Low RPM Sputter

[radman3120]

The other day i replaced my Lower Intake Manifold and Fuel Pressure Regulator and I got rid of the coolant leak and the car starts right away now but now i have a sputter below like 3000. I have a 93 Z34 with the manual tranny. The sputer is most noticeable in first gear but can be felt in second too. When it sputters it acts like my bike when i am running out of gas or if its not warmed up yet in the morning. When i take off it will sputter for about two seconds before it winds up. Once the rpms get above about 3500 it will run smooth again but im not sure if it has all the power it should. I am wondering what i should check first. Since i did disconnect the fuel lines and pull the fuel rail i am wondering
1) could i have gotten dirt or something in the fuel lines?
2) could one of the lines not be connected correctly?
3) could i have gotten an injector messed up or reinstalled incorrectly in the process?
4) would a vacum leak cause such behavior?

Thats what i could come up with. Where do you guys think i should start or is there something else i should look at? The fuel filter is pretty new, same with the iac, and i just installed the 60v6 chip.

Edit: The other day it gave a big puff of smoke at startup for the first time ever...hasnt really done it since though

[gpse3400]

I'm sure you put everything together right up top. if it cruises well and starts... I'd start thinking about replacing the ignition modual. They will do things like that as well as other things. Stuttering is usually an igition problem 9 out of 10. You can try swapping the computer chip just to rule that out, But I'm leaning on the ignition.

[z34phoenix]

im having a stuttering prob with mine at low RPM when the car shifts into like 3rd at about 30 mph. the car registers KR spikes but from all other conditions, it doesnt apear to be actual Knock. but its at low RPM like 2300.

[radman3120]

if it would be the iginition module would it possibly only do it sometimes? I made this thread because the car had been doing this for a couple days but today when i drove it i couldnt get it to do it for some reason

[gpse3400]

yeah I know I had a problem every time I approached 4000 rpm the car would like cut out fast and keep accelerating. Load had no bearing on it, it was totally engine speed related. You live in Penna?

[radman3120]

Yea i live near harrisburg, pa and i go to school in hoboken, nj

Yesterday, on the drive to school the sputter was very predictable and consistent. For example, in fourth gear it would sputter somewhere between 2000 and 2500 every time i hit the gas. The other gears did the same thing at slightly different engine speeds for each gear. So it seems like the problem is in the ignition like you said. The ignition module can be tested at like Advance Auto or Auto Zone, right? anything else i should check out?

[Eric's93z]

my z sputter's too!

hey guys iam having the same problem with mine too so please help......i have a 93 z and my valve cover gaskets went so i replaced them along with plugs wires egr valve fuel filter and a vacum hose, cleaned the entire plenum for an half an hour and its been terrible since???? hesitates at 600 700 rpm's and then goes , the past couple of days its been better so wtf? please help

[gpse3400]

hey guys iam having the same problem with mine too so please help......i have a 93 z and my valve cover gaskets went so i replaced them along with plugs wires egr valve fuel filter and a vacum hose, cleaned the entire plenum for an half an hour and its been terrible since???? hesitates at 600 700 rpm's and then goes , the past couple of days its been better so wtf? please help

Yeah that sounds like the ignition module is going bad. Idle is were they ususally mess up the most. If you live near a junk yard, get set of coils and an ignition module from a 3100 or 3400 car, transfere th e parts over. Its cway cheaper than buying new, and you at least get parts that arent heat cycled a whole lot so they should last a long while.

[gpse3400]

Yea i live near harrisburg, pa and i go to school in hoboken, nj

Yesterday, on the drive to school the sputter was very predictable and consistent. For example, in fourth gear it would sputter somewhere between 2000 and 2500 every time i hit the gas. The other gears did the same thing at slightly different engine speeds for each gear. So it seems like the problem is in the ignition like you said. The ignition module can be tested at like Advance Auto or Auto Zone, right? anything else i should check out?

I think AZ does it. Although I don't think all of them do as the one by me doesn't...Like ?I said above Geta used mlodule from the yard. If you get one from a 511/3400 it's bound to work. Stop by Harrys on your way home or somthing. The best way to changew the coils and module out, id to remove dipstick, torque strut, the fans and fan support, and usea 5.5 mm socket and un bolt the coils one by one, the remove the ignition module. I say do it like this because the to remove the whole brakect is very time consuming ad isa pain. don't forget to disconnect the battery. also it take alittle work but you can get around the ac line without an extension. the onlky way the technique will not work is if the bolts are rusted and you cant get the socket to rotate the bolt. Chances are unlikely thats the case. I'm always out at harry's maybe i'll see you out there.

[radman3120]

Well, im going to go home this weekend so i will swap the chip back to the original to drive it home then i will check out everything once im home. Thanks for the input i will let you know what i come up with

[radman3120]

Well this is my second problem with a Very Stupid Fix, but hey I didnt have to spend any money.

After the car still sputtered after the removal of the chip we decided to check out the spark.......One of the wires was loose! Ig uess we somehow pulled it loose when we did the top end work, i dunno, but it runs fine now.

Makes me feel dumb, haha

[gpse3400]

Well there you go!

[radman3120]

ok unless the wire came loose again (it shouldnt have) i lied about it being fixed.......it sputter exactly the same on my way to and from work the last two days.

we did check the spark and the center coil had a little big of orange at the end of the spark but wasnt very noticeable. it stayed like that no matter how much i moved the gap on the tester. the other two coils were totally clean. is this enough of a difference to cause my problem?

also, we only tested the front bank of wires because each coil is connected to both banks and the rear ones are a pain to get to (plus it was starting to rain). is it likely for one pin on a coil to be bad and the other ok?