Throttle position sensor question
Something I noticed today. When I start the engine, the fuel pump gets REALLY laud to pressurize the fuel lines. It sounds like somebody is drilling into the metal. This lasts for about 5-10 secs. I don't know if this affects anything but it definitely sounds abnormal. Wes, we didn't hear this sound when I was at your place. But again, the fuel pressure was normal. This is a new present that my Q threw me today. Maybe it points to somethings ... . Any ideas???
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texasoil
- Posts: 875
- Joined: Mon Sep 02, 2002 3:18 pm
- Car: '92 Infiniti Q45A
'94 Infiniti Q45A
'94 Mercedes-Benz SL600
Did you check the TPS at differnet throttle positions? A faulty one will normally throw a check engine light, but? Clogged fuel injectors and cruddy intake valves will choke it down. What does the O2 sensor outputs look like--it is controlling or not.
Check the intake manifold vacuum--if the timing chain is a tooth off, the vacuum will be way low. If valves are clogged, vacuum may be OK at idle, way low at higher RPM's.
Ignition timing late will also drastically reduce power. I presume you have checked things like dragging brakes to rule them out. If engine is 'normal' in neutral, but sluggish in gear--look to brakes or transmission. Dragging lock up clutch in torque convertor chews up lots of power till it cooks.
Check the intake manifold vacuum--if the timing chain is a tooth off, the vacuum will be way low. If valves are clogged, vacuum may be OK at idle, way low at higher RPM's.
Ignition timing late will also drastically reduce power. I presume you have checked things like dragging brakes to rule them out. If engine is 'normal' in neutral, but sluggish in gear--look to brakes or transmission. Dragging lock up clutch in torque convertor chews up lots of power till it cooks.
TPS gives the correct voltages, the same as on Wes' car. So, I rule this one out. Both O2 sensors are new. I rule these out. On March I did air and fuel BG clean up service. Just five minutes ago, I disconnected the air hose from PCV and check with finger if its taking any air. I didn't feel anything at all. The rpms drop a bit and I block the pcv. It seems that its just not sucking the air?? Could it be bad timing - because after the dealership "adjusted" my timing this problem appeared. Also, the air hose before the PCV and the inlet where the PCV sits are wet in oil. It is normal??
Today I bought BG44K and poured it into the tank. However, now it seems that air is the problem. Any suggestions how to proceed?
Today I bought BG44K and poured it into the tank. However, now it seems that air is the problem. Any suggestions how to proceed?
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texasoil
- Posts: 875
- Joined: Mon Sep 02, 2002 3:18 pm
- Car: '92 Infiniti Q45A
'94 Infiniti Q45A
'94 Mercedes-Benz SL600
ah ha! now we are getting to the bottom--the problem showed up only AFTER the timing was adjusted? well, that's the first thing to have checked.
Rule 1 if things get worse when something is 'adjusted' or 'fixed', it wasn't done properly.
Rule 2--See Rule 1
Put a vacuum gauge on it and check the vacuum (between the throttle plate and the intake valves. )
Rule 1 if things get worse when something is 'adjusted' or 'fixed', it wasn't done properly.
Rule 2--See Rule 1
Put a vacuum gauge on it and check the vacuum (between the throttle plate and the intake valves. )
The PCV valve may have some oil and deposits. Overall this sounds like a timing problem to me. Engines will run flat or lose acceleration and top end with improper timing. Couple of thoughts -- the knock sensor codes jump out at me here. That has to be taken care of for the integrety of the other diagnostics. THey adjust the detonation. Further Dennis has stated that Q's go flat with bad knock sensors. Also, have the under plenum hoses been replaced? Lots of vacuum leaks to be had. Also, even though the fuel filter has been replaced recently, it can clog quickly. ALWAYS start with the easy stuff. Also, "after the dealership "adjusted" my timing this problem appeared" says to me (a) bad timing adjustment; (b) they left off a hose or some other connector. Have the timing adjusted again.
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Look at the CAS top front: the position adjustment slot is roughly 3/4" long that's 45 degrees of adjustment range.
15 degrees BTDC is roughly when the left of the screw shows 2/3 and the right space is 1/3 exposed.
I can imagine a tech might get the timing wrong by 1,2,3 degrees but not enough to show your symptoms. They see the CAS all the time [when checking for corroded connectors] and they know what looks about right.
Because it is difficult to loosen the 3 screw bolts without double swivels it doesn't just get randomly adjusted because of the special ingition transformer necessary to couple a timing light to the system.
15 degrees BTDC is roughly when the left of the screw shows 2/3 and the right space is 1/3 exposed.
I can imagine a tech might get the timing wrong by 1,2,3 degrees but not enough to show your symptoms. They see the CAS all the time [when checking for corroded connectors] and they know what looks about right.
Because it is difficult to loosen the 3 screw bolts without double swivels it doesn't just get randomly adjusted because of the special ingition transformer necessary to couple a timing light to the system.
Just took it to local Nissan dealership. Tech adjusted timing, he said it was a fraction off but nothing serious. We drove the car, and he connected consult tool to it. He said that everything is nearly perfect. Tps is working properly, air fuel mixture is excellent, and no error codes. He told me, that to him it seems that my Q is just fine - yeah right, you can tell he never drove Q before.
I replaced PCV - no change. I was wondering, I have bosch platinum 4 plugs. Should I switch to NGK, I mean can it make the difference?
I replaced PCV - no change. I was wondering, I have bosch platinum 4 plugs. Should I switch to NGK, I mean can it make the difference?
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texasoil
- Posts: 875
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- Car: '92 Infiniti Q45A
'94 Infiniti Q45A
'94 Mercedes-Benz SL600
until you check the intake manifold vacuum at idle and steady 2500 rpm you will not be able to determine if valves are crudded up or cats plugged.
Fuel air mix at idle being OK does not mean its OK at other conditions. Plugged fuel filter will pass enough for idle, not enough for any power.
It always pays to check basics first--filters,hoses, timing, intake vacuum--then hunt for other subtle failures like plugged cats and electronic stuff based on the fundamental test results. Phsyics of engine performance have not changed in 100 years, only the precision of adjustment of parameters to optimize combustion.
Fuel air mix at idle being OK does not mean its OK at other conditions. Plugged fuel filter will pass enough for idle, not enough for any power.
It always pays to check basics first--filters,hoses, timing, intake vacuum--then hunt for other subtle failures like plugged cats and electronic stuff based on the fundamental test results. Phsyics of engine performance have not changed in 100 years, only the precision of adjustment of parameters to optimize combustion.
The tech drove with me having the consult tool with him connected at all times. So, we checked idle as well as driving under cruise, then WOT ... . Now that I read more about Bosch plugs, I suspect that plugs are probably the cause. When I put the Bosch, I didn't know about NICO, it was almost two years ago. We will see, I hope plugs will do it. I am going for PFR5G-11, which is according to owner's manual are the standard NGK plugs.
Great news! BG44K is a miracle! Even though my Q is not in top shape by performance measures, it has definitely improved for the last two or three days after I added BG44K. I can't be more happy! I will pour another can in the next refill to see if this will cure the whole problem. I will also replace spark plugs with OEM to avoid potential complications. So it seems that fuel system was dirty or intake valves as some of you suggested.
It was such a pleasure to wash my Q, now that I know that my babe is getting back to shape. I will be out of states for two months, but I will post more info when I come back and drive a little bit more with the second can of BG44K and new plugs.
Don't want conclude anything yet but there is a light at the end of the tunnel.
It was such a pleasure to wash my Q, now that I know that my babe is getting back to shape. I will be out of states for two months, but I will post more info when I come back and drive a little bit more with the second can of BG44K and new plugs.
Don't want conclude anything yet but there is a light at the end of the tunnel.
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elwesso
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2007 BMW M Coupe
2007 Infiniti G35 S 6MT - Location: Indiana
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For the seafoam, it comes in a liquid form (not aerosol, like BG44k)... It helps to have a small funnel, ideally we should have done it at my house since I have these little tiny funnels that fit perfectly inside the booster hose...
The other way you can do it is pour it into a small cup or something like that and stick the hose in the fluid a little bit at a time.. YOU DO NOT WANT TO FLOOD THE ENGINE OUT..... its easiest to have someone inside the cabin running the engine at 1500rpm or so..
Make sure the car is at operating temp first....
So the procedure would be1. Take off the brake booster hose, the one on the booster near the master cylinder......2. Figure out how your going to get the fluid in there, by one of the things i mentioned...3. Start the engine, run it up to 1500rpm (have a helper) and slowly add the seafoam through the hose... Dont let the enigne die, and it it struggles let off and then go again.... Under no circumstances should the engine die4. As soon as you add the whole can, immediately shut off the engine and let it sit for a while (20 mins or so)...
After this, take it out and run the poop out of it... Many redlines thorugh 1st and 2nd gears to blow all that crap out of there..
Be warned, you may not want to do this in a residental area, as it gives off a TON of smoke, so if someone would be offended you might go somewhere else.....
I have my sub installed but im still having problems with it, apparently my connections arent very good...
The other way you can do it is pour it into a small cup or something like that and stick the hose in the fluid a little bit at a time.. YOU DO NOT WANT TO FLOOD THE ENGINE OUT..... its easiest to have someone inside the cabin running the engine at 1500rpm or so..
Make sure the car is at operating temp first....
So the procedure would be1. Take off the brake booster hose, the one on the booster near the master cylinder......2. Figure out how your going to get the fluid in there, by one of the things i mentioned...3. Start the engine, run it up to 1500rpm (have a helper) and slowly add the seafoam through the hose... Dont let the enigne die, and it it struggles let off and then go again.... Under no circumstances should the engine die4. As soon as you add the whole can, immediately shut off the engine and let it sit for a while (20 mins or so)...
After this, take it out and run the poop out of it... Many redlines thorugh 1st and 2nd gears to blow all that crap out of there..
Be warned, you may not want to do this in a residental area, as it gives off a TON of smoke, so if someone would be offended you might go somewhere else.....
I have my sub installed but im still having problems with it, apparently my connections arent very good...