Datascan results from my VG30DE.. Comments please!

Ok, so i finally got a chance to run my laptop in my car connected to a DataScan unit that have made.

Here are my observations, and questions...

First observation. Exhaust temp reading sat on 5V the whole time, no movement at all. I guess this means its buggered or not plugged in (bypassed). Does anyone know what the effects of this would be? I'm getting piss-poor fuel economy (330km/51L around town driving like a grandma)...

Second observation. Engine timing was at 20 deg but this went down to 9 degrees or so when i revved it. Is that normal? I thought the NA should only be run on 10 deg?? Could that contribute to the fuel economy issue?

Third, and most important observation. I wanted to see the effects of revving the engine on the engine temp because i have an overheating problem. Engine temp started at 83. After thrashing it up and down my street, the temp started rising, about 1 degree every minute or 2. Right up to 104 degrees, at which point i pulled over, idled for a bit and then cut the engine. Outside temp was cool (night time) so there is definitely a problem there

Does anyone know what the normal operating temp of the NA VG30 is? I've seen a few people quote 80-105, but what is the recommended maximum?


Naturally i will be taking it to a radiator specialist to have a look, but should my cooling system have been trying to cool it down by that stage?

Coolant was perfect, right up to the top still when i went to check this morning. No oil in coolant, no water in oil, good pressure in the top hose when it was hot. I think my radiator needs help (its a new water pump/thermostat/secondhand clutchfan)

Any comments guys? And yes i realise this is not for a Z, but you guys seem to be very knowlegable about engine stuff, and it is a VG30DE

 

ok....

firstly, if you select a sensor in datascan that the zed does not have it will just sit there and not move. Hence why I think you get no movement when you select that sensor. The zed does not have an exhaust temp sensor. Not sure if your car does. What is your car?

As for the timing, not sure about that one. The stock timing should be 15 degree's but that can only be set at the crank as the ECU has no idea what the CAS setting is. The timing you see in datascan is from the timing settings programmed into the ECU which assume the timing at the CAS is set at 15 degree's. That sounds confusing, easier to explain in person..

Normal operating temp for the VG30 NA on a nice day is about 80-85 degree's. At least in a zed. Yes you have an overheating problem as 104 degree's is excessive and will damage your engine in no time. Get it checked asap.

 

you mean the LEMON is COOL !!!

My Na showed a temp of 74 the whole damn time, except when forced to idle on a warm day for about 2 min at lights, then it went all the way to 76.

Perhaps I will not have to put in the dual-pass radiator after all.

I post this just to give info on my NA's temp - I'm NOT a post junkie.:LOL::LOL::LOL::LOL::LOL:

 

You may well have a partially blocked radiator

Definitely agree with JEDI - get it checked out! Best to have radiator rodded if it is in any way blocked.

Also you may like to consider a Temperature Warning Device (TWD) or something similar. TWD is a device sold by one of the members of this site (try search) that connects into the ECU wiring and sets a LED flashing (which you mount in the dash) when coolant temp reaches 95 degrees.

Cheers,

Peter

 

Re: You may well have a partially blocked radiator

Yes, i am very much considering the TWD as i think it will be quite useful

The radiator was supposed to be cleaned when they put new end tanks on it (had a cracked end tank), but i dont know how far they went to clean it...

Jedi-77 I have a Y32 Nissan Cedric. If the Z doesnt have an Exhaust Temp Sensor, then i'm gonna assume mine doesnt either. I was using TECU, and that allowed me to 'scan ECU for available functions'. The Exhaust gas temp came up as available so i selected it... But if it dont need it then i am fine!

Ok, so the timing thing was a red herring. I think i understand what you mean. I will check with the mechanic as to what he set it at...

Thanks for your help guys, I hope the radiator is the culprit here. This overheating thing is giving me a headache!

 

Re: You may well have a partially blocked radiator

Ok, some more results; drove to the city with it while my gf held the laptop. It was 85 by the time i got to the freeway, but driving on the freeway at 80-100km/h the engine actually cooled all the way to 80.

Then when i had to go up a hill to the exit it shot up to 90 within a minute. A few km on the Princes Hwy (hit a few traffic lights during that time), and it had hit 95, at which point i pulled over and opened the bonnet.

I'm thinking the TT clutchfan i put in there is also playing a part in this. I will be putting a thermo fan in there as well tomorrow, and i'll get the radiator rodded/replaced after i test that...

 

Re: You may well have a partially blocked radiator

My NA sits under 80deg's most of the time. Check the cooling system checked out ASAP. Its no way to fry a perfectly good engine.

 

FYI

Not sure about Auspec Z's but the JDM TT Z's we import into NZ have EGT sensors. They are fitted just before the catalytic converters.

 

Re: FYI

Is that different to the O2 sensor? Or is the O2 sensor after the Cat?

 

yes different.

o2 sensor measure whether exhaust gas is rich (less than 14.7:1 air:fuel ratio) or lean (greater than 14.7:1 air:fuel ratio). it is located just after (or just before??) turbo.

EGT is an exhaust gas temperature sensor. it does as its name says, and is located as lurker said, just before the cats.

 

When I got my car in February, I had to deal with an overheating problem, my temp gauge would rise to 3/4 and I had lots of engine gurgling after shutdown. When I had my car checked, it had a blocked radiator and my electric fan was non-functional. I got my radiator flushed and replaced my fan. No more overheating. I also installed KZED's TWD, a very worth while investment.

 

Re: you mean the LEMON is COOL !!!

Considering that both those temps are under the OEM thermostat temperature, you either have a jamed open thermostat, no thermostat or one that opens too cool.

Mine will run on 81 degrees on the hottest day, and about 79-80 on the coolest evening (well if you call Brisbane evenings cool , say around 10 degrees ambient ). I think I was able to push the temp up to the mid 80s on the last mountain cruiZe on a 33 degree day, air con on, two turbos boosting like crazy etc etc.

I believe the engine won't run at it's most efficient until the coolant is around 80 degrees.

 

Re: you mean the LEMON is COOL !!!

Ok, so i take it anything above 85 is considered overheating?

I think i'll be getting the radiator core replaced (it was supposedly flushed/cleaned, but its still the original radiator and i'm not convinced its up to the task anymore).

And on Boxing day (when supercheap has 20% off), i'll buy me a thermo fan to put between the clutchfan and the radiator cos there's a big gap there

Unless someone has a decent thermo lying around??

 

ZEd engine can operate happily right up to 95-100ish for

short periods in peak hour traffic with ac on etc. As long as the temps drop once you are moving, it's fine...

 

no....

some of the other figures below 80 that some of the guys have mentioned seem a bit low to me. I have been told by a few zed experts that the normal operating temp is about 82 degree's. So I would consider anything between 80-85 to be normal. On hot days however, and with the A/C on the temp can rise into the 90's and still be fine.

Cheers

 

More Results... Survived a 8hr drive to Coffs Harbour (with some stops )

Ok... despite common sense telling me to leave it at home i decided to take it up to see my parents in Coffs Harbour. Left at 3:30am to make sure it was nice and cool outside and hit the highway.

Very quickly found out that it is very unhappy going up hills. Temperature climbs very quickly on even slight inclines. But On flat or downhill sections it COOLS DOWN! So with my gf keeping an eagle-eye on the temp reading on my laptop i continued driving to coffs

Whenever it got above 95 i'd pull over for a rest and let the car cool down for 30 minutes or so. After some experimentation, it turns out that by 'pulsing' the throttle, i was able to make it up even steep hills with minimal if any temp rises (the ensuing downhill would bring the temp back down).

Admittedly i couldnt keep the speed limit (i was the one holding up lines of traffic :unsure::sick::unsure::sick, and the 5-6hr drive took more than 8hrs (with 4 'cooldown stops').


This got me thinking. Why would pulsing the throttle be better than keeping a constant throttle pressure?

An idea that i came up with:
* Could the engine be running very lean (and hence hotter than the cooling system can keep up with)? By pulsing the throttle it would be constantly forcing a richer mixture into it?? Could a faulty Exhaust Temp sensor be causing this (Datascan shows a constant 5v reading for EGT, even though it is clearly present in the Cat)?

Any way to diagnose a lean system? Other than connecting an AFR meter?

Any more advice or other ideas is greatly appreciated. I think i might be close to solving this one...

 

Hey!

I havn't read the posts before yours but.....

Temperature rising on a hill and going back down when the load to the engine is reduced is a 'CLASSIC' symptom of a blocked radiator.

I would go as far as to say bet you $100!

99% radiator
0.5% Thermestat
0.5% Water pump

I have just done a full rrebuild and have extra temp guages etc installed and have learnt a lot.

PM me if you want to know any of my other experiences.

 

Re: Hey!

Great! Thanks for that info... I'm gonna spend some time tomorrow looking at it. Just checked the exhaust and there is a nice layer of soot on it, so your suggestion is sounding quite feasible right now.

The only thing that i'm not so sure of is the fact my mechanic said he did a flush and a chemical clean of the radiator. Surely he would have noticed if it was blocked??

 

Hi Dominik - I still suggest rodding the radiator which consists of

taking the top and bottom off the radiator then pushing rods through the radiator to push out any blockages and gunk. A flush often won't clear these blockages.

Cheers,

Peter

 

Seconded... rod the radiator and get the block reverse powerflushed