Jump to content
SAU Community

Rb25det Weird spluttering / dying while driving.

Saul007

By Saul007,
in Engines & Forced Induction

 Share

Recommended Posts

Saul007 Newbie

Saul007

Posted
Posted (edited)

Hey guys, have a weird one here. The car is a r32 with a 25det s2. Basic bolt on mods that has been tuned by previous owner. Power figures unknown. Currently running on 10psi. 

First issue is the car is losing voltage on startup. Turn the key to crank her over and it drops from 12.8v to about 6 or 7v. Only started doing this after I changed the coilpacks and plugs around to new ones but I can't see why they would do this ?

Second issue is the car will randomly hesitate and splutter almost like it's fuel / boost cutting. Hard to explain. On acceleration it'll splutter, die out and come back to life. It's like the car just loses all power and dies down until it jerks itself back to life. Or when I try to accelerate slowly at low cruising speeds it will do it then too. Fuel pump is a walbrough that's a few years old and new recent fuel filter. Haven't check injectors just yet. It also has a new O2 and ecu coolant temp sensor. A few people have told me that AFM going faulty has similar issues. Intermittent hesitation and spluttering then eventually dying out and working again after letting it sit for a while. I've cleaned it but no difference. Again it doesn't always have this issue, it pulls and drives like it should most times then other times itll have this issue. Any info would be really appreciated on what I could try myself before I take it in to a shop and get charged the heaven and the earth. Cheers 

Edited by Saul007
Chopstick Tuner Enthusiast

Chopstick Tuner

Posted
Posted

If you're concerned about battery voltage, put it on a load tester. If it drops below 9v put it in the bin. Could even have a loose battery terminal (forgive me for starting so basic, I don't know how mechanically minded you are) and therefore losing electrical power and spark etc. 

Start with that before diving in deep, charging problems and lack of voltage will affect spark, how much power the fuel pump gets and so on. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • sinn3r
      R34 Skyline climate control unit transistor

      By sinn3r · Posted

      I know why it happened and I’m embarrassed to say but I was testing the polarity of one of the led bulb to see which side was positive with a 12v battery and that’s when it decided to fry hoping I didn’t damage anything else
    • MBS206
      R34 Skyline climate control unit transistor

      By MBS206 · Posted

      I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • GTSBoy
      R34 GTR Seats / No longer reclining

      By GTSBoy · Posted

      Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • GTSBoy
      Questions on potential new purchase

      By GTSBoy · Posted

      Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • GTSBoy
      Ethanol Content Sensor - Always at 11%?

      By GTSBoy · Posted

      Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
×
×
  • Create New...