Took the car out for a test run with the scanmaster and this was the result-12.7 deg. of retard in third gear at 14 psi.Fuel pressure was 46psi line off.I raised fuel pressure to 48 and the result was 8.7 deg. of retard in third gear.The o2 millivolts were 830-850.I was even getting 1.5-3.5 deg. retard when I took my foot off the pedal.There was no retard in first and very little in second.Other readings were 00 IAC at idle,.48 tps at idle and 3.2 at WOT.Engine coolant temps were 167 deg.I thought I might be getting false knock because the car pulls strong,doesnt ping and doesnt leave any black clouds behind,but there is no retard if I dont floor it.I just want to get the car running right,so what do I do now?Any suggestions? dunno
Need Some Help
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first that tps at full throtle should be above 4.50 . what is your mass numbers at full throtle? and what fuel octane. also make sure there is not a race chip in it that has to much timing.
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43,745 Posts
Actually, anything over 3.75 volts will make sure you have power enrichment, but, I like to see 4.0+ to be sure the ac compressor kicks out.
And, as posted before, your idle tps is too high.
Why don't you start off by trying to reset the tps to something around .40 at idle and 4.0+ at wot.
Try reading the tps section on my site under Basics/Tuning.
Normally the LV8 should kick PE in even at 3.2 volts tps, but, better to be safe than sorry.
Also, is your fuel pump hot wired and has it been replaced with a higher output pump? MIght be sure your fuel filter has been changed.
The fact that it got better with more fuel pressure kinda suggests that it had gone into PE as the fp increase did not really increase flow all that much.
And, as posted before, your idle tps is too high.
Why don't you start off by trying to reset the tps to something around .40 at idle and 4.0+ at wot.
Try reading the tps section on my site under Basics/Tuning.
Normally the LV8 should kick PE in even at 3.2 volts tps, but, better to be safe than sorry.
Also, is your fuel pump hot wired and has it been replaced with a higher output pump? MIght be sure your fuel filter has been changed.
The fact that it got better with more fuel pressure kinda suggests that it had gone into PE as the fp increase did not really increase flow all that much.
The car has twin in-tank pumps(I do not know the flow however)they are hot wired and the fuel filter is new.All runs were made with 93 oct. in the tank.With the IAC being 00 at idle,is that the reason the car has a wandering idle? dunno
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43,745 Posts
set at zero, the idle is basically off the throttle plate rather than the bypass. therefore the iac is pretty much ineffective and it could contribute to a varying idle when the engine load changes....a 25 rpm idle increment is pretty common on many cars.
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