Idle problems & slight surging

Saleen308 · 03-16-2001, 09:16 PM

My car has been put up for most of the winter. I decided to get her out and start driving her again. I had a dead battery and my alarm decided to go out. I got both of those things resolved.

When the car is cold the idle is fine but, when it is warmed up it trys to idle any where around 1400rpms to 2100 rpms. Even after reving it a couple of times it still does it. Sometimes going down the highway it acts like it is trying to surge. It does it more at lower rpms than it does at higher rpms.

I added a bottle of fuel injector cleaner but, I haven't ran that tank out yet. I am thinking about adding a bottle of HEET just in case the surging is related to water being in the gas tank.

Any guesses?

------------------
347 stroker, TFS track heat heads ported and polished, ported GT-40 intake,70mm TB ans spacer,75mm MAF,K&N,24lb injectors,1 5/8" mac long tubes, off road h-pipe, FMS "z" cam, FMS plug wires, NGK plugs, FMS aluminum drive shaft, Omega 1.6 RR, FMS 3 core radiator, Flowkooler waterpump, World class T5, Pro 5.0 shifter, Autometer Fuel psi gauge, Autometer A/F gauge, caster camber plates, Koni reds, Pan hard bar, S.S. brake lines, Centerforce Dual Friction clutch, Walbro 255lph FP, Lakewood drivesha

slider · 03-17-2001, 06:27 AM

The right way would be to scann for codes first. You might have a faulty sensor.

And if you want my quick guess from your description, I would say clogged fuel filter and fuel regulator. The injector cleaners pick up alot of deposits from the fuel tank, sending them to your rails.

david

86GT · 03-17-2001, 11:08 AM

Do the regular fuel filter, pcv valve, and tune up if you haven't done that in a while. I'd also think that maybe the IAB on the side of the throttle body is sticking, it might need a cleaning.

Saleen308 · 03-17-2001, 01:20 PM

I have a fuel pressure gauge mounted on the cowl. Fuel pressure looks just like it always has. Normally when I get a clogged fuel filter the pressure starts acting funny.

The check engine light has not come on at all so I am not sure if there would be any codes to retrieve.

poopstang · 03-17-2001, 04:51 PM

clean the TB, IAB and check the MAPsensor?

slider · 03-17-2001, 04:53 PM

hmm no codes, eh

If the fuel regulator its clogged or bad, can you tell by looking at a fuel pressure guage?

how about distributor cap and rotor?

MY91GT · 03-17-2001, 05:16 PM

How about the idle air motor? It might need to be reset or it went bad. With an X cam, you are going to run into problems with a steady idle but if it was running fine before then something is probally wrong. You can also try to adjust your FP and timing...when mine goes out of wack, i can fix it with just tuning it.
just my opinion

------------------
TW Heads, Edlebrock RPM, 75mm TB, 75mm MM, Anderson N-2 cam, stock block, underdrives, paxton regulator, bbk 155 intank, 30lbers, motorsport alum rad msd ignition and coil, 3.73 gear, Tremec 3550, Motorsport HD clutch, K&N, hooker shorties, pacesetter h-pipe, and dynomax cat back, mac upper and lower control arms, no front sway bar. I think that's it. GO ILLINI!!!
Waiting for good weather for new times.

slider · 03-17-2001, 05:41 PM

A code scanner
quick, use it

Saleen308 · 03-17-2001, 07:21 PM

Poopstang:

What does the map sensor do? and how can you tell if it is going bad?

03-16-2001, 09:16 PM	#1
Saleen308 Registered Member Join Date: Apr 2000 Location: Houston, Texas Posts: 142	Idle problems & slight surging My car has been put up for most of the winter. I decided to get her out and start driving her again. I had a dead battery and my alarm decided to go out. I got both of those things resolved. When the car is cold the idle is fine but, when it is warmed up it trys to idle any where around 1400rpms to 2100 rpms. Even after reving it a couple of times it still does it. Sometimes going down the highway it acts like it is trying to surge. It does it more at lower rpms than it does at higher rpms. I added a bottle of fuel injector cleaner but, I haven't ran that tank out yet. I am thinking about adding a bottle of HEET just in case the surging is related to water being in the gas tank. Any guesses? ------------------ 347 stroker, TFS track heat heads ported and polished, ported GT-40 intake,70mm TB ans spacer,75mm MAF,K&N,24lb injectors,1 5/8" mac long tubes, off road h-pipe, FMS "z" cam, FMS plug wires, NGK plugs, FMS aluminum drive shaft, Omega 1.6 RR, FMS 3 core radiator, Flowkooler waterpump, World class T5, Pro 5.0 shifter, Autometer Fuel psi gauge, Autometer A/F gauge, caster camber plates, Koni reds, Pan hard bar, S.S. brake lines, Centerforce Dual Friction clutch, Walbro 255lph FP, Lakewood drivesha

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03-17-2001, 06:27 AM	#2
slider Registered Member Join Date: Mar 2001 Location: San Diego, CA, USA Posts: 86	The right way would be to scann for codes first. You might have a faulty sensor. And if you want my quick guess from your description, I would say clogged fuel filter and fuel regulator. The injector cleaners pick up alot of deposits from the fuel tank, sending them to your rails. david

03-17-2001, 11:08 AM	#3
86GT Sniffed too much n20 Join Date: Oct 1998 Location: Ont, Canada Posts: 1,018	Do the regular fuel filter, pcv valve, and tune up if you haven't done that in a while. I'd also think that maybe the IAB on the side of the throttle body is sticking, it might need a cleaning.

03-17-2001, 01:20 PM	#4
Saleen308 Registered Member Join Date: Apr 2000 Location: Houston, Texas Posts: 142	I have a fuel pressure gauge mounted on the cowl. Fuel pressure looks just like it always has. Normally when I get a clogged fuel filter the pressure starts acting funny. The check engine light has not come on at all so I am not sure if there would be any codes to retrieve.

03-17-2001, 04:51 PM	#5
poopstang Registered Member Join Date: Mar 2001 Location: palmbayFL Posts: 184	clean the TB, IAB and check the MAPsensor?

03-17-2001, 04:53 PM	#6
slider Registered Member Join Date: Mar 2001 Location: San Diego, CA, USA Posts: 86	hmm no codes, eh If the fuel regulator its clogged or bad, can you tell by looking at a fuel pressure guage? how about distributor cap and rotor?

03-17-2001, 05:16 PM	#7
MY91GT Registered Member Join Date: Mar 1999 Location: University of Illinois-Urbana/Champaign Posts: 370	How about the idle air motor? It might need to be reset or it went bad. With an X cam, you are going to run into problems with a steady idle but if it was running fine before then something is probally wrong. You can also try to adjust your FP and timing...when mine goes out of wack, i can fix it with just tuning it. just my opinion ------------------ TW Heads, Edlebrock RPM, 75mm TB, 75mm MM, Anderson N-2 cam, stock block, underdrives, paxton regulator, bbk 155 intank, 30lbers, motorsport alum rad msd ignition and coil, 3.73 gear, Tremec 3550, Motorsport HD clutch, K&N, hooker shorties, pacesetter h-pipe, and dynomax cat back, mac upper and lower control arms, no front sway bar. I think that's it. GO ILLINI!!! Waiting for good weather for new times.

03-17-2001, 05:41 PM	#8
slider Registered Member Join Date: Mar 2001 Location: San Diego, CA, USA Posts: 86	A code scanner quick, use it

03-17-2001, 07:21 PM	#9
Saleen308 Registered Member Join Date: Apr 2000 Location: Houston, Texas Posts: 142	Poopstang: What does the map sensor do? and how can you tell if it is going bad?