A&Q about 350Z
Q:
Actually an old Renault Alliance, another rarity....
A:
Right up there with the Encore and Fuego.
A:
Well the stud is back on the head, rocker arm assembly back on and ready to try, problem is I left something on and killed the battery, tomorrow morning hopefully will bring sucess!
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Good luck!
A:
Back again, OK I was able to fix the stripped stud, retorked the rocker assembly back down and appears all valves are moving. The engine runs, no backfiring now but has no power, Idles or runs wide open, moving the throttle slowing causes it to stall, sounds like its starving for air. The plugs get completely carbon fouled, which to me is indicating its running rich. Could this also indicate a timing issue? The engine has a chain for timing, no belt so Id think its just the ignition timing that would be off. Going to borrow a timing light this week.
Ive tried disconnecting various ignition devices one at a time and then all and the engine still runs the same. IE disconnected the throttle position indicator, MAP sensor, WOT switch and no difference.
I do not know how to trouble shoot this any futher, my understanding of throttle body fuel Inject is that when its cold, it only relies on the throttle position indicator, MAP sensor and maybe the engine speed to gauge how much to pulse the injector. How can a find out what part is broke or what is wrong??
Thanks guys.
~ PHil
A:
I,m not a seasoned mechanic but was just dealing with my own fuel injector problem for the last couple of days. After searching several forums, I found that the crankshaft position sensor controls the timing for the firing of the injectors, via the Electronic Control Unit. The ECU shorts/grounds the 12 volt signal that is applied to the injectors which then causes them to fire. It was also mentioned that if you want to know if the injector is recieving the signal to fire, you can use a testlight (or a noid which is specificly designed for this). One guy said that he tried gounding the injector signal directly to the chassis ground. His result was that the injectors fired continuiosly causing the engine to run extremely rich. Don't Know if this is possibly something for you to check, but if your crankshaft position sensor, ECU, or Injector circuit (wiring being grounded somehow) are causing the injectors to dump more fuel than they should, the symptoms you have described may appear. Just thought I'd drop in my two sents.
A:
Hi Pathfinder007 this car has a throttlebody injection, with only one injector so there isnt crankshaft position sensor. Thanks for trying to help though.
~ Phil
A:
Mine is throttle body injected as well. The point is more this. The throttle body houses a fuel injector and is controlled by the ECU. The ECU needs a reference in order to know when to fire. Some vehicles use a cam shaft sensor and some call it something else. My crankshaft position sensor is located inside of the distributor. The injector should only fire once at the point when one of however many cylinders is pulling back for the intake stroke. For a four cylinder, the injector should fire four times. If the problem I stated previously is occuring. The injector could be on all the time. The noid or test light would tell you if the injector stays on all the time or if it pulses once for each cylinder.
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Hmm OK, Ill have to read up to see how it sences when to fire, I have not read anything about the crankshaft sensor but will look into it. Thanks
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OK well Ive read in the Chilton book and found nothing about a crank shaft position sensor. But also I cannot figure out from the book how it knows when to fire. To be honest I figured it was continuously firing and its timing didnt matter since its firing before the intake manifold. IE a carb is always supplying fuel, not pulsing to match each cylinder firing. Can anyone clairify this??
Thanks ~ Phil
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l2sail, There are a couple TBI versions, but most can operate in synchronized or un-synchronized mode. Some will fire at a set time interval based on rpm and some will sync. to the ignition timing. It depends on engine variables and changes automatically. They trigger from the iginiton pick-up, thus have no need for a crank or cam sensor. You are correct that they behave like an electronic carb., not a port-fuel engine. Do you have a good vacuum signal to the MAP sensor? Also, is the TBI making a ticking sound when it's injecting, or just dumping fuel (this is what the noid light will tell you also)? And, does the ticking (if there) change when the throttle is opened and closed?
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UPDATE!! Since I dont have a compression gauge or a timing light and havent had a chance to get them I tried testing what I can. On Wells Manufacturing Site it described how to test the MAP sensor and the TPI. Heres what I found:
MAP Sensor, had a hard time finding it, its located behind the firewall by the wiper mech area. The test basically consists of disconnecting from the 3 wire connector, jumpering the two outer wires and monitoring the voltage on the center pin to ground. With just the key on (engine not running I got 4.9 volts which it indicates as correct) I could not start the engine and thus couldnt check to see if its varying correctly.
TPI: This test was just measuring the resistance between pins 1 and 2 and between 2 and three with it unplugged from the harness. THen move the throttle through its range to WOT
Pins 1 to 2 at idle 2.79k
Pins 1 to 2 at WOT 5.65K
Smooth change in resistance, no drops through range.
Pins 2 to 3 at idle 3.82K
Pins 2 to 3 at WOT 3.82K
Same through the range.
THe test says both should vary smoothly. Im thinking this could be my problem.
I also tested the voltage change with the key on.
Pin one appears to be the sense lead, at idle it was 3.38 volts and at WOT was .21 volts. THis is opposite of what the test described should happen, says it should be near 0v at idle and increase going to WOT. The second pin had 4.37v always and the third pin was at .01v always.
So is the TPI the problem or is it different cause its a french car? Im french so I can make fun of it, but really any thoughts on this??
Thanks, Phil
PS Im going to also post this as a new thread so please ignore the other thread if you see it.
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Reply to Benchtest - thanks for the help, I appreciate it. OK Dont know about good vacuum to the MAP, no vacuum guage, I will try just sucking on it to see if it leaks if thats valid. Whe the engine was running I do not recall hearing a ticking sound.
What is the Noid light? THis is a very basic test indication setup, there are two electrical connectors and I have test points for the following:
Tach
Ignition
ground
battery
fuel pump
trouble code
neutral switch
AC on
WOT switch
sensor ground
air temp sensor
egr solenoid
Canister purge sol
ISC moter forward
coolant temp sensor
Closed throttle switch
ISC moter reverse
Auto trans potentiometer.
The problem is the book doesnt describe how to test these items.....
Thanks Phil
A:
No need to suck on the line. Just pull the vacuum hose off the MAP sensor and see if there is a good vacuum there when it is running. If not, trace the hose and find the problem. A noid light is a light that plugs-in in place of the injector. It flashes when the computer pulses the injector. Why couldn't you start the engine when you were testing the MAP?
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Im not sure why it wont start now. Been frigging with it too much. I may have to pull the plugs and clean them again, they get excessivly carbon fouled. Ill try pulling the vacuum line tomorrow after getting it running,
As for the noid light, anything special about it? Certain voltage/current requirement? Can I make my own with a _______ bulb?
Thanks
~ Phil