Accelerator effort, hesitation

[duke3478]

Hi, I have an '86 with the original non-WG banks turbo, giant 40lb rectangle airbox style. Seems like I really have to mash on the go pedal to crack the IP open. I wrestled off the giant Banks safe that they call an airbox, pulled off the cruise and freed the throttle cable from the bracket.

It had no binding or unusual resistance (at the pedal) when it was free of the bracket and off the IP. When I snaked it back to the stock location, it was binding. So I re-routed it as well as I could, and it's better, but still not ideal. Seems about a foot longer than it needs to be.

I also notice what I would call hesitation in a gasser, at just partly open throttle. This seems to be lessened with the banks vault open or off. I tested this at the IP, using the lever, with the throttle cable detatched. With the airbox open, it revs right up, but with it closed, it hesitates nearly a half-second, then revs. Added with the high pedal effort, it feels like a dog at takeoff.

Is this turbo lag? I thought lag referred to boost, not acceleration. I'm getting decent boost, around 5-6 pounds when the c6 kicks down at 65-70mph, not towing, with EGT's in the 600s. About a pound when holding those speeds.

I don't think the filter is an issue. (original K&N rectangle) It's not clean, but black. Not pink K&N oil color, but it doesn't look restricted; I can see daylight through it pretty well all around. I have a K&N kit and I'll give it a good cleaning tomorrow to see, unless someone can point me in the right direction.

As for the pedal effort, I'm thinking of just shortening the cable and sleeve at the pedal end, reinstalling the firewall bracket and trying a new routing after doing that, but thought there might be a trick or something I'm missing.

Thanks!

 

[towcat]

your throttle cable assembly is worn out. do yourself a favor and go to Ford and get yourself a new throttle cable before disaster strikes.
http://www.oilburners.net/forums/showthread.php?t=40064

 

[duke3478]

your throttle cable assembly is worn out.

Yes, maybe, but it only binds when the extra foot or so requires the whole deal to be bent in a double "s" shape. It doesn't have that feeling a cable has when the core is digging into the casing, or when the cable is fraying or stretching.

When detached from the IP, or even when it's attached in a sweeping curve not crammed under the Banks box, it's smooth and free in both directions. I'd need to find the right length anyway, to know what new one to get.

 

[duke3478]

Installed a new cable today. My routing was too close to the exhaust and it melted the sleeve. Luckily it hung up on accel, not decel.

Problem is, it's just as sticky with the new cable. When I uninstall the end from the bracket at the IP, and "unroute" it, it's smooth and easy. It just doesn't seem to like the double bend.

Anyone have correct routing? This is with the big banks airbox.

Oh, and a P.S. cleaning the K&N made a huge difference, hitting 5-6 PSI now without really trying. Much less hesitation.

 

[duke3478]

I have a new cable, and there's no issue with travel or resistance at the pedal until I install it in the bracket near the IP, which forces it to make a tight bend.

I've tried routing between the airbox and turbo, between the oil return line and airbox, above the turbo, and the stock routing. In every case, the 90° turn it has to make at the bracket seems to make it bind. The arm on the IP is smooth and has normal resistance through it's travel. In fact, the return spring on the IP is the only thing that makes the pedal return quickly enough. In the bracket, off the IP, the cable's own spring just eases it back, it doesn't spring back.

This can't be right, but I can't figure out what's wrong. I first thought it was too long, but even if I shortened the cable, it still has to make the turn. I know I'm doing damage to the cable casing every time I accelerate.

Anyone have a loop in theirs? I'm thinking that might work better.

 

[towcat]

did you get a factory cable or the aftermarket?
also, can you post a pic of the cable routing without the airbox installed?

 

[duke3478]

I got an aftermarket, the Pioneer. I know the factory part might be better, but the issue is the routing. I can just tell by feel. I've had motorcycle throttle cables and clutch cables feel the same way when they bind, or have too sharp a bend.

I don't have a picture right now, and I don't want to go out in the street in my drawers to take one, but I can illustrate it:

Not to scale, but that's about the path it takes. It seems like the downward pressure of the banks box at the last bend is the main problem.

 

[Vfelix702]

i would try a loop

 

[duke3478]

I might. Not sure if I have enough. I'm gonna mess around with it tomorrow. Rode my bike in the 65mph gusts tonight, stupid... not gonna go underhood in the blow.

 

[jonathan]

ill try to post a pic of mine later or tomorrow

 

[duke3478]

That would be awesome. I've got to have something wrong, just not sure what.

 

[duke3478]

SOLVED!

My issue wasn't in the cable, it was at the cable end, on the IP side. I routed it, (vault removed) and tested it at the pedal, detatched from the IP, only had coil spring resistance. Connected it, it was binding. Hmmm. The IP itself offered little binding, so something was up.

The angle it had to take to draw back the arm on the IP was off just a bit, causing it to bind up there. The bracketed angle didn't agree with the required arc for the arm. A few tweaks to the bracket with a pair of channel-loks, and it was pulling in a straight line, and happy.

Wrestled the vault back on, and I'm set. Thanks, everyone for their input!

 

[duke3478]

SOLVED!

My issue wasn't in the cable, it was at the cable end, on the IP side. I re-routed it, (vault removed) and tested it at the pedal, detatched from the IP, only had coil spring resistance. Connected it to the IP, it was binding. Hmmm. The IP itself, moved manually, offered very little resistance, so something was up.

The angle it had to take to draw back the arm on the IP was off just a bit, causing it to bind up there. The bracketed angle didn't agree with the required arc for the arm. A few tweaks to the bracket with a pair of channel-loks, and it was pulling in a straight line, and happy.

Wrestled the vault back on, and I'm set. Thanks, everyone for their input!