gman
Boosting 10 psi
Posts: 35
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Post by gman on Mar 9, 2016 8:30:00 GMT -5
Attached is a copy of the msq and a log of a recent pull at 80-90% throttle (~12# boost) after I changed the injector dead time down to 0.6 ms. Seems like I am running out of fuel a bit. Everything is stock except no VAM/CAI. Next I will try replacing the fuel filter, which from the looks of it probably has never been done on this 130K mile car. Any thoughts? Attachment Deleted
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Post by wesk on Mar 9, 2016 9:30:12 GMT -5
With the car idling, measure battery voltage across the battery positve and the base of the distributor. After doing that, measure battery voltage across the battery positive and negative.
What was done with TFI "ignition ground" (runs from TFI to EEC pin 16 in factory TFI)?
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Misfire
Mar 9, 2016 11:43:01 GMT -5
Post by Stinger on Mar 9, 2016 11:43:01 GMT -5
Seems like I am running out of fuel a bit. Everything is stock except no VAM/CAI. Any thoughts? It's not the cause of the RPM spike but you're WAY out of fuel, not just a bit. Your duty cycle is at 115.9 which means the ECU is calling for 15.9% more fuel than your injectors can supply when running wide open (never closing).
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gman
Boosting 10 psi
Posts: 35
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Misfire
Mar 9, 2016 17:38:07 GMT -5
Post by gman on Mar 9, 2016 17:38:07 GMT -5
Seems like I am running out of fuel a bit. Everything is stock except no VAM/CAI. Any thoughts? It's not the cause of the RPM spike but you're WAY out of fuel, not just a bit. Your duty cycle is at 115.9 which means the ECU is calling for 15.9% more fuel than your injectors can supply when running wide open (never closing). Yeah, I was trying to be "a bit" funny. Seriously though, what I don't get is how stock injectors on a stock engine can underperform by 15% when I'm not even running the engine at rated boost (15#). The only mechanical modification I made was to install a CAI and delete the VAM? The VAM isn't that much of a restriction, is it? Wes, TFI- is wired to DB37 pin 1 at MS side. I will take the voltage measurements and report back.
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Misfire
Mar 10, 2016 0:24:50 GMT -5
Post by Stinger on Mar 10, 2016 0:24:50 GMT -5
How do you know the injectors weren't maxed out before?
The VAM is a decent restriction.
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gman
Boosting 10 psi
Posts: 35
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Misfire
Mar 10, 2016 6:26:54 GMT -5
Post by gman on Mar 10, 2016 6:26:54 GMT -5
How do you know the injectors weren't maxed out before? The VAM is a decent restriction. I couldn't know that b/c I never tuned the car before removing the VAM. I forgot to mention that the PO removed the tailpipes and put on new mufflers. That change may also have increased flow. How much I don't know. With the assumption that the car in a completely stock configuration was designed properly by the engineers at Ford, the stock injectors should not be maxed out. I suppose I could put the VAM back on, and then see the difference made by removing it?
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Misfire
Mar 10, 2016 12:59:22 GMT -5
Post by Stinger on Mar 10, 2016 12:59:22 GMT -5
You could but what's the point? You can see they are maxed out. The only thing that can make them maxed out but not because of the power you're making is if your fuel pump isn't keeping up and pressure is dropping under boost. This can be checked with a fuel pressure gauge that you can see while driving (diagnostic gauge with 3 foot hose you can run outside the hood). Backtracking and installing a VAM or stock mufflers or anything else won't help diagnosis.
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gman
Boosting 10 psi
Posts: 35
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Misfire
Mar 11, 2016 5:58:37 GMT -5
Post by gman on Mar 11, 2016 5:58:37 GMT -5
Wes, Battery voltage was 13.59V. Voltage from BAT+ to dizzy was the same, with an occasional drop to various lesser values, as seen on a DMM. It seemed like the same thing that I was witnessed with the MS2 a while ago, before I installed the cap on the H1 boot header: Attachment DeletedI did not see any positive spikes, though, on DMM. I looked at the EVTM. I noted that G601 (engine) & G602 (body) ground strap were installed and looked fine. Then I discovered a problem that is probably not be related. I wiggled the black connector C387 for the injectors, and the car died. Disconnecting and reconnecting the connector did not bring it back. I found that wiggling the red injector +12V power wire at the harness end of C387 is the culprit. I cut the red wire at the engine side and rewired -- no wiggle issue now. I took this log in fifth: Attachment DeletedWhat might cause noise in speed?
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gman
Boosting 10 psi
Posts: 35
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Misfire
Mar 13, 2016 16:44:24 GMT -5
Post by gman on Mar 13, 2016 16:44:24 GMT -5
I went to Autozone and rented their fuel system diagnosis kit. The Schrader valve adapter is a pita, but I was able to get the gauge reading at 38# with the pump running / engine off. I disconnected the return line and the regulator flowed fine. The pump delivered 30# with the engine running, vacuum hose connected, and pressure went up when I revved the engine. So except for WOT pressure measurements, everything seems to be in spec. I'm a bit hesitant to route the gauge to the windshield and run the car, given the crappy valve adapter.
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Misfire
Mar 13, 2016 19:39:28 GMT -5
Post by Stinger on Mar 13, 2016 19:39:28 GMT -5
Well, without testing under load, you'll just have to assume your pump is good and get larger injectors, or assume the pump is bad and replace it with a better pump....then end up upgrading injectors anyway after you turn up the boost. The only other way to not max out the fuel system is to turn down the boost but I'm certain you don't want to do that.
Wes will have to comment on the RPM noise issue.
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gman
Boosting 10 psi
Posts: 35
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Misfire
Mar 14, 2016 7:16:23 GMT -5
Post by gman on Mar 14, 2016 7:16:23 GMT -5
Hi Stinger, I did a bit more research and found this article: Stock 88 LPH pumpIf that poster is correct, then the pump is not adequate. If I have time this week, I will double check his results, but I expect pressure to fall off at load. And it appears that the stock 35 lph injectors are inadequate too, even at stock conditions: Attachment DeletedBest regards, Rob
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Misfire
Mar 14, 2016 11:05:19 GMT -5
Post by Stinger on Mar 14, 2016 11:05:19 GMT -5
Yeah, that's what I've been saying.
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gman
Boosting 10 psi
Posts: 35
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Misfire
Mar 14, 2016 11:50:46 GMT -5
Post by gman on Mar 14, 2016 11:50:46 GMT -5
Yes, you did. I just couldn't believe that the Ford engineers designed the car with both the 88 lph fuel pump and the 35 #/hr injectors being too small. Maybe it was a cost issue and they figured 10-15# boost would not be reached frequently enough to cause problems?
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Misfire
Mar 14, 2016 12:14:57 GMT -5
Post by Stinger on Mar 14, 2016 12:14:57 GMT -5
We'll, that calculator is at 80% duty cycle so there is "technically" 20% more fuel flow available than calculated which means they weren't undersized, they just certainly weren't extra large. These engines ran rich in stock form so they had sufficient fuel flow from the factory. They just didn't leave much room for growth without bumping up fuel pressure, upgrading the pump, etc.
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gman
Boosting 10 psi
Posts: 35
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Misfire
Mar 19, 2016 13:36:23 GMT -5
Post by gman on Mar 19, 2016 13:36:23 GMT -5
The fuel pressure is 40# with the hose removed at idle, same thing KO engine off and pump running. Fuel pressure is 30# with vacuum connected, which correlates with 35 KPa at idle. But I took it for a ride and at 70 mph, fuel pressure would rise to 40# when I opened the throttle, but no higher when I applied 5-10# of boost. And I could hear rattling, like knock. Fuel pressure never went above 40#, until I parked, and then at idle it went up to almost 50#. Does that mean there is something wrong with either the fuel pump or the pressure regulator, or that pressure damper thing near the firewall?
Would it be easiest to just replace the fuel pressure regulator, and go from there?
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