Good Morning everyone. I'm new to the forum so please bear with me. Recently I purchased a 1990 GT 5.0 as my project car and aside from general maintenance there is nothing special about it. The individual(s) before me did install a cold air intake, 65mm throttle body, exhaust from the header back, and an E303. The issue I am having is that the car seems to idle very low at about 550 to 650 rpms. As a bit of background, recently I took the car to a shop and was determined that there was no vacuum leak, compression was good, and after finding out that the timing was retard a bit it was adjusted to 14 degrees. This in fact made the idle more stable as it was worse before; however, its not where it should be and the car does turn itself off after a few minutes of sitting at idle. Now I have heard that because the intake and heads are stock, that the e cam is the cause of the problem and the ecu either needs to be chipped or flashed or go to standalone in order to correct the issue. Can anyone validate this or perhaps give me some other ideas of where to continue. Thank You very much. happy new years to all.
New To Forum... 1990 Gt Idle Problems
- Thread starter dadrkknght
- Start date
-
Sponsors (?)
mikestang63
SN Certified Technician
Welcome. The problem s the e cam.IMO. You have essentially a stock motor with a cam that has a 110 LSA, which inherently is going to cause some idle problems. You should raise the idle up to compensate.
Sorry to be the bearer of bad news but that cam is doing nothing for you with your setup. The power band is from 3000 and up and with the stock heads and intake you are making less torque down low where you need it. It was swapped in probably for the lopey sound that newbs think equates to power. If it were me, I would put a stock cam back in until you change the heads, intake, etc.
Sorry to be the bearer of bad news but that cam is doing nothing for you with your setup. The power band is from 3000 and up and with the stock heads and intake you are making less torque down low where you need it. It was swapped in probably for the lopey sound that newbs think equates to power. If it were me, I would put a stock cam back in until you change the heads, intake, etc.
You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix. 
It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 159,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 159,000 hits, which indicates it does help fix idle problems quickly and inexpensively.
turn up the idle. My personal experience with the e cam is that it likes to idle closer to 900 rpms
mikestang63
SN Certified Technician
OneWheelPeel
Active Member
Check and clean your pcv valve. Once I replaced mine and cleaned the filter my car idled better. I also have an E cam.
Phillip123
Active Member
- Jan 5, 2015
- 125
- 17
- 28
I run the e303 myself, before doing heads and intake the car was a lopey turd...
Get the car up to operating temp.
Unplug the iac (it's the electric valve on the throttle body), and pull the spout connector (the little chip that inserts into the wiring for the distributor) and PUT THAT THING IN YOUR POCKET! If you loose it your up a creek.
Start the car (if it will start) if it won't adjust the throttle stop until the car starts and idles, you are looking for 750-850 rpm. Shut off the car and put the spout back in and plug in the iac. Disconnect the battery negative and turn the headlights on, let it sit for a minute. Reconnect the battery and start the car.
Get the car up to operating temp.
Unplug the iac (it's the electric valve on the throttle body), and pull the spout connector (the little chip that inserts into the wiring for the distributor) and PUT THAT THING IN YOUR POCKET! If you loose it your up a creek.
Start the car (if it will start) if it won't adjust the throttle stop until the car starts and idles, you are looking for 750-850 rpm. Shut off the car and put the spout back in and plug in the iac. Disconnect the battery negative and turn the headlights on, let it sit for a minute. Reconnect the battery and start the car.
Similar threads
