Project Dumpy - '88 chassis cab dump truck (1 Viewer)
- Thread starter justinhw
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- #22
That's awesome
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- #24
New TPS - 89452-20050
Adjusted per spec of the TSM - the trick I found was to set up the open circuit (test 3) with a 0.85mm feeler gauge. The rest of the tests fell in spec after that.
Also cleaned a bunch of carbon off the throttle body - need to get a new idle adjustment screw o-ring, it's on order now
Adjusted per spec of the TSM - the trick I found was to set up the open circuit (test 3) with a 0.85mm feeler gauge. The rest of the tests fell in spec after that.
Also cleaned a bunch of carbon off the throttle body - need to get a new idle adjustment screw o-ring, it's on order now
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- #25
I took off the water temp sender that goes to the gauge cluster - the top got busted and wasn't connected. When I took it out I found the threads were a little crusty and I couldn't thread the new sender in. I went at it with a pick for awhile but ended up giving up. So i cut the sender in half and found out the threads were M16-1.5. Ordered a thread chaser, which was harder than I thought, and hopefully that will be here soon
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- #26
Looks like there are new freeze plugs so someone must have pulled the motor at some point
But when I went to pull the 17mm block coolant drain plug, it was caked in this black soot and couldn't drain. I had to use a pick and poke at it until the coolant could drain out.
But when I went to pull the 17mm block coolant drain plug, it was caked in this black soot and couldn't drain. I had to use a pick and poke at it until the coolant could drain out.
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- #27
Took a razor blade and cleaned off the left over throttle body gasket
Got a new o-ring installed in the idle screw - old one was hard as a rock
Chased out the threads too on the temp gauge sender - kind of looks like there should be a washer or gasket to seal fluids?
Got a new o-ring installed in the idle screw - old one was hard as a rock
Chased out the threads too on the temp gauge sender - kind of looks like there should be a washer or gasket to seal fluids?
Are those pink butt connectors not shrink tube? I have some end connectors like that and they shrink down nice and tight.
I've never had a problem with a temp sensor leaking. The brass is good at sealing. That said, I just us Teflon paste on the threads.
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- #31
Yah I did end up going back over with a heat gun
For the temp gauge sender - It's not leaking so far, but good tip on the pipe dope
New plugs and wires;
Changed the oil, buttoned everything back together (except the vacuum lines - i have those plugged right now)- and started it up.
It ran like S***- couldn't idle - then i realized when i deleted the IACV I forgot to plug the throttle body nipple - so there was a massive air leak
plugged that, and now it's running much better. When I bought it, it would hardly idle, die at stops, idle would jump up and down. Now seems to be idling smoothly
Not sure if the audio works, but here:
For the temp gauge sender - It's not leaking so far, but good tip on the pipe dope
New plugs and wires;
Changed the oil, buttoned everything back together (except the vacuum lines - i have those plugged right now)- and started it up.
It ran like S***- couldn't idle - then i realized when i deleted the IACV I forgot to plug the throttle body nipple - so there was a massive air leak
plugged that, and now it's running much better. When I bought it, it would hardly idle, die at stops, idle would jump up and down. Now seems to be idling smoothly
Not sure if the audio works, but here:
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- #32
vacuum at idle was borderline at first
but if i blip the throttle, then let it idle - it will come back
Didn't pass smog - but due to high HC - I'm running too rich, I can smell it too, I should have know before I went for the test, wishful thinking.. I think I have to go looking for a leaky cold start injector (or just a leaky injector in general). I checked that i'm getting vacuum to the fuel pump regulator, so it should be the lower pressure which is correct. I have to do some reading up to see what else to look for.
My EGR isn't working currently as well, the valve works (I pull vacuum and the car dies). but the modulating valve I don't think works. I got a dorman one, we'll see if i can get it to work. I don't think that would effect my HC at idle though.
but if i blip the throttle, then let it idle - it will come back
Didn't pass smog - but due to high HC - I'm running too rich, I can smell it too, I should have know before I went for the test, wishful thinking.. I think I have to go looking for a leaky cold start injector (or just a leaky injector in general). I checked that i'm getting vacuum to the fuel pump regulator, so it should be the lower pressure which is correct. I have to do some reading up to see what else to look for.
My EGR isn't working currently as well, the valve works (I pull vacuum and the car dies). but the modulating valve I don't think works. I got a dorman one, we'll see if i can get it to work. I don't think that would effect my HC at idle though.
EGR lowers NOx. It won't help HC. I don't see that test on your report, so I wouldn't worry about it.
As far as HC, start with a basic tuneup, which you have sort of done. Check your timing, 5°. Make sure you short TE1 and E1 in the diag box. It's likely you will need a new cat. As you have noted, check for vacuum leaks. I seem to recall in one of your pics some hoses were missing. Lots of folks delete hose thinking it will make their truck into a rocket ship ... it won't. All of that hose has a purpose. Also, don't rule out your Ox sensor. I can't remember, but did you pull any codes?
Something to consider. Many of these sensors are not straight metric thread. Instead they are BSPT, or British Standard Pipe Thread. Basically, this is the metric equivalent of our SAE pipe threads.
I had found a write up on checking and possibly soldering the connections in the ECM. I have done this to two neighboring Yota's with much improved idle and engine running issues. Might be worth checking.
I posted a picture here: 1981 Pickup Rebuild - SR5 Longbed - https://forum.ih8mud.com/threads/1981-pickup-rebuild-sr5-longbed.1219169/
I posted a picture here: 1981 Pickup Rebuild - SR5 Longbed - https://forum.ih8mud.com/threads/1981-pickup-rebuild-sr5-longbed.1219169/
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- #36
OK, did a little digging this evening. I apologize ahead of time this is very nerdy.
First up - looking into the high HC issue. My idle and timing is set to FSM spec, around 750-800rpm and 5deg BTDC with the diagnostic terminal jumped.
I wanted to see if I had a leaky cold start injector. I put a borescope there through a sacrificial vacuum plug and started up the truck -
Here's the video - it sprays as it should for just a second, then stops. no leaks. I adjusted the scope to look at the base of the injector but looks good to me.
I checked and I get manifold vacuum to the fuel pump pressure regulator, but I don't know what my fuel pressure is. My next step would be to check, but I don't have the correct fitting so I will have to figure something out.
In the meantime, I wanted to see if the ECU was getting into closed loop mode. Looking at the FSM the ECU will default to closed loop, it will go open loop is in the following conditions:
1. Engine start (briefly)
2. Cold operation
3. Acceleration/Decel
4. Moderate to heavy loads
5. WOT
I wanted to check if the ECU was getting correct temp data for point (2). I first jumped the connections on the ECU temp sender and checked resistance:
My clamps kept falling off so I used an extra connector
I'm getting
1000ohm cold, 400ohm warm. I didn't have a chance to fully warm it up but seems like at least the sensor is working. I will assume it gets to the ECU for now.
Next, I went to check O2 sensor operation. Looking back if the O2 sensor is cycling then I know I'm in closed loop (I think) and I probably could have skipped the above step. So with the car warmed up a bit, connected to the O2 diagnostic terminal, this is my scope:
So it looks to me like it's functioning. According to the FSM it's supposed to swing from below 400mV to above 550mV (page FI-76) and I'm going from 150mV to like 700mV. It's supposed to change 8 times in 10 seconds at 2500rpm but I didn't check that. I probably should have.
So I'm thinking my O2 sensor works, and I must be in closed loop if it is cycling because the ECU is causing the cycling between rich and lean by altering injection duration.
I also forced a lean condition by pulling a vacuum line:
And I see the sensor go way lean around 150mV so that makes sense.
The thing I don't know about these older toyotas is if the ECU does any short and long term fuel trim adjustments. I don't know if that is something I can access. But seems to me at least that I'm not overly rich, at least by the O2 sensor. So I think? I can also assume I don't have a fuel pressure issue?
That kind of puzzles me because given my HC levels, I would have assumed that I was running rich. I mean, I have to be to get those HC levels right? The other potential culprits are my O2 sensor is wrong, the Air Injection pump not working, or Cat not catting.
I'm not 100% on my thought process here but just thinking out loud before buying parts.
First up - looking into the high HC issue. My idle and timing is set to FSM spec, around 750-800rpm and 5deg BTDC with the diagnostic terminal jumped.
I wanted to see if I had a leaky cold start injector. I put a borescope there through a sacrificial vacuum plug and started up the truck -
Here's the video - it sprays as it should for just a second, then stops. no leaks. I adjusted the scope to look at the base of the injector but looks good to me.
I checked and I get manifold vacuum to the fuel pump pressure regulator, but I don't know what my fuel pressure is. My next step would be to check, but I don't have the correct fitting so I will have to figure something out.
In the meantime, I wanted to see if the ECU was getting into closed loop mode. Looking at the FSM the ECU will default to closed loop, it will go open loop is in the following conditions:
1. Engine start (briefly)
2. Cold operation
3. Acceleration/Decel
4. Moderate to heavy loads
5. WOT
I wanted to check if the ECU was getting correct temp data for point (2). I first jumped the connections on the ECU temp sender and checked resistance:
My clamps kept falling off so I used an extra connector
I'm getting
1000ohm cold, 400ohm warm. I didn't have a chance to fully warm it up but seems like at least the sensor is working. I will assume it gets to the ECU for now.
Next, I went to check O2 sensor operation. Looking back if the O2 sensor is cycling then I know I'm in closed loop (I think) and I probably could have skipped the above step. So with the car warmed up a bit, connected to the O2 diagnostic terminal, this is my scope:
So it looks to me like it's functioning. According to the FSM it's supposed to swing from below 400mV to above 550mV (page FI-76) and I'm going from 150mV to like 700mV. It's supposed to change 8 times in 10 seconds at 2500rpm but I didn't check that. I probably should have.
So I'm thinking my O2 sensor works, and I must be in closed loop if it is cycling because the ECU is causing the cycling between rich and lean by altering injection duration.
I also forced a lean condition by pulling a vacuum line:
And I see the sensor go way lean around 150mV so that makes sense.
The thing I don't know about these older toyotas is if the ECU does any short and long term fuel trim adjustments. I don't know if that is something I can access. But seems to me at least that I'm not overly rich, at least by the O2 sensor. So I think? I can also assume I don't have a fuel pressure issue?
That kind of puzzles me because given my HC levels, I would have assumed that I was running rich. I mean, I have to be to get those HC levels right? The other potential culprits are my O2 sensor is wrong, the Air Injection pump not working, or Cat not catting.
I'm not 100% on my thought process here but just thinking out loud before buying parts.
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- #37
Good points. I rerouted all my vacuum lines so I think I am OK there. I had some EGR and water temp sensor codes but that was because I was pulling the sensor wires on and off.
As to the pipe thread - yikes, I didn't know that. I may have royally messed up those threads, but it seems to be holding for now so time will tell. I threaded the temp gauge sensor to an M16 thread checker but admittedly not a lot - you know sometimes it will thread OK for a few rounds then bind? Maybe that would have happened if I was more careful. Darn.
Thanks - I checked out your thread on the soldering - if I can't find a simple solution I may have to look into that.
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- #38
Next for the EGR issue - I checked my BVSV cold and could not blow through the top port which I think is correct. I forgot to check it warm. I did pull a vacuum on the actual EGR valve and I get exhaust gas through (died from idle). I also checked just with my finger to see if exhaust backpressure is getting through the tube that is supposed to go to the EGR modulating valve (it does). I checked my old valve and I cannot blow through the Q and P ports. In fact, I pulled a vacuum on the P port and it held, which is not what is supposed to happen. It's supposed to be connected to atmosphere through the filter.
It's pretty crusty in there and I think the ports are clogged
So, I got a new one from O'reilly's - Dorman 911-609 (online would have been like $25, I ended up paying $50 for it).
I haven't tested the new one yet but that's on the to-do list. I'm fairly certain that is all that is wrong. The other possibility is that my BVSV is not working but it is simple to just bypass it for the smog test since its whole job is just to connect 2 vacuum lines between the EGR modulating valve and EGR valve when warm and it's going to be warmed up anyways.
It's pretty crusty in there and I think the ports are clogged
So, I got a new one from O'reilly's - Dorman 911-609 (online would have been like $25, I ended up paying $50 for it).
I haven't tested the new one yet but that's on the to-do list. I'm fairly certain that is all that is wrong. The other possibility is that my BVSV is not working but it is simple to just bypass it for the smog test since its whole job is just to connect 2 vacuum lines between the EGR modulating valve and EGR valve when warm and it's going to be warmed up anyways.
that o2 sensor looks lazy. sensor should swing at least .2-.8v typically a good sensor will swing nearly 0-1 fully.
i would also suspect timing or fuel.
ime stock timing spec sucks and low octane causes pings.
just food for thought.
there is a fuel trim check but ive really never needed it on these motors. lmk and I will upload the page
i would also suspect timing or fuel.
ime stock timing spec sucks and low octane causes pings.
just food for thought.
there is a fuel trim check but ive really never needed it on these motors. lmk and I will upload the page
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- #40
Oh man you are absolutely right about the O2 sensor! I learned I shouldn't have checked it idling - evidently not enough gasses pass through to get a true reading. So I redid it at 2500RPM - and it has more amplitude, and higher frequency - it is the 8 times in 10 sec that the FSM says
If you can upload the fuel trim check (long term is what I'm interested in) I would appreciate it. Mainly just for my learning.
One thought is that before I bought it, it was misfiring a lot and driven like that for a number of months. Maybe I have HC in my exhaust that will work it's way out over time. I haven't driven more than 20 miles since I bought it. But not sure if that make sense or just my wishful thinking.
My carbon monoxide is in range, so I think that mean that currently the combustion is relatively complete.
I don't know why there isn't a NOx test- -maybe that is for the dyno (ASM) test only, not the two speed idle (TSI). I am thinking of advancing the timing to max allowable (+- 3 deg from factory spec) to help to reduce HC.
