bad sputtering and backfiring problems....
06-21-2008, 02:04 AM
#11
5th Gear Member
Join Date: Jul 2003
Location: United States
Posts: 3,451
RE: bad sputtering and backfiring problems....
Sounds like a bad IAT or coolant temp sensor to me if it's only doing it when cold.
The surging you're feeling when driving sounds to me like lean surging & generally what causes it when cold is either of those two sensors not working. If one isn't working the computer will read it like it's getting normal warm air in the engine. When the engines cold it will dump in more fuel to compensate for the air being more dense. Gasoline engines generally start surging around 16.6:1 a/f ratio.
as you know there's more air getting in your engine when it's cooler than when it's warmer, obviously the eec must tell the injectors to put more fuel in otherwise it will cause it to run lean.
Both can cause an eratic idle. If the bad idle persists after that, try cleaning the IAC.
As for location. The IAT is on the drivers side in the (i believe) #5 runner (the front driver side one) on the lower intake. Should have two wires coming out of it.
The coolant temp sensor for the EEC is on the passenger side. I believe the top tube of the two black tubes that go to the heater core. It'll be more toward the front of the engine.
Just to let you know there are two coolant temp sensors. The one on the passenger side like i described above is for the EEC only. The one wire one on the drivers side is for the gauge only & has nothing to do with the eec so don't worry about checking that one.
You can check both if you have a volt/olm meter. Here's an image to help you out.
BTW, you can check both sensors when the engine is cold & not been running. As long as they have the correct cold reading. With the key off both should read around 20-30 ohms if the engine is cold (obviously this will vary depending on the outside temp, check the table above for reference)
Or you can check the voltage reading with the key in the on position.
Both sensors are very important for spark & fuel curves so either one could do it.
Hope this helps.
The surging you're feeling when driving sounds to me like lean surging & generally what causes it when cold is either of those two sensors not working. If one isn't working the computer will read it like it's getting normal warm air in the engine. When the engines cold it will dump in more fuel to compensate for the air being more dense. Gasoline engines generally start surging around 16.6:1 a/f ratio.
as you know there's more air getting in your engine when it's cooler than when it's warmer, obviously the eec must tell the injectors to put more fuel in otherwise it will cause it to run lean.
Both can cause an eratic idle. If the bad idle persists after that, try cleaning the IAC.
As for location. The IAT is on the drivers side in the (i believe) #5 runner (the front driver side one) on the lower intake. Should have two wires coming out of it.
The coolant temp sensor for the EEC is on the passenger side. I believe the top tube of the two black tubes that go to the heater core. It'll be more toward the front of the engine.
Just to let you know there are two coolant temp sensors. The one on the passenger side like i described above is for the EEC only. The one wire one on the drivers side is for the gauge only & has nothing to do with the eec so don't worry about checking that one.
You can check both if you have a volt/olm meter. Here's an image to help you out.
BTW, you can check both sensors when the engine is cold & not been running. As long as they have the correct cold reading. With the key off both should read around 20-30 ohms if the engine is cold (obviously this will vary depending on the outside temp, check the table above for reference)
Or you can check the voltage reading with the key in the on position.
Both sensors are very important for spark & fuel curves so either one could do it.
Hope this helps.
06-23-2008, 12:11 PM
#12
Thread Starter
Join Date: Jun 2008
Location:
Posts: 9
RE: bad sputtering and backfiring problems....
well i took it to my mech. he looked under the hood and saw the vaccum hose from my maf to the sensor wasnt connected. it actually had a bolt in the end of the hose blocking it.... anyhow, once i took it for a test drive it ran great, not problems at all. so i head home, im turning my car off and nottice my check engine light is on now... but the car is running better than it did when it wasnt on... im supposed to take it back tom, to have them run codes on it. is there anyway i can run codes on it without the machine? any help would be appriciated ty 
06-23-2008, 09:24 PM
#15
2nd Gear Member
Join Date: Mar 2008
Location: Ft Worth, TX
Posts: 346
RE: bad sputtering and backfiring problems....
07-02-2008, 07:13 AM
#17
Thread Starter
Join Date: Jun 2008
Location:
Posts: 9
RE: bad sputtering and backfiring problems....
ok so i took it too my mech, the codes returned a bad maf sensor, part number e7ef-9f479-a2a. i did a google search and couldnt find anything relevant.. its the peice that the hose plugs into, its on the firewall. anyways the guy told me to get a new one and see what happened. i havent had time to look for this part, was wondering if anyone knew the name of it so i could find it easier. also my car is running worse than ever on start up. also was wondering what IAC stood for. and what my tps voltage should be at. thanks for the help guys, i am greatly indebt to ya'll
10-17-2008, 07:29 AM
#20
4th Gear Member
Join Date: Jul 2008
Location: texas
Posts: 1,175
i second the opinion, there is no vac line to the maf, and also if the vac line to the map sensor was plug, it is because your converted to maf. its suppose to be this way, when you convert, you plug the map sensor vac line and leave the map sesor open so it can read the air temp of outside or something like that