Let's, please, get a TBI car running again, if you don't mind....

[diesel4me]

In many cases the electric fuel pump is not the fault,it is the power wire coming from the front of the car (fuse box,to ignition switch) that is the culprit..the wire degrades over time and gets gangrene,and the connector at the fuel tank is noted for poor connections and corrosion--several new pumps come with a new connector,and the warranty is voided if you do not install it--but if the wire is faulty,it wont cure the issue..

My friend who runs an auto repair shop has learned not to condem the fuel pump right away when a car gets towed in and he's told by the tow truck driver "I think its the fuel pump--didn't hear it running,and I banged on the tank and heard it start working,then I could drive it up on the ramp truck"...

Too many times he just pulled the gas tank out,bought a new pump,installed it,and the new pump worked,the car ran fine again--but some came back dead a short time later--then he'd do what he should have done at first--test for power at the fuel pump ,but DO NOT use a simple test light,volt meter,or LED test light--those may light up or show 12 volts,but it is the amperage the wire will pass that matters...
He has now made up a test lamp using an old halogen headlamp--he hooks that to the pump's power wire and ground,leaves the key on several minutes,and watches the lamp,more than once it starts to dim,or flickers,then finally goes out or just glows dimly..
The faulty wire just cant maintain the amount of current flow it needs to run the pump continuously ..
To fix that ,he runs a new wire from a spot in the fuse box that only gets power with the key "on" and during cranking..and uses a new connector plug at the pump...

One car he had,an Oldsmobile,"ate" 2 new fuel pumps before he found out it was the bad wiring causing them to fail,low voltage tends to burn up electric motors..on that car,he also found a bundle of ground wires hidden behind the passenger side kick panel were all corroded to death,that were plugged onto a bus bar type of ground junction..he cut them all back to clean copper and crimped a ring connector on them all,and ground a bare spot on the sheet metal ,used a sheet metal screw to ground them--the car never had the issue return again..

Some cars with HEI have the module control both spark & fuel delivery,and either side of the module can fail or work intermittently --other cars using a crank sensor wont get and fuel pump pressure or injector pulses if it fails..
If one injector shorts to ground the engine wont start or run either,seen a '86 Buick Somerset do that not long ago,my friend figured it out,after several other shops in town gave up on the car..(and raped the owner for over $600!)..most cars with electric fuel pumps also have the oil pressure switch wired in the circuit,if that fails it can shut the pump down,but still work the idiot light or gauge..

Chances are after sitting so long the car may well need a new fuel pump,but I'd check the wiring good first..a new pump might work temporarily with poor voltage or connections,but you cant trust it and it can ruin the new pump in short order..

 

[Fordum]

Like Rampage said, that size wire is fine for the small load the pump will generate. Just remember that the wire is hot at all times after you hook it to the battery, and pretty much every metal part on the car is a dead short waiting for you to touch it.
A 5 amp or so inline fuse between the battery terminal and the test wire would be nice.
For instance: https://www.autozone.com/electrical...bussmann-atc-fuse-holder-with-cover/32415_0_0

As for the propane, its way safer in general than starter fluid. Harder to ignite, and unless its mixed just right, will only burn when ignited whereas ether (starter fluid) likes to explode.
Also much safer on the engine. Propane is fairly close to gasoline as to its "octane" rating, and will ignite at the proper time when its used as fuel. Which is why its often used as engine fuel instead of gasoline.
Starter fluid is much easier to ignite and will often ignite due to the compression heat before the spark fires. Which is why it has been known to damage engines when used excessively.

 

[vandelay industries]

1) Any idea of to get this apart? The fuel pump pigtail:

2) It may be time for a new fuel module irregardless. i forgot to mention the car has 344,000K and this is the original pump as far as i know.

There is much more to report, but have to rush off to work (on night shift this week which, in a way, is good because i can borrow ol' man's car without facing "federal prosecution."). The fuel pump relay may have melted. i have to confirm which one as it's not in the factory location/or i'm not interpreting the diagram right.

 

[rampage]

Looks like the tab broke off the pigtail and someone jammed that plastic piece in there to hold it together. Slide the white plastic tab out and it should fall apart. IIRC, there should be a tab where I marked up your photo in red.




Those are some fine looking inlets on your tank.
I’d replace those and while the tank is down you might find a decent amount of rust on top too. And seeing how much rust you have I wouldn’t be surprised if the ground for the sending unit/fuel pump is making a bad connection, which would explain the no pump issue.

 

[Noek]

All along i thought TBI was actually simpler than carb (at least on paper.....) And deep down, i thought/knew i would eventually switch to FI exclusively and i should try to push myself to learn FI. But i've never really had a problem with carb and distributor setups.

i think TBI does run great----when everything is 100% perfect. It does seem finicky is something is "off." At least with carbs/distributors i may not be able to get it to run smoothly, but it will run. So, i'm not totally convinced about fuel injection just yet. Maybe if you designed your own system using megasquirt or something?

Honestly if you google K5 blazer TBI no spark condition, there are so many posts related to no spark at the injectors and reading through most of them, never finds a solution. There are a multitude of sensors, coupled with the ignition coil, and the ecm that can affect spark at the injectors on the throttle body. There are like 3 or 4 main grounds that can affect this as well. Stick with a carb setup since its mechanical, it's easy to diagnose. I basically tore apart the whole wiring harness that runs from the drivers side firewall (fuse box in the cab) to the passenger side firewall where it goes back into the cab to the ecm (located behind the glove box).

The way gm wired this thing is horrid. Wires split off and go all over the place. A good example, there is one wire for the knock sensor which is located down low on the block near the starter, they bundle this one wire in with like 20 others and bury it and run it behind the distributor past the oil pressure sensor and then it disappears. If you ever have an issue with one sensor or wire, you basically have to tear the whole damned harness apart and its an ungodly mess.

 

[dyeager535]

Thats a factory lock on the connector.

Pinch the end opposite the little pull tab, and it will come out.

As bad as that tank looks, I'd expect needing a new tank and sending unit. Just prepping you.

Unless you can get the pump to run without touching that stuff. I agree, ground would be a good place to start.

 

[rampage]

Thats a factory lock on the connector.

Pinch the end opposite the little pull tab, and it will come out.

I don’t remember doing that on my ‘89, but it has been many years since I’ve had to disconnect mine so you’re more than likely correct.

 

[imiceman44]

Honestly if you google K5 blazer TBI no spark condition, there are so many posts related to no spark at the injectors and reading through most of them, never finds a solution. There are a multitude of sensors, coupled with the ignition coil, and the ecm that can affect spark at the injectors on the throttle body. There are like 3 or 4 main grounds that can affect this as well. Stick with a carb setup since its mechanical, it's easy to diagnose. I basically tore apart the whole wiring harness that runs from the drivers side firewall (fuse box in the cab) to the passenger side firewall where it goes back into the cab to the ecm (located behind the glove box).

The way gm wired this thing is horrid. Wires split off and go all over the place. A good example, there is one wire for the knock sensor which is located down low on the block near the starter, they bundle this one wire in with like 20 others and bury it and run it behind the distributor past the oil pressure sensor and then it disappears. If you ever have an issue with one sensor or wire, you basically have to tear the whole damned harness apart and its an ungodly mess.

I don’t remember doing that on my ‘89, but it has been many years since I’ve had to disconnect mine so you’re more than likely correct.

Remember, this is not a k5 but a 90 cavalier 4 cylinder car so there will be some difference

 

[rampage]

Remember, this is not a k5 but a 90 cavalier 4 cylinder car so there will be some difference

Just a minor detail hidden at the bottom of the first post.

 

[imiceman44]

Just a minor detail hidden at the bottom of the first post.

I saw a lot of posts giving him details from a k5, I had to say something.
The concept of tbi stays the same, it is the details that change

 

[Blue85]

Looks like the tab broke off the pigtail and someone jammed that plastic piece in there to hold it together. Slide the white plastic tab out and it should fall apart.

Officially these are known as CPA - connector position assurance. Basically when it's installed at the factory, that demonstrates that the connector is properly seated. It also serves as a secondary lock to keep it together. Many auto connectors have provisions for these, but they aren't always installed from the factory. Combine that with people who break them off with screwdrivers or just never bother to put them back and they get rarer over the years.

 

[vandelay industries]

Don't know nothing about relays, but this looks melted......
FPR:

i'm not bullshitting----just very busy with work. And considering how F'd i am automotively, i'm going to need all that income.......
i'll apply B+ directly to the pigtail asap.

My outside guess is that all that corrosion back there is/was causing massive resistance, thus causing the fuel pump relay to melt?

 

[vandelay industries]

Honestly if you google K5 blazer TBI no spark condition, there are so many posts related to no spark at the injectors and reading through most of them, never finds a solution. There are a multitude of sensors, coupled with the ignition coil, and the ecm that can affect spark at the injectors on the throttle body. There are like 3 or 4 main grounds that can affect this as well. Stick with a carb setup since its mechanical, it's easy to diagnose. I basically tore apart the whole wiring harness that runs from the drivers side firewall (fuse box in the cab) to the passenger side firewall where it goes back into the cab to the ecm (located behind the glove box).

The way gm wired this thing is horrid. Wires split off and go all over the place. A good example, there is one wire for the knock sensor which is located down low on the block near the starter, they bundle this one wire in with like 20 others and bury it and run it behind the distributor past the oil pressure sensor and then it disappears. If you ever have an issue with one sensor or wire, you basically have to tear the whole damned harness apart and its an ungodly mess.

i'm temped to plop a carb on there, not because i don't like TBI or FI. i like TBI, but this seems like it's turning into a little mess and i don't have a whole lot of time to F with it. Not shying away, just no time.

A nice holley 5210 would work good with this engine, i think? Or a 2GC. Just need an adapter plate made---even i can handle that. Could probably use the same throttle cable.

But does spark happen even if no fuel? In other words, will the computer allow the ignition modules to fire ,when the crank is rotating, even it doesn't "see" fuel or even if there is no fuel pump at all?

NOTE here: i think a big difference here between car and truck is most cars had coil on plug/no distributor by then, whereas i think the trucks still had distributor for a while.

This may have to be more of a project car vs. daily driver at this point.....

 

[rampage]

Yeah, that relay doesn’t look good.
A higher resistance due to corrosion will allow fewer amps to flow, just the opposite of what you’re thinking, whereas a short will allow a lot of current to flow.
Know how to use an ohm meter? Set your resistance setting to around 200 ohms and measure the how many ohms there are between the grey wire on the fuel pump and a good ground (note: you may need to adjust this setting either up or down depending on your meter). An “Error” or infinite resistance indicates an open and the fuel pump is blown. A good pump should have at least a few dozen ohms. That doesn’t mean it’s a good pump necessarily - only seeing it operate and at the correct pressure will tell you that.

 

[bp71k5]

Don't know nothing about relays, but this looks melted......
FPR:

i'm not bullshitting----just very busy with work. And considering how F'd i am automotively, i'm going to need all that income.......
i'll apply B+ directly to the pigtail asap.

My outside guess is that all that corrosion back there is/was causing massive resistance, thus causing the fuel pump relay to melt?

just in case it wasn’t obvious, that isn’t a relay. It’s only the relay socket. You said you were a bit of a noob electrically so thought it’d be best to make sure.

 

[diesel4me]

Sure that black goop isn't just the stuff GM uses around electrical parts like the underside of fuse boxes ?...or is it really melted plastic ?..

 

[bp71k5]

just in case it wasn’t obvious, that isn’t a relay. It’s only the relay socket. You said you were a bit of a noob electrically so thought it’d be best to make sure.

So get a picture of the relay that’s supposed to be in that socket. If there isn’t one, you may have found your problem.

 

[Noek]

i'm temped to plop a carb on there, not because i don't like TBI or FI. i like TBI, but this seems like it's turning into a little mess and i don't have a whole lot of time to F with it. Not shying away, just no time.

A nice holley 5210 would work good with this engine, i think? Or a 2GC. Just need an adapter plate made---even i can handle that. Could probably use the same throttle cable.

But does spark happen even if no fuel? In other words, will the computer allow the ignition modules to fire ,when the crank is rotating, even it doesn't "see" fuel or even if there is no fuel pump at all?

NOTE here: i think a big difference here between car and truck is most cars had coil on plug/no distributor by then, whereas i think the trucks still had distributor for a while.

This may have to be more of a project car vs. daily driver at this point.....

I understand a few posters above are poking fun at me for my post re: K5 but early TBI is early TBI, it doesn't matter what application it is, it sucks when it goes bad. It's not like troubleshooting a carb. It's not like plugging a computer into an obd. Even if you get a code it's vague at best.

Like you, I also considered changing to a carb, which meant a new intake manifold, unless they make spacer adapters but I doubt it....Also pulling the gas tank again for a new fuel pump because if memory serves my tbi required 10psi. New ignition system, scrapping all of the ecm and sensors....I mean it's like, creating all new problems.

 

[imiceman44]

I understand a few posters above are poking fun at me for my post re: K5 but early TBI is early TBI, it doesn't matter what application it is, it sucks when it goes bad. It's not like troubleshooting a carb. It's not like plugging a computer into an obd. Even if you get a code it's vague at best.

Like you, I also considered changing to a carb, which meant a new intake manifold, unless they make spacer adapters but I doubt it....Also pulling the gas tank again for a new fuel pump because if memory serves my tbi required 10psi. New ignition system, scrapping all of the ecm and sensors....I mean it's like, creating all new problems.

I did not make fun of you but you were telling him details on where to find a test plug on a k5. Just pointed out that it's a tbi, and all tbi technology applies but not specific locations from a k5.
I was very careful with my post.

 

[imiceman44]

I understand a few posters above are poking fun at me for my post re: K5 but early TBI is early TBI, it doesn't matter what application it is, it sucks when it goes bad. It's not like troubleshooting a carb. It's not like plugging a computer into an obd. Even if you get a code it's vague at best.

Like you, I also considered changing to a carb, which meant a new intake manifold, unless they make spacer adapters but I doubt it....Also pulling the gas tank again for a new fuel pump because if memory serves my tbi required 10psi. New ignition system, scrapping all of the ecm and sensors....I mean it's like, creating all new problems.

And I agree changing it to carburetor is more trouble than it is worth.
It shouldn't be too hard to track down the problems and get it going.