Popping throught the intake...please help!!!!

Ostang351 · Jun 3, 2004

Popping through the intake...please help!!!!

I can't fix it. I need some help. I have Edlbrock heads, B303, 1.72's, Pro M mass air, bigger TB, MAC Cold Air Intake kit, Cobra upper and lower, pullies, stock bottom end with 57k original, shorties, Basani high flow cat pipe, 19lb injectors, kirban adj fuel regulator at 40 psi, and the smog is still on. It is like 80 degrees at 8:00 in the morning here in Florida and when I start the car to go to work around that time, I let it idle for a bit, then start to drive. First gear feels fine, shift easy at about 3000 rpm and start to ease into 2nd. It will hesitate and if I keep accelerating, it will jerk and pop out the intake a few times. Then it will clean up and not do it anymore. After it warms the car runs great. I replaced the IAC, ECT, ACT, O2's, Mass Air (I have the chrome Pro-M, not sure what size, but it is big), fuel filter, cap, rotor, wires, and plugs. It had an idle problem, but it is better after the new IAC went in. Some one please give me some advice. I am not sure what fuel pump is in there because I bought the car used, but I would think it would do it all the time if the pump was going bad. Don't know what else to replace besides the EGR. No vacuum leaks. Sprayed the enitre engine with carb cleaner and no change in idle. Timing is at 15 degrees. Any suggestions? Thanks in advance!!!

powershift351 · Jun 3, 2004

is your MAF calibrated for thoise 19's? Bring your timing back to 12 degrees. What grade of fuel are you running? Just a few troubleshooting tips for you . Also throw a fuel pressure guage on there and see where your fuel pressure is at.

Ostang351 · Jun 3, 2004

The MAF is calibrated correctly. It says it on the meter. I run 93 octane always. The gauge on the fuel rail reads 40psi. I will try the timing soon when I get a light. I have that Kirban regulator and I have read that I can adjust the pressure with vacuum on. With vac on it is at 40psi. I have played with it and it still will pop even if I lower or raise the pressure.

noslow5_0 · Jun 3, 2004

well the poping is from it running lean... i have the same problem... if i crank up the f.p to like 50 it goes away, but low end really suffers from the rich condition.... I was thinking the 02's, but youve replaced them too...

powershift351 · Jun 3, 2004

hmmmmmm, I run 40 psi on mine right now, everyone thinks I should be running lean with my #24 injectors. What are your plugs gapped at? You might want to bump up to 24's or even 30s would work well with your set-up. Also check the meter on your TPS. I don't think that would cause your problem, but it wouldnt hurt to make sure it is between .95-.97.

Ostang351 · Jun 3, 2004

I am at a .45 gap, that is what the Chilton's said for my year (1990), but the popping was there before I did the new plugs. The old plugs that came out looked good, pretty white though. The TPS is at .98. I would hate to buy all new injectors and recalibrate the mass air if that is not it...I plan on selling the car soon, but I want to fix this before I put it up for sale. I might try to lower the timing and fatten it up....think that will work?

powershift351 · Jun 3, 2004

hopefully, I think you have replaced everything. Only other possible thing might be the Computer

powershift351 · Jun 3, 2004

the only other thing I could think is that you could reset your computer and have it re-learn your settings.

Ostang351 · Jun 3, 2004

Reset it as well.....left it off for about 2 hours and started it up. Idled fine and drive good. No popping. It only happens when it fully cools and sits overnight.

ECU5.0 · Jun 3, 2004

try upping the fuel pressure a few pounds. i had the same popping problem too and upped my fp and it stopped. go to like 42 and see if its gone

Sanford · Jun 3, 2004

popping threw the intake is usually timing related, that can also cause a lean condition... i would check my timing..

jrichker · Jun 3, 2004

Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

Look for codes 21 (ACT) & 24 (ECT) if either of those sensors were bad, you could get a lean condition.

Here's the table for the sensors

The ACT & ECT have the same thermistor, so the table values are the same

ACT & ECT test data:

Use Pin 46 on the computer for ground for both ECT & ACT to get most accurate readings.

Pin 7 on the computer - ECT signal in. at 176 degrees F it should be .80 volts

Pin 25 on the computer - ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.

Voltages may be measured across the ECT/ACT by probing the connector from the rear. Use care in doing it so that you don't damage the wiring or connector.

Here's the table :

68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms

Ostang351 · Jun 3, 2004

I turn up the fuel pressure and eventually turn down the timing when I get a light. I pull the codes again. I'll let you know. Thanks for all the posts!

blown93feature · Jun 3, 2004

I personaly would increase gap to 50 to try to decrease that could start pop,I am almost willing to bet that's it.I would try this to prove my point,when you start the car first thing in the morning alow it to fully warm up to 180 or until you see the gauge drop from the thermostat opening.I would say around 5 to 6 minutes then take off.The increase in plug gap helps to decrease detonation (pinging)in the slower burning 93oct fuels required to be run by these cars hence longer burn time in the chamber to fully consume the fuel.When you take off in the morning before the car heats all the way there is unburned fuel in the cylinder that you know have added to, buy taking off and dumping even more and after increasing rpms you have just created enough heat to burn the rest of the fuel which by now has saturated the the plug.Boom..Believe it or not but plug gaps are pretty big deal and the type of plug as well,also running 15degree's of timing ?why? I would put it at
14and leave it.
I have also seen where a wire was on but not pushed on all the way and the motor would run fine with the exception of first thing in the morning on cold start it would pop violently once and that was it go figure!

noslow5_0 · Jun 3, 2004

just as blown93 said.... plug type and gap can really affect performace... they arent platinum plugs are they???

Mizark347 · Jun 3, 2004

Vacuum leak......improper intake seal......check vacs

Ostang351 · Jun 3, 2004

Nope, they are autolite 3925's. The timing is at 15 degrees because that is where it was when I checked it to be honest. The previous owner had it there and since it didn't ping I left it. I'll regap to .50 or .54 and turn down the timing and see if that works. When I set the timing I have to pull out that little grey chip before I mess with the distributor right? Then plug it back in when I am done....

Ostang351 · Jun 4, 2004

I turned up the fuel pressure last night to about 45psi and it didn't pop this morning. I hope that is it. I will test it out for the next few mornings and I will let everyone know. I'll also re-gap to .54 just for the heck of it. Thanks everyone for the help. This has been a problem since I bought the car, it actually did it during the test drive and he told me that it was because of the cold air intake kit; the air was too cold going in when the engine was cold....hmmmm. Nope.

powershift351 · Jun 4, 2004

good luck man

Ostang351 · Jun 7, 2004

Well, we can rule the fuel pressure out, It popped that last two mornings. Still didn't redo the timing or the plugs...ran out of time this weekend and still don't have a light. Keep ya posted.

Popping throught the intake...please help!!!!

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