Tuner confused Help JZ troubles again :s

[trd-drifting]

Alright i have a stock 1JZ in my supra with a g3 link ecu last dyno tune it made 255rwkw at 0.9bar or 13.2psi i have upgraded fuel system and put in a bosch 044 walbro in tank and a surge tank and a Fuel pressure reg. The car ran on the dyno today and old fuel map got remapped and made 247rwkw but at 16psi. The tunners put this down to the motor getting tired etc.. which doesnt worry me. The motor never missed a beat on the dyno now as i was driving home i ran into problems at 1pm and it was rather hot today.



The motor oil temp was 75 degress and water 100 degress not overly hot and as i put my foot down it would shit it self at 5grand. Huge miss fire (double barrel shout gun loud) and sounded like a limiter i backed off the tried again then just kept sounding like a limiter and then wouldnt let me rev past 4 then down to 3grand etc.. so i drove it back nicley the tunner brent got in the car with me and we went for a drive car was fine for about 10minutes of a thrashing then it happend. All Brent notcied was as the car started to get into boost the voltage would drop from about 13.6volts down to 12 down to 10.9volts at the lowest. The link has a cut off at 10volts or somthing also the inlet temp was about 55 to 60 degress. Nothing else all the tiggers etc.. could be faulted pulled out plugs all looked perfect he said. After it cooled down i thrashed it just to try get it to do it again a good 25min drive and it didnt but the air temp around me was alot colder as was 5:30ish. Car running same operating temps but ran mint all the way home could't fault it. Also has a brand new battery, but when the alternator is charging max gets up to 13.7volts not around 14.4-14.7vots as it should be.





Any ideas appreciated.



Josh

[IH8TEC]

check what your rpm limit is when the water is that hot. i'm suprised it's getting that hot, seems high.

you running an oil cooler to have your oil temps that low? i've got my oil cooler off at the moment and my temps are getting up to 100-120 instead of about 70-85.

[trd-drifting]

Oil temp never goes above 90 unless im am being a dick doing o's for 3 or 4 minutes, runs a standard water to oil cooler under the oil filter. Rpm limit is set at 6500 i think and it is not passing that, and they said all the limits or somthing i didnt quite understand were turned off just weird how it ran mint on the dyna pac and never played up at all but mint on the road. Oil temp sender is in sump pan and normal driving on open road sits 60 degrees and 70 to 75 stuck in traffic

[johndoe1025]

alaternator wont neccesarily sit at 14.4 all the time, depends on how many amps being drawn etc eg high amps low volts, low amps high volts. sounds like either air temp sensor, coil or airflow meter to me. i think?

[the fallen303]

check alt regulator, mine $&#$% out and did missing under boost, really undrivable. ended up fixing it by putting in a 4age bluetop regulator, that way, plugs were the same, so no changing that.

[AceSniper]

my thinking out be the coils are getting to hot and are on the way out, battery holds charge?

[matt dunn]

All Brent notcied was as the car started to get into boost the voltage would drop from about 13.6volts down to 12 down to 10.9volts at the lowest.
Josh

At 10.9 volts the coils wont create enough spark to fire the mixture,
and so seems like a limiter.

So my bet would be a voltage problem.

[johndoe1025]

All Brent notcied was as the car started to get into boost the voltage would drop from about 13.6volts down to 12 down to 10.9volts at the lowest.
Josh

At 10.9 volts the coils wont create enough spark to fire the mixture,
and so seems like a limiter.

So my bet would be a voltage problem.

hmm yeah so its fuel cutting due to that or intake temp etc (or faulty sensors)

[matt dunn]

hmm yeah so its fuel cutting due to that or intake temp etc (or faulty sensors)

no, and no.

re-read what I wrote.

it will still be injecting fuel, and all the sensors will read fine.

[johndoe1025]

oh, whoops, cutting spark not fuel im quite keen to find the problem for this, my mates car got same symptoms

[Lloyd]

Are you saying battery voltage is dropping to 10V at the ECU or somewhere else?

[BlakeNZ]

faulty voltage to your fuel pump perhaps? check all your earths. check all new/recent wiring.

[trd-drifting]

Cheers for everyones responces great to get some feedback and a different angle every time i no it it hard without seeing the problem.

My question is if it was a sensor out it would should of played up as it was getting remaped for the fuel and on the dyno for 3 hours. All the triggers seem to be working, first they thought it would be a crank angle sensor but eliminated that apprently

It shouldnt have a fuel cut on the link ? and as matt says all the sensors should be reading right so did the guys where the car was taken.


Brand new Battery and holds it charge very well not a cheapie either.

Matt could this be the case as i was talking to a friend but the ecu is earthed through the engine if there is a bad earth or not enough earth strapping from the engine to the chassis this could cause the voltage difference as the voltmeter in the car and turbo timer still read 13ish while under boost when the link is only reading 10-11volts ??

Cheers for the txt to John might get the alternator tested tomorrow as i dont have work just for peace of mind.[/quote]

[matt dunn]

It will be the alternator, we strike the same thing on the 2JZGTE enduro car, a few laps after the alt light comes on the car will miss.


To re-create the fault, unplug the 3 pin plug from the alt, drive down the road for a while and see if you get the same fault.
When you do plug the alt back in and see if the fault goes away.

[trd-drifting]

Sorry the battery voltage when the laptop is pluged in at idel reads 13.7volts on the laptop but when it hits boost depends how much you open the throttle can jump down to 10volts and does.

But the car will rev quite freely with no load ( ie clutch in or out of gear)

and the screwed up thing is that it drove home without a glitch but played up all afternoon didnt change anything and then drove ok on the drive home that afternoon and ran mint on the dyno in the morning.

Fuel pump voltage is good at both pumps as they checked that but also seems fine on the map of the computer while driving round underboost etc.. so that eliminates fuel.

Cheers heaps for all the ideas

[trd-drifting]

It will be the alternator, we strike the same thing on the 2JZGTE enduro car, a few laps after the alt light comes on the car will miss.


To re-create the fault, unplug the 3 pin plug from the alt, drive down the road for a while and see if you get the same fault.
When you do plug the alt back in and see if the fault goes away.

I will do that first thing in the morning... and see. When you say will be alternator it will just not be working properly you mean still charging but not good enough, as when the alternator shat it self a year ago i replaced with a second hand one (yes i know i should of rebuilt the second hand one) but when it wasnt charging the charge light always came one, the charge light still works but doesnt come on.

Thanks heaps for the responce will check it out 2moz and let you know what happens

[MAGN1T]

13.8 volts is about normal but it should never drop while driving. Is the belt still tight? Otherwise it's as others said, the alternator.

As far as your tune goes, the only thing that's changed is fuel supply. It should have been possible to adjust the reg without changing the programme in the computer and get the same HP as before at the same boost. Maybe a bit of timing has been removed so it's running slightly hotter now on boost.

Steve

[matt dunn]

13.8 volts is about normal but it should never drop while driving. Is the belt still tight?
Steve

Good point to check the belt too.

[trd-drifting]

As far as your tune goes, the only thing that's changed is fuel supply. It should have been possible to adjust the reg without changing the programme in the computer and get the same HP as before at the same boost. Maybe a bit of timing has been removed so it's running slightly hotter now on boost.

Steve

The belt is tight and has never made any nosies one big drive belt with a automatic tensioner and does not appear to slip I will get alternator checked tomorrow

Yes that what i thought exactly so i installed a Fuel pressure reg and the walbro removed staandard fpr and reset the pressure like i was told to by the tunners. The car wouldnt even boost and bearly drive. I didnt think it would need the fuel side remapped but i rang a few different tunners and they said the same sometimes it does need to be remapped but not all the time. It is weird as my mates 180sx and s13 and s14 all have intank walbros and a fpr and there cars still run fine but mine didnt. I put another pump in the 044 just cause i made a surge tank and got remaped and it ran mint on the dyno but i could bearly drive the thing before the retune and i was considering putting it on a trailer that how bad it was just from changing the pump.

[RedMist]

Yes that what i thought exactly so i installed a Fuel pressure reg and the walbro removed staandard fpr and reset the pressure like i was told to by the tunners.

Although I doubt this is the cause of the original fault I would never alter the FPR setup without remapping.... EVER.
Post up your map, or at least a link to your MAP. I suspect that you're going over temp and its reducing the RPM limit to match. I'd temporarily remove the temp based limiters.
Remember that your ECU will have a temp sender in a different location to your gauge and can read considerably different.
By the way, your ECU temp sender isn't anywhere near the turbo water vent is it?