Assuming it cranks, have you checked the fuses?
Other than you may have to tell the computer the fault was repaired with a scan tool
Other than you may have to tell the computer the fault was repaired with a scan tool
CK5
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'86 Jimmy 4in Lift, 40’s, tons, 8.1 Swap- 700r4 said PNNNNN
- Thread starter GWeakland620
- Start date
This is not a dedicated trail rig, but does trailer to the destination usually. I am currently in the planning phase of doing a 52/56" spring swap, and getting back to being more road worthy.
I’m so confused at this point. You may have popped a fuse again.
Long story short, the crank sensor I though was bad actually wasn’t, and the new one I swapped in to replace it was bad.
It now cracks off with a squirt of eather. Unfortunately there’s a massive fuel leak and it doesn’t run longer than a few seconds.
4 years later and I finally feel some noteworthy progress!
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It now cracks off with a squirt of eather. Unfortunately there’s a massive fuel leak and it doesn’t run longer than a few seconds.
4 years later and I finally feel some noteworthy progress!
View attachment IMG_4329.mov
View attachment IMG_4330.mov
View attachment IMG_4331.mov
It works! Man what a battle
My dad always told me that the good ones will put up a fight. He also said the same thing about women.
Failed new parts suck! They will kick your ass every time when working on something. "I just replaced that, it's not the problem" so you search and search for something else. I've seen a ton of failed sensors and such from parts stores. Some stuff is better to go OEM if possible but sometimes price and availability make you go aftermarket and the quality is horrible now days. Glad you are making progress. This will be way fun to drive when you are done. Quit getting more projects Greg! LOL!
I have some bad sensors and switches even miss boxed stuff from Rock Auto. They are selling parts store old stock. If people returned a damaged part to the store, and the store put back on the self, then rock auto sells it well........... I try to get ac delco, as much as possible, so far I haven't disappointed.
Yeah, I ran into the failed parts issue with a brake switch once, and it kicked my butt.
Also, I don’t come to this website to be told not to buy more projects lol.
Aaaaaaannnnnd, you’re the last one to say stop buying projects! Old McDonald!!!
Yeah I'd have way more than you if I had some dang money. Or if they fell in my lap like your lucky ass! Continue on...I just want to see this one doing smokey burnouts!
I had a buddy that’s kind of a car guy ask if this will be able to do a burnout with the smaller 31’s on it lol.
I said; Big block, Detroit and 4.56 gears with 31’s…..it better haha.
Very glad to see you getting back into this truck!
I need to dig into it more with my buddy’s scanner, but the injectors aren’t firing for some reason. I’ve got fuel up to the rail, but it only runs on starting fluid.
View attachment IMG_4355.mov
I’ve also got a consistent code for the accelerator pedal position sensor (APPS) and the throttle does nothing more than twitch when the truck is first turned on as seen in the video above.
I tried another throttle body I had, but that was not the issue. I’m going to grab an OEM pedal sensor today and see if that takes care of the throttle issue.
So with both of those issues I have questions:
1. Does low fuel pressure prevent the injectors from firing? If so, what’s the threshold?
2. Would the faulty APPS contribute the the injectors at all?
View attachment IMG_4355.mov
I’ve also got a consistent code for the accelerator pedal position sensor (APPS) and the throttle does nothing more than twitch when the truck is first turned on as seen in the video above.
I tried another throttle body I had, but that was not the issue. I’m going to grab an OEM pedal sensor today and see if that takes care of the throttle issue.
So with both of those issues I have questions:
1. Does low fuel pressure prevent the injectors from firing? If so, what’s the threshold?
2. Would the faulty APPS contribute the the injectors at all?
Do you still have access to the scanner? You need the crank signal to get spark or fuel and the cam sensor tells it when to inject fuel. If it runs on spray, then you probably have spark.
Minimum pressure for the injectors to work is between 40-45 psi. Any less and the injector can’t open up. Spec is 55-62.
You should be able to put a noid light on one of the injectors to see if it’s getting the signal to fire.
But you got to have fuel pressure still for it to work.
You should be able to put a noid light on one of the injectors to see if it’s getting the signal to fire.
But you got to have fuel pressure still for it to work.
I do not have access, but he can swing by soon hopefully. Yes it definitely has spark.
Ok so maybe I’m less that 40psi. I’ll hook up a gauge tonight and go from there.
View attachment IMG_4366.mov
So a couple things from this video.
First off the pressure bleeds off super fast, is that normal? There are no leaks, so not sure what else to do.
Second, the pressure is dead on while running on starting fluid, and that makes me really happy.
The APPS will be here tomorrow, so I’ll see what swapping that out does, if anything at all.
Next step will be getting a scanner over here.
So a couple things from this video.
First off the pressure bleeds off super fast, is that normal? There are no leaks, so not sure what else to do.
Second, the pressure is dead on while running on starting fluid, and that makes me really happy.
The APPS will be here tomorrow, so I’ll see what swapping that out does, if anything at all.
Next step will be getting a scanner over here.
Pressure shouldn’t drop that fast. You either have a pressure regulator that is bleeding it off or an injector hanging up and bleeding it into a cylinder.
I’d check your oil for fuel content. If there is any section of rubber on your return line pinch it off and cycle the key on long enough for the pump to prime and shut it off again. See if it bleeds off fast still. If it don’t, the regulator was leaking. If it still does, you have a leaky injector or multiple.
If that’s the case I’d pull plugs and see which ones are wet. Plan on a full set of injectors if even one is wet.
I’d check your oil for fuel content. If there is any section of rubber on your return line pinch it off and cycle the key on long enough for the pump to prime and shut it off again. See if it bleeds off fast still. If it don’t, the regulator was leaking. If it still does, you have a leaky injector or multiple.
If that’s the case I’d pull plugs and see which ones are wet. Plan on a full set of injectors if even one is wet.
I am using a regulator/filter like the one Howell mentions in the installation paperwork.
No fuel on any of the injectors. No contamination in the oil.
No fuel on any of the injectors. No contamination in the oil.
I have a similar problem on my l29, pressure drops instantly after a spike up in pressure, I have to cycle the ignition on and and off a couple of times before it will start.
It will run fine once it starts.
My guess is regulator but I have not done anything yet to confirm the problem.
When I had the pressure guage on I tried the cycling of the ignition to confirm it was buildu pressure and dropping less every time until it builds enough to start.
Try this and see if it works for you to confirm everything else is good
I had a similar issue with my pedal not responding initially. After some tracing I figured out my throttle control module didn't have a good ground. I'd start with verifying that you have power and ground going to your module first.
When you first key on the throttle will do it's little test to reset where it needs to be for idle cranking, that's normal. When you have a working pedal, with key on, engine off, the throttle will move a full range of motion matching your pedal input. If it's quiet you can hear the throttle blade open and close. You can also watch it in real time with a scanner.
What setup do you have for your pedal?
I also had a fuel delivery issue as well when I was testing it on the stand a while back. I had fuel pressure but no injection. It would run on starting fluid. I ended up tracing it down to the injectors. A noid light confirmed I had injector pulse. I figured what are the chances all 8 injectors are plugged up or seized? Surely some must be firing enough for the thing to cough or sputter, but it would crank and crank and nothing. Sure enough I replaced the injectors and it fired on the first half crank.
How long have your injectors been sitting? Have they been dry or sitting with old fuel in the rail?
