I think you saw my vented gas cap working well in Moab...yup, dumping gas everywhere anytime the truck was nose up...
CK5
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'89 R3500 Crew Cab 2wd to 4wd conversion & beyond
- Thread starter mrk5
- Start date
Started out with 2wd TBI350 with SM465 to current 4wd with 454, 700r4, NP241
bp71k5
3/4 ton status
I had to wedge a twig under my gas cap seal the last time I was in Moab, since the heat was causing a pressure rise and a loud hissing from my gas cap. Definitely need a vent both ways I’d think.
I think the heat and slow moving play huge role in that at Blazer Bash.
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I have a vented cap and an open vent line but it still built up pressure so I drilled a small hill in the cap, no more pressure build up.
I have a rather large vent thing I built for Twinkie, the fuel would condense on the old vent and then run down the hose a drip everywhere. So I built a can for the vent to go into. which then keeps the fuel from running everywhere.
A few things after running 5 trails yesterday.
I'm starting to think I might have the incorrect sending unit. I wonder if I got a 30gal tank sending unit; it fits my issues. Topped off the tank with the new fill. Drove part way to our trail run, topped off again, and the amount I put in was inline with the miles driven. On the way home from the trail I start losing fuel pressure on turns and acceleration, clear signs I'm low on fuel. Just make it to a gas station and put 29.5 gallons in. In retrospect, I think pretty much every time I've run it out of gas it takes 25 to 30 gallons. So that's why I'm wondering about the sender. It could also explain why the fuel level doesn't jive. The only other thing I can think is the sender has some sort of malfunction going one. Either way, I need to pop the sending unit out and investigate.
About 45 minutes from home I happen to notice battery voltage is reading about 12 volts!
Luckily running 2 batteries pays off and I don't have any trouble making it home. Normally it reads in the mid 13's for voltage. I have noticed lately voltage seemed to drop more with the fans and/or compressor running.
I've gotta do something with my seat! Driving to Blazer Bash in 2020, I noticed my hip/leg getting sore when driving over an hour. It's been bugging me consistently since then. This morning it's absolutely killing me! Can hardly walk. Don't have this problem riding in other vehicles. When my son drives I've noticed the passenger seat seams to sit lower in the front compared to the driver seat. I'm thinking I need to change the angle of the driver seat.
And this happened...
It's from a tree, you can feel the sap. I don't remember backing into a tree, but obviously I did. I think I'm going to take it as an excuse to make design tweaks. Maybe include heavier wall tube.
It was a great day on the trail, but now I feel like my truck is going to pieces.
I'm starting to think I might have the incorrect sending unit. I wonder if I got a 30gal tank sending unit; it fits my issues. Topped off the tank with the new fill. Drove part way to our trail run, topped off again, and the amount I put in was inline with the miles driven. On the way home from the trail I start losing fuel pressure on turns and acceleration, clear signs I'm low on fuel. Just make it to a gas station and put 29.5 gallons in. In retrospect, I think pretty much every time I've run it out of gas it takes 25 to 30 gallons. So that's why I'm wondering about the sender. It could also explain why the fuel level doesn't jive. The only other thing I can think is the sender has some sort of malfunction going one. Either way, I need to pop the sending unit out and investigate.
About 45 minutes from home I happen to notice battery voltage is reading about 12 volts!
Luckily running 2 batteries pays off and I don't have any trouble making it home. Normally it reads in the mid 13's for voltage. I have noticed lately voltage seemed to drop more with the fans and/or compressor running. I've gotta do something with my seat! Driving to Blazer Bash in 2020, I noticed my hip/leg getting sore when driving over an hour. It's been bugging me consistently since then. This morning it's absolutely killing me! Can hardly walk. Don't have this problem riding in other vehicles. When my son drives I've noticed the passenger seat seams to sit lower in the front compared to the driver seat. I'm thinking I need to change the angle of the driver seat.
And this happened...
It's from a tree, you can feel the sap. I don't remember backing into a tree, but obviously I did. I think I'm going to take it as an excuse to make design tweaks. Maybe include heavier wall tube.
It was a great day on the trail, but now I feel like my truck is going to pieces.
If you are only getting 30 gallons out of a 40 gallon tank, it is the wrong fuel pickup unit. Take it out and measure the length into the tank, compared to the tank. You want is sitting right at the bottom.
if i recall the 25gal tank is short depth and the 31 is deeper and same as 40 gal from suburban but the suburban 40 is longer in length for the extra . R/A shows same sender for 31 or 40 gal tnaks . so you might have the 25 gal sender .
The only other even shittier thing would be if I got a 31 gal tank. 
I didn't measure it.
I didn't measure it.
no ....... 25 gal be the worst for rear mount tank . 
Interesting Spectra has a different sender for 40gal vs 31gal. I'm looking at the 89 TBI stuff but I notice the carb tanks have the same sending unit like @sweetk30 mentioned. The dimensions do show 3/8" taller for the 40 gallon tank. But that doesn't seem like enough for a 31gal sender in a 40gal tank to matter that much. Really makes me wonder why they have different senders.
If the wrong sender isn't the answer, them I'm back to a faulty unit. I feel like because I'm having trouble with both the fuel level indication and running out of fuel too soon, the sender is likely to blame. Either way it looks like I'm stuck with pulling it and doing some investigation.
I think I have a 40gal tank. I'm not sure how they actually measure the length, specifically if they include the flange. I did a quick measurement from the sidewalk and it's much closer to being 35" than 28" if I include the flange. If I don't include the flange it's still longer than the 31gal tank.
If the wrong sender isn't the answer, them I'm back to a faulty unit. I feel like because I'm having trouble with both the fuel level indication and running out of fuel too soon, the sender is likely to blame. Either way it looks like I'm stuck with pulling it and doing some investigation.
I think I have a 40gal tank. I'm not sure how they actually measure the length, specifically if they include the flange. I did a quick measurement from the sidewalk and it's much closer to being 35" than 28" if I include the flange. If I don't include the flange it's still longer than the 31gal tank.
Definitely something up with the alternator. It's reading 13volts with the engine running and fans off. I used to see 14 volts. When the fans kick on it drops down to the low 12's. This is at the batteries with the multimeter.
A couple of months before blazerbash I bought a new 200amp alternator and it usually shows close to 14v, but I noticed several times during BB that I would dip below 12v. It really ticked me off because I was trying to fix voltage drops when the stereo (and amp), electric fans, and lights were all going. I was thinking I got a bum alternator until I was wheeling back home a couple of weeks ago and the truck died. Turns out my positive battery cable was loose.
Got it tightened down and haven't noticed the problem since.
That's a good idea. I did grab the negative terminals while I was volt checking because I've had one of them loosen up, but I didn't think to check the positives. I also checked the belt tightness after Blazer Bash when I first noticed the voltage dip and it did need tightened.
I looked up my purchases and I've had this alternator almost 8 years. It has a hard life. I use the winch quite a bit (especially in the winter), electric fans, ARB twin compressor, and the stereo.
I looked up my purchases and I've had this alternator almost 8 years. It has a hard life. I use the winch quite a bit (especially in the winter), electric fans, ARB twin compressor, and the stereo.
Driving the crew cab in to work this morning I was thinking about the seat position. It doesn't seem like it should be an issue. Then it occurred to me this truck is the only vehicle I drive for hours in a single day. Plus it doesn't have cruise control and the leg that bothers me is the right one. So it's probably not the seat that's the issue, but the way I use the truck.
You need cruise. Larry and I are working on a way to adapt the GM cruise servo from the late gmt400 trucks and the early cable throttle gmt800 trucks. Needs a vss signal and the signal input from the cruise switch on the turn signal lever.
I'm over simplifying it but based on my quick review of the schematic I think it's possible.
You just need a stick between the seat and pedal. Don't over think it.
Snap-on has one with a turn knob for easy adjustments .
Brick on the throttle pedal. You will not be in the truck as long either.
