PC-85-928S

after completing my upper intake refresh, my car continues to be hard to start. It turns over right away, but is not getting a steady idle, and stalls itself a few times. It will then run, but initially crawl, and buck. Once it warms up, and at highway speeds it is running smooth and well. However at a light the idle is irratic. I redid all the vacuum lines with Rogers's kit. I changed the plugs, rotors and caps. My wires are in good condition. I cleaned the mas.
I am considering changing the sensor in the air cleaner, however i changed it once already.

I am wondering if while replacing the u shaped fuel line on the rear center of the firewall, if I made it shorter than the original, and with a tighter bend.
I matched it to the old one, but then I had a bad cut, so i made it slightly smaller.
I also did not remove the throttle body, or change the tps on it.

Ducman82

Idle air control hooked up?

PC-85-928S

New one
Pretty sure I hooked it up correctly
If it did not involve removing the intake I would hook the old one back up

Mike Frye

The ICV can be swapped out without removing the intake. You have to remove the air intake box and MAF but then you have enough room if you're careful.


This sounds to me like more than one issue and the rule is, the last thing you did is the most likely suspect.


You'll need to work through the test plan in the WSM.

Could be electrical, could be ground, could be fuel, could be vac leak, could be a bad O2 sensor or Temp II sensor. Could be any combination of these and you have to isolate and rule out each one all the way back to the LH/EZ.

Did you use anything to verify there are no vacuum leaks? There are a million places that you can get one and unmetered air is the biggest cause of erratic idle IMO.

I would suggest building a jig to test for vac leaks and deal with all of them until you can maintain 4-5 psi with this setup for at least 30 seconds.
I found leaks in the:
dipstick tube O-ring, and dipstick O-ring itself...
throttle body O-rings on the side of the throttle plate
hose going to the ICV (forgot to tighten that hose clamp)
check valve on the top of the oil fill neck (that one was a b!tch)
I also found that although my TPS was clicking and read good when the car was cold, when it warmed up it was changing the geometry just enough that it wasn't working. Replacing or adjusting the TPS is not so easy with the intake on but it's possible. Also, I recommend replacing those screws with allen head bolts, they're easier to adjust in situ.

Here's the vac/pressure tester I made:

WICruiser

Confirm the vacuum hoses that connect to the throttle body are on the correct ones. One port is open at idle and the other is not. If they are switched you have a significant vacuum leak at idle.

MarkRobinson

Confirm vacuum: 17-18" is about normal. Vacuum less, then trace the lines: there are plenty of references on this forum for the proper routing.

Can you try another MAF to ensure yours is well within spec?

Temp II sensor is the god for most maps & such: a flaky temp II or freyed wiring near/at the plug will also cause incredible frustration.

Is your fuel filter under a few years old? a clogged/clogging fuel filter will cause issues such as this as well.

Mark

PC-85-928S

Couple questions:
Mike, with your test unit, you place it in the MAS and hook the other end to a air compressor? The car does not have to be running?

Mark, when you say 17"-18" is normal for vacuum, you are referring to the pressure, correct? Not the length of the lines. I altered the length of many lines when converting to the new vacuum set- up.
How do you measure the pressure?

Shane

Actually 17-18" would be refering to the opposite of pressure. Vacuum is measured in inches of Hg. If you have a mityvac you can "T" into the vacuum line going to the EZF and be able to read the gauge inside the car. If you don't have a mityvac you can buy a cheap boost/vacuum gauge and connect it up the same way.

Mrmerlin

check the rubber couplers for the plenums and then if they are good,
check the dampers and FPR for fuel smell,'
if no fuel leaks,
Then put in a rebuilt MAF

PorKen

As Stan indicated, if the MAF is original, then it is very likely time to replace it.

PC-85-928S

Are MAF's rebuildable?
I know they are pricey.
Are aftermarket units avail?

namasgt

Rogers sells rebuilt units for a very reasonable price. Ask him.

PC-85-928S

I am getting a flashing gear indicator
It is flashing in park, and continuing to flash in drive

I am also getting a very high pitch squeal-almost like a tea pot

I know my drivers side cam caps are leaking oil, because I did not replace the small rubber o rings on them.

Could the leaking plastic cam caps be causing the irratic idle?

Mrmerlin

the flashing gear indicator is a belt tension warning,

dont run the engine till you have confirmed the belt tension is correct.
looking at the owners manual will provide you the info about your warning lights and what they mean,

Andrew Olsen has links on his posting page for owners manual PDF files

Mrmerlin

https://rennlist.com/forums/928-foru...al-online.html