shaved intake 280zx, now won't start

[Mobious5]

yea i tried that but cant get it to idle anywhere above 500. and it only raise that high when i put thumbs over the ends and barely let air through.

it seems as if everyone who does this has done it with 240 TB's.

 

If i've done this right should there be ANY vacume lines leading into the throttle body???

thanks

[FlatBlack]

Mobious how cold is it over there? Im telling you without the IAC it is going to idle really low until the motor warms up. When it is warm its not much of a problem but will still idle a bit low at start up. If you adjust the idle screw its going to run at higher RPMS at normal running temperature.

[woldson]

To get my car to idel properly it was a fun game of adjusting the afm, that idel screw, and timing.

Without proper tools I have her running very good! I'm na so not toooooo worryed about detenation.

 

A dyno party is coming up, so I will get to see how badly I suck, or.........

[Mobious5]

whenever i work on the car its between 60-70+ degrees outside so i should worm up pretty fast you would think.

even then, when its warm, that pipe under the TB just keeps sucking in air then causes the car to die. then whenever i plug it, the same thing happens.

???

[dhp123166]

I know when I keep doing the "wrong" thing, I should not be surprised when all I receive is the "wrong" results.

 

That's just common sense...

[srbigbutt]

Mobius5,

Here is an intake swap with a 60mm TB conversion I just completed yesterday for a local customer. Some of the details may be of help in your project. Local customer located a non-EGR N-42 intake, 60mm TB, Pallnet fuel rail and TB spacer kit then dropped the car off and wanted it installed and tidied up similar to what we have done for many others, including rerouting the EFI harness along the firewall and under the fuel rail instead of over the middle of the plenum. Fired the car up yesterday, runs great, just as it did when it came in, other than the deleted air flow regulator as described below, other than that, no differnet!

 

This is a bone stock L-28 EFI.

 

Items deleted;

1) EGR, (This is a ’75 car registered outside of CA)

2) Air Flow Regulator (for a cold idle speed that the engine will idle on its own without holding the gas pedal, a "warm" idle speed has to be approx 1000-1200 RPM on a properly tuned L-28. If a warm idle speed of 650-800 is desired, then you’ll have to hold the gas pedal to keep the car running when cold till the car warms up, or reinstall the Air Flow Regulator.)

3) Coolant by pass that ran under the Air Flow Regulator.

4) Cold start injector and Thermo time switch. Tapped the cold start injector hole for 1/8" NPT, brass pipe plug installed. (left the Thermo-time switch in the thermostat housing, just deleted the wiring.)

5) A/C equipment in the engine bay.

 

Items rearranged; but still functioning as OE!

1) Carbon Canister vacuum line has new port drilled and tapped into the back of the plenum and vacuum line rerouted along passenger frame rail and across the lower firewall.

2) Fuel Pressure regulator relocated to the firewall, fuel rail plumbed in a pseudo dead head style arrangement, (before anyone jumps on the “dead end EFI fuel systems cant be done†bandwagon, SEARCH! It can, has, and is still being successfully done, by the OE and tuners such as myself with NO ill effects NO vapor lock etc). Vacuum port of the FPR also has its own new dedicated vacuum port added to the back of the plenum next to the canister port.

3) PCV is now drawing fresh air, K&N filter on valve cover. (This caused the engine to ingest "false air" as the air being drawn in through the PCV system is no longer being measured by the AFM, yet the engine is breathing that air, i.e. “false airâ€), as such I will be fine tuning the part throttle tune with a combination of the water temp resistance and AFM adjustments, todays project. For those new to the stock EFI or EFI in general, just leave the valve cover breather plumbed to any port between the Throttle body-butterfly and the AFM and you’ll be just fine!

4) Removed the EFI harness and removed the outer sheathing from the harness that resides in the engine bay. Deleted the Thermo-time switching wiring back to the splice, also deleted the cold start injector wiring. (Just leave the wires cut, but protected from grounding/shorting. The computer doesn’t know the difference nor does the engine.) Separated the injector wires and the water temp sensor wires of the AFM and TPS wires into two separate runs. Retaped those as 2 runs. Reinstalled harness, routed the injector and water temp wires along firewall and then under the fuel rail, (can’t even really see them in this photo below, but they are there) and routed the AFM and TPS wires back in the stock location.

 

Customer wasn’t ready to for a shaved intake, so this one was just painted and installed. Original fuel pressure regulator port plugged as well as a couple other deleted vacuum ports.

 

Here is the picture, below that is a diagram of the dead-head fuel rail system.

 

Boot between TB and AFM is not secured in picture, it needs to be secured!

 

 

 

 

 

 

Hope this helps,

Paul

 

 

Wow! Awesome post. Inspired me to start cleaning up my intake. Now I need to install my new JSK fuel rail, new injector clips, and re-route the wireing.

 

So if I want to install a valve cover filter, it would best to wait till I get Megasquirt??

[Mobious5]

i finally got the car running ok... i adjusted the idle screw on the TB and i hooked that pipe under it to my PVC valve then to a vacume line to the pump. i didnt screw the PVC onto the intake i just leave it sitting there.

 

i have the to hoses leaving the charcol canister unpluged. (i dont no if thats good or not)

 

i have another problem though, at first the car wouldnt come out of first gear (automatic trans) till 45mhp and 4k rpm. i was like wtf.. then i noticed a tear in the vacume line from the intake manifold to the trans line. i replaced it just now and is all better.

 

but where the problem lies is, the car dosent have the same get up and go as it used to. i cant squeel tires and now my o-60 is like 20sec. a 50 ton 18 wheeler would destroy me off the line.

 

do you have any clue what could be going on? i checked vacume... could it be the timing? i dont no

 

i hope its the timing because the car sounds like its caming. i can hear the rockers clicking pretty loudly. the vacuum advance is still hooked up..

 

help...

[woldson]

but where the problem lies is, the car dosent have the same get up and go as it used to. i cant squeel tires and now my o-60 is like 20sec. a 50 ton 18 wheeler would destroy me off the line.

 

 

Thats funny!

 

Good job on the progress, personally I don't have any advice at this moment.

[FlatBlack]

i finally got the car running ok... i adjusted the idle screw on the TB and i hooked that pipe under it to my PVC valve then to a vacume line to the pump. i didnt screw the PVC onto the intake i just leave it sitting there.

 

i have the to hoses leaving the charcol canister unpluged. (i dont no if thats good or not)

 

i have another problem though, at first the car wouldnt come out of first gear (automatic trans) till 45mhp and 4k rpm. i was like wtf.. then i noticed a tear in the vacume line from the intake manifold to the trans line. i replaced it just now and is all better.

 

but where the problem lies is, the car dosent have the same get up and go as it used to. i cant squeel tires and now my o-60 is like 20sec. a 50 ton 18 wheeler would destroy me off the line.

 

do you have any clue what could be going on? i checked vacume... could it be the timing? i dont no

 

i hope its the timing because the car sounds like its caming. i can hear the rockers clicking pretty loudly. the vacuum advance is still hooked up..

 

help...

 

You're using PVC on your Z car?? haha

 

PCV = Positive Crankcase Ventilation.

 

The car sounds like it's camming? What does that mean?

 

Revv the motor up manually to about half throttle, and then play with the AFM under its plastic cover. If it runs better when you pull the weight counterclockwise its running too lean, and too rich if it runs better the other way.

[Mobious5]

You're using PVC on your Z car?? haha

 

PCV = Positive Crankcase Ventilation.

 

The car sounds like it's camming? What does that mean?

 

Revv the motor up manually to about half throttle, and then play with the AFM under its plastic cover. If it runs better when you pull the weight counterclockwise its running too lean, and too rich if it runs better the other way.

 

haha oops.

 

yes sir, i have it between the bottom pipe under the TB and a vacuum line...

 

i'll try that this afternoon!

[FlatBlack]

haha oops.

 

yes sir, i have it between the bottom pipe under the TB and a vacuum line...

 

i'll try that this afternoon!

 

Good luck! Do you have any spare AFMs? I have about 3 or 4 so I actually adjust the spring rate on mine to get the AFR in range. It's usually frowned upon but I have several so if I mess one up it's not a problem.

[Mobious5]

i think i may have found my problem causeing my power lag and loss of acceleration. im missing furthest left and furthest right exhaust/intake gasket.... sooo theres black carbon and exhaust leaking everywhere.

 

i got a new gasket and two bolts so im hoping this will fix my problem!!!!

[texanredneck]

My 2 Cents

 

Deffinately sounds to me like your piping isn't ran right all the way and u deffinately still have a vacuum leak

 

I do remember another thread that was discussed stating if your not going to hook up both pcv hoses to the intake, the one ontop the valve cover and from the block you should put a filter on them because it will cause a another vac leak. As for the idle screw, I don't beleive it will work properly with out the iac tubing (mess) is hooked up.

Edited May 5, 2009 by texanredneck
Rememberd other thread

[FlatBlack]

i think i may have found my problem causeing my power lag and loss of acceleration. im missing furthest left and furthest right exhaust/intake gasket.... sooo theres black carbon and exhaust leaking everywhere.

 

i got a new gasket and two bolts so im hoping this will fix my problem!!!!

 

I left two injector o-rings off when I shaved my manifold and my car ran like crap :facepalm:

 

Just remembered that, if that doesn't fix the problem you should go back and make sure one or two didn't fall out.

[superduner]

word to he wise from experience start from the easy things and cheap things to fix thing first. i learned the hard way on my zxT project i just started. i even have a thread about it asking for help. except mine wouldn't start PERIOD. (turned out i had 4 bad injectors)

 

start off by making sure theres even GAS going into the injectors(maybe ur only running a few)

move into checking if gas even comes OUT of the injectors.

then spark

then timing. then vacuum leaks. since lines are difficult to get right without a 280zx haynes

 

if all else fails buy it off ebay

[feero101]

Well I just finished shaving my intake and adding a custom fuel rail. Its an 83 ZX and for some reason I cannot get it to rev? It will idle, low.. but it will idle. But once I barely touch the throttle it boggs out. I cannot for the life of me find a vac leak. Everything is grounded.... And I am just completely stumped. I also followed Braaps little write up for shaving the intake. At a total loss, for some reason everyone else has the complete opposite?

 

 

[feero101]

Aslo should add, I'm running turbo injectors. Bought them on accident. But when it idles it actually does not seem to be rich.

[JSM]

3) PCV is now drawing fresh air, K&N filter on valve cover. (This caused the engine to ingest "false air" as the air being drawn in through the PCV system is no longer being measured by the AFM, yet the engine is breathing that air, i.e. “false airâ€), as such I will be fine tuning the part throttle tune with a combination of the water temp resistance and AFM adjustments, todays project. For those new to the stock EFI or EFI in general, just leave the valve cover breather plumbed to any port between the Throttle body-butterfly and the AFM and you’ll be just fine!

 

Old thread yes.  Paul is there a reason the Valve Cover Breather has to be tied there?  Can it be tied back into the PCV valve underneath the intake like the block? I was wanting to eliminate it from the TB.

[Chickenman]

Not Paul, but on EFI if you are using an AFM ( flappy doodle ) or MAF ( Mass Air Flow ), ALL of the air that is ingested by the engine has to be maesured by the AFM or MAF.

 

The PCV system is a loop system. Fresh air is drawn through the Valve Cover ( and naturally needs to have some form of Air Filter ) into the crankcase ( big freaking hole though timing cover to oil pan ) and then extracted through a breather port in the block and then finally drawn into the inlet manifold through the PCV valve. The PCV Valve is nothing but a metering valve. Now the crankcase fumes ( mainly ring blow-by ) are somewhat combustible and the outside air flowing through the system has to be accounted for by the ECU on a AFM or MAF EFI system. Otherwise the  will be thrown out of whack. Early L-Jetronic  EFI systems have no feed back loop ( O2 sensor ) to self correct the mixture. So you must make sure that the PCV system is properly routed and the Intake air is drawn through the AFM.

 

One exception is if you are using a Speed Density EFI system. Speed density does not use any type of Air Flow measurement device.  Only a MAP or Manifold Absolute Pressure  sensor . Then you can use a K&N style filter on the Valce Cover vent. There is no advantage to doing that, other than esthetics.

 

The other exception is carburation. Carburated cars are already calibrated for the bypassed air used by the PCV. The vent line goes from the valve cover to the inside lid of the air cleaner to draw in fresh air. You can use a K&N style filter on the Valve Cover of carbed cars as well. It will make no difference to the closed loop function of the PCV system nor the fueling calibration.

 

Hope this helps. And BTW... you ALWAYS want to run a PCV system on a Daily Driver. The Positive Crankcase Ventilation systems main job is to remove contaminants and acids in the engine oil caused by ring blow by. Secondary action is that it provides a negative crankcase pressure under most operating conditions that improves Piston ring seals and also reduces oil leaks from crank shaft seals and engine gaskets. The seal lips are designed to operate normally with a Negative crankcase pressure, not a positive crankcase pressure.

 

Race cars can get away with Vent To Atmosphere oil breathers and catch tanks. They change oil often ( gets rid of contaminated oil ) and run Dry Sumps or Vacuum pumps that create negative crankcase pressure ( for improved piston ring seal )  But VTA is not a good idea on a street car, IMHO.

[JSM]

Thanks. Totally forgot about the timing chain hole. Why is the crankcase vented to the PCV with no vacuum at WOT but the valve cover is run to the intake hose after the AFM but before the TB? At WOT, why wouldnt both be Plummed between TB and AFM? Or even at idle for that matter.

At WOT there is no vacuum and the PCV is closed. So the closed loop is drawn back through the valve cover but is not metered because it's after the AFM? Or because it is after the AFM it's already been read?

 

EDIT: I got it I read the FSM! Go figure.  It does reverse at WOT.  Thanks Chickenman.

Edited January 28, 2017 by JSM