hard start

[JimN696]

Recently my 94 atx developed this problem:
It starts fine when cold, but once it has warmed up, and I've shut it off and left it for awhile, it won't restart on the first try unless I turn the key on for a couple of seconds first. Sounds like a loss of fuel pressure in the rail, but there are no leaks or fuel smell. Could it be that the pump is on it's way out? Clogged filter (the filter was replaced a month or two ago)? What else?

------------------
Red 94 ATX, all options, bone stock.

 

[sdpatt]

It sounds like the fuel return line check valve is not maintaining perssure in the return line. This allows the hot fuel to depressurize when the engine is shut off and boil to vapor. Do you hear a low frequency rumbling coming from under the rear seat when the car is idling? That would be the fuel vapor bubbling up throught the fuel in the tank. The rumbling gets deeper in tone and louder when the gas tank is full and the fuel level is higher.

The fuel return line check valve is mounted on the end of the ~3/8" return line on the pump and sender assembly. The valve looks more like a rubber duck call and is held on the line by a simple clip. To access the valve, you have to drop the nearly empty gas tank and rotate the pump assembly retainer ring CCW to remove the assembly. The valve is quite cheap, but not nearly as cheap as it should be through Ford. You may want to check at local auto parts stores for it since many fuel injected cars will need a similar part. Should be just a few bucks.


------------------
Scott

1991, 252K miles, glass hood, police grill, SVO shifter, Catz fogs,
K&N, 73mm MAF, Superchip, PP Y-pipe, Borla cat-back, 190 lph pump
Eibach/Tokico/polyurethane, SHO Shop front & rear strut braces,
16x7.5" Moda R1, 225/55ZR16 Bridgestone RE730, -1 deg camber x 4,
Class II hitch, Silver award at the SHOklahoma Car Show

[This message has been edited by sdpatt (edited 11-17-2001).]

 

[Tommy the Greek]

My '95 ATX has the same exact problem, the only thing mine does now is that when it finally does start up the engine shakes and it jumps from 600-900 rpm's. When I press the accelerator pass 3000 rpms then let go it will idle normally. What is wrong?
It only does this when engine is hot.

------------------
'95 SHO ATX, 55W foglights, coneless, fishtank mod, white/mocha cloth interior, 45K, Mobil 1 10W-30, build date 12/13/94.
Below is a pic of her @ 28K miles (Nov. 6, 2000)off interstate 87, overlooking Lake George, NY.

www.roushind.com

 

[slosho]

Try cleaning your IAB valve.

------------------
95' ATX Opal Frost
Cone Filter W/ heat shield
TB coolant Bypass
Bypassed a "PCV" line
Fog light mod
Reverse light mod
Sony head unit (el cheapo cdx-650)
JL Monoblock 500
JL 2-12w3's
Rear tint
More to come.

 

[JimN696]

what is an iab valve and what does it do?

------------------
Red 94 ATX, all options, bone stock.

 

[fredhurderjr]

It's on the driver's side of the intake manifold, inside the plenums by the runners. It looks like a silver cylinder about 4-6 inches long with a black wiring harness out the back by the firewall side. It regulates the airflow into the intake. When mine was flukey with the blower, my idle would surge/cycle from 800-1500rpm.

 

[sdpatt]

An oscillating idle speed is usually caused by a sticking IAB valve. The idle air bypass (IAB) valve does just that - it is an electrically controlled valve that adjusts the amount of air that bypasses the closed throttle plate. This is to allow the ECC to hold the idle speed at the programmed level when the various accessories are loading/unloading the engine. If you look at the intake manifold picture at the header of the Forum's pages, it is the device immediately to the right of the rightmost intake runner. The valve portion is the size of a D-cell battery and the servo is the size of a C-cell.

To remove it, you must remove the two 5mm Allen screws that hold it to the manifold. This can be challenging without many adapters and extensions to an allen socket. Once removed, use an intake or carb cleaner to hose out the normally blackened interior. You may also need to use a toothpick or Q-Tip to get the seating surface clean.

Scott

 

[Mikeys_Taurus]

I don't think that that is his problem. I just cleaned out my throttle body and IAC 2 weeks ago and I still have the problem with the oscillating idle. I ALSO can give it some gas and it will return to normal level. Here is my post from the TCCA:

Ok. So people that peruse the board or talk to me on a regular basis know that lately I have been having a serious problem with my car running lean and I think after much trouble shooting that I may have found the problem.

At first I thought the timing was advanced too much. So I put it back down to 10 degrees. Then I thought it was because the MAF was bad. It turns out the MAF isn't bad though. Then I became frustrated. Lately this week the fuel pumps wine has been getting a little huskier and a little louder. I turn on the car tonight and then turn on the headlights and the fuel pump nearly shuts off and all the lights dim really quick. It was enough of a power draw to turn my radio off and then on. So I'm thinking that my fuel pump is bad. Questions follow:

1. Where do I connect my fuel pressure gauge to?

2. Why is it straining my power when other things are turned on?

Before any electric people attack... The voltage on the battery with the vehicle on is 14.3 and with the car off it 12.8. So the battery and alternator are fine. I also cleaned the contacts on the battery to no avail.

Sorry for the long ass post!

Come to think of it, my fuel pump does sound deeper as well as louder. If anyone has anything... Please feel free, because I'm stumped.

------------------

[This message has been edited by Mikeys_Taurus (edited 11-17-2001).]

 

[JimN696]

When my engine starts, it idles and runs fine. it is just that hard start that is bothering me.

------------------
Red 94 ATX, all options, bone stock.

 

[sdpatt]

A hard start condition can be caused by a faulty CID (cylinder identification) sensor also knowm as the camshaft position sensor. The purpose of this device is to identify the location of the number one cylinder to synchronize the signals from the crankshaft position sensor to allow the DIS to get the correct spark order. If the CID signal is not present, the ECC tries the six different possibilities for which cylinder is number one until the engine runs. This sensor is usually less than $30 and is attached to the passenger side end of the firewall side exhaust camshaft with two 5.5mm bolts.

Scott

 

[JimN696]

i had that sensor replaced during the 60K service recently so i may have gone bad. Sounds like it is either that sensor or the fuel return check valve that you mentioned earlier. Is there any way to check the sensor?

------------------
Red 94 ATX, all options, bone stock.