R33 Gtr Starting Problem... Starts When It Wants.

[bilaldabab]

Hi Guys

I've tried reading multiple related threads but i can't seem to find any that entirely relate to my issue.

My GTR randomly starts whenever it wants. It cranks fine but just struggles to start. I find it struggles more when warmer, but occasionally doesn't start when cold also.

I've replaced coilpacks, spark plugs, ignitor.

I've re-grounded all the earthing points.

I've changed the battery

I've played around with the cranking ignition timing on the Power FC hand controller

It's got a forged motor and running a power fc with supporting mods.

Sometimes when I give it gas while cranking it helps and other times it makes no difference.

the thing which i can't figure out is that whenever i connect a jumper pack to the battery, it always starts up. Any ideas what this could be?

Thanks

[GTSBoy]

I think what you really mean is that it doesn't randomly start when it wants. If it did, it would imply that it would start itself even if/when you weren't present.

If what you really mean is that it is just difficult to get it to start and that it sometimes does and sometimes doesn't, then there would have to be thousands of threads on here all about that. Coolant temp sensor is a prime candiate here. As is AFM dirty and/or cracked solder joints. And dirty injectors, weak fuel pump, and about a bazziliion other things that have been posted about.

[bilaldabab]

I assumed people would understand what I meant when I said randomly starting...

And like I said I've read many threads but none of them seem to entirely relate to my issue. From what I have read, I have tried to fix/replace.

I've also tried cleaning the AFMS, and have also opened them up and resoldered the joints. It's got a fairly new fuel pump which primes fine.

My question is.. why would it start fine when I put a jumper pack on? but without it, it struggles or doesn't turn on?

I'll try checking the coolant temp sensor and cleaning the injectors this weekend.

[Ben C34]

So it is happy when you connect a jumper onto it?

Do you connect the jumper leads onto the terminals or one onto the chassis?

Could it be corrosion in the cable going into the earth terminal on the battery?

And there's no reason why the battery you put in couldn't be rooted.

Edited September 18, 2014 by Ben C34

[bilaldabab]

So it is happy when you connect a jumper onto it?

Do you connect the jumper leads onto the terminals or one onto the chassis?

Could it be corrosion in the cable going into the earth terminal on the battery?

And there's no reason why the battery you put in couldn't be rooted.

Yes it always starts up when i connect a jumper pack to the battery terminals in the boot.

The battery I put in was new so there shouldn't be any reason for it to be rooted.

[Ben C34]

Shouldn't be a reason. But seems like it is.

If it was me I would try a a different battery.

And ensure battery terminals are clean.

Edited September 18, 2014 by Ben C34

[Shoota_77]

The starter could be an issue. It might be 'poling' I think we used to call it where the starter directly connects + and - internally and draws huge current, enough to drop voltage under 12V which takes out some of the systems required to start the engine (injectors, coils, computer etc can cease to operate under 12v's).

Do a voltage current draw test to see how much current draw there is when cranking. If it's super high I would first check the main terminal to the starter. If that's fine I would then presume you have an internal issue in the starter.

Or, it might have not one fu(king thing to do with the starter.....

[R.3.2.G.T.R]

I'm betting it's your CAS, had something similar happen, signal seen by ecu was all over the place, replaced and started first time

[Dose Pipe Sutututu]

Does it always start easier with the water temperature sensor disconnected? (the one to the ECU not the dash)

Could be your cranking tables are too lean OR injectors are clogged and spraying less fuel than before with low pulse widths.

[bilaldabab]

So battery voltage sits around 11-12 when car is off. As soon as I start cranking it drops to 8-9. When I put the jumper pack on and crank it drops to 10-11 and turns on.

[scotty nm35]

Have you tried charging the battery?

Sounds like the battery has dropped a cell, as in the plates are touching or something. If it's new take it back and get it checked, it may be under warranty.

[GTSBoy]

So battery voltage sits around 11-12 when car is off. As soon as I start cranking it drops to 8-9. When I put the jumper pack on and crank it drops to 10-11 and turns on.

Fully charged voltage on a lead acid battery is AT LEAST 12.7v. Should sit quite happily at 12.9v switched off. 11-12v with nothing running indicates a f**ked battery.

[blind_elk]

The starter could be an issue. It might be 'poling' I think we used to call it where the starter directly connects + and - internally and draws huge current, enough to drop voltage under 12V which takes out some of the systems required to start the engine (injectors, coils, computer etc can cease to operate under 12v's).

Do a voltage current draw test to see how much current draw there is when cranking. If it's super high I would first check the main terminal to the starter. If that's fine I would then presume you have an internal issue in the starter.

Or, it might have not one fu(king thing to do with the starter.....

I'm going for this one. Had a similar problem with my 32, and it only got worse, to the point that even a jump start wasn't always enough to start properly.

Replaced the starter motor and don't have starting problems any more.

[Ben C34]

I'm going for this one. Had a similar problem with my 32, and it only got worse, to the point that even a jump start wasn't always enough to start properly.

Replaced the starter motor and don't have starting problems any more.

Even based on his flat battery volt test?

[bilaldabab]

I ended up taking the battery back and they replaced it with one double the size. It still cranks for a while but has turned on every time so far. I guess if I get the same problem again, I'll try a new starter motor.

[GTR_JOEY]

so in other words the old battery was shit and had dropped a cell, like stated before 11-12 volts means its probably dropped a cell..

A good battery will have an output of around 2.2 volts per cell, so 13.6 in total.

You must remember RB's are very sensitive and will play silly f**ks with you if you don't have enough voltage

[Emrarrr]

Is your fuel pump priming? I just changed mine as starts were slow and then finally just cranked but wouldn't turn over. Maybe low voltage to the fuel pump relay?

[Wongy]

I'm 'not sure if this is a similar issue but sometimes when i turn the key it starts right away, and sometimes it struggles and i need to give it abit of gas to get it to start.Thought it was the battery but replaced it and still same issue, is it the starter motor? Any advice?

Thanks