Why won't my car idle? New 306 build w/ edelbrock performer HCI

[drakesdad]

Well ... A 190lph pump is plenty for a typical h/c/i combo
but
The larger 255lph can be had for ... IIRC ... 10 more bux or less

I just can't see how the larger size can hurt you
and
Many others besides myself have done that with no ill effects

I would like to make it clear
the OEM pump you now have should not cause any issues
at idle or driving around town with loads of 75% or less

Sounds like you still got some issues from the h/c/i project

Grady

spend the extra few bucks and go 255....will save you end the end if you keep modding......Summit has good prices and I have not had any issues with it......but as Grady states.....the pump isn't your problem at idle or regular.....now hammering it ....

 

[DLo]

Cool, thanks for the help. Would the BBK-1607 do me just fine in a 255?

Grady, I've been searching up old threads. I saw the one on idle surging, which seems to be what I'm experiencing. Right now the car will idle on its own, but every few seconds, it will bump up an extra couple RPMs. It's kind of hard to describe. On another note, when my friend pulled it out of the shop yesterday, he had to keep on the gas a couple of times to keep it from dying and work the clutch a little bit. Looks like I will go through that idle surging check list and see if I can pinpoint the problem.

I've also read that my combo is mild enough to the point where it should drive, and that I should fix the problems before going in for a full on tune. Will get back to you all. Thanks!

 

[final5-0]

Cool, thanks for the help. Would the BBK-1607 do me just fine in a 255?

Grady, I've been searching up old threads. I saw the one on idle surging, which seems to be what I'm experiencing. Right now the car will idle on its own, but every few seconds, it will bump up an extra couple RPMs. It's kind of hard to describe. On another note, when my friend pulled it out of the shop yesterday, he had to keep on the gas a couple of times to keep it from dying and work the clutch a little bit. Looks like I will go through that idle surging check list and see if I can pinpoint the problem.

Yes ... the old h/c/i surge gremlin has reared its ugly head

I've also read that my combo is mild enough to the point where it should drive, and that I should fix the problems before going in for a full on tune. Will get back to you all. Thanks!

Well ... You have gotten some wise info here from a mix of ..........
Wise Guys

Here is a copy & paste from your original post

I've dropped a 306 into my 94. HCI is all edelbrock performer stuff

I don't know how aggressive that cam is
but
I got a sneaking suspicion that h/c/i kit is not as mild as you think

never the less ... Yes ... You are correct in making sure ALL issues from
the recent upgrade are dealt with.

I just can't stress ENOUGH how many times over the years

I've seen peeps chasing their tail like a little dog around and around

Trying to adjust this & that
Buying tuning equipment
Paying a Pro to burn chips
etc etc etc

Only to find

vacuum leaks
improper valve adjustment
and
other simple little things

Causing most of their grief, frustration, and heart ache

Hey ... With motor mods ... Stuff has gotta be like Stuff needs to be :Word:
and
I guess I'll never understand

Why some peeps don't consider a thought similar to this

Hummm ... My car didn't

Make that sucking sound
Leak that fluid
Make that tapping noise
etc etc etc

before I did all this recent work

Good Luck and let us know how it all works out for you

Grady

 

[DLo]

Well, Duration 282/282, Lift .498/.498 - that's the specs for the cam I ordered. Nevertheless, like you said, I'm going to go through that list and I'll let you know if it gets any better if we end up finding something.

 

[DLo]

Okay, so far I've found two issues. #1 - the adapter that came with my Granatelli MAF had a couple wires that had bad connections. Found this out after a couple of them actually got pulled out! #2 - At idle, we found it's at 10 inches of vacuum.

I'm going to slap the adapter back in after we fixed those connections, but what do I do about that vacuum issue?

 

[DLo]

The adapter is back in, but the car still barely idles. It sits at about 500 rpms and nearly dies. Do I need to turn the idle screw to get it up to 1k?

 

[Methodical]

Open up the IAC screw some

 

[DLo]

Turned the screw out a little, idles now around 600-700 rpms. Once it gets warm and I try to drive it though, the car dies. I think I might take it to the local tuner.

 

[R.J.]

Try resetting your idle with the following procedure. If your idle problem is NOT being caused by a bad part then I have never seen this not fix the problem!

Begin with a cold vehicle. The idea here is to get the car to a firm cold idle with enough air bleed capacity left in the idle circuit for IAC adjustment.

The idle stop should be set first. Back out the idle stop screw, away from the bell crank arm, until about 1/2 turn past the point where it no longer makes contact (blade fully closed). Using a 0.010" feeler gauge, tighten until gauge just drags between screw and bell crank arm. Remove feeler gauge. Tighten screw exactly 1 1/2 turns. If the screw is very loose, put a drop of loc-tite or silicone on it, so it doesn't work out of adjustment.

Now remove the connector to the Idle Air Controller (IAC) just on the other side of the throttle body. Start the car and allow vehicle to warm for 2 minutes. Give a small "blip" to let it settle. If it is having a hard time staying running you may have to get an assistant until you can get to the front of the car. Now open or close the air bleed screw (CCW opens) next to the IAC until the car idles at 575 to 600 rpm. For guys with aftermarket cams and an EEC tuner, you might want to idle a bit more briskly, say 650 to 675.

Obviously, this rpm range is by what the car and driver wants...IE, no set idle speed, whatever works for YOU.

Turn off the car. Now count the number of turns clockwise to close on the idle air bleed screw. If it falls between 1/2 and 2, it's okay, now reverse it out the same number of turns. Log the number somewhere in case you need it for the future. Reconnect the IAC. You are done.

If the air bleed screw is above 2 turns, it's a good idea to tighten the idle stop screw another 1/2 turn, and then repeat the idle setting. If it is below 1/2 turn, then loosen the idle stop screw by 1/4 to 1/2 a turn, and repeat the idle setting. Be sure to put another drop of silicone RTV on the stop screw if it was disturbed. Reconnect the IAC.

Now remember we adjusted the set screw on the throttle body. That means that the voltage reading from the TPS sensor has changed. It should read between .96 and .99 volts. Anything outside of that range will cause all sorts of issues including misfires and rough idle.

you will have to back probe the TPS connector. With the connector attached to the TPS stick a paper clip into the rubber boot on the connector where the top and middle wires go into the connector. The rubber is very flexible the paper clip will slide in between the rubber and the wire.

Set your multimeter to volts. Turn ignition to ON. Then place your multimeter leads on the metal pins. If it comes up as a negative that is okay as long as you are -.96 to -.99. If you get this reading then great you are done and hopefully your issues are gone. If not proceed to step 9

This is where and extra pair of hands come in handy. Using a large screw driver you will need to loosen the bolts that hold the TPS. DO NOT USE A SCREWDRIVER THAT IS TOO SMALL BECAUSE YOU WILL STRIP THE BOLTS. They probably will be really tight so you have to really lean on the screwdriver and use some finesse.

Once the bolts are loose you will need to move the TPS up or down and continue to read the voltage. Once you get it to the desired setting you can retighten the bolts. What I do is I find .97 and then as carefully as possible I tighten the TPS down. what will happen is the voltage will change usually to .96 or .98 but that it okay. Once you are done with this manually open the throttle body a few times and close it then reread the voltage and make sure it is still within our desired range.

Depending upon how loose your set screw was you might want to cover it in RTV to hold your setting. At this point you have CORRECTLY reset you idle.

 

[TheRedBlur]

If you put bigger injectors in without changing/tuning the chip, you are running pig rich, I'd be surprised if you could even get it to run down the road. Put the 19lb injectors back in, give it a shot. Then go about looking for vacuum leaks, valve adjustments, bad plugs, etc. It's still gonna run like ****, SN95 motors don't like cams.

:edit:
So I was posting in another thread and did some math about injector swapping minus tune.

if you think about it:
at idle, lets say, for the sake of argument, that you're using %30 injector of 19lb/hr, that equates to about 5.7lb/hr of fuel at idle,
swap the injectors without telling the computer to 24lb/hr, you'll be using 7.2lb/hr of fuel at idle.
The computer is gonna go HOLY ****! WAY TOO MUCH FUEL, CUT BACK!

It gets worse if you have a cam, when it cuts back the fuel, it's at a rate that changes against the airflow allowed by the stock cam, if you have a bigger cam, then it's gonna lean at a much higher rate than the computer predicted and will never be in tune, it's just gonna go from one extreme to the other, always on the verge of stalling. All the tps work and spout timing work won't help.

 

[DLo]

Thanks for the info. One question about spark plugs - I was told the stock ford motorcraft ones won't seat properly. One of the local tuners recommended me to get Autolite 3924's, and take down the gap to .45 or so. I did a little bit of searching and found a lot of you guys were doing .35. Could this be a cause of my current problem as well?

 

[TheRedBlur]

stay focused on the big problems, then work out the little things later.

 

[greenlantern]

Heres a tip I kind of learned by trial and error and has worked on plenty of guys cars who were having idle issues similar to yours.

If you have a cold air intake with the almost 90 degree bend into the fender you probably have a problem most people overlook. How is your mass air meter positioned? If you look down and the black box of the mass air is in the 12 O' clock postion facing you, in most cases this can pose a serious idle problem. Especially after the car has been moded. Try this, clock your mass air meter to about the 9 O'clock postion. The idea here is to get the element too the inside bend radius, of the cold air flow. Air always takest the path of least resistance. If the element in your mass air meter is clocked the wrong way your car could have a tough time trying to idle. Very little air is comming in at idle and the little bit of air that is comming in may not be hitting the element enough to give it an accurate reading. In this case the computer doesn't know exactly what kind of air is comming in so the fuel it throws at it during idle is going to be off. This equals rich gas odor which can be mistaken for running rich and stalls. This is another reason why most guys have to end up running a higher idle. Trust me it works, I wouldn't at all be surprised if your able to drop your idle down after doing this.

I don't know how many times I have done this for guys who have been chasing down idle gremlins and never could quite figure out what the problem was.

 

[DLo]

stay focused on the big problems, then work out the little things later.

Well, right now I'm just lost as to what to do, short of taking it to someone. I'd stick the stock injectors back in but I don't have them anymore. My friend tried sticking propane in certain areas to check if the idle would change to indicate a vacuum leak, but nothing happened.

 

[dartvader]

I told you before, telling you again first ting you need to do is tune the car, my car would not even run after the HIC swap until i got a chip from Don La Sota.

 

[TheRedBlur]

Well, right now I'm just lost as to what to do, short of taking it to someone. I'd stick the stock injectors back in but I don't have them anymore. My friend tried sticking propane in certain areas to check if the idle would change to indicate a vacuum leak, but nothing happened.

Did you read my prior post about changing injectors without tuning the computer? You gotta understand that all the mothballs and blinker fluid you throw at the her isn't going to make it run until the computer knows what injectors/cam it has.

YOUR CAR WILL NEVER RUN PROPERLY UNLESS YOU TUNE THE COMPUTER OR PUT THE STOCK INJECTORS IT.

That's it, no tps voltage, or plug gaps. I'll try to make an analogy:
If you have a brain tumor, the doc tells you that you need to remove it.
Instead you buy aspirin, and the problem doesn't go away.
your friend tells you that you need to take vitamins to be healthy, so you try that, but the tumor doesn't go away.

Aspirin and vitamins will help a healthy person, but if you have a really huge problem that needs a specific solution, it won't make a difference.

Buy stock injectors, or tune your computer.

 

[final5-0]

I went back and re-read the entire thread ... again

Unless I'm not understanding things

Hint ... Hint ... Hint

A sig listing all mods .........
would simplify things for everybody when they try and help you

anyway ... You got 24's and a meter caled to match em

NOW ... if this is so ... You should be close enough to drive the car and it
should have no major problems

You have already found disconnected wires at the meter

You have already talked about only seeing 10 inches of vacuum at idle

You gotta get EVERY ONE of those kinds of issues cleaned up that were
caused when the h/c/i were installed :Word:

Until you get stuff like that fixed .......
Anything else you would do would be like .........

Burnin down the barn to get rid of the rats
Throwin out the baby with the bath water
Pissin against the wind
etc etc etc

Again ... if I did not understand something correctly

Please elaborate ....... and I'd bet ....... Many friendly folks can help

Grady

 

[The O.G.]

i fixed a vacuum leak on my car

lots of problems i had went away! but not all

it idles now and would not before, bucking etc

do u have GOOD local hot rod shop maybe someone who knows these cars fairly

well?

where do u live? i dont see it for your location

maybe someone here lives near you and could point you to a good shop

 

[DLo]

Alright, here's a list of what I've gotten installed:

Bottom end - Fully machined production block (.030 over), Federal Mogul main bearings(#4125M), production crank, Keith Black Silvolite pistons(10.1 comp w/58cc), Hastings rings, Federal Mogul rod bearings(#8-2600CP) and Federal Mogul cam bearings(#1204M

Edelbrock 60379 Performer Heads
FMS 1.6" roller rockers
Edelbrock 3722 Performer Cam
Edelbrock 3821 Intake
Edelbrock 3845 70mm throttle body
FMS 24 lb injectors
Granatelli MAF for 24 lb injectors
BBK cold air intake

I just pulled codes the other day to find I have 157. I ran a search but couldn't find anything. I'm located in San Jose, CA. Local speed shop specializing in Mustangs just closed down. The other one, AED, base location is in Sacramento which is 2 hours away, but they say they do tuning in my area.

I guess I'm just lost and have no idea who to listen to or what to look for anymore.

 

[final5-0]

I took a quick look through my notes about 94-95 codes and found ...

157 = Mass Air Flow Sensor below minimum voltage

That is all I had for that code

Grady