Hi,

 

I have a Jap NA, auto with decat exhaust system.

 

I have been having a problem with smooth power delivery at or below 2500 revs. Seems to idle fine after about 1 min. Does not accelerate well, can be lags in acceleration for 1 or more secs when pulling away. Sometimes the car is ok (get nice smooth acceleration) but 90% of the time now it has the problem.. sometimes notice the RPM counter fluctuating slightly as if fighting to keep the engine going slightly...

 

I have done a ecu diagnostics and it came up with Detonation sensor circuit problem.

 

So bearing in mind I am not a great mechanic ;) what could be causing it & what DIY should i be looking at.

 

I also cleaned the PTU & TPS connectors before doing the ECU check, whilst i had the hood up.. Checked for loose connectors etc.

 

Cheers

 

Barry

its probably the det sensor or harness causing the code 34. you can do a bypass as a test by installing a 1Mohm resistor in the circuit. do a search.

 

TBH, on a NA its only gonna retard the timing by a few degrees, im not sure how much difference it would really make to the running even if this was faulty - worth a try 1st tho i suppose.

 

when it messes around, it it just lacking power or misfiring?

Hi,

 

I dont think it is miss firing (I cant detect any different engine noise) there just seems a lack of power for about 1 sec and then it cuts in - but not great. Also get non smooth acceleration as if it is struggling to accelerate alot of the time...

 

I have just found out where the det sensor is, I think I found this with a broken wire when i first bought the car about 2 years ago. Its a pig to get to at the back of the engine block & there was a bit of whire sticking out of the top on the sensor thing, so I got a terminal block and a bit of wire & joined the two wires together.

 

Though at the time the car was running fine before & after the repair job!

Recently I got the decat exhaust and it has been alot worse..

 

Can the NA work ok then without the det sensor working - as it seemed to when i first got it? Is it the det sensor that would cause my problem??

 

Cheers

 

Barry

Check for air leaks, check throttle balance and clean the throttle bodies, the last been a very common cause of hesitance when pulling away.

 

Det sensor failure WILL lead to lethargic performance from a non turbo, if you decide to replace the sensor relocate it to a more friendly installation site, accuracy of the det sensor will not be as good as how Nissan intended however quite acceptable provided a good check of the timing is made and good quality fuel is always used.

 

Jeff TT

I have read that you can put a resistor in to bypass the det sensor - a few people seemed to have tried it & it has worked ok (as the det sensor repair is expensive..). Is it ok to do on the NA??

 

I am sure the det sensor wire out the top of it was broken & the car running ok when i first got it...

 

Cheers

 

Barry

bypassing mine tpmmorow on my tt after ive had it on the afm the bypass works on tha na aswell but make sure it is faulty and not actually sensing det