CAR WON'T RUN AFTER HCI

JOEGTS · May 16, 2006

This weekend I did my HCI swap. I got the car running yesterday afternoon and it ran for a good 15 minutes until I shut it off to get the air pocket out of the coolant system. After getting that worked out I started the car again and it would surge up and down and then die. I installed a Trick Flow street heat, GT40 heads and a Steeda 19 cam. I let the car sit overnight and it ran just as bad cold. This afternoon I got the car to actually run for a couple of minutes before it would die. The last time I had it running I could hardly keep it running while giving it throttle, it almost acted like a car with the air flow meter unplugged. I can't find any form of vacuum leak and I am 99.9% sure I have the timing at 10 degrees. When I first bought the car I found an empty Hypertech chip box under the seat. The only reason I added that is because I have read that people have great luck with the Steeda 19 cam and stock computers. I have never checked to see if it does have the chip installed or not. From the symptoms I am explaining does my car have the dreaded idle surge or is it something totally different? Should I be able to drive it around when its first started cold like normal until it gets hot?

The Green GT · May 16, 2006

Im not an expert but dont you need a chip and tune after and H/C/I?

Zero Signal · May 16, 2006

Yeah I say try removing that chip and go from there. The stock computer should be able to figure out the Steeda 19.

Make sure everything is plugged in (check spout connector and all wiring harnesses). You say you are sure the timing is right, but did you actually check it?

You might try getting someone to keep it running while you twist the distributor around and see if it smooths it out. That's how I found out my timing was wrong when I first did my HCI.

m0l0 · May 16, 2006

Off-Topic :

Also i can suggest hat you take the time to Retorque the heads and the headers , it cant do any harm

xr8d302 · May 16, 2006

+1 for rechecking the dizzy....

drakesdad · May 16, 2006

Throwing my 2 cents in....after doing my H/C/I swap I had the same problem could not keep it running. The main reason was I had the wrong spark plugs in that were not long enough.....I ran it for quite a while without a tune.......make sure you have correct spark plugs and good wires and rule that out but if timing is on and no vacuum leaks it will run with idle surge...

94gts · May 16, 2006

i would recheck the timing

mine runs perfectly fine with h/c/i, 14* timing, no tune, and a farely decent cam.

MysticKeith50 · May 17, 2006

I would check the puter, but to save the time and aggravation call JMS and get an sct chip made for yourself. problem solved as long as everything else is fine....oh and make sure you install it properly

JOEGTS · May 17, 2006

I don't have a stock chip to try in the ECU. I called and ordered a chip from JMS. Hopefully in a week I'll be able to drive my car again.

urban96 · May 17, 2006

you dont need a stock chip. simply remove the aftermarket chip and it returns it to stock

gcomfx.com · May 17, 2006

urban96 said:
you dont need a stock chip. simply remove the aftermarket chip and it returns it to stock

x2 - just unplug it and see what it does.

nmcgrawj · May 18, 2006

Try turning the idle adjustment screw on the TB up...may not be getting enough air to hold an idle.

But like the other guys said, take out that chip and see what it does.

JOEGTS · May 18, 2006

I tried to adjust the idle and it still didn,t work. I didn't know I could just pull the Hypertech chip out and it returns it to the stock settings. I'll try it today if I get a chance.

MysticKeith50 · May 18, 2006

yeah just remeber that if your car runs fine after a h/c/i swap you are one of the choosen few. If you order a chip with your specs you will be fine.

Green 94 5.0 · May 18, 2006

did you reset the eec after all these mods? that could very well be the root of your issues. you have increased airflow considerably and the computer may not be able to make the correct adjustments for it without a complete reset. that may at least get you on the road until the new chip comes. also, the spark plug thing is correct. the iron heads use a shorter plug. autolite 3925's are what you are looking for if you are n/a.

1994Vib.RedGT · May 18, 2006

how do you resest the EEC?

nmcgrawj · May 18, 2006

unplug the negative battery cable for 20-30 minutes

drakesdad · May 18, 2006

Green 94 5.0 said:
did you reset the eec after all these mods? that could very well be the root of your issues. you have increased airflow considerably and the computer may not be able to make the correct adjustments for it without a complete reset. that may at least get you on the road until the new chip comes. also, the spark plug thing is correct. the iron heads use a shorter plug. autolite 3925's are what you are looking for if you are n/a.ono:

Thanks for seconding.....I went through all the things he is trying and even pulled the plastic plug out of the passenger fender to reset everything and later found out of the spark plug problem.....damn did I feel stupid but when I got my kit I did not see any recommended plugs......I hope he gets it figured out because I remember I was an inch short to taken it back stock .... I'm glad I didn't but that's how aggrivated I was..

GRGT1994 · May 18, 2006

I gotta say, I really doubt that ordering a chip will solve your problems. You should be able to get the car running as it is (with or without that chip you already have).

If I were you, I'd pull the chip out. Then go back over everything real slow, 2 or 3 times. I think most others who have done an HCI (me included) will tell you a story or 3 about the stupid little connector left off or fuel pump cut-off left off, etc. I would suspect something simple like that right now. Especially a vac leak like mentioned above. Our harnesses are getting old and fragile, and easy to crack, it's common problem. ((edit)) Oh, another famously common problem is setting the timing 180 degrees off. ((edit))

((edit)) Then try to set your base timing as suggested above. If you can't get it to idle without the spout, then try moving the dizzy back and forth a bit (just a bit - dont go crazy) until you find a point where the idle settles down a bit. ((edit))

Then I would look to adjusting your TB (especially if that's new and not just the idle set screw).

Good luck.

JOEGTS · May 19, 2006

I pulled the Hypertech chip out and the car will idle somewhat, but pops like the timing is off. I tried to start it with the Spout pulled and it won't start. I will try to set the timing again when i get a chance. I was told that Iron GT40 heads use Autoliye764's?

CAR WON'T RUN AFTER HCI

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