Thanks!

The battery did not fix the issue Still a voltage drop at idle. We did notice the alternator is getting too hot so our feeling is there is something making a big draw on the alt. Amps are fine so I am not sure how this can happen but it is. We did also note the AC fan relays felt hotter than the other relays (oil fan, rad fan) so we are starting there to look for the draw. This is wiring done by the guy in California that totally screwed me so it wouldn't be a big surprise it is wrong. Has to be something causing a too large voltage draw.

On the water temp front, noticed yesterday the rad fans did not kick on until 95 degrees. I had thought the fans were set to come on at 90 so the shop is checking this out today. If this is the case, it explains why the temps go up to 95 pretty consistently.

Fun, fun!

 

David

Since you have spendt so much money on the car already, would it not maybe just be a good idea to swap out the engine bay harness. With either a new one or a very good second hand one?

If you are suspecting a dodgy wire harness done by wolf i would def get it changed out.

Im my new car, we will make a brand new harnes, as i don't need alot in a race car. As i don't want to strip down the stock harnes, as it's crap. The wires are quite fragile.

JT

 

The engine harness was brand new before the hack job so maybe another is needed. Doesn't seem like wiring though from yesterday's visit to the shop. They traced the wiring and found no shorts or crazy amp draws so I am more than perplexed on this. Ihor from IRP is helping out on the alternator side so we shall see.

 

ok hmm, did you messure the voltage on the volt sensing cable? And have you spoken to a alternator shop about getting a diode or what it is on that cable. That will make the alternator charge more. At what revs does the voltage increase on the alternator? As i have understood the volts are low at idle, but goes up once the revs go up?

JT

 

We're taking one step back to ensure we know what amps are at idle and then we'll go from there. When we checked the voltage sensing cable, we just looked for wether is was "powered" and it was as we read 12 volts. The way we checked this was with the car off. We assumed the cable was hooked to the battery and should be "charged" even with the car off and it was.

Can we check the cable with the car on and if so, what should it read?

Regarding the diode, one shop I spoke with didn't know anything about this at all so I need to check with other shops. Not too many good alt shops here in Jacksonville though.

Regarding revs, the alt puts out fine at 1,500 RPMs (volts are above 13) and above, it is just sitting at lights that drains the battery and I really need to fix this. The alt pulley I am using is very small and I can't go any smaller here. I do have a set of 20B main pulleys that are slightly larger than the stock 13B ones on the car so we might put these on. The group I bought the new 150 amp alternator is checking to ensure what the upper limit is on the alt rpms before we do this to make sure we don't spin it too fast. Right now, with my pulleys we are at a 2:1 ratio so the alt needs to spin at 16,000 RPMs at 8,000 engine RPMs.

 

The volt sensing cable should read the same as the volt out from the alternator. They should be equal. I just spoke with the ppl that i bought the diode from. It's a diode that lowers the voltage on the cable. So that the alternator thinks it's putting out lower volts then it is. I think you can get it at radio shack. Just tell them you need a diode that will lower the volt from one end to the other. They come in the range from 0.4-0.9 volts or something. And is about 30-50 cent a piece.

You could try that out and see if that works. But make sure you do not have above 14.5 volts at higher revs.

But it could be as simple as your alt not giving out enough amps at idle when you got alot of stuff on.

JT

 

Well, after much much testing and checking, it appears my current 150 amp alternator just won't put out enough alts at idle and this is what is causing the problem. Can't figure out why this is but it is. I have just ordered a custom 200 amp alternator (direct bolt on) which will produce 130 amps at idle which is certainly more than I will need The unit is being hand wired and built to produce this level of amps and is also being configured to spin up to 20,000 alt RPMs, which will give me about 9,500 engine RPMs. If this doesn't fix the problem, then it's time to shoot the car!

So, in another few weeks, I'll know if I have the problem solved.

 

hmmmm david, what to say

there is always something that needs to be done. but i don't understand why you where told it would deliver enough amps at idle, when it is not doing so. hmmmmm

not good

i do belive the new alternator will be perfect for you. im going to go with a custom 200 amp race alternator my self in my new car. as the 4 rotor will be reved to 9500 rpm

i reved it to 8500 rpms this weekend. and man it pulls hard from 7500 to 8500 rpm can't wait to feel the extra 1000 rpm

keep us updated on the progress about the volt issue, as it's quite interesting.

 

never thought I would need as many amps as what I do at idle so I thought the current alt would work. it's a great alt and I will sell it once the new unit arrives.

 

Did you shoot the car yet? If so, can I come collect the remains? LOL

 

No but I did wash it, install some new LED bulbs in the turn signals and center stop light, and install a LIM heat shield

I'm pretty much in a holding period with the voltage issue until the new alt shows up which will probably be in two weeks. Then we'll know much more. If this doesn't work I am going to have to find someone to again go through the entire electrical system - hope it doesn't come to that.

On the water temp issue, the mechanic measured via his infrared thermal gun the water temps of the car. He let the car warm up and the fans cycle thru multiple times and he never saw temps increase above 198 F (92C), even though the PLX gauge had temps at above 96C. So, the good news is it doesn't seem I have a temp issue after all. But why the difference? After thinking about it, he has concluded the sensor location is giving a false reading. It's right next to the turbo (about two inches away at the radiator fill neck).

So, I am going to relocate the sensor and it seems the best location would be towards the front of the car in the upper radiator hose. The hose has two bends at this point connected with a metal coupler. I am looking for a coupler that would come with a sensor bung installed. Anyone know where I can get one?

Other than that, I hope in a few weeks to be back on the road and to go to Kilo for the final tune and dyno session. The car is currently idling in the high 10s in AFR which is making the idle pretty crappy. Unless I am mistaken, I can only change this thru Microtech if I buy a Microtech "dongle" that allows the PC to talk to the EMS and these run up to $100 so I'll probably just wait until I take the car to Jesus.

 

I know times are rough and the economy is still a little shaky, but $100 doesn't seem too terribly expensive...

 

David,

Are you looking for something like this?


http://www.steigerperformance.com/dif.cgi?sp40002

I haven't read all regarding to your electrical issue so I have nothing to say... except good luck!

 

Yes ,that's it. Thanks!

 

$100 is not too bad but it pisses me off when companies do this. You pay $1,500 for the EMS and they offer the PC software for free but then you need to buy something else to make it work?

I know all too well about "dongles". I used to use them in the early 90's with the software I sold to hospital to ensure only the right users had access to the product. Didn't know anyone was doing this in today's world.

 

Make sure you're temp sensor it a two-wire. If a single-wire, it will need a separate ground from the metal adapter.

BTW: I know a local Master ASE who can track down just about any electrical issue.

:-) neil

 

It's a two wire sensor. Just measured it and ordered the adaptor. $29 with shipping so not too shabby.

I may need your mechanic if the alt doesn't pan out. I'd say come see the car but it's kind of back to the way when you saw it last Prior to regrounding the car, it was spot on and a lot of fun. Now that I have more amps available the tune is way off especially at idle.

 

NO--Don't do that! This puts the sensor post thermostat, assuming you are running a thermostat--which makes it close to useless. The best place is where coolant circulates from within the block and around the sensor constantly.

4deg C is not a lot of differential between different devices, so I would not worry about it at all. One must consider calibrations; it is not unusual to have a few percent discrepancy between the different types of devices you're using. For a lot of reasons, non-contact thermometers are not going to be exact (despite some claims). The important thing here is that the measurements are close, not the exact measurement.

 

So where do you recommend I relocate it to? I know the temp sensor won't work until the thermostat opens with the new setup but this will happen at 180 F.

My current location is about one inch from the turbo and I'd like to find a better location. You are correct it would be better with full coolant circulation but where?

 

Behind the thermostat near the stock location is best in my experiences. Putting the sensor in front of the thermostat like some do will make the gauge useless until the t stat opens.

 

David, stop wasting money and time on crap.. do what i did is proven to work, my temps are 82-84-86 on 100* weather with 0 problems and is also a lot cheaper.

you should of went with the microtech DASH insted of all those confusing plx gauges.. if you find a hand controller or a dah i can tell you how do it or just bring the car to jesus

 

and by moving the water temp sensor is not going to fix anything.. you are still going to get high temps. just letting you know because i tried that too.

 

but in my case the sensor is now one inch from the turbo and the thought is this location is causing a false reading.

Is there another location I can move the sensor to that will keep it before the t-stat but away from the turbo?

 

Carlo, the theory here is my temps are fine but due to where the sensor is located (one inch from the turbo) I am getting false readings. This would be true whether I use the controller or dash or even if I go with your mod.

The mechanic that noticed this was using a laser thermal temp gun and he found the temps under the hood never went above 195 or so which would put the car at 92 C which is where the fans come on.

Because of where the PLX sensor is located, the readings on the gauge were much higher and this is what I am trying to fix.

Could all turn out to be nothing and maybe I have a temp problem, but I would like to solve the sensor location first and go from there.

 

Could very well be right but I have nothing better to do while I wait for the new alt anyway