[johnny_261]

Hey Everyone,

I recently completed a HCI swap. The car fired up fine first try, but there are a few issues that I'm experiencing and was wondering if you guys could provide some input on where to start.

I initially had started up the car without adjusting the TPS. The car seemed to idle okay, but when I revved it up, the throttle response was very delayed. I didn't have much time to work on it, so I shut it down for the night.

The next day, I adjusted the TPS to ~0.9V (it was at like 0.4V or something previously). This caused the idle to surge a bit and the throttle response was still very delayed. In addition, when I let rev it up a bit and let off the gas, the RPMs drop below idle and the car almost stalls out. When the car started to get up to operating temperature, RPMs dropped and the car stalled out...I couldn't get it to fire back up again. It almost fired...it would sputter around and I gave it some gas but would eventually die.

Any thoughts on where to start? I'm eventually going to get a dyno tune, but I want to get it running well enough so that I can drive it there.

I haven't check the timing since I stabbed the distributor, so I will be checking that...but any other ideas??? I probably won't be working on it until this weekend, but I'm hoping to get a list of things that I can check going.

 

[2Manystangs]

ok "not eventually" to the dyno, get it done like today, no way the stock ECU can handle those mods, esp the injectors, remember it's programmed for 19s so it's impossible for the motor to run "right"...
By the way, your intake sucks big time, it will suffocate those heads...sell it and get the Trick Flow to match

If nothing else put the stock injectors and mass air back in...

 

[306Notch]

Wow. That's friendly. ^

Anyway, switch back to the 19's like suggested until you can get a calibrated maf. OR sell the 42s and pick up some 24's. They would be enough for that combo.

Once you have done that you shouldn't have to go to the dyno. With the right Maf and injectors, a some tinkering you should be able to tune that yourself pretty well. Sure they might squeeze out a few more HP but I wouldn't bother for the $$$. At least not yet

Go through the "base idle reset" procedure (just search that and you'll find it) get your timing dialed in and you should be in biz.

 

[johnny_261]

The reason why I have the 42's is I also have a blower that is going to get put in the future.

I know they are not the best...but I have the C&L MAF "calibrated" for the 42lb's right now.

I'll give the Base Idle Reset procedure a try this weekend and get the timing dialed in and see how that goes.

As for the GT40 intake, I heard they are actually pretty good once they are ported???

Although it probably won't run great, thing should be able to run "good" enough with the C&L MAF for th 42's shouldn't it?

 

[FISHTAIL]

It should run alright with the 42's and the "calibrated" MAF. You might have some minor drivability issues, but it should run well enough. If you want to learn to play, do LOTS of reading, and get yourself a TwEECer or a MQ.

Anyway, #1, check your timing. If it's way out, that is NOT helping your issue. That should have been the first thing you checked once you started the car, before the TPS settings.

Do a base Idle reset as mentioned. Verify your timing is set, and start around 10* btdc. Check for vacuum leaks. Once you've checked all the basics, if you still have issues report back and we can try to help you sort it out. I'm thinking you have a timing issue though, if your timing is extremely retarded, it could cause the problems you are seeing. FWIW the computer bases all of it's calculations on the assumption that the Dizzy is at 10* BTDC.

Other things to check, unrelated to your problem;
Are your pushrods the proper length for your setup?
Are your rocker arms torqued properly? Did you re-torque them after a couple of heat cycles?
Etc.

 

[killer94vert]

The 42's are way too big for your combo without the blower.I would stick some 24's in the with the calibrated MAF and you should be able to get it to run ok without the tune.Get the tune done after the blower install.As far as the intake, I wouldn't say it sucks but it won't let those heads breath as well as they can.Once you put the blower on it will only be worse.I would strongly advise you to sell it and look at the Performer RPM II or the Holley Systemax. You will be short changing yourself with the GT40.

 

[YLDPONY]

As for the GT40 intake, I heard they are actually pretty good once they are ported???

If yours ported? And yes, you're right. Don't believe everything you hear, especially from someone who doesn't own a 5.0 Mustang.

Anyway, about your problems, I have heard marginal reports about MAFs "calibrated" for anything bigger than 30 lb/hr injectors. You may slap your stock MAF and injectors back in and see if it fixes the problem.

When you set the TPS voltage, you are doing it with the ignition on, right?

Make sure you have the SPOUT pulled when you set the base timing.

Good luck!

 

[Smurf stang]

Do an idle reset.

Summarized/Corrected Base Idle Reset Procedure

Run your codes.

DIY KOEO/KOER/Cylinder Balance Self-Test Procedure

Check for vacuum leaks.

Those 42's are a bit big for a NA combo so till you get the blower and tune I probably wouldn't run them as they will cause more issues.

 

[johnny_261]

Hey Guys,

Thanks for the ideas. Got the timing dialed in and was doing the base idle reset process. I backed the TB screw all the way out, but it did not seem to lower the idle. Also, when I removed the IAC connector nothing happened.

This should not normally happen correct? What does this mean? Vacuum leak? Where should I start looking?

Thanks again! Really appreciate the help guys.

 

[FISHTAIL]

Hey Guys,

Thanks for the ideas. Got the timing dialed in and was doing the base idle reset process. I backed the TB screw all the way out, but it did not seem to lower the idle. Also, when I removed the IAC connector nothing happened.

This should not normally happen correct? What does this mean? Vacuum leak? Where should I start looking?

Thanks again! Really appreciate the help guys.

Sounds like your IAC is stuck. Take it off and clean it out, and try again. If it still doesn't work, replace it.