Baseline new (to me) Jimmy

[green55]

Just acquired an '89 Jimmy. I'm sure I'll be posting a good bit on here as I work through issues.

First things first, what should I do to get off on the right foot? The truck had been sitting on and off for ~10 years before I got it.

Got it running now recently. So far, the following has been done: engine oil/filter, pulled old fuel out of tank. Also got new fuel pump/fuel lines, battery, wiper blades, windshield. Paid for someone to do most of that to get it going, but would like to try to do most work myself from here on out.

What else should I do?

Issues that I know of:

• Bit of a rough idle, especially when cold start.
• Runs rough at low speeds, especially around 30-35. It runs great at 55 though.
• Fuel gauge always on empty
• Temp gauge goes up to 155 (quarter of the way) but no higher

 

[Clark75K5]

Injectors may need a good cleaning.
Fuel gauge issue sounds like either the ground wire popped off, or the sending unit is bad.
My gauge only goes up that high too, I'm thinking it must just be off, though I wouldn't have put it past the PO to have put a 160 t-stat in it.

 

[green55]

Thanks for the suggestions! I'll take a look at your suggestions for the fuel gauge.

I'm pretty green when it comes to working on cars, so forgive my stupid questions lol
For the injectors, do you mean cleaning the throttle body? Or is that 2 separate things on these TBI engines. Found this walk-through for cleaning the throttle body, obviously a newer model so the removal process would be slightly different, but I imagine the cleaning part would be the same.

 

[Clark75K5]

The injectors are in the throttle body, if you pop the air cleaner off you can see the wires running to them.
May as well clean the throttle body while you're at it, depending on your comfort level. Cleaning injectors may involve removal, but for now just run some fuel injector cleaner through the fuel tank, such as techron.

 

[green55]

Ok did some digging tonight. Decided to check out the air filter and took a peek at (what I believe to be) the throttle body/fuel injectors. They honestly seem f’ed to me, but I don’t know what I’m talking about, which should be obvious considering I don’t even know what parts I’m looking at lol. I posted it pic. Looked like there was a good bit of gunk built up, as well as some frayed wires. Any opinions on how this looks and what I should do with it?

On the fuel gauge, it seemed like the ground was good. Posted a pic of this too. Not sure how to test that it is actually working though. How can I test this?

 

[green55]

I feel like I should rebuild the throttle body. Kits don’t look too expensive and there’s a thorough video on YouTube about it here. Seems like I could tackle it.

That still leaves those charred wires though...I guess that’s a separate harness I would need?

 

[Gentleman Jimmy]

If you buy injectors with the rebuild kit, they come with pigtails, you’ll just need to splice them into the harness.
The map sensor and coolant temp sensor are cheap and easy sensors to replace and are typical culprits to rough running tbi’s in addition to your throttle body which looks to be do for a rebuild/cleaning. Make sure and get the fuel pressure regulator rebuild with the kit.

 

[green55]

I’ll look into replacing those other sensors as well.

should I just replace the injectors while I’m in there? That increase the cost considerably. $100/each for the injectors. The rebuild kit is only like $40. I don’t want to spend money for no reason, but if it’s worth it to replace them, then I will.

Is the fuel pressure regulator rebuild the part of the throttle body with the spring?

Also, not real confident with splicing wires. But if I can do the rebuild/clean part myself, hopefully it would be a lot cheaper to get someone else to just replace the wires.

 

[Gentleman Jimmy]

My bad, the injector pigtails are separate... been a while. They’re like $15 each. You could start by cleaning the injectors and changing the o-rings that come with the kit. And verify they still pulse when you have them out. If it were me I would put new pigtails on for sure, yours look pretty crispy.

 

[green55]

Yeah I def need to put on new pigtails, I just don’t feel super comfortable with electrical stuff like splicing wires yet. I can hire someone to do that part though.
Y’all do mainly AcDelco parts for these kinds of things (tb rebuilt kit, fuel injectors)? Are they usually the highest quality?

 

[green55]

Watched some videos on splicing wires. Looks easy as hell. My only concern is doing it so close to a fuel source? I know there shouldn't be too much fuel that comes out of the fuel lines when I disconnect them from the throttle body if I pull the fuel pump fuse and let the engine die, but there still will be some. Would y'all recommend just cleaning up any spilled fuel as best I can and giving it a day or two to evaporate before I splice the wires? Or maybe I'm just over thinking it...

 

[Clark75K5]

Those only have power with the key in start and run. Just disco your battery first - as you should do with any electrical work.

 

[Bent77]

Wouldn’t worry about the TBi injector wires. They all look like that

I would spray carb cleaner in there, especially around the IAC drive motor. Then I would change the plugs and wires. Maybe worry about a rebuild on the throttle body or the regulator after you know the ignition stuff is right

 

[Wes Harden]

That throttle body looks like it has been worked on recently, also looks like a new sending unit in tank.

the injector wires do always look trashed. take the air cleaner spacer off check the wires where they are attached to throttle body, look for bare copper, If insulation looks ok make sure the spacer isn't pinching any wires when you put it back on.

 

[green55]

That throttle body looks like it’s been worked on recently, also looks like a new sending unit in tank. look for bare copper.

I don’t think the sending unit is new. We didn’t replace it when we got it running again, just the fuel pump.

there’s definitely bare copper inside the air cleaner spacer, but not outside of it. Just once it goes into the throttle body/fuel injector area

 

[JT88K5]

Is the injector pigtail for the injector at 1 o’clock in the picture missing a wire? Or, is that bare wire I see that’s leaning on the Tbi housing the wire I think is missing? I would replace the pigtails.

 

[green55]

It's there. Just crusty as heel, bare wire, and bent at crazy angles

 

[chevyjunky77]

Just replaced my injectors, remans, for 40 each. Should have done it from the get go but decided to try to salvage them. Never could get them to stop dripping while in operation. One of the best things I ever did was buy a diagnostic tool (Actron Elite Auto Scanner CP9690). Let me know real quick which sensor and such were not working correctly. No guess work.

 

[dyeager535]

Is the injector pigtail for the injector at 1 o’clock in the picture missing a wire? Or, is that bare wire I see that’s leaning on the Tbi housing the wire I think is missing? I would replace the pigtails.

I agree. That green wire looks like it takes a square 90* turn that wire typically can't without solidified and broken insulation. You can perhaps get an idea what is going on by starting the truck with the air cleaner off, and with a flashlight, look at the spray pattern. If the injector's have issues, typically they will drop or not have a smooth cone shaped spray pattern. But I wouldn't mess with the injector's until I knew the wiring was good. A good injector won't work right if the wiring is bad.

Fuel gauge on "e" or below e?

What kind of connector does the temp sender have? Should be a single green wire going to a temp sender in the driver's side head between the first two cylinders on that side. The sender should have a "nail head" looking terminal that the connecter slips over.

 

[green55]

I agree. That green wire looks like it takes a square 90* turn that wire typically can't without solidified and broken insulation. You can perhaps get an idea what is going on by starting the truck with the air cleaner off, and with a flashlight, look at the spray pattern. If the injector's have issues, typically they will drop or not have a smooth cone shaped spray pattern. But I wouldn't mess with the injector's until I knew the wiring was good. A good injector won't work right if the wiring is bad.

We're on the same page there. I'm taking it in Monday to get someone to replace the pigtails for me. I don't feel comfortable splicing wires that close to the injectors. Just too many gas fumes, combined with the heat from the soldering iron, makes me nervous. We'll see what the spray pattern looks like after that and will address it if needed.

Fuel gauge on "e" or below e?

Below e. Never seen it move since we got her going again.

What kind of connector does the temp sender have? Should be a single green wire going to a temp sender in the driver's side head between the first two cylinders on that side. The sender should have a "nail head" looking terminal that the connecter slips over.

I'll have to check on this. I haven't looked much into the temp gauge yet. Although the other day I did notice it got all the way to 210 before dropping back down to 155. Not sure if that means anything other than it is capable of getting there and somethings stopping it from doing so.

One of the best things I ever did was buy a diagnostic tool (Actron Elite Auto Scanner CP9690). Let me know real quick which sensor and such were not working correctly. No guess work.

Sounds like a good idea. Looks like that one is ~$200. I'm sure that'd pay off quickly though.

Also, I started a build thread so I'm not bombarding this forum with questions everyday. Follow along if you'd like: https://ck5.com/forums/builds/jimmy-89.708/