out throttle body and intake manifold. I’ve also replaced my IAC, brand nee distributor, even my EGR and injectors. I don’t know what else it could be, there is no vavcum leaks and it’s seems to be working since it’s a a new egr and I’m pretty sure the Air injection pump is working. But I honestly have no clue what it could be and I need this truck to use for work. I would greatly appreciate anyones knowledgeable thoughts and options on this issue.

 

Ignition Timing

 

it’s already set, although I checked my fuel return line and it doesn’t smell like fuel but the vaccum does? Could my fuel regulator be bad?

 

Well, sure, lots of things could be bad.

It's pretty easy to check. Replace the fuel return with a 6mm clear vinyl to a suitable container. Run the fuel pump with the jumper. There is no spec, but I get about 1/2 liter/min. If you get substantially less, your fuel pump may not be able to keep up with the fuel demand. Though, I would expect the engine to die, not delay.

If the diaphragm is leaking into the vacuum line, I would expect murderously rich running.

You can do a full check of the FPR with a fuel pressure gauge and a hand vacuum pump.

 

Did you hook up the fuel return line to vacuum? It will flood like crazy. Ask me how I know...LOL.

 

it’s pumping way to much fuel, and I tested the old fuel pump regulator and just put a new one and it’s not changing the flow at all, way too much fuel is coming out, I’ll get maybe 1 1/2 or maybe 2 liters of furl pumped out in a minute, it’s not the regulator, maybe fuel filter or fuel pump?

 

You might need to pick up a fuel pressure gauge. This one come with the 12mm adapter that one uses on the 3VZE. I suspect you might need a 10mm banjo-schraeder adaptor for the 22re.

"Too much" bypass fuel isn't a problem. If your pump is just a little better than mine, that's okay, as long as the FPR sets the pressure in the rail to spec. (Too little bypass fuel is a problem.)

You have checked for codes, have you not?

 

So I have 40-44 psi with vaccum hooked up to the FPR, i don’t have any codes that’s the other issue. I went ahead and tested the cold start injector to see if it’s leaking but it’s not, I also noticed when I pulled out the cold start injector that the manifold tracked and smelled strongly of gas like very fresh raw fuel not burnt fuel fresh gas, likes it’s been dripping, could boggibg be caused by bad vaccum?
i have no leaks but I’m doubting my vaccum routing.

 

Advance the timing and see how it runs. If nothing changes just put it back where it was

 

I did, and I tried it again and it still bogs out, if you go slow it will raise rpms fine, if you do it fast it chokes out and fuel just smokes out the exhuast and reams of gas.

 

Following. I've got a '93 doing the same thing. New fuel filter, vacuum lines, spark plugs and wires, fuel injector additive, and cat punched out, all to no effect. Next move was TPS and then maybe fuel pump, although it was replaced in 2016.

 

Get a fuel pressure gauge and tape it to your windshield and go for a drive and see if it’s adequate. If it is then you need to go down the line and check and make sure you’re getting good healthy spark, your ignition timing is set correctly using the correct procedure, then check your valves and make sure one isn’t hanging or out of spec. Maybe even install a wide band o2 sensor to be able to know how it’s running at idle and throughout the throttle travel. Stuff like this can be hard because both rich and lean can cause bogging down on acceleration. Does it idle perfect and only gets funky when you punch it? Is it any acceleration it stumbles then wakes up perfectly and drives well till you let off the throttle? Throttle cable smooth? How’s your MPG looking? There’s a few things than can cause what your describing.

 

I have good fuel pressure and went for a drive and it was good, I might double check my lines biw that I think about that. My throttle line has no slack and my valves are in spec,it’s all the time it does this, it just delays once you stomp it or accelerate quickly, if you rev up slowly it will the rpm’s will climb, but it will almost die out every tine I stomp it, I’m thinking it’s my AFM even tho it’s brand new something was definitely not right, I tested it and it says there is suppose to be a range of 20-1000ohms when open the vein Flap, at closed it was at 80ohms, 50% was 400ohms, and 100% was 250ohms, which does not correlate correct air flow readings to the ECU could this be it?

 

Depends what terminals you’re checking. Here’s the test procedure for a 22re

 

I found that exact same testing procedure, I followed and made sure I was correct, it failed the last test and when opening and closing the AFM it gave me way off readings like it was set to low or something, I double checked my tps and made sure it was right and it is, the only thing I could think of is my AFM

 

Okay AFM makes sense then if it’s sucking in extra air and the AMF isn’t talking to the ECU properly it might lean out and bog hard like you’re describing. Kinda like when you’re running out of fuel before you switch to reserve on a Dirtbike?

 

yes very much similar like that, I got this AFM from napa a reman and I I ruled it out but after further testing and I ordered a new one and will be here soon. Hopefully this works, I appreciate the help from you all thank you very much for taking ge time too help me solve this problem.

 

• Update: I installed a new AFM and ran it, it immediately died, did this twice and reset the ecu. Started it up for a third time and again it died… so I went ahead and unplugged the wires to the ecu and checked them put to make sure the contacts are clean, did this and let it run. Next I attempted to adjust the idle but it would idke up or down and I jumó the TE1 and E1 wires, i revved it and it didn’t want to bog as much, almost like it improved. I then set the timing and tried advancing it a little and took the wire out and it idle up like it normally would but it was very steady and I adjusted the idle screw and got it very spot on with the idle, i revved it and booted out, and it threw a code 31 against… I’m very confused now, I didn’t have this code before but now I do.. it’s very puzzling

 

31 is for the AFM if I remember correctly. Are you sure it’s plugged in all the way? And instant die after start sounds like an unplugged AFM. It has a little metal retaining clip you have to make sure seats properly. You have have received a junk part from the parts house. Bench test it if the plug is installed correctly.

 

It’s plugged in all the way and the clip is on there, I’m going to do that next, this is my third AFM now the old one did have any codes but akso wasn’t giving the ecu the corrects signals, this one however does and then cut outs and runs bad… I will definitely bench test. If I had a ground or short I would have a code 31 regardless whether good or bad AFM correct?