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Engine Idles great - but won't rev up!


trwebb26

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I've got a stock 78' 280z with MS&SE running 3.0 hardware & 3.0 bar map sensor. I'm running the 83' turbo dizzy and 240sx tb. I'm running the aeromotive FPR with idle (800rpm & 38kPa) at 36psi. Stock 19 lb injectors. The car idles great... but when I step on the go-pedal it gets up to ~2500 rpm and really sputters, coughs, backfires, etc. My first thought was that my tables were screwed up... but after 2 full days of tuning them I've gotten nowhere fast! I've disabled all of the enrichments to try and nail down the problem, but that didn't help. What could it be? I'm begining to be desperate! Thanks!

 

280z_04JUN06.jpg

 

Here is my *.msq file... because yahoo is a beyotch.. you have to download it as a txt file (an approved yahoo file extension) and rename it to msq.

 

http://www.geocities.com/trwebb26/280z/280z-04JUN06.txt

 

I appreciate the help!

 

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What I would do is slowly bring the car up in RPMS setting in neutral until it starts to sputter, then hold it there and adjust the VE value at that spot to see if you can smooth it out. Just tuning by ear at this point without a wideband, narrowband or some indicator.

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I had the exact same behaviour (note: could be a totally different problem) with my first MS (v2.2, 280zxt dist, 240sx tps.) After weeks of hairpulling, I finally swapped in a friend's MS with the exact same settings, and it ran fine. Turns out that I had fried something with an unregulated power supply earlier on. My MS box seemed fine, responded correctly, everything displayed on the laptop was normal, but it wasn't working correctly.

 

Again, your MS box might be 100% fine, but it's nice to have a spare to swap in to check.

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Guest 280ZForce

i'm pretty sure those required fuel rates on the top left corner of your image arent supposed to be that high....I'm thinking somewhere in between 6.9-7.5 for both of those settings. dunno if thats what's causing this, but it's a shot.

 

also are you still running an afm or did you remove that?

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I'm running stock 19lb injectors... That is the setting that other people have used for those injectors (reccomended by MS using their calculator).

 

I'm somehow convinced it's timing - so i started it up and put a timing light on every wire. 1, 2, 5, & 6 show the timings mark lining up and only 3 & 4 show 180 degrees out. Is that correct?

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I figured it out .... when you rev it up it is getting WAY!!! too much advance. By the time I'm at 2000 RPM - i'm at 40+ degrees advance - and it just keeps going up if you push more on the throttle. Any ideas what could be wrong in MS?

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  • 3 weeks later...

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