DIY Electric Car Forums banner

1 - 20 of 37 Posts

·
Registered
Joined
·
369 Posts
Discussion Starter · #1 ·
I drove the truck 55 miles just to see how far it'd go in 20 degree weather. As I got home, the brakes blew the front drivers side line. So today I replaced it, it fought me all the way, and I got back in the truck to test drive it. I idled down hill but when I started stepping on the gas, lightly, the motor surged like a newbie trying to learn how to drive a stick. Got home and tested it neutral. Seemed to make funny vibrating sound only when accelerating fast. When just getting the motor to spin, it spun up normally.

Checked HV connections, even re-crimped a motor wire. Everything seems connected OK, and I'll re-check tomorrow, I took it for another drive and it still surges. I kinda gave up on it for today- nothing on that truck wants to work.

Oh yeah, Chevy S10, 46 Thundersky's 160AH's, Zilla 1K LV, Warp 9", MiniBMS, and a main disconnect I haven't check connections on yet.

Why would this happen after brake failure? Co-incidence?:eek:
 

·
Registered
Joined
·
1,580 Posts
Did you check your throttle pot box? I know the pot that I use to adjust my automatic transmission shift points gets all screwed up in the cold, and sometimes causes my auto to jump gears when the resistance goes all screwy. I also notice in with my cheap pot box for my Zilla, but I have a torque converter that sucks the surges, and lot of performance fun at the same time.
 

·
Registered
Joined
·
369 Posts
Discussion Starter · #4 ·
Did you check your throttle pot box? I know the pot that I use to adjust my automatic transmission shift points gets all screwed up in the cold, and sometimes causes my auto to jump gears when the resistance goes all screwy. I also notice in with my cheap pot box for my Zilla, but I have a torque converter that sucks the surges, and lot of performance fun at the same time.
I would have, and will, but the weirdness only happens when spinning the motor quickly or trying to accellerate when driving, (faster than 4-5 mph)so didn't seem like a TP problem. It happens on all ranges of the pot when testing, though it is alot colder than it has been so far this year. Time to warm up the garage, and move a pot to inside with the Zilla.

I was about to sell my gas guzzling Prius thinking my EV was going to be my only needed transport. Might hold on to it till after winter.:)
 

·
Registered
Joined
·
369 Posts
Discussion Starter · #5 ·
Could you have interfered with the cable to the pot box or the throttle pedal, causing some binding/sticking?
Cable is fine, works in neutral. Wires appear fine. Odd thing is this happens after a 55 mile drive and a broken brake line, though it is aweful cold today.:cool:
 

·
Registered
Joined
·
1,378 Posts
Any chance brake fluid sprayed into the pot box, or onto the brushes of the motor? BTW a wire short can do that. You accelerate hard, so the wired gets pulled and shorts, power goes away, motor moves back, connection reestablished, accelerates hard, breaking the connection... I had a car that did this once with ignition wires. It was very hard to debug because it only happened under high torque -- I eventually figured it out by finding a rubbed wire.
Did you bleed the brakes correctly? It sounds like a dragging brake rotor to me.
 

·
Registered
Joined
·
168 Posts
I would have, and will, but the weirdness only happens when spinning the motor quickly or trying to accellerate when driving, (faster than 4-5 mph)so didn't seem like a TP problem. It happens on all ranges of the pot when testing, though it is alot colder than it has been so far this year. Time to warm up the garage, and move a pot to inside with the Zilla.

I was about to sell my gas guzzling Prius thinking my EV was going to be my only needed transport. Might hold on to it till after winter.:)
Sounds like a loose battery or current shunt connection or internal battery connection issue. Have you monitored your voltage when this happens?
 

·
Registered
Joined
·
369 Posts
Discussion Starter · #9 ·
Did you bleed the brakes correctly? It sounds like a dragging brake rotor to me.
No. The bleeder screw was stuck, so I bled them from the hose as it goes into the caliper.

Normally, I'd say thats crazy, but then again just maybe...:eek: guess it could drag when trying to go faster than a few MPH.
 

·
Registered
Joined
·
369 Posts
Discussion Starter · #10 ·
Any chance brake fluid sprayed into the pot box, or onto the brushes of the motor? BTW a wire short can do that. You accelerate hard, so the wired gets pulled and shorts, power goes away, motor moves back, connection reestablished, accelerates hard, braking the connection... I had a car that did this once with ignition wires. It was very hard to debug because it only happened under high torque -- I eventually figured it out by finding a rubbed wire.
First thing I checked was where did the brake fluid squirt out to. Every drop hit the tire. Motor, controller box, pot and all wires looked fine. Another post suggests dragging brake. Working right now, but I'll get to look at wires and brakes soon.
 

·
Registered
Joined
·
369 Posts
Discussion Starter · #11 ·
Sounds like a loose battery or current shunt connection or internal battery connection issue. Have you monitored your voltage when this happens?
It was dark and the meter isn't lit, and of course I only thought of that myself at 2AM. But I'll check it and some other stuff today. Gotta remember where the meter is connect across to elliminate those connections in between if it shows OK.

I really would like the hanging brake idea best, otherwise I have issues with wiring...

So why did Chevy put a nipple of metal next to the bleeder screw? To keep anyone from putting vise grips on it and getting that darn bleeder out!
 

·
Registered
Joined
·
369 Posts
Discussion Starter · #14 ·
I just jacked up the rear end and got it up to 35. It was still running funny, can't tell what really going on. Gotta check it again and watch voltage this time. Can rear drum brakes drag like that? But then it was a front brake line that gave way. UHGG!! I've got problems!!!
 

·
Registered
Joined
·
1,199 Posts
I idled down hill but when I started stepping on the gas, lightly, the motor surged like a newbie trying to learn how to drive a stick. Got home and tested it neutral. Seemed to make funny vibrating sound only when accelerating fast. When just getting the motor to spin, it spun up normally.
I'm voteing that you have something mis-assembled/mis-aligned in the wheel, brake disc, wheel bearing, wheel speed sensor or caliper.

A speed sensor and cog wheel misalignment could be causing your antilocks to act up. A loose or misaligned caliper, disk or wheel can cause some really weird reactions. If it's the antilocks they won't start acting up until you have traveled a specified distance. Look for a fouled cog wheel or a sensor damaged or out of position

I recommend that you take down that whole assembly and recheck it. Autozone I beleive has diagrams of how all that is supposed to go together available. Also the diagrams can be found on some repair sites for a nominal fee.
 

·
Registered
Joined
·
137 Posts
When the hose broke, you introduced air into the brake system. You need to bleed all 4 wheels. Whether or not this is your surge problem, it needs to be done asap.

Take it to a shop if you haven't done a bleed before. Or, google to learn the process...
 

·
Registered
Joined
·
369 Posts
Discussion Starter · #17 ·
I'm voteing that you have something mis-assembled/mis-aligned in the wheel, brake disc, wheel bearing, wheel speed sensor or caliper.

A speed sensor ... or out of position

I recommend ...available. Also the diagrams can be found on some repair sites for a nominal fee.
Not anything to do with brakes. I jacked rear tires, ran it, it torqued pumpkin real bad, removed rear drums, ran again, still torqued, seems like the Zilla is putting out power then shutting off, then back on, makes the whole rear end, pumpkin torque like my old Firebird! Checked the Throttle Pot, resistance was steady all the way up.
 

·
Registered
Joined
·
369 Posts
Discussion Starter · #18 ·
When the hose broke, you introduced air into the brake system. You need to bleed all 4 wheels. Whether or not this is your surge problem, it needs to be done asap.

Take it to a shop if you haven't done a bleed before. Or, google to learn the process...
Yeah the brakes are mushy, and trust me, I have done brakes before! I'm just working the drive system problem first. Brakes are optional at this point!
 

·
Registered
Joined
·
369 Posts
Discussion Starter · #19 ·
So front tires on ground, rear in the air with tires and brake drums removed. Even pulled the pumpkin cover off to check fluid level and wear / metal shavings, all look OK. Throttle Pot measured OK through entire movement, and even warmed it up just for kicks. In 5th gear, can go pretty fast before a load develops were the pumpkin starts to torque over, on and off pretty fast. I had figured it was the Zilla giving full power then dropping off and hitting it again with full power (at least what I had held the TP to), but thinking of that, why would it only do it with a load? So not Zilla programming issue?

I tried connecting Hyperterminal, but of all 4 of my devices including a Palm, configured properly, naturally, none would actually connect, though they said they were. I guess you have to know your connection is really connected? The laptop I'm using right now used to work, but darn if the hyperterminal program went and expired! I am not paying $59.00 for it! And my driver for the USB cable dissappeard! Who knows where the driver is? Not me!

So back to motor giving full commanded juice then not. Going to pull HV connections and check for bad connections. The battery Volts do not show a change when this happens. I've got a better chance of looking at motor amps while driving, but I don't have that connected.

And I thought this would be easy to troubleshoot! At least the ceramic heater kicks butt!
 

·
Registered
Joined
·
541 Posts
Yeah the brakes are mushy, and trust me, I have done brakes before! I'm just working the drive system problem first. Brakes are optional at this point!
Is it possible that you have an intermittant brake light switch. I guess that when the hose broke, the brake pedal went to the floor, displacing something. I think Zilla cuts power on brake signal, so what you describe as a surge is actually a loss of power followed by a recovery.
Gerhard
 
1 - 20 of 37 Posts
Top