97 FZJ80 Stumbling off idle (1 Viewer)

[jjg]

I took some videos so you can listen to the truck and see the fuel pressure.

 

[ppc]

I don't think fuel pressure is the issue after viewing the videos. In reviewing the entire thread I don't see anywhere that you have tested the TPS - Throttle Position Sensor. Given what I saw in the videos with the irregularity of throttle response I would test that according to the procedure in the FSM.

 

[jjg]

The torque app connected to the Bluetooth elm ODBII port has a data value called throttle position which it gets from the ECU TPS data. With the ignition turn on but the engine off and the Torque app connected to ODBII I have monitored the throttle position change smoothly, linearly and I believe accurately from a starting position of 9% to pedal to the floor value of 79%. I will check the TPS with the procedure in the FSM tomorrow none the less.

 

[jjg]

Well I checked the TPS as per FSM it was dead on. I even broke out the .020 and .030 feeler gauges. The transition from 2.somthing Kohm to infinity is precisely at .68MM where it should be. Yoda wants these things adjusted to .25mm Thats freakin rediculous. What even more rediculous is after 21 years mine is still dead on! I could see it has never been moved by the faded dab of pain marking the relationship of the tps to the housing. Anyway, about the only discrepancy is I found my +5V on pin4 of the connector (red wire with green tracer) where the manual said it would be on pin 1. I am chalking this up to a typo in the manual as everything else seems correct.

Any other ideas? How bout my old friends from the 80's cool list. I know its been a long time but you guys still out here? George C? Doug M? Any idea's? Where is norm when we need him.

 

[ppc]

The only suggestions I have would be to clean and test the MAF and also followup with the engine coolant temp sensor.

What happens when the O2 sensors are disconnected?

 

[jjg]

I disconnected the 02 sensors an hour or so ago. It made the truck worse. To make matters worse one of the wires disintegrated out of the harness side of the rear connector. Now I guess I will need to rebuild that connector somehow. I will take a look at the MAF tomorrow but again, I don't think that is the problem. I also monitor MAF values with the Torque app. They have been looking inline with what I would expect the truck to be doing at a given speed. I will test the maf as per FSM non the less. Here screen shot of the torque app when I was traveling down the road and the truck was running pretty good at a steady 39 or so MPH

 

[jjg]

Arg Looks like the MAF is checking out as per FSM. I almost wanted it to be bad even though they are about 900 from Toyota and back ordered until December something even if you want did to pay that much. At this point, I am still lost. I went through all the troubleshooting trees and I am down to Replace ECM. Just some more things I checked. The primary and secondary coil resistance was checked. Both Good. Resistance of the pickup coils in the distributor was checked as per FSM.

Looks like I will be hunting without my cruiser for the first time in about 18 years.

 

[jjg]

I just wanted to give you guys some good news I got it fixed. When I wrote the above post the mass airflow sensor was sitting on my workbench disassembled as the manual states to test it disassembled. Even after it tested well including the test to check the voltage while blowing air through it I decided I'd clean it for the heck of it before I put it back in. Anyway when I got everthing assembled and started the truck up it ran decent! It's not perfect but it's a heck of a lot better than it was in the video and I feel it is good enough to take on the road! Thank you everyone for your help especially Phil!

 

[jjg]

Well I hate to say it guys but my joy is short lived. Friday got in the car and headed up to my hunting camp upstate. The truck made the 180 mile drive just fine. We hunted sat and sun with 2 bucks to show for it. One for my son and one for my good friend Lee. The Sunday buck was a good uphill drag so I fired up the cruiser to go retrieve him.

Unfortunately what I found was a truck stumbling just as it did all last week when I was struggling with it. Also unfortunately I am in a much more remote location this time with not much support around me. I plan on disconnecting the distributor coil and maf like I did the day I got it running but I don't have any maf cleaner with me as if figured it was fixed. Anyway now I'm not so sure that was what did the trick. Here are some pics for you in case your interested.

 

[whaler]

Nice deer! Shot an 8pt yesterday with the bow, the rut is still happening, big boys are coming out more and more now, all the small deer got whacked on the highway, have seen more spikes and forks roadkill than in years past.



As far as the cruiser, thats a heartbreaker, just repeat what you did to get it running and cross your fingers until youre not remote and can devote time in a shop to it?

 

[jjg]

Nice Buck Whaler! That is exactly what I did. IT did not seem to make a difference this time. Then I fooled with it some more, Added my jumper back in to drive the fuel pump at full voltage and let it warm up real good. It still has a hesitation but it ran ok. Good enough to get me home. I think what I really need another 80 to swap some parts with. Sure wish I knew someone local.

 

[Gabriel 71]

Whaler. Did you figure out what the cause was on your rig. I'm having same issues with mine. Stumble off idle etc

 

[Squash]

Memories!
Identical stumbling issues after a cold start, could not get above 2000 rpm. Engine needed to hit 194 degrees in order to drive normally.
I did change out the TPS and ECU temp sensor.
Also cleaned out the MAF with a Sensor Cleaner though a good Toyota mechanic swears by brake clean.
That was over a year ago and my only issue is sometimes the TPS sits at zero until I give her some gas.
I would try the ECU temp sensor...just because my app always correlated engine temp and the ability to get past 2000 rpm.
Good luck

 

[jjg]

Hi Guys, no I still have not figured out what my problem is. Squash Just like you, my rig needs to be fully warmed up before it will drive. I have cleaned the Maf a couple of times and it seemed to help but its certainly far from right. I really don't think its the ECU temp sensor because I can see that the ECU see the proper temp through the ECU reporting the proper temp through the Bluetooth ODBII adapter and the torque app. I think it really might be the MAF but I am not ready to drop the crazy coin for a new Toyota one without knowing for sure.

 

[Tedward]

I have a functioning MAF as a back up. It works as it should.
If you want to borrow it you may.
We can mail it back and forth to each other.
I'll be home in less than a week.
PM me if ya care to.

 

[jjg]

Tedward your awesome! I will take you up on that. I am pming you my address. A week is fine as I am currently out of town fishing down in the keys. Your welcome to join me fishing too if you like. I always seem to have room on the boat.

 

[culturedredneck]

I’m having a similar issue right now, we’re you able to resolve yours?

 

[jjg]

Unfortunately no. It has gotten a little better on its own and If I let it warm all the way up it is drivable. Its not my daily driver so it tends to get forgotten sometimes. I still think the problem is the MAF. Another member was supposed to send me a MAF to try. Also, unfortunately, that has not happened yet and I am still not ready to pay the $$$ for a new one just to try. If you can gain access to a MAF to try please do so and report back here.

 

[jjg]

I will also mention some things I did since I last posted. One was to install a brand new FRP. Even though I determined my FRP was working I figured I go ahead and get a new one anyway. The second thing I did was bypass the fuel pump resistor with a jumper wire to drive the pump at full voltage all the time. Both of these changes richened the mixture and both helped with the drivability of the vehicle. Again while these help, I do not believe they are the answer. I believe the MAF is underreporting the true amount of air going into the engine causing the ECU to feed less fuel then the engine really needs. Now I just need another MAF to prove it.

 

[Squash]

Just to be clear.
There are two coolant temp sensors.
The first one picks up the dash gauge, number 2 works with the ECU.
Disconnect the one closest to the rad as it is easy to reach....see if OBII is live. If not change the #2 coolant sensor.