rough idle after rebuild

[cenok is family]

as most of you know i just rebuilt my motor. i had the block bored .040 over, line honed, and brass freeze plugs. i used all clevite bearings, power seal moly rings, durabond cam bearings and all felpro gaskets. it's got a stock, balanced rotating assembly (pressure plate balanced too) with Ross forged pistons. i also converted to mass air using an 80mm PMAS "velocity" maf meter and a9p ecu, i installed a cobra intake, 65mm tb, 24# injectors, kirban afpr, crane 1.7 rr's, underdrive crank and waterpump pullies. i reused some factory lifters that had about 10k miles on them. i also got new autolite spark plugs gapped to .048, new cap and rotor, new ford racing 9mm wires, new waterpump, new timing chain, and a new oil pump. i also got a new pcv valve, but i didn't get a new screen and there wasn't one in the lower when i got it. do i need a screen or is it going to do anything to not have one? i set my tps to .99v, set base timing to 14*, and fuel pressure is at 38 with vacuum line ON. i hooked up a mechanical oil pressure gauge just to check the pressure and it's at about 55 at idle(if i remember correctly). it starts up easily but when idling, the motor is kinda shaky and i don't like it. it doesn't really surge either, just shakes. Is it supposed to be like that being a brand new motor? i'm not driving it until i put an exhaust on it later on in the week so i can hear if there are any odd sounds coming from the motor. anyways, what do you guys think could really cause the rough idle? i don't have a code reader, i know i need to invest in one. i appreciate the help, as always! :SNSign:

also, i noticed whenever i was turning my distributor while i was timing my car, when i had the ignition on the "on" position with the car off, i could hear my injectors clicking on and off. my cousin said he saw my fuel pressure gauge jumping around when i was doing it too. is it supposed to do that? thanks!

 

[jrichker]

You don't need a code reader, all you need is a paper clip and a test lamp.

Dump the codes and see what the computer says is wrong…Codes may be present in the computer even if the Check Engine light isn’t on.

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/

IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see http://www.midwayautosupply.com/pc-7208-90-equus-digital-ford-code-reader-3145.aspx – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.

After you have dumped the codes with your 2 cent code reader, post them and I will try to help.

More suggestions:

See "Surging Idle Checklist for help with all your idle problems. The first two posts contain all the updates to the fixes. I continue to update it as more people post fixes or ask questions.

 

[cenok is family]

thanks jrichker, as always, very informative. does anyone have any input on the other issues i'm having such as my distributor engaging my fuel system or whether or not i absolutely need a pcv valve screen? thanks!

 

[backfocus]

You said the exhaust isn't hooked up. Do you have the O2 sensors on at least? Just checking. And are you sure that the distributor was stabbed correctly.

Fairly obvious questions, but just doing a double check.

 

[cenok is family]

You said the exhaust isn't hooked up. Do you have the O2 sensors on at least? Just checking. And are you sure that the distributor was stabbed correctly.

Fairly obvious questions, but just doing a double check.

yeah the o2's were hooked up in the long tubes. i actually just drove it down to a local muffler shop this morning and had the exhaust put on. it ran like crap the whole drive there and was misfiring and backfiring like crazy. same thing even after the exhaust was put on. i'm thinking that the distributor wasnt stabbed correctly. when i put it in, i turned the crank over so that the pointer, not the circle on the pointer, was pointing to zero on the balancer, then stabbed the distributor in and the rotor seemed to have been where the first post it would have fired was #1 but i'm not completely sure. and i think i can hear a vacuum leak or something cause i can hear air whistling. i have a guy that got my 4cyl conversion coupe running for me coming this wednesday to check it all out. but what do you guys think?

 

[cenok is family]

ttt

 

[irish]

I would make sure the distributor is stabbed correctly, I think there is a sticky on that. I would recheck firing order, and pull codes. Did you re-use old balancer or get a new one?

 

[cenok is family]

I would make sure the distributor is stabbed correctly, I think there is a sticky on that. I would recheck firing order, and pull codes. Did you re-use old balancer or get a new one?

i re-used a balancer i have that has about 10k on it. it's still good. i'll go check out that sticky.