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Discussion Starter · #1 ·
Hey, first post, have spent the last week reading all about the various trucks and issues in a pre-OBDII 2.6

My wife likes to drive a manual and I found her a 1993 Rodeo with the 2.6

It was running with functional A/C when we bought it, it ran a little rough but to me just looked like they'd bypassed too much of the CA smog equipment and left to many unplugged places for vacuum.

I've got it back together and it ALMOST starts but won't. It's cranking, sounds like there's some ignition, but it doesn't actually fire up. Felt like the computer is stopping the injectors getting fuel. It threw codes for TPS & ECT, so I figured I broke off some of the sensor circuit. Went back in and for sure the TPS wasn't plugged all the way in, and I broke off the little condensor/resistor. Problem I have left is that I've got 3 loose wires down by the starter, it has to be for both the oil safety switch and the oil sensor. They're all either broken off or replaced with a spade connector, one blue, one yellow, one black. I only have one switch/sensor/sender, and it just has a single spade connector on it, and it's right by the starter. The spade looks like it could have been jammed inside there as a backyard mod to get the thing running, could have been an oil pressure safety switch/sensor with two or three wires at one time.

The single wire to the condensor/resistor has continuity to the TPS but neither battery cable, I'm thinking I could figure this out by continuity testing that wire to the wires down below by the starter, to identify which two are on that sensor circuit with the condensor and TPS sensor, to connect them together get the ECM to let the thing fire up.

Any advice? Maybe even connect all 3 of them together at the single spade connector on the one oil sensor I do have on the truck? If the third is a ground would that damage the ECM? I realize I won't have a functional gauge or idiot light, but this car doesn't need to go very far ever. Mostly just for her to get to work 1 minute down the way, have a place to keep her stuff, and have something air conditioned to sit in on her break. Please help! (Cuz I secretly really really like this truck and think it's fun to work on)
 

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First: be more descriptive about the "condenser / resistor". Is this the one on top of the valve cover? That is really only for radio noise.
Second "wont start". Try squirting some starter fluid or a little gasoline in the intake (air cleaner cover removed). Does it run like this? If yes look up "Fuel pump relay bypass" The fuel pumps (electric, in the tank) are notorious for failing on these. One trick that sometimes works is to have someone crank the engine while you are tapping on the fuel tank with a rubber mallet. Sometimes this works (temporary) sometimes it doesn't.
It may be tomorrow, but I'll check to see where those wires go around the oil sender. Some of these had a sender for the oil light AND a sender for a gauge. IIRC the A/C clutch wire is in this batch too. Dennis
 

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Discussion Starter · #3 ·
Thanks for the reply! If you can take pics of the various sensors and the associated wire colors for me, that'd be really helpful!

Yes, it's the little sensor on top of the valve cover. I know it's function is to reduce interference to the radio (isn't that against FCC rules lol) but I thought perhaps being part of the sensor circuit if it's ripped off and the wire is touching the valve cover, maybe my ECU would be getting inaccurate readings from the sensor... Even if that's not the case and the condensor being broken off with a loose wire would never prevent start, wouldn't testing continuity with this wire could help me identify if any loose wiring is on the same circuit? If the blue and yellow wire both read less than one ohm to the broken off condensor wire, but the black does not, I'd conclude the blue and yellow wire are oil/coolant sensor/sender wires for sure... unless my thinking here is flawed?

My AC compressor only has a single wire to it, terminating it looks like right in the middle of the pulley. That circuit is in rough shape to say the least haha, it goes green wire to white/brown wire to busted black connector that looks like an inline fuse holder but doesn't actually have a fuse in it, to bundle of electrical tape, to wire that was soldered to AC compressor at the compressor manufacturer. I'll be replacing all of that with an inline fuse holder as soon as I type this up. The dash cluster was replaced with one out of a slightly different vehicle, I just realized it only has an idiot light, no oil pressure gauge. It also has a push button in the dash going to battery positive and starter solenoid, replacing the crank position on the ignition switch. My current guess is that the blue and yellow wire will have continuity to the wire I'm about to solder back onto the condensor on top of the valve cover, in which case they probably are supposed to both connect to an oil pressure safety switch with two leads, that also controls the idiot light. I'm thinking previous owner put in the cheapest single spade oil sender autozone had just to plug the hole but without the correct two lead oil pressure safety switch, it'll be best to just connect them to each other for the time being, no light, completes sensor circuit, ECM more likely to allow spark, right?

That leaves the black wire. If I get up under my dash, in close proximity to the push button start, there's two black wires with ring terminals with a blue plastic collar, just like the black wire next to the broken off yellow and blue wire I'm almost positive are sensor/sender leads. they are coming out of what looks like a relay holder glued to the underside of the dash, definitely a DIY PO job. I'm guessing it's for the fuel pump to power up before the alternator takes over. I almost just want to connect it to the starter solenoid same terminal as the push button wire and see if it starts, but I haven't fully convinced myself I understand how all that works. Could be a ground, or want to be on the thick battery cable constant connection on the other side of the starter. If I guess wrong right there, am I gonna blow anything?

But could DEFINITELY use pictures of each sensor (Oil Pressure, Oil Sender, ECT, Coolant Sender, o2, MUA5 speed) where you can really see their wire colors (or a 1993 Rodeo FSM PDF 🤞)

Or even just someone to concur that if I connect the blue and yellow wire together, and my starter switch and the black wire together at the solenoid side of the starter, that's probably what will get her back on the road without high risk of ****ing anything up. Going out there with a multimeter and some alligator clips crimped on to various lengths of wire right now, wish me luck!
 

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I can only check the schematic in my Haynes manual. I haven't owned an Isuzu for about 5 years now. I did convert my 1989 pickup from the 1989 style ITEC to the 1993 round throttle body type intake and injectors. Dennis
 

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Discussion Starter · #5 ·
That was actually a super helpful reply, haha.
I couldn't figure out some of the differences between what's under my hood and what I was looking at in the 5tec mod video on youtube.
I think this was a 94 4WD automatic that's been converted to a 2wd manual using a lot of 93 parts.
#5 head.
I've been doing a lot of wire tracing to reduce fire risk it being modded to have a push button start.
Found a Jerry reference on Isuzupup that says if you find a little blue wire it goes to the single terminal oil pressure sender on a 93, the way the wire is bent and a couple videos of 93 engines I think the yellow and black goes to the coolant sender. Push button is connected to starter terminal and battery, directly, no relays outside the fuse box like I thought I could see without removing any dash panels.
Leads me to beleive my two extra wires, yellow, and black with a color coded connector, probably just go together to link the ignition coil to the ignition switch.
I'll see if I can figure out uploading photos once it gets dark and my hands hurt too bad to keep going.
Compression tester came in today. So if you're a praying man.... lol
 

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Discussion Starter · #6 ·
Hey Dennis DSUZU what you said about the 93 Rodeo only coming in 2wd Automatic in another thread really tripped me out.

I think it makes sense to go into it here since I finally got into my account on my phone and got decent pictures.

So under hood it says 93 CA spec, computer is CA spec made by Hitachi, has air pump and MAP that were partially disconnected, but the door panel sticker says manufactured to federal spec but the word federal was obviously stamped on at a different time from the rest of the text it's offset pretty far, tailgate has a 4wd emblem but there's no front driveshaft or T- Case shifter, Transmission shift knob and boot looks very out of place compared to the plastic around it, the center consoles got a place for a hand brake that pulls up but the actual parking brake is a handle you twist shoved through the firewall. Up underneath behind the starter I noticed a gap where the transmission and engine come together, they don't look like they were factory designed to be mated together and I think I can see flywheel in the picture I got with flash, but I guess it could be a missing cover piece or cross member (I'm guessing one is a lot worse to be missing than the other haha).

But, compared to all these trucks I see people excited about on Isuzu forums, it's an exceptionally cosmetically clean truck. Although I'm sure the dash cluster is off a donor, it says 414,000 miles. I like it for the same reason I like the late 60s Craftsman mower I left out all winter cuz I was tired of stepping over it to work on the garage, I expect it to have issues but I'm gonna be able to make it work without taking it in or spending a lot on it. There's also not a lot of running manual transmission vehicles available and on the rare occasion I can find something running in a manual either the A/C is broken and they lied about it in the ad, or I'd have to take out a 5 year loan for a ridiculously overpriced dealer used car knowing the engines never hit 200k and only a dealer can do the replacement only with a brand new engine when it does happen...

When a 2011 Escape 130,000 miles is 10k and the only new Bronco with a stick for sale in this state is $68k this for $1850 was real appealing even if it has had some headaches and I'm still not sure if it needs a rebuild or new head:

Wheel Tire Automotive parking light Vehicle Land vehicle

Car Vehicle Automotive tail & brake light Motor vehicle Plant

Automotive tire Helmet Bicycle part Rim Bicycle chain

Automotive tire Font Gas Paper Number

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That was a battery positive to push button, push button to starter solenoid blue wire 😬
 

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Sorry I haven't been able to check the manual for you yet. Absolutely wiped out yesterday. I can say this: A. the 4 bangers only came with the 5 speed stick and 2 wheel drive. B. EVERYTHING on yours looks corrrect and original except the 4WD emblem on the back tailgate. Could be a replacement tailgate ot just an emblem added on (I actually have an emblem in my junk somewhere). there is a missing filler plate d=from the console. Rodeo / pickup used the same floor opening for 2 or 4 wheel drive. 2 wd had the "boot" you have and 4wd had a large base with two boots. There was a floor boot and the interior "leather" boot.
Sometime in the next day, I'll get to the book. Dennis
 

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Discussion Starter · #8 ·
I think I'm good on the wiring diagrams, 1993 Rodeo Electrical Troubleshooting Manual should land today. OK so there's supposed to be a little plastic ashtray coin holder that snaps in there, looked like there used to be a transfer case shifter there and they carpeted over it! I think at the bell housing I'm looking at a WC T5 with a missing plastic or rubber cover when I was expecting to see a MUA5 that bolted up flush. There was also a reference to (A/T) on the fusebox cover.

So what happened is getting it home it was driving fine then the temp gauge started climbing so I immediately pulled over, having spent at least an hour reading 2.6 posts on here at the time. It was super low on coolant, but the guy said it'd been sitting and wasn't quite fully put back together with the vacuum lines after a rebuild. The valve cover has really fresh RTV, I think what happened is the guy's story about his uncle getting too old to drive and work on it was total BS, probably got it dirt cheap in CA when after a lot of time and money someone still couldn't pass smog. AZ smog standards are way lower so people expect to pass even if they won't in CA, usually without a CEL you pass, guessing he couldn't get it to pass either and tried several vacuum lines, luckily I live in a part of AZ that will never have smog checks. It ran like it lacked power from open vac lines and there certainly were a lot unplugged. But once I hit an uphill after topping off coolant getting it home, it started heating up quicker, and I again immediately pulled over but a CEL came on right before I got it to the shoulder. It started up again after I let it cool down but I immediately shut it off and had AAA tow it home. Checked dipstick/spark plugs/oil cap for coolant and coolant reservoir for oil, never had white smoke out the back figured I risked a HG but probably got lucky, changed plugs and wires, all 4 plugs looked the same, fouled, old with blackness, but not really bad like it burns a ton of oil. I had plug #1 out and oil cap open before that checking for coolant and a monsoon came through right then, just absolutely pouring out of nowhere, started to run inside and remembered I had the cap open and a plug out and I just screamed FFFF. Couldn't get the plug to thread so I set it in the hole and got the oil cap on thinking shutting the hood ASAP would be safer than leaving it open till I could thread the plug. Next day I found water under the #1 plug, sprayed it out with compressed air, squirted in some seafoam with a syringe several times. Turned engine. More seafoam and compressed air. Got the plugs and wires in, tried to start it, it was cranking and sounding like it wanted to start but just didn't quite start. Realized the battery was probably low from turning it so much that day. I found bare wire in the middle of a 12 volt hot to a momentary push button start switch where both contacts were held on by a thread, some electrical tape, and a prayer and some really dirty grounds so I've been trying to get the wiring all squared away before I pull the battery from my 86 Sami on Land Cruiser axles project to get it started again.

So I had a little water under plug one, tiny bit under 2 could've came from turning it to get it to splash out of one, a little water in my crankcase after the rain but I'm pretty sure it didn't have any before it rained at the most unexpected moment cuz it's not milkshake it was seperated, maybe a pint of water first then several quarts of oil came out of the crankcase, and there were drips from several places between the exhaust manifold and the cat, so I certainly could have blown the HG or cracked the block, or it could've just vented coolant from all the old cracking small coolant lines near the throttle body, could have a burnt valve, or could've just gotten some rain in plug #1's hole and the crankcase. But I can't even start to diagnose it till I get the wiring squared away unless I wanted third degree burns. Decent car batteries are slim pickins and very expensive right now at all 3 parts shops in the nearest city (Prescott Valley). IIf I can't fix it at the valve cover or timing cover I'm kind of on the fence about dropping $600 on a full clearwater head with the valves already done for you or getting rid of it. More of a project than I was expecting it to be from the test drive, but now I'm emotionally invested hahaha

I've always drawn the line at HG replacements or transmission work, it required more reading than I had time for and more parts than I had money for, but I'm at a different place in life so we'll see what it needs once I get this wiring fixed up!
 

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IIRC, the 4 cylinder Rodeos came with a BRAZILIAN made transmission. At least the 96-97 year models did. Could also be others.
Head gaskets aren't all that bad of a job. Dennis
 

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Discussion Starter · #10 ·
IIRC, the 4 cylinder Rodeos came with a BRAZILIAN made transmission. At least the 96-97 year models did. Could also be others.
Head gaskets aren't all that bad of a job. Dennis
I've got psoriatic arthritis and to get the best treatment for it I'm having to also do 3 months of heavy antibiotics for latent tuberculosis cuz I tested positive. Both kill all feeling to my fingertips, not sure I can trust them to line up edges of something as heavy as an engine head...

I think I found my crank/no start though, looks like on this year of rodeo the "condenser" that a few online sources say is just a resistor is actually a capacitor as well as the ignition coil's only path to ground. Also my single spade I thought was a sender is the oil safety switch it's the sender they left off the 2.6 this year, used to have a plastic cap and two yellow leads coming out of it that want to go to my yellow wire and my light blue wire, that last black one is all that's left. Maybe it's a ground to effectively bypass the oil switch
Font Rectangle Parallel Pattern Engineering

Font Line Material property Schematic Parallel

. Feel a lot safer figuring out what one wire is. I really didn't want to tear up any more of that loom but there's a hot to the coil and and one of the more important grounds that are both black/yellow right down there.

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Discussion Starter · #11 ·
She's world class 🧐

Maybe I will fix it no matter what if needs...

Hand Shoe Automotive tire Tread Tire
 

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The coil is bolted to the valve cover (Yeah, DUH), but the valve cover itself is NOT grounded. There is supposed to be a separate ground, a braided wire going from the VC to the firewall. If it's missing, you can make your own. Dennis
 

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Discussion Starter · #13 ·
The coil is bolted to the valve cover (Yeah, DUH), but the valve cover itself is NOT grounded. There is supposed to be a separate ground, a braided wire going from the VC to the firewall. If it's missing, you can make your own. Dennis
Yeah cleaning grounds, replacing a few, adding a couple extras is one of today's projects.

I heard you mention an IAC relocation somewhere... That hose is split at the end and after cutting the ends off to where they aren't cracked it no longer reaches between IAC and intake manifold. Closest hose I could find at Autozone, Orielly, or NAPA was 7/16 fuel line and it is just not going to stretch that far. Heard that 5tec videos solution doesn't really work. What did you do with it? Is it just the straight up and down orientation that matters?
 

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It's probably around page 35 - to page 40 of my build thread where I did my "relocates". My goal was to clean up the valve cover / engine by removing crap that i didn't think needed to be there (coil, EGR transducer,) and relocate the idle air compensator to the firewall. KIND of the same thought pattern a Johnny did with the 5TEC, but I didn't mess with sensors (the part of his conversion some people had trouble with. The correct hose is 12MM (1/2") I believe. There are a lot of problems with cracks on the ends of the vacuum lines on these. We usually suggest replacing all the small (4MM?) hoses.
If you haven't figured out how to access people's build threads, just click on the highlited section in a signature.
BTW. The fire that damaged my truck had nothing to do with any of my modifications. It was the result of a failed injector O-ring. Dennis
 

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Discussion Starter · #15 ·
It's probably around page 35 - to page 40 of my build thread where I did my "relocates". My goal was to clean up the valve cover / engine by removing crap that i didn't think needed to be there (coil, EGR transducer,) and relocate the idle air compensator to the firewall. KIND of the same thought pattern a Johnny did with the 5TEC, but I didn't mess with sensors (the part of his conversion some people had trouble with. The correct hose is 12MM (1/2") I believe. There are a lot of problems with cracks on the ends of the vacuum lines on these. We usually suggest replacing all the small (4MM?) hoses.
If you haven't figured out how to access people's build threads, just click on the highlited section in a signature.
BTW. The fire that damaged my truck had nothing to do with any of my modifications. It was the result of a failed injector O-ring. Dennis
Hey, speaking of 5tec, I'm trying to figure out how many of these cooling lines I can delete without making any more mistakes on this thing, haha. I do have that single barrel throttle, I also found a heater resistor in the glovebox and looks like a good chunk of the heater box is completely missing, blower is there core is there but its just hanging there so it'll be bypassed for awhile.

So aside from the main top and bottom out and in hoses on the radiator, and the overflow, you got any kind of cheat sheet for what other coolant hoses are absolutely necessary to cool the engine?

Mark B's diagram is pretty good and 5tec is pretty good, but it's hard to get a feel for how the coolant runs through the engine still.
 

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Personally, the only coolant lines I ever deleted were the small ones that went to the throttle body (Don't even remember if the round TB had coolant lines) 5TEC eliminated the ones to the manifold. Personally, I wouldn't do that as heating the manifold helps the fuel atomization process. There is a reason that a lot of this was designed and put on that way.
Now if you're in a non emissions area, and you REALLY want to simplify your rig, you might consider the carb conversion. You'd need the intake manifold, carb, and complete distributor (there is an extra plate that bolts to the head) as well as a low pressure electric fuel pump. All this has to come from a pre 1995 2.3 engine and it all just bolts up. Dennis
 

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Discussion Starter · #17 ·
I am in a non-emissions area. This county is the very anti-democrat part Northern Arizona, 2nd amendment sanctuary, we'll never have smog checks haha.If it ends up needing an HG, I might spring for a new head and carb conversion. With the T5 might look into what whole engine swaps it opens me up to...

Still hoping this thing just fires up. It looks like it lost the coolant from the intake manifold coolant lines, deleted all the small coolant lines to the TB and intake, there was rust on many of those fittings and it's 6% relative humidity here, December January it might snow twice and be 20° at night so I think it's a good climate for those deletes.

Redid the rest of the coolant lines, all new vacuum lines and a lot of rewiring, fresh battery. Just tried to start it today, crank no start. Throwing codes 12 and 15 so unless I'm mistaken just low coolant temp. Does sound like it wants to start but gets flooded, but that could be optimism and it needs an HG. Probably check spark and compression tonight or tomorrow.
 

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Discussion Starter · #18 ·
I didn't relocate the ECT so I'll source a fresh one and replace the thermo housing bleeder nipple with it and see how it goes. ECT currently has dry high 60s air behind it, not sure if that'd be a crank no start cause.
 

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Discussion Starter · #19 ·
IIRC, the 4 cylinder Rodeos came with a BRAZILIAN made transmission. At least the 96-97 year models did. Could also be others.
Head gaskets aren't all that bad of a job. Dennis
Finally got some compression numbers!

I was solo, it hasn't been running, and the gauge I wound up with is in increments of 5... so it's not the ideal compression test but #1-75 #2-30 #3-30 #4-115. Wet it with a little Lucas high mileage in the plug wells of 1 through 3 and each of them came back with an additional 15-20 PSI.

Obviously not ideal but also not the typical overheat-blown HG numbers I've been reading about. Any chance I got lucky and my compression will be satisfactory with a valve job and head bolt retorquing, maybe a couple replacement exhaust valves?
 

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First, have you checked valve clearance yet? if not:
From my experience, many, if not most of these engines are in need of a valve job. There is a post called "Head gasket" from a guy named Harry. It has some good information, Because you have two cylinders with at least SOME compression, you should be okay with a valve job.
When I started with my truck, it had one cylinder with ZERO compression. I did the valve job and head resurface. In the long term, I found out that from the P.O. driving the truck with the dead cylinder, the rings in that cylinder had worn because of the constant washing down with unburnt fuel, Dennis
 
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