I have a 1994 SL2 saturn.It will not start unless you floor the throtle. It has new tuneup,and no service engine light on. When it starts, it runs ok, but rich. I checked for vacuum leaks,found none.I checked all engine sensors to specks, all are ok. Any help is appreciated
The problem might be a flooded condition when you attempt to start the engine.
When you floor the throttle, the computer goes into the flooded mode. This causes the computer to only deliver half the fuel from the injectors to help clear the flooded condition. And because you say it runs rich points to it being flooded.
The most common cause for a complete flooded condition is a leaking fuel pressure regulator. The regulator is on the fuel rail. It’s a small metal canister with a single vacuum hose attached to it. Remove the vacuum hose from the regulator, and gas leaks out of this connection, replace the regulator.
Tester
Thank you, it seemed to solve that problem. It started right up. I ran it for 1hr then I drove it. I got two miles out and it stalled at a corner. It started but I had to give it some gas for it to start, not to the floor, just a little. Now it needs to have a little gas to start. It no longer runs rich,but now after it completly warmsup, it will stumble every 2 or 3 min, only for a second or so, then smooth out .It runs strong and great when driving, but will stumble at a corner, then it might or might not stall It is a 5spd trans> exceleration is smooth and strong Thank you for your help
It might still be a bit rich. Has the check engine light come on? It might come on to indicate a misfire. You could throw several expensive parts at a misfire, if you chose to go that way. Instead, start small. Change the air filter. Test, or just replace, the engine coolant temperature sensor. Change the spark plugs. If it still misses, change the spark plug wires. After that, pull out Mr. Haynes, or Mr. Chilton’s, and do those tests of the ignition system and the fuel system (which includes the fuel injectors). // You can get an inexpensive code reader to read the check engine light (less that the price of a MAF), and post whatever codes it may have, here. Someone will give an interpretation of the code(s) and advice you.
“no service engine light on”
You still might want to check to see if any codes have been stored. Since some parts stores will check it for free, give it a try.
I think that Mr. Meehan is forgetting that this is an OBD1 (On Board Diagnostics) car, those before 1996 (2, or 3 exceptions for 1995). The auto parts stores won’t/can’t read OBD1 codes. They will/can read 1996 and later cars and trucks, all of which have OBD2. Save money on guess-parts; get an inexpensive OBD code reader, if the check engine light has come on.
Thanks to all of you. I have a code reader for obdII and a code reader for obdI.There is no service engine light on. There was when I started this project, but, I corrected them. The inlet air temp sensor was missing, the cooling fon was plugged into a spot for an auto trans conection in the relay box, causing a code 26 and several others. Those are all corrected now and the stumble is the latest and hopfully the last issue!
I would suspect that you may have a water temperature sensor gone bad. If it fails to send the wrong signal to the ECM it may think it is very cold outside and allow the fuel injectors to stay open longer to put more fuel in causing the over rich problem. Just a thought.
Shows how to test it here:
http://www.autozone.com/az/cds/en_us/0900823d/80/19/a0/36/0900823d8019a036/repairInfoPages.htm
May also be the MAS Sensor also. Again here shows how to check it:
http://www.autozone.com/az/cds/en_us/0900823d/80/19/a0/77/0900823d8019a077/repairInfoPages.htm