Base Timing

[Vettefan87]

I think the base timing might be set a little to low, but before I went out, and starting poking around I wanted some feedback. I let my brother drive it and he said "Yeah it is real doggish out of the hole, but at 2500 it starts to run" and by doggish he means no tire spin, at all. This is just letting off of the brake, and mashing the go pedal. It is like the secondaries are opening up on a carb when it hits 2500. The tires are Michelin HGT-H4 Pilots. Could the base timing being set to low cause this?

 

[Vettefan87]

Anybody have an opinion on this?

 

[jsinga]

You can check it just like anything else. Unplug the tan wire connector up by the distributor. If you bump it much, stock is 6 btdc, it will ping and the ESC will start pulling timming back and it will lay down. If the tires are new and sticky they might be hooking up! My SZ50 are about gone and they will spin now where when new they would hook and not spin.

JS

 

[Hib Halverson]

Changing the base timing will not change the full spark advance which is controlled by the engine computer.

If the car is a dog off the line, the first thing I'll ask is if it's always been this way or you're trying to fix a new problem.

Also, what's the car's axle ratio?

 

[Vettefan87]

The car has not always been like this. The axle ratio is 2:73's. Before I could light the tires up forever. This was the first time I had really gotten on it after the engine rebuild and according to my brother it is a "major dog".

Hib, what would make my throttle response Lag so bad? If I open the hood, and advance the linkage manually you can really hear it hesistate bad. I want to put my tires on my brothers car, but I don't think thats the problem.

 

[Edmond]

I think you just need to step on the gas harder.:L

Think it could be weather related?

 

[Vettefan87]

Yeah, I always thought the car would run better when it is cold out....

 

[vetteboy86]

The car is not right. Any L98 should light the back wheels up. It isn't the tires. The only thing I can think of is the maybe the timing isn't advancing far enough, and the bad hesitation it has. Perhaps the poor throttle response is contributing. What I can understand is that it is a rebuilt engine with a little over 1000 miles. What causes poor throttle response?

 

[Edmond]

There are too many things that would cause bad throttle response to list here! If you can think of it, it can cause bad throttle response.

 

[vetteboy86]

Yeah Edmond, but on a practically new motor? I just dont know what to tell the kid, other then have him take the builder for a ride.

 

[Edmond]

Do you think it's also possible that you got a not so premium tank of gas last time?

I would take it back to the builder and ask him what the issue is. You paid money for a service and should expect the results for your money.

 

[wishuwerehere82]

Considering your antifreeze leaks that are on a different post, I would be thinking along the lines of an intake manifold gasket leak that's affecting your overall vacuum level in the intake.

 

[Vettefan87]

Yeah, but there were two people involved in this. And I will almost bet my bottom dollar the other will blame the other person :argue . A different person rebuild it, and a differnet person put on the plenum, runner, and intake, and put the motor in.

 

[WhalePirot]

I think you just need to step on the gas harder.

Somehow, that thought never entered my mind.

Sounds like a total and methodical tune up is due, including timing, firing order, fuel pressure, TPS settings, etc. All that stuff was messed with, and maybe even wires from some sensors were damaged.

A new motor takes time to loosen up, as well. It won't happen in 1000 miles.

 

[vetteboy86]

We adjusted the TPS sensor per a post here on the CAC. The firing order is correct, that would be hard to miss. The set the fuel pressure while we were there, not sure what it was set to, probably stock. He isn't getting any service engine soon light, and the car idles fine. It sounds good, but has a TERRIBLE hesitation.

 

[vetteboy86]

Yeah It is pretty bad, if I had a way to record it I would, and I would upload it.

 

[jsinga]

Put a vacuum gauge on it and see if it has more than 18" at idle. If it's low it very well may have a leaking intake gasket. Were the heads milled? How about a fuel filter? It might have gotten trash in it while the car was sitting up. Are you all setting the timing the right way? You have to disconnect the tan wire up by the distributor to set the timing. If all else fails try disconnecting the battery so the computer will re-learn things it might help.
I'm not exactly sure how the computer decides to open the injector pulse, TPS and MAF or MAP is about all there referenced to RPM. I don't think the oxygen sensor has much to do with response
I would think if it idles smooth the injectors are in fair shape. Might try a bottle of Red Line injector cleaner, I swear it fixed a leaker on my hi mileage 87.
Is it just as bad from a 20mph roll?

JS

 

[Vettefan87]

After about 2000 it seems to pull fairly decent, it is like secondaries opening up on a carb. I am not sure why it is doing this. All these problems this car has had is really taking a toll on everyone near it

 

[Hib Halverson]

The car has not always been like this. The axle ratio is 2:73's. Before I could light the tires up forever. This was the first time I had really gotten on it after the engine rebuild and according to my brother it is a "major dog".

Hib, what would make my throttle response Lag so bad? If I open the hood, and advance the linkage manually you can really hear it hesistate bad. I want to put my tires on my brothers car, but I don't think thats the problem.

What modifications have been done to this engine?

What are the conditions of:
Ign. system.
O2 Sensor
Cat converter
Fuel filter
Air filter.
Injectors?
How many miles on the engine.
Has a compression or leakage test been done?

 

[Vettefan87]

What modifications have been done to this engine?

What are the conditions of:
Ign. system.
O2 Sensor
Cat converter
Fuel filter
Air filter.
Injectors?
How many miles on the engine.
Has a compression or leakage test been done?

The ignition system to my knowledge is stock, if that answers your question.

The O2 sensor is brand new.

All three cats are stock to my knowledge, same with the fuel filter.

I have the air filter sitting right here on my desk drying and waiting for it to stop snowing.

Injectors were just rebuilt with the last rebuild, From what the guy said all 8 were leaking... and there is a little over 1200 miles on the motor.

No a compression test has not been done. Is this something that I can do? Thanks for your concern Hib.