went to the track... long story.

46callaway

46callaway

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I went to the track today for test and tune. First run with the cutouts closed, stock exhaust except ultraflow mufflers, it went 2.1/14.3/98mph. Next I take off the cutouts and go right back to the line, run a 2.1/14.1/99mph. I let the car cool off 15 min and went back and did a really big smokey burnout. Did a 2.0/13.9/100.3mph. Next run I hotlap it and do the exact same 2.0/13.91/100.5mph. This run it was a very low 2.0 60 foot so I thought for sure I would be able to at least match the 13.8 run I did about a month ago. On the 13.8 run I only had a 2.125 60 foot time and it did 101.3mph. I did have over an hour cool down before that 13.8 run but still it left me wandering. I pulled into the pits and did a cylynder balance test. It said 3 or 4 were not contributing 100%! I didn't think much of it, thought the obd1 tester was faulty or something because the car felt fine. Next run the car just bogs when I launch and felt low powered so I coasted all the way down. Turned off the car, checked everything under the hood seemed connected, nothing out of place. I start back the car and it's misfiring. That's when I remembered I set the fuel pressure to 35 at idle (taking ponyfreak's advice to keep the fuel pressure a bit high) with the cutouts closed... with the cutouts open it was at over 40 at idle and ~50 at WOT. Way too much for NA! I'm pretty sure I fouled several plugs, I'm gonna pull them and change them tomorrow. I had to have the car towed back home. ::nono::
 
RE: went to the track... long story.

Very interesting.

The last time I touched my AFPR was at a T&T last year where I was able to make several runs with consistant conditions. I don't remember the exact numbers, but basically I kept bumping the fuel pressure each run comparing the time slips after each. When the last pressure increase resulted in zero gain, I backed it off a tad to the previous setting.

I remember reading once where the battery was disconnected after jacking up the fuel pressure with the car on the dyno. The dyno showed a measurable increase in HP, but presumably forcing the EEC to baseline values with higher FP was the reason. I would assume this meant the EEC over time would correct the A/F ratios, even WOT values.

So, knowing the EEC would change the A/F ratio to adjust for FP, why change the FP? Why even bother with an AFPR? In my mind, Mike hit the nail on the head. It is the 'spray pattern'. You only need to imagine the difference in the spray at different pressures delivering the same amount of fuel demanded by the EEC.

BTW, nice times. ;)
 
RE: went to the track... long story.

Well the only reason I got the Kirban AFPR was because I had a feeling my stock FPR was on it's way out. Call it preventive maintaince. The ECU does adjust back to stock levels, but in my experience it takes at least a couple days... the ECU doesn't compensate that fast. I wish it did so I wouldn't have fouled my plugs. It sounds like at least 3 plugs are fouled on my car. I'm about to go to Napa and get another set of Autolite 103 copper plugs. BTW, I changed my setup around a bit before going to TNT yesterday... full pulley set instead of just the crank pulley, Maurader harmonic balancer, and new crank/cam sensors. I'm pretty happy with how the car ran, it launched really hard. I think if I had new plugs in I would have easily got a new best ET and probably new best MPH as well. After the burnouts yesterday, my Dayton tires are just about done for... time for some Nitto drag radials. }(
 
RE: went to the track... long story.

Well I took out all the plugs today and every single one of them were fouled. Replaced them with 1 step colder copper Champion plugs, started up the car and same thing, crucial misfiring and then engine stalls and dies. Checked memory codes and got code 211: PIP circuit fault. I then tried to swap the Ignition Control Module from another Mark VIII and nothing changed. I then did more research on alldata and the pip signal from the ICM to the PCM tells the PCM about injector timing and some other things. One of the wires from the ICM to the PCM got fried. Can anyone tell me which wire is the pip signal to the pcm?
 
RE: went to the track... long story.

[div class="dcquote"][strong]Quote[/strong]
... Can anyone tell me which wire is the pip signal to the pcm?
[/div]

Circuit 395
GY/O
ICM pin 1
PCM pin 56
 
RE: went to the track... long story.

I gave up on trying to fix my car myself. It cranks over and starts but then it seems like it gets no spark. I think it's getting flooded. BRand new plugs, crank and cam sensor... I'm thinking the IAC might not be working anymore. Still getting the PIP circuit fault code though?
 
RE: went to the track... long story.

I would need to check my manuals, but it sound like the ICM is gone for some reason if you are still getting a DTC.
 
RE: went to the track... long story.

Well I swapped the ICM from a 93 Mark VIII and still it did the same thing... The 93-95 all use the same ICM, it changed in 96 with OBD2.
 
RE: went to the track... long story.

Looks like it jumped a tooth on the timing chain... Not 100% sure but I've had 3 places check it out and that's the most reasonable answer I got.
 
RE: went to the track... long story.

Ok, I'll be the first one to admit I'm speaking from an orifice located lower then my mouth right now but, that sounds ridiculous...

If that were to happen... wouldn't there be some sort of, oh I don't know... catastrophic valve / piston thing... where they at some point try to occupy the same physical space at the same moment in time?

I'm just guessing here... I don't really know...

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RE: went to the track... long story.

[div class="dcquote"][strong]Quote[/strong]
...catastrophic valve / piston thing... where they at some point try to occupy the same physical space at the same moment in time?
[/div]

Kind of what I was thinking. ::roll::
 
RE: went to the track... long story.

Well the point is that no one can figure out what's really wrong with the car so that is why it can't get fixed.
 
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