tps.. how to check it..

[Vilpo]

Yeah, thanks. But i don't have a vacuum gauge so i guess im out of luck...

[NAJ]

Vacuum Gauge,Fuel Pressure Gauge,Test Light and Digital Volt/Ohm Meter are must haves to diagnois 95 % of the driveability concerns with our vehicles.
Vacuum Gauge is $20.00.
For what you would spend guessing and throwing parts at a problem and not fixing it or paying someone to diagnoise you could own all of the above diagnostic tools.
Add a Hand Held Vacuum Pump,Noid Lights,Injector Tester,Jumper Leads and Backprobe Pins and you are good to go.The only thing missing would be a Scan Tool.
Better get that Chrismas list started.
If you want to check out Hand Tools and Diagnostic Equipment I listed go to ;
Automotive Tools, Air Tools, Robinair A/C Equipment at ToolTopia.com.

[Vilpo]

I gotta agree with you on the "throwing parts at a problem and not fixing it"-comment and same goes with taking it to the repair shop, since i've done that before and even taking it to the repair shop wouldn't help.. Just cost money. I used to do all that with a previous car i had. That's why nowadays i test everything, so there wouldn't be waste of money on nothing and best of chance to get everything working..
Anyways, about the vacuum meter.. I think i already have a equus turbo gauge with vacuum display also, would that be accurate enough to test this?

[NAJ]

If it is portable and not mounted in the car it should work fine.Will be difficult to tee into a vacuum line if it is inside the vehicle.

[Vilpo]

I actually got to borrow a vacuum pump to use, with a gauge too.
So, at 22,15 InHG it was 1,23volts, 13,29 InHG was 2,72 volts and without vacuum it showed 4,65volts. I checked also with another volt meter because mine was cheaper one, but there was only 0,01 volts difference between them. So i would read the results that it gives about 0.3 volts too high reading. Is this enough to make a difference?

[NAJ]

You will have to refresh my memory.What was the original problem with the vehicle?

[Vilpo]

Well, the problem ain't that big but it seems to take a little bit too much fuel at the moment. And also throttle response a bit sluggish, quick push of throttle seems to give better response than same amount of throttle, but slower adding it. I hope you understand the explanation.
I've just replaced the oxygen sensor and it seems to give nice, steady pulse on idle. Also i've checked many times for exhaust leaks and haven't found any. Fuel pressure has been checked a while ago and seemed good. Engine has had a head rebuild a while ago also, so i don't expect much blowby.

[NAJ]

So the head was off. Are we positive that Cam and Ignition Timing are correct?
1 tooth of on the Cam will create a lot of driveability concerns.

[Vilpo]

Quote:

Originally Posted by NAJ So the head was off. Are we positive that Cam and Ignition Timing are correct? 1 tooth of on the Cam will create a lot of driveability concerns.

Yes, we are. I checked it many times when i was putting the belt back on. The marks were all aligned.
I was wondering if it's possible to try and put an adjustable resistor next to the map sensor to lower the voltage so i could see if there's an effect?

[NAJ]

I am assuming you do not have access to a scan tool.
I think you need to check Map Vacuum and Voltage under real time driving conditions especially when the problem occurs.
This is all much easier with a scanner but if you do not have access then....,
You will need to tee the vacuum gauge inline and tape it to the windshield or run a vacuum line long enough to reach inside the vehicle and backprobe the MAP with your voltmeter using jumper wires (be sure your connections are tight and secure)to reach inside the vehicle and with a helper drive the vehicle and record your vacuum to voltages under different load conditions. You will want to backprobe at the MAP and Controller to be sure the Controller is recieving the same signal that is coming from the Map.
Your loss of .3 volts at the MAP may be due to damaged,loose,dirty connections at the MAP or controller,so check very thoroughly.

[Vilpo]

Well, actually i already tested it with wires that i pulled in the car and probed with a multimeter. So i could read it while driving, i didn't have a gauge for it though. It was reading around 1,6-1,7 volts when going downhill without throttle and i remember it was 4,7 volts when giving it full throttle momentarily.
Now, i don't think i have loss of 0,3 volts, but i have 0,3 volts too much. Could there be some problem with sensor grounding maybe, so it would give too much voltage on the output? Is this sensor grounded on the ecu pin n.5 signal ground?

[NAJ]

I posted the Map cavity ID earlier in this thread.
You said you were reading 1.6-1.7 volts on decel? On decel engine vacuum would be 20-22 " hg and voltage should be under .9 volts.According to the chart 18"hg = .93 volts.
Did you check Map output with the key on/engine off with a hand held vacuum pump and voltmeter?
And from what I am reading your driveability concern is a slight tip in hesitation under light throttle.Did you sweep TPS? Are the plugs gapped properly?

[Vilpo]

Ok, i did the MAP voltage test again and now all seems normal again.. I tested on idle it gave 1,2-1,3 volts and tested while driving it gave about 0,9v on decel and about 2,5volts on slight acc. All i did was i unscrewed the MAP from it's place and put it back again. I'm guessing maybe the grounding was bad on my earlier measurement or something. I left the wire i put there for measurement, so i can retest it after a while to see if it stays ok.
Fuel consumption didn't get better though.. TPS seems good since it gave good output when adding gradually from about 1 volt up to around 4 volts..

[NAJ]

Fuel consumption can be caused by numerous things.
One of the major culprits would be a "Lazy" O2 sensor which can decrease fuel economy by as much as 7 mpg.
Also since about 9/15 winter fuel blends have been being used depending on your location and this and cooler temps will also contribute to decreased fuel economy.

[Vilpo]

Well, i just replaced the o2 sensor and it seems to give quite quick pulse to my opinion so i don't suspect that but i guess the winter temperatures give their contribution to this.. Though i have suspected also from time to time if my thermostat is good since most of the times when i drive on the highway, the temp stays just under the first line on the temp gauge.