ECUs and Tuning Discuss Engine Management, Tuning, & Programming

Hot restart and Deatschewerks 600cc injectors

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Old 05-03-2010 | 03:24 AM
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Default Hot restart and Deatschewerks 600cc injectors

Has anyone had trouble getting them to idle smoothly after a hot restart?
I wonder if this is a major disadvantage of large hi impedance injectors.

I'm having all kinds of trouble with them and my AEM after a hot restart. They seem to increase their latency by 150-200 us after a hot restart. The result is a very unstable idle, where it oscillates and goes abruptly lean, misfires, and often dies. The cure I've found so far is to tune the latency table when very hot, and live with a rich idle when colder.
Old 05-03-2010 | 10:10 AM
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i have not experienced this problem

what does your latency table look like? i posted the specs that i got straight from DW the other day, which seem to work quite well for me.
Old 05-04-2010 | 05:54 PM
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I first tried the numbers from Deatschewerks. They resulted in very rich operation at low MAP. My fuel map is relatively flat and my AEM is set up to mimic what Adaptronic users call "VE" - that is, the fuel map numbers are multiplied by MAP to come up with injector on time.

I ended up with this curve:

10-16V
1480 1300 1160 1040 950 870 810

At 14V for example, the recommended latency from Deatschewerks is 1.35 ms - I run 950 us.

One possibility for the difference is a difference in the injector drivers of the AEM and that which Deatschewerks used.

( A possible solution to this "problem" is for Deatschewerks to send an injector to AEM and they will measure the latency as used with the AEM ).

If I use Deatschewerks' latency numbers I need to use very low numbers in the low MAP areas, and the problem gets WORSE.
Old 05-06-2010 | 03:15 AM
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I haven't used the AEM software in a while, but it does sound like you need to tune your 10s afterstart enrichments.

Dimitris
Old 05-06-2010 | 09:18 PM
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That's what I did.
It fixes my hot restart, but it makes first start pig rich.
Old 05-07-2010 | 03:34 AM
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I discovered too that heatsoak on the intake air temp sensor is making it worse.
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