Would a worn throttle cable hurt power?
Would a worn throttle cable hurt power? I got on the dyno (Dynojet) last night after shop hours (gotta love free dyno runs with wideband 
) to test the air/fuel. Out of 3 runs, the most it put down was 327rwhp SAE corrected with a perfect air/fuel tune at 12.9-13/1. The last time I was on the dyno, the car put down 340rwhp/351 ft lbs SAE running slightly leaner and with old plugs (TR-55's gapped at .055). Since that last run I put in new NGK TR-55's with the same gap and Seafoamed the engine.
The reason I think the throttle cable may be at issue here is that it is very loose feeling if you move it, and I've been getting lazy throttle response lately. Last time I had the intake assembly off to change a knock sensor, I noticed at WOT position, the throttle blade is not horizontal but at about 15 degrees from it. Isn't the blade supposed to be at a flat 180 degree angle at WOT? Has anyone had any of these issues before from worn cables? I tried a new TPS with no luck. The car has 95k on it. thanks in advance
Jason
) to test the air/fuel. Out of 3 runs, the most it put down was 327rwhp SAE corrected with a perfect air/fuel tune at 12.9-13/1. The last time I was on the dyno, the car put down 340rwhp/351 ft lbs SAE running slightly leaner and with old plugs (TR-55's gapped at .055). Since that last run I put in new NGK TR-55's with the same gap and Seafoamed the engine.The reason I think the throttle cable may be at issue here is that it is very loose feeling if you move it, and I've been getting lazy throttle response lately. Last time I had the intake assembly off to change a knock sensor, I noticed at WOT position, the throttle blade is not horizontal but at about 15 degrees from it. Isn't the blade supposed to be at a flat 180 degree angle at WOT? Has anyone had any of these issues before from worn cables? I tried a new TPS with no luck. The car has 95k on it. thanks in advance
Jason
Launching!
Joined: Feb 2006
Posts: 274
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From: DeKalb/ Yorkville, IL
The blade comes well short of 90 degrees stock. That is why people like me do the throtle body bump stop to allow the blade to open up more. But you said the cable is loose then Id say thats youre problem.
TECH Addict
Joined: Jun 2005
Posts: 2,660
Likes: 14
From: England
If the cable is opening the throttle blade all the way to the stop then NO it won't be affecting PEAK power on a dyno. If the linkage has slop in it then it may well affect response, but this wouldn't show up on a dyno.
If you work with dyno's I guess you know a bit more about them than I do.
1. But what was the temp/humidity levels like for these runs and previous?
2. Did you use any correction factors to equal out atompheric conditions?
3. When was the dyno last calibrated? (Also need to know for the previous runs also)
4. What level graph smoothing was being used on each run?
5. Are you using the same grade fuel this time and last time?
6. Was the knock sensor retarding the timing on any of the runs?
7. If the car was lean last time, but not this time then that may explain the bhp difference, but why was it not running lean this time?
8. Are you still running the same wheels/tyres?
9. What psi where your tyres at this time and last time?
10. Do you have any increased drivetrain loss (worn wheel bearing)?
If you work with dyno's I guess you know a bit more about them than I do.
1. But what was the temp/humidity levels like for these runs and previous?
2. Did you use any correction factors to equal out atompheric conditions?
3. When was the dyno last calibrated? (Also need to know for the previous runs also)
4. What level graph smoothing was being used on each run?
5. Are you using the same grade fuel this time and last time?
6. Was the knock sensor retarding the timing on any of the runs?
7. If the car was lean last time, but not this time then that may explain the bhp difference, but why was it not running lean this time?
8. Are you still running the same wheels/tyres?
9. What psi where your tyres at this time and last time?
10. Do you have any increased drivetrain loss (worn wheel bearing)?
Originally Posted by 300bhp/ton
1. But what was the temp/humidity levels like for these runs and previous?
Originally Posted by 300bhp/ton
2. Did you use any correction factors to equal out atompheric conditions?
Originally Posted by 300bhp/ton
3. When was the dyno last calibrated? (Also need to know for the previous runs also)
Originally Posted by 300bhp/ton
4. What level graph smoothing was being used on each run?
Originally Posted by 300bhp/ton
5. Are you using the same grade fuel this time and last time?
Originally Posted by 300bhp/ton
6. Was the knock sensor retarding the timing on any of the runs?
Originally Posted by 300bhp/ton
7. If the car was lean last time, but not this time then that may explain the bhp difference, but why was it not running lean this time?
Originally Posted by 300bhp/ton
8. Are you still running the same wheels/tyres?
Originally Posted by 300bhp/ton
9. What psi where your tyres at this time and last time?
Originally Posted by 300bhp/ton
10. Do you have any increased drivetrain loss (worn wheel bearing)?
No, the wheels spin freely when the car is on a lift.
No, the wheels spin freely when the car is on a lift.
Originally Posted by wamp42
The blade comes well short of 90 degrees stock. That is why people like me do the throtle body bump stop to allow the blade to open up more. But you said the cable is loose then Id say thats youre problem.
Bump stop mod was done and set to 90 degrees. So yeah, it sounds like I need to adjust the cable or buy a new one.
Jason
Do you have TCS? There's a 'adjuster' halfway up the cable from the TCS to the firewall. It has a cover on it. Take it off, readjust till the cable is tight, and put it back on. When you take it off you'll notice grooves; this is how it stays on.
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Staging Lane
Joined: Oct 2005
Posts: 92
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Originally Posted by wamp42
The blade comes well short of 90 degrees stock. That is why people like me do the throtle body bump stop to allow the blade to open up more. But you said the cable is loose then Id say thats youre problem.
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Verdad Gallardo You grind down the bumpstop where the throttle body hits ( at WOT ) to allow a full 90 opening, Using a voltmeter, you measure and try to attain at least 4.63v. Better than trying to 'eyeball' it.
