maxvp01

**SOLVED**
If you don’t feel like reading the whole post, my particular problem ended up being my new aftermarket fuel injectors being broken.

Hi, I have a 1989 toyota pickup 3vze with the R150F trans. The truck had a ton of problems when I bought it so I have never had it running right, hence all the work put into it.

There is a lot of history to the motor as I had rebuilt it and put a lot of new parts on it.
-New injectors (CS performance upgraded design)
-Fuel pressure regulator, fuel pump, sending unit, tank, filter
-plugs (NGK V-power), Plug wires (denso 7mm), rotor and cap
- TPS (beck and arnley), ECT sensor, O2 sensor (bosch)
- Complete emissions delete (no more EGR, Pair valve)

I’m sure there is more but I can’t think of anything else on the top of my head.

The truck has had a rougher idle, sounds like it surges a little bit, it’s a little jerky when driving too. Engine and transmission have approximately 250 miles on them. Currently running non-ethanol fuel.

The first time it backfired it sounded like a 12 gauge going off in my ear, then every time after that since there’s no more muffler to explode it’s just a really loud pop. (I get little pop pop pops too but i’ve experienced that with other manual cars too.)

I tried readjusting the TPS, checked for vacuum leaks probably 5 times, ignition timing checked and set using the diagnostic box, RPMs have been set too. I have parked the truck on a 45 degree angled hill out back to bleed coolant air out to make sure no air pockets are messing with anything. Throttle body has been cleaned, IAC passage as well (hole in the bore). I made sure there was vacuum going to the fuel pressure regulator. I have pulled the CSI out when engine was warm, stuck it in a bottle and started truck, did not drip fuel when engine was warm.

I was wondering what you guys would recommend I do next. I thought about looking at the O2 sensor but I have a feeling its just going to be black. I was going to build some 8mm plug wires because one of the denso wires pulled the spade out when I was checking the plugs (brand new and it’s the second set that’s had a wire broke on me &#129327.

2ToyGuy

First off, from what I understand, get rid of the Bosch O2 sensor. It's designed for German cars, not Japanese. Get the Denso or NTK one from Rock Auto, or whatever source you like.

Next, and I don't have the 3VZE engine in mine so I'm going by what I've read in these forums, did you try replacing the knock sensor and it's associated pigtail? It's supposed to prevent backfiring and knocking. It sounds to me like it may have gone south on you. Hard to get to, buuuuut...

Finally, did you set the timing In Accordance With (IAW) the FSM? I believe backfiring is associated with too far advanced timing, but I may be wrong on that.

Good luck to you! I'm sure someone much more knowledgeable than I am will chime in with the exact problem soon...
Pat☺

moto809

Do you have an engine code? The 3vz is pretty bulletproof (once the head gasket issue is taken care of). A wrong 02 sensor wouldn't cause crazy issues like misfires and backfires, and if you deleted the EGR, the sensors aren't going to relay the proper info to the ECU anyways.
It sounds, to me, like there's still a possible timing issue, and/or an intake sensor issue.
Good luck, hope you get it ironed out.

maxvp01

I will look into getting a denso O2 sensor, it’s possible it could help a little bit. I have not replaced the knock sensor, but i did replace the pigtail during the rebuild. I did set timing according to the FSM to 10BTDC, then i advanced two degrees to 12BTDC and it runs a little smoother like that. The TPS was also set using the FSM.
Thanks Pat!


Currently no engine codes, light just blinks steadily. As for the EGR sensor, when I removed all the emissions components, there was already a resistor in place on the connector. (looked like it was something from the factory, or something a tech at a dealership did. I ohmed that piece out at the time and the resistance was there so I left it attached.)

As for the “intake sensor” if your referring to the vane sensor, when the engine is running if I unplug the connector the truck instantly dies. But if I unplug the TPS connector the truck revs up quite a bit. I can borrow a vane sensor from my buddy and see if there is any difference.

Thanks Moto!

Co_94_PU

iTrader: (-1)

Lose the BA tps, get the correct O2 sensor, the KNK pigtail is part of the sensor (IE physically attached on the vze, a bad repair here is going to introduce noise. If you're inclined to hook up an audio amp or oscilloscope you're likely to hear/see some noise..)

You say "backfire" but you probably mean after fire. The difference between backfire and after fire is a backfire flows out the intake where afterfire happens in the exhaust.. You're running a different O2 and injectors than the engineer specified, this confuses the ECU. If you plugged in a wide band sensor I expect you'll see you're running rich, it doesn't help you've deactivated the PAIR system which is designed to help burn off hydrocarbons before they hit the hot catalytic converter.. Excess fuel on the cat causes it to run hotter this will eventually melt the screens and at best blow out the back of the exhaust pipe and worse case restrict the exhaust.

maxvp01

An update, still waiting on the O2 sensor to arrive, however in the mean time i switched out the AFM just for the hell of it (junkyard one from a 3vze runner). No difference.

This morning was also pretty cold about 35 degrees. I’ve noticed when the truck is cold it runs really rough until it starts warming up. Especially at lower RPMs. It bucks on me really bad. Possible ECT or Cold start injector?) I had replaced the ECT during the rebuild with a Standard or a WVE (can’t recall exactly which one.) Is this one of those sensors that needs to be Denso?

EDIT: Starting to think it may not be related to CSI, fires up pretty much instantly when I start the truck (even when it was 35 degrees this moening), I also tested the CSI (not the switch) by sticking the injector in a jar and running the truck when it was warm to see if it was leaking, did not leak.

My spark plug wires came in the mail too. I will build those this weekend. I also read a thread about rough low end rpm performance and it was the spark plug gap as the culprit. When I do my wires I will clean the plugs and check gap. Using NGK V-Power Platinums currently.

Forgot to mention the catalytic converters is currently just a shell, had to hollow it out a while back due to a rats nest clogging it. I plan on getting a new one on there soon, just need to get the engine running good first.

Sounds like there’s a possibility of multiple issues going on.

dbittle

Just to be double sure, check the plug wire routing. I have done that before and it makes the same symptoms you are seeing.

maxvp01

Checked the plug wire routing and nothing is really overlapping, ziptied nicely over the timing cover. Wires appear to have no burn spots either.

I noticed my fuel return line rubber hose was kinked, got some fuel hose and fixed that. Also pulled vacuum line and vent line from charcoal canister. No wet fuel on either. I also temporarily plugged the vacuum line with a bolt to see if that will make a difference.

Pics of fuel line kink and repair:


Maybe this will solve one of the problems 🤷‍♂️

maxvp01

This next post is very in depth and any suggestions would be great

Put in a denso O2 sensor, this is how rich my truck is running (pic of new to old)



Tested the O2 sensor on my teachers scope. The reading builds up to 0.9V and is pretty much pegged there. I even unhooked the brake booster hose to try and force a lean condition. Jumps back to Rich instantaneously. Correct me if i’m wrong but this tells me something is not communicating with my ECM?

This led me to testing some sensors
I tested the ECT THW - E2 terminals on the ECM. This tested out good per FSM (.76V)

Next I tested VAFM.
Vc - E2 was 5V (Spec 4V-6V)
Vs -E2 with measuring plate fully closed: 3.9V(Spec 3.7V-4.3V)
Vs-E2 with measuring plate fully open: 0.4V(Spec 0.2V-0.5V)
Vs-E2 at idle: 1.7V (Spec 2.3V-2.8V)
THA-E2 was 2.2V (Spec 1-3V)

After seeing the bad results from Vs-E2 at idling, I pulled the sensor and tested that.

Vs-E2 I got 630ohms most of the times I tested it (sometimes it would be lower but many times it was 630) (Spec is 200-600 ohms)

Vc-E2 I got 255 Ohms. (Spec is 200-400 ohms)

THA-E2 I got 2.2 ohms (was good according to temp)

Fc-E1 I got OL (spec is OL).
There is also a few dead spots in the sweep.


I put the sensor back in and hooked up my teachers scope to O2 sensor. The voltage is still pegged at 0.9V (rich). I turned the truck off and unplugged the vane sensor. Doing this prevents the fuel pump from running ive read in some posts on here. I jumped the Fp and B+ terminals and started the truck with connector to VAFM still off. (had to hold the throttle a little bit to prevent from dying)
It ran very very bad from what I can only assume is the ECM not knowing what is going on. BUT the scope had good readings between 0.7-0.2 bouncing back and forth




The goal of me doing this was to try and put that sensor into an open loop mode. I got home from class and I have a spare VAFM, tested the specs on that, and the everything was in spec (instead of reading 630 I read about 340 for the one that was out of spec the first time). I did get a few dead spots on the sweep however.

I put this VAFM on and plugged it in, and used my multimeter to see what voltage I was getting on O2 sensor. Still pegged at 0.9V.

Any suggestions? Should I be going down a different approach to figure this out?

Also a side note, unfortunately I will not be able to get my hands on a scope as the state is starting to shut down again and i’ll be unable to go to school.

Co_94_PU

iTrader: (-1)

Try faking the ect resistance, the ECU runs an "enrichment program" to warm up. If the ECU doesn't see the right engine temp it's not going to go to closed loop and use the o² sensor. If it's in closed loop and constant rich it will set a code when the learned trim maxes out..

.. Some other things you can look at...

You have aftermarket injectors, you might try adjusting the spring wheel in the AFM. Make sure you mark it's original position and don't unwind, that's not something you're likely to find information to fix.

All these signals are hackable with a few potentiometer..


You're still running the beck-arnley tps you should check the VTA signal, and VC voltage, it runs open loop above a throttle angle.

maxvp01

How would I go about faking the ECT resistance? Unplugging the connector and running it?

I will check the TPS signals today and see what I get. Last night however I checked some 5V references. Looked like the VAFM had two 5V signals. TPS and ECT both had 5V as well.

Also since I am at a constant rich condition, and still no codes, does this mean I am staying in open loop? I know my code light works because it blinks when jumping out the diag terminal

As for messing with the gear in the AFM I will try that as a last resort, don’t really like messing with that stuff because if I mess up i’m screwed.

Thanks for the reply

maxvp01

TPS Readings
ECU side:
IDL-E2 11.67V Spec 8-14V
Vc-E2 5.01V Spec 4-6V
VTA-E2 (Fully open) 0.507V Spec 0.1-1.0V
VTA-E2 (fully closed) 4.037V Spec 3-5V

TPS Connector side:
IDL-E2 11.63V
Vc-E2 5.01V
VTA-E2 (fully open) 0.505V
VTA-E2 (fully closed) 4.013V

Appears to not be dropping voltage from connector to ECU, and readings are all within spec

EDIT:
unplugged ECT when engine was warmed up then started.
Checked O2 sensor, still pegged at 0.9 volts. Then I checked O2 sensor wire at ECU to make sure it’s getting the same reading. ECU reads 0.9V from O2 sensor too.

Co_94_PU

iTrader: (-1)

VC is your five volt reference, it looks good Bo obvious shorts or failures.

Your VTA looks backwards. It should be lower voltage closed higher voltage open.




Check VTA and IDl again

maxvp01

I will check those readings again and get back to you on that.

As for the beck arnly TPS, its now a toyota. My friend gave me one from his supra. (part number was the same). It was used but within spec and I adjusted it according to FSM.

Today I also got around to finally building my plug wires, I also pulled the plugs and cleaned them. I also gapped the plugs accordingly:
2 plugs at 0.031 (FSM)
2 plugs at 0.035
2 plugs at 0.040

I did this to see if any of those different gaps will cause the plug to burn any different other than rich. A shot in the dark, but worth a try.

Thanks again

millball

Have you determined for certain that the cold start injector is not leaking???

Co_94_PU

iTrader: (-1)

Yes that's been checked.

maxvp01

I have a question about this wire (picture for reference is below)

The BR-B wire from the ECU splices off to the MAF and the ECT

The G-L wire is the 5V reference to the ECT, and i’m assuming the 5V reference goes through the ECT and coverts it to whatever it’s suppose to be and transfer to the MAF and ECU.

Does the 5V reference come through the ECT to the MAF/ECU? Or is the reference suppose to go the other way?

I measured and got 5V from G-L, with the ECT disconnected I jumpered the ECT connector with a paper clip hoping to see the 5V transferred to the MAF, but all I got was 0.020V.

I then took out the paper clip, plugged in ECT and still got 0.020V. I am thinking there might be a break in the wire if my theory is correct about this wire needing to communicate.

I did get my ohms out and I did get continuity but that doesn’t mean much because it could just be one strand connected.

Really hoping I am on to something here

maxvp01

Confirmed that they are good, I made the mistake of swapping the results.

As for the wires I was looking at on the wiring diagram:
i believe the BR-B wire is shorted out somewhere, when I jump the G-L wire to BR-B (paper clip in ECT connector), it drops all 5v to 0.020V-0.050V.

I then bypassed the connector and jumped the G-L pin from connector straight to the BR-B right under the connector, same result- it drops all the volts. I also jumped the 5V to after the splice to the MAF, no change.

I also opened up the wiring harness from MAF to ECT sensor, and wiggled wires when doing those tests to see if it’s a wire broken internally. No change.

The BR-B wire on the TPS connector has the same voltage as listed above.

Would someone be able to unplug their MAF and test the voltage from the BR-B pin on the connector with key on engine off? This is to make sure I am actually chasing the right thing here.

Co_94_PU

iTrader: (-1)

Use signal names not wire colors, it makes it a lot clearer to follow.. It's late here and this color that color doesn't track in my head.

Always try to make it easy for use to help, we tend to lose interest if we have to do lots of interpretation and stuff.

maxvp01

My bad

The 5V reference to the ECT is working, but as soon as I jump the 5V reference to the signal output (paperclip across ECT connector) everything pretty much zeros out. I’ve even bypassed the connector to rule that out.

This leads me to believe this (signal output) wire is grounding out. By any chance would you be able to see if on your VAF sensor if you are getting voltage to your E2 pin on the VAF and TPS connector.

I am reading between 0.020-0.050V on this pin, whether the ECT is jumped (with a paperclip) or not jumped.


Edit: just tested THW-E2 again on the pcm side but it’s reading within spec.. 0.45V
spec is 0.1v-1.0V

This is the circuit i thought was messed up.. urrgg this is frustrating. THW is the 5V reference I believe. i don’t understand how it’s coming back to the computer as 0.45V when the circuit zeros out at the ect connector