My car PEAKS about 100kpa at some part throttle openings durring normal driving. It seems to be when I'm around 40-60% tps. I noticed this from a log file. Is it normal to PEAK 100kpa when craking the throttle 50%?

 

When you say it "PEAKS" at 40 to 60% tps, do you mean that you get less kPa over 60%?

Having 100 kPa at 40% tps doesn't sound usual at all- this would be saying that the intact tract, air filter, throttle body and manifold were providing no restriction to flow from 40% throttle opening onwards. This may also indicate that you'd have a very sensitive throttle action, and that you'd gone way oversize in throttle body.

John

 

Are you sure you have a MAP sensor?.
There are some sensors from the carb days that look like a MAP sensor but aren't.

Did you have some serious backfires?, that may have ruined it?.

It'd take kind of a loud car with a large TB to do that. If you have a large TB did you do any before and after testing to see if it helped or not?. The large TB can be lots of fun to drive, but may in fact slow the car down.

 

I mean that the kpa peak at 100kpa at part throttle openings. I have never used more than 45-60% throttle under normal driving so I'm not sure of the kpa at 65tps.The engine goes straight to 100kpa once wot. I would go with the first thing you said. My engine is a 406,242/250* cam,58mm tb, 3" intake tract. So I don't think it's too much throttle body. Besides the same engine with a lg4 cam and tpi didn't do that.

I am aware of that sensor. I think it's a baro sensor. ONE way to tell them apart is the clip going into the map sensor tends to be green. I'm sure it's the right one.

My 406 has been in my car for about 3 years and has never backfired. I use the tps and other log data to check if the sensor is working. It seems to be working great. I have a f/p guage in my car. I use it as a vac reference also,generally. It's in sync with what the f/p regulator is doing which matches the map..

That is exactly what I have, a loud engine and a large tb. The car is a monster. I spend alot of time letting off the gas in normal driving.So do you think it's "norma"l to break 100kpa durring part throttle?

 

I do not reach 100kPa during normal part throttle. But, at the same time ... I never use 50-60% during normal part throttle. Maybe the first thing is to figure out why you are using 50-60% during part throttle. If I use that much throttle then I am spinning the rear hides from a stop. When in second or third I just have no need for that much throttle. I'll run some tests then next time I have my car out and try that exact thing .... 50-60% throttle while in 2nd or 3rd gear.

One of the reasons I don't need that much throttle is due to the 58mm TB. Small throttle openings let so much more air in than a stock TB.

Tim

 

I'll go through some log data and figure out when/why my throttle peaks at 40-60%. I might have been just trying to get more map rpm data points. But you have me thinking that my t/v cable might be off.I'm going to check some log data. Then I'm going to go out and fix the rear tires from rubbing(18x10.5" 295's). Skulte machined those spacers just right. The rear tires rubbed just a hair on both sides, perfect fit!. I'm just going to pull the rear coils and jack the axle up to find the contact point. Then I'll get some more data and figure out why I was @ 45-60% tps under "normal" driving.GOOD QUESTION!!!!