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Project Dumpy
Hey all,
Originally posted to IH8mud but a friend mentioned it may be good to post here too since it's not really an off roader Picked up a 1988 mini truck, mini dump truck that is. Goal is to make it reliable and use as intended. It was hard for me to find a short wheelbase model and this was the only one I've seen locally. https://i.imgur.com/9EsYlQ2l.jpg https://i.imgur.com/HfcgiDAl.jpg https://i.imgur.com/KEr1FMNl.jpg It is a dually, with the fronts being the same rims as the rear (I've seen a lot of 5 lug fronts with dually rears, which I think are conversions?). https://i.imgur.com/bVGJlUql.jpg https://i.imgur.com/pbucDnAl.jpg Driver door window didn't really work, so I took out the mechanism and it was just wallowed out. I think I'm going to just get one of those reman ones off ebay? https://i.imgur.com/Yoc3LLEm.jpg https://i.imgur.com/JvxZvlsm.jpg https://i.imgur.com/OBJHWSNm.jpg 22RE with an A43D auto trans. The radiator trans cooling line was bypassed and someone installed a trans cooler at some point which is probably a good thing. https://i.imgur.com/EvSPPD9l.jpg https://i.imgur.com/rWqviPvl.jpg Started to diagnose a misfire, started to pull a plug and it just came apart https://i.imgur.com/KCf67ne.jpg No idea how well it was connecting prior to me stripping it, so I guess my first order of business is getting new wires, plugs too while I'm at it. Interior is pretty rough. Looking now for the plastic pieces around the doors. I'm guessing they are pretty interchangeable from most toyotas of the 80's? https://i.imgur.com/s8Ty27vm.jpg https://i.imgur.com/G2zAWxlm.jpg https://i.imgur.com/uqPYisVm.jpg https://i.imgur.com/yLHCnrMm.jpg If anyone has some spares I can buy let me know. https://i.imgur.com/XO2QEnOm.jpg There is a radio but no speakers... https://i.imgur.com/Ag96PCZm.jpg and the "HVAC" leaves a lot to be desired Has a bracket as if it had A/C at one point, but no compressor or lines. Haven't looked into the dash to see if there is an evaporator in there or not. https://i.imgur.com/QQc7IS5m.jpg Chassis code - I figured out the RN55L means 112" wheelbase, but the SRTEA3W doesn't match the info I can find online. I have 4.1 gears 8" axle full floating looks like which I think is awesome that it came stock like this. https://i.imgur.com/SUTrbHAm.jpg This inside the cab is blank or faded over the years.. best I can tell from a PDF online of the specs of different models is that the GWVR is 5500lbs - what I've read is the frames are all the same even 1/2 to 1 ton just the suspension, brakes (I assume). |
Took the valve cover off - doesn't look too bad
https://i.imgur.com/k7Z0a6zl.jpg https://i.imgur.com/BgFudRpl.jpg Chain looked fair, guides were intact I am learning there were different vacuum systems. The motor in my truck is not original and I don't know what year it's from. It has a throttle body missing a vacuum line here: https://i.imgur.com/wnQjnf0l.jpg Well not missing per-ce, just was made that way. Also doesn't have the Idle air control valve right under the throttle body, it's separate down here: https://i.imgur.com/59svCFHl.jpg I don't know if that is a new or older style. The air line that feeds air to it is cracked but just slightly. May be small source of vacuum leak. https://i.imgur.com/mKTyZHel.jpg The throttle body itself has coolant lines to it, but doesn't do anything. Maybe to prevent icing in cold weather? https://i.imgur.com/JXkug2Cl.jpg I have half a mind to just get rid of the coolant lines to the throttle body/IACV and delete the IACV. It rarely gets below 60F here. I figure to reduce sources of future vacuum leaks. |
Cool truck. That is the pre 89 style of IACV, I have same thing on my 1988.
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The parts catalog page here>>> Search by frame number in Toyota electronic parts catalog (epc-data.com)
includes specific parts breakdown for RN55L-SRTEA3W |
whoa this is awesome! thanks!
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The sensor on the right sends temp data to the ECU. "water temp switch."
https://i.imgur.com/4xeLpeJl.jpg It is a resistance sensor - and that splice probably doesn't help with those values https://i.imgur.com/0qWVFaol.jpg If resistance is high the ECU will think the motor is cold all the time. I'll try soldering the connection. |
Just for my own learning I traced some of the lines. This large one closer to the timing chain than the PCV, is connected to the intake, but routed to before the throttle - this takes clean/metered, atmospheric pressure air and brings it to the crankcase to replace the air pulled into the intake through vacuum when the PCV valve is open. I guess it's important that the air is metered because the extra air coming into the engine from the PCV has to be accounted for somehow. That would mean if the oil fill cap or oil dipstick was open potentially there would be some sort of mismatch, maybe not significant.
https://i.imgur.com/Obkok2El.jpg That circled on the left on the back of the throttle body goes to this: https://i.imgur.com/cpr3iMXl.jpg on the left side (right side goes to idle screw) which ultimately goes here: https://i.imgur.com/gZpXfGrl.jpg Sorry if this is boring everyone, I do this basically to document to myself in the future. I have another truck that I didn't work on for 7 years and looking back at my old posts helped me remember what i was doing |
Dump works well and is freakin' awesome.
https://i.imgur.com/vKdTZxMl.jpg https://i.imgur.com/cO0JCp5l.jpg https://i.imgur.com/dOJewpTl.jpg https://i.imgur.com/nzPXDZSl.jpg https://i.imgur.com/7yhTmKBl.jpg The plastic on the control broke and I have to jump it with the wire - but I found the part number Monarch 03240 https://i.imgur.com/lFEOR6Hl.jpg |
Intake gummed from EGR and oil vapor - I'm thinking of making a catch can
https://i.imgur.com/xacpySQl.jpg This makes the rear axle easy to work on https://i.imgur.com/6ACMi5Tl.jpg |
Heater core was bypassed previously - I don't really need it anyways. I'll probably just blow some compressed air in the heater core to make sure it's drained out and I think I can just cap off the motor side hoses rather than bypass?
https://i.imgur.com/CyqtZtyl.jpg |
At first I thought there may have been another bad splice on these wires from the distributor but after peeling it back it is just insulation around the wires. Never seen that before, maybe to reduce electrical noise?
https://i.imgur.com/1uE1u21l.jpg IACV coolant lines are pretty plugged https://i.imgur.com/9q7hXUHl.jpg Took it out for now https://i.imgur.com/hqiPJ7fl.jpg The bypass ends up here - I will have to plug it https://i.imgur.com/ff3Q4c2l.jpg There is a coolant line next to the thermostat that I will have to plug, as well as this https://i.imgur.com/t9gWby4l.jpg Door pull was all bent up - had to straighten it https://i.imgur.com/hAd4RuPl.jpg Someone cored out the thermostat - new one on the way. I bet it had overheating issues.. not a good sign. https://i.imgur.com/mPUdIaEl.jpg Spark plugs https://i.imgur.com/KPSVWFWl.jpg Cyl 1 and 2 (left, right) https://i.imgur.com/xWwWdmYl.jpg 3 and 4 https://i.imgur.com/7Abndl4l.jpg Big size difference but I love how the toyo is 1 ton and the ford is 3/4 ton https://i.imgur.com/l6nfC1Ul.jpg |
Compression tests:
1: https://i.imgur.com/M5kCgIWm.jpg 2: 3: https://i.imgur.com/JPzRCSqm.jpg 4: https://i.imgur.com/64LmOljm.jpg 1-3 are around 150, #4 is about 135psi |
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. https://i.imgur.com/9aGDmR4l.jpg 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 |
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
https://i.imgur.com/s2IApkll.jpg https://i.imgur.com/kShchVjl.jpg |
Looks like there are new freeze plugs so someone must have pulled the motor at some point
https://i.imgur.com/vZJQ754l.jpg 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. https://i.imgur.com/2A94IV1l.jpg https://i.imgur.com/5I6rRevl.jpg |
Took a razor blade and cleaned off the left over throttle body gasket
https://i.imgur.com/pNpNraDl.jpg https://i.imgur.com/sU21Jlhl.jpg Got a new o-ring installed in the idle screw - old one was hard as a rock https://i.imgur.com/7omAn9wl.jpg Chased out the threads too on the temp gauge sender - kind of looks like there should be a washer or gasket to seal fluids? https://i.imgur.com/Dk6lNABl.jpg |
ended up putting an 8mm o-ring on the end of the temp sender. it should still ground out from the threads. We'll see how it works
https://i.imgur.com/hFf1As7l.jpg https://i.imgur.com/rC7NHmIl.jpg New thermostat https://i.imgur.com/F6JaGQUl.jpg I was surprised I found a new pigtail on rockauto https://i.imgur.com/DBTXwMXl.jpg https://i.imgur.com/W5ezsF2l.jpg |
I ended up going back over with a heat gun
https://i.imgur.com/CisyayQl.jpg New plugs and wires; https://i.imgur.com/VbJwaKjl.jpg 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: https://imgur.com/nP96ZQx |
vacuum at idle was borderline at first
https://i.imgur.com/b6FzBBrl.jpg but if i blip the throttle, then let it idle - it will come back https://i.imgur.com/8D05asDl.jpg 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. https://i.imgur.com/UHFXgJHl.jpg 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. |
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 - https://i.imgur.com/NSNBhYxl.jpg https://i.imgur.com/SEs6K46l.jpg 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. https://imgur.com/caLtK5E 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: https://i.imgur.com/O3k4wIYl.jpg My clamps kept falling off so I used an extra connector https://i.imgur.com/39DgnUul.jpg I'm getting https://i.imgur.com/XoZ6QMzl.jpg https://i.imgur.com/XIBZzZ7l.jpg 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: https://i.imgur.com/AipK15jl.jpg 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: https://imgur.com/6wkvZqM 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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