So ...................... you think the old one got too hot and degraded ?

 

Awesome news!!!

 

I've not seen a resistor fail like that before. Either shorted or open but not increased resistance.

 

its fairly common failure, its called resistance drift. fixed film resistor have a 40% chance of this type of failure, and about 26% chance in all other types of resister, the cause is overheating, I should probably check mine, I moved it to under the fender for the wire tuck so it should be fine there. you might consider moving yours too slash128

 

Good info, thx! I find it an interesting failure and wonder if it played any part in the demise of my motor.

 

Maybe............. maybe not . A detonation event is just a matter of time on the boost you were running .
You know how amazed i was that it didn't happen sooner on your stock block .

 

But it was worth it I have plans for the old motor....

 

All that matters is whether or not you have adequate fuel pressure. With the larger pump my argument is that you want more resistance to slow it down for low load operation.

 

Agreed, and in high speed mode the resistor is bypassed. My only thought was perhaps with the resistor being higher than normal causing low speed mode to be lower flow than normal just as threshold was being reached where it would switch from low to high speed mode it may have starved slightly very briefly before high speed mode was triggered. It was only a thought. Probably far fetched, especially since it is a higher flow pump.

 

True . But where the ecu programs in the step is all wrong for FI as you get a pressure spike when it cuts in due to the larger pump overwhelming the siphon assembly .

 

Bit late now Slash but it seems we were all wrong ................
Video showing light connected to 'fuel' relay on startup. So .... the high speed relay IS engauged at startup.

https://www.youtube.com/watch?v=eV4K...ature=youtu.be

 

Interesting. Would you be up for another test? Disconnect the resistor and see if your pump still turns on at startup. If the FUEL relay is truly triggered then the pump will still run.

The reason why I question is because I can measure just shy of 12v (about 11.6v or so if I remember) on both the FUEL and CIRCUIT relay at startup, however, only the CIRCUIT relay closes. I have swapped relays back a forth and tested both with an external 12v source and they both close the contacts, which I verified with a continuity check. The difference is the CIRCUIT relay voltage jumps just slightly, like .2v or so, at startup but the FUEL relay voltage doesn't fluctuate.

 

ok ...
With resistor disconnected :

When cranking ,light comes on and the engine starts. The engine then stops straight away as soon as the light goes out .

 

Well that's pretty definitive. Someone else posted that with the resistor disconnected the car would start or the pump would run. Any chance there is a difference in our ECU? This is disconcerting for me as it could mean mine never goes high speed.

 

With the ignition on and resistor disconnected , the pump wont turn on . But when cranking it does and the engine starts ..... momentarily.

That's why I did the video , because there is no argument about what happens .

That other guy was ................... wrong . I very much doubt there is any difference in ecus .

 

So the easy test is : Disconnect your resistor . If the engine starts then dies straight away ,like mine does, then you do have a working high speed circuit.

 

Ok, I see the difference. When I was listening for the pump I was only turning the ignition to ON and not actually starting it, because then I couldn't hear the pump. I just tried your test myself and I have the same results. Car fires up for a few seconds, then dies with the resistor disconnected. However, when switching the key to ON with the resistor disconnected I cannot here the pump at all, so the relay must not close until it's actually cranking.

I feel ok again. Changing the resistor did make the pump sound louder, so I think that's what my original problem was.

 

Also, Brettus, thank you for testing!

 

Good thing is , I have been able to acertain exactly when it kicks into high pressure mode while driving . Now looking for the map so i can change the setting

 

Nice work! What would anticipate changing it to? I just jumped it and ran high speed all the time for a while during troubleshooting.

 

That is going to depend on the pump . The DW 300 i have in there ATM flows too much on high speed settting at low rpm . I'm actually considering going back to the Walbro and leaving it stock . Maybe even fitting a higher resistance than stock ...... like your 'faulty' one LOL.

 

I feel silly I have a fuel gauge but I look at everything else but the fuel gauge. I can only say that cruising fuel pressure gets lower after the car has been running a long time, I should try to see the spike and drop you speak of, about what rpm should this happen?

I also just went and listened to my pump prime. it is quieter then the day I bought it, and quieter then my other car that has a walbro255 in it. so my resister is probably high too
however reading all this other stuff maybe its better I leave it?

 

I checked mine . It reduces the voltage from 13.5V down to 10V . Some stuff I was reading (AEM fuel pump controller ) suggested that you shouldn't go below 9V .So you wouldn't want much higher resistance than stock but if you see 9V or more I would say you are fine to leave it.

 

Looking into injector alternatives to uncapping stock injectors. I was thinking of going all ID725's but looks like they may not fit in the P1 position. Maybe something like ID1000's for P2 and sec with stock yellows in P1. ID's seems to be a good option and are cheaper than stock injectors. The threads I've read thru so far don't seem to be definitive on their use with ATR, but I am still looking. In the meantime thought I'd post for thoughts and advice.

 

I've seen some posts by Brettus and Tofu_Box that seem to indicate the latency data from ID was copy and paste. Looks like in ATR the values are mislabeled as milliseconds when they are in fact microseconds. Regarding the X-Axis for Baro Pressure I can't make out what units this is in. Also, when I try to edit those values they just revert to zero, however I can multiply them...