have a problem with my auto 3ltr. when accelerating, gets to around 3grand and then stops accelerating egts, boost stays the same, no Eng lights. lift my foot and reapply and all is fine till next time. could be maf or tps by my guess but wanted to make sure what it is as haven't got the dosh to wast, so took to local diesel mechanic to diagnose but when he hooked up his computer it could not read the CPU. anybody got a clue whats going on and why he cant talk to the comp, he said i would have to take it to Nissan to find out why
sensors make no sense
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not maf, changed it and still the same, well not quite the same. now ive got more problems after reconecting battery after having it off for 24hrs, now dash lights are on, sub tank, at temp, seatbelt, handbreaK and alt lights are all light
Hi ashbee, it sounds like a crappy fault to find. I would start with cleaning all the main elec connections with contact cleaner. Have a good look at them incase of corrosion, then use some dialectric grease on the contacts and put them back together. Check your earth straps, undo and clean them. Your main harness to the ecu is in drivers footwell LHS check that and clean. and check the batteries are in good nick. Check any wires that you can for rubbing. Do you know how to check codes? If not have a look at ref doc. That's all i got, good luck.
Cheers Beaver
Do the batteries first.
Cheers Beaver
Do the batteries first.
thanks Beaver, the first thing i did was check codes and got 0505, all good. what a load of BS then as i said took it to mechanic and his computer wouldn't even talk to mine. checked all fuses and there OK. the lights on dash may be alternator so removing it tomorrow and taking to auto leck to get it checked. but why would it only show problems after changing maf and disconnecting battery, too scared to drive it anywhere in-case problem causes it to blow up or something and certainly can't afford to just keep replacing everything, been a good truck till now dammit
A couple of thoughts....
My guess would be overboost protection.
Either a faulty MAP sensor (mounted on the I/C) or VGT not working correctly.
Throttle body gunged up restricting airflow - result to much pressure in I/C
Try disconnecting the MAP sensor and see what happens when you drive.
My guess would be overboost protection.
Either a faulty MAP sensor (mounted on the I/C) or VGT not working correctly.
Throttle body gunged up restricting airflow - result to much pressure in I/C
Try disconnecting the MAP sensor and see what happens when you drive.
hey Rayf , thanks for the suggestions, I'll try that as soon as i get it back together. the alternator was dead so i had to get a new one and when taking well trying to take drive belt of the tensioner was at a 45deg angle so, new one of them and while reading manual i saw that its recommended you change timing chain every 100thou so seeing its just clocked over 200thou and don't know when it was changed last well, I'm doing that as well. the throttle body doesn't seem to be gunged up(if that's the one over the top of the tappet cover your talking about) but it does feel like an over boost but did all the mods and was running fine. but i will check the sensors your talking about. i know the map but whats the "vgt"
hey again, worked out what the vgt is, turbo. as with the over boost , when it plays up the boost doesn't go up or down and egts stay the same. I'm thinking throttle sensor maybe
sorry typo, I meant VNT.
The turbo control, pulse width modulated vacuum control etc...
Any of this control stuff could be "sticky" resulting in a possible overboost condition.
A preliminary check would be to ensure the control rod to the turbo is able to move when you rev the engine.
I doubt it will be the (TPS) throttle sensor. But do check the throttle switch this tells the ECU when you do NOT have your foot on the gas. (when on over run)
Equally the is a signal from the brake pedal to the ECU, I have known these give problems too. (not much point in adding fuel if you are braking!)
Replace your throttle pedal assy mate
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