car wont rev????????
- Thread starter nismoboy
- Start date
C
charlie
Guest
sounds like its running in limp home mode to me. Ar ethe rad fans on full time too?
Do a fault code check and find out
Do a fault code check and find out
J
J-GTi-R
Guest
Limp home mode isn't necessarily caused by detting (don't confuse limp home with safe mode). I've had it twice, once caused when a sensor bracket broke, once when the cat temp sensor was cut out of the cat when my exhaust was replaced.
If the fault code check is showing 55, you may have to take the car to Nissan and get them to plug it into the consult machine, as that should show up the fault (btw, don't let them tell you they can't do it to an import, my local Nissan did it to mine the first time).
If the fault code check is showing 55, you may have to take the car to Nissan and get them to plug it into the consult machine, as that should show up the fault (btw, don't let them tell you they can't do it to an import, my local Nissan did it to mine the first time).
The DET sensor being triggered doesn't cause limp home mode. It triggers safe mode - it retards the timing for a while until the det goes away again. This doesn't stop u going over 3000rpm.
The fault code check is fairly basic - it only confirms that the ECU can interrogate each sensor and get a response - it doesn't check that those sensors are performing correctly.
The Nissan consult gives a lot more information about the values being sent from each sensor dynamically. But to be honest most Nisan dealers will run a mile if you ask then to plug your car into their Consult as they may not have the expected values on file and don't want to look stupid.
You need to check the output from each sensor in turn based onthe manual figures. Not easy and bloody time consuming. Check ecu water temp feed, maf values, tps values, lambda values etc. You'll probably find that one of them isn't returning anything or is shorted to earth.
Good Luck - u'll need it.
Cheers
GeeTee 8)
The fault code check is fairly basic - it only confirms that the ECU can interrogate each sensor and get a response - it doesn't check that those sensors are performing correctly.
The Nissan consult gives a lot more information about the values being sent from each sensor dynamically. But to be honest most Nisan dealers will run a mile if you ask then to plug your car into their Consult as they may not have the expected values on file and don't want to look stupid.
You need to check the output from each sensor in turn based onthe manual figures. Not easy and bloody time consuming. Check ecu water temp feed, maf values, tps values, lambda values etc. You'll probably find that one of them isn't returning anything or is shorted to earth.
Good Luck - u'll need it.
Cheers
GeeTee 8)
the commonly referred to "limp-home mode" is actully called the "fail-safe system" in the manual
(people don't call it that as it would confused with "safe mode", which incedentally doesnt actually have a name, just comes under "wastegate valve control")
according to the manual - the "limiting of engine speed to 2400rpm" can only be triggered by 2 things:
1) malfunction of the CPU circuit in the ECU (the check engine light should turn on)
2) air flow meter malfunction (output voltage above or below the specified value)
hth,
shalom
ps. "Activation of the fail-safe system is cancelled each time the ignition is turned OFF"
(people don't call it that as it would confused with "safe mode", which incedentally doesnt actually have a name, just comes under "wastegate valve control")
according to the manual - the "limiting of engine speed to 2400rpm" can only be triggered by 2 things:
1) malfunction of the CPU circuit in the ECU (the check engine light should turn on)
2) air flow meter malfunction (output voltage above or below the specified value)
hth,
shalom
ps. "Activation of the fail-safe system is cancelled each time the ignition is turned OFF"
J
J-GTi-R
Guest
How odd, neither time I got that was there a problem with the ECU or the AFM.
it drives above 3k but if u put your foot right down it holds back! then it cuts the boost from o.65 to 0.5 also the coolant temperature gauge drops from half way on the guage to nearly cold as the accelerator is pressed :?: ive tried cleaning the afm and checking all hoses,got the timing checked again and all are fine. please help :?:
Checked the coolant sensor and it looks ok but one of the wires was faulty and the plug was dirty so ive cleaned it all up and fitted a new plug and this seems to have fixed my coolant temp sensor gauge problem as before it kept dropping from middle of the gauge to cold but only when u put ur foot down.its also stopped detting and now will boost to 0.65 every time.Fast Guy said:
Back to the real problem it still wont rev!!!!!!!!!
ive found out by driving it tonight that it will rev all the way to the limiter boosting as it should when out of gear.As soon as its in gear and driven it wont let me rev and come on boost as it should,it will let u build up revs gradually but as soon as u put ur foot to the floor it holds back wont rev and nearly splutters.The ecu is showing no fault codes what the hell is going on with this thing please help before i torch it :evil:
A
AndrewD
Guest
nismoboy said:
sounds like ignition problems, how bout your fuel pump?
it just wont make positive boost as soon as i go past 0 on the standard boost gauge it just holds back and splutters but off boost its fine and when out of gear it revs all the way upto the limiter and the boost comes on hard but as soon as u drive it in any gear and it just holds back and slputter when the boost comes on :?: please help any ideas? :?:
possibly but i cant seem to find it if it is,ive checked all intercooler pipes,vacum pipes the timing has been checked twice,ive disconect the dump valve and then cleaned the afm and tested it all ok.I took the car out this morning and it now seems to rev a little bit better and it makes boost but its still holding back loads.Two other things are possible lambada sesor buggered and the coolant temp sensor is loose but the ecu show no fault codes and the car runs fine apart from on boost it just hold back :?:Fast Guy said:
A
AndrewD
Guest
dude what sort of afm are you using?
cause if its a hot wire type you could have destroyed it by touching it
cause if its a hot wire type you could have destroyed it by touching it