Idle Problems on a 1.8L (4g37)

[Zombie94Talon]

Ok I hope that sumone out there in DSMTuners can help me out on this. I bought a 1994 Eagle Talon wit the 1.8L 4g37 in it (dont laugh pls ). Paid $400 for it. The car sat for 7 yrs in the guys backyard. Needless to say I've had to replace almost everything under the hood (rad, water pump, alt, slave cyl, batt, fan control switch, thermo, power steering pump, belts, plugs, wires, cv axels, and almost all the gasgets). But now my problem is the idle, it does one of two things depending on the climate conditions it seems. First, when starting it cold it will idle high at around 1500rpm then after a few mins come down to around 1000 rpm and if I try to rev the motor at all for about 5mins it will stall out then not want to start back up unless I hold the gas down and keep it at 2000rpm for about 5mins, then it will finally stay running at about 1000-1100rpms. OR the second thing that it does is, when starting from a cold start it will idle low at 450-500rpm, which is very rough and wants to try to stall, then after about 5mins the idle will pick up to 1000-1100rpm & it will also do the stalling if I try to rev the motor before it runs for a good 5mins or more. Then what it will do after I get it started is, after driving around town for 30 or more mins (like coming home from work on the freeway), when I come to a stop at a red light the idle will only come down to 1300 to 1500rpms. Then when I tape the gas to rev the motor it will finally drop to 1000 or 1100rpms. I have replaced the ISC Motor and the ISC Sensor plus the TPS. I also know that sumone has done a EGR Elimination(which I dont think will cause bad idle) and they also have removed the silencer from the MAF, and I am not too sure but I think the small lower honeycomb also has been removed from the MAF, but again not sure ### havent seen one other then mine. Also, I am not getting any CELs either. PLEASE sumone help me figure this ish out.

 

[DSM1G90]

(I'm not laughing about the 4G37 .. tons more robust of a motor than the 4G63 in a long shot...if you can get that thing to breathe easier...I've known 4G37's to run half a million miles without overhauls...IF properly maintained..)

Sat for 7 yrs? DANG! change the fuel filter, and flush out the fuel tank to get some clean new fuel in there!


Have you done a belt/balancer belt replacement on that thing as well since it sat so long? Plus, did you check base timing-which is the same as with the 4G63 - at 5*BTDC with the ECU grounded?

The Coolant Temp Sensor (TPS) has gone kaput - why you have to sit on the throttle a bit til it warms up when cold.

Head to this link http://www.dsm1eights.org/ for 4G37 specific information and forums to join

Good luck -DSM

 

[audiomaster1990]

as a fellow 1.8 owner, mayb i can help. first, try unplugging the mass airflow sensor all together. this will cause your car to run rich as hell, but it will also idle smooth, accelerate smooth , and you should be able to redline without any stuttering (not that you would want to). that will tell you if your maf sensor is bad(thats how i found out mine was) if that doesnt work, replace the fuel filter, and pull the fuel rail and clean the injectors. most people wouldn't advise this, but iv done it in a pinch. (if there is dirt or anything in the injectors, use a bobby pin with a rounded edge to clean)

You should also invest in an air/fuel ratio gauge, even if its a cheap one from autozone, mine has helped me out alot

 

[little-razcal]

7 yrs???
Replace everything or give it back and take it as a lose. You will go broke tracking down problems on old cars. Its better just to say screw it sometimes and start over. GL

 

[93ETGOCART]

7 yrs???
Replace everything or give it back and take it as a lose. You will go broke tracking down problems on old cars. Its better just to say screw it sometimes and start over. GL

+1 on replacing everything. or if you want to take a loss let me know and ill have my dad pick it up and bring it back to missouri so it can be brought back to glory. main thing i would check is the MAF and plugs/wires and make sure your timing is set right its very easy to set the timing on a 1.8 if you need to know how i can tell you

 

[spartan ninja]

as a fellow 1.8 owner, mayb i can help. first, try unplugging the mass airflow sensor all together. this will cause your car to run rich as hell, but it will also idle smooth, accelerate smooth , and you should be able to redline without any stuttering (not that you would want to). that will tell you if your maf sensor is bad(thats how i found out mine was) if that doesnt work, replace the fuel filter, and pull the fuel rail and clean the injectors. most people wouldn't advise this, but iv done it in a pinch. (if there is dirt or anything in the injectors, use a bobby pin with a rounded edge to clean)

You should also invest in an air/fuel ratio gauge, even if its a cheap one from autozone, mine has helped me out alot

If its not the MAF its your Coolant Temperature Sensor and/or Temperature Sender.

I had the same problem. I changed the two sensors and now the car starts and idles almost perfect (it's not perfect, well... because the car is ancient )

The sensors are located on the underside of the thermostat housing. You can't miss them. One of them is pretty small (the sender) and the sensor looks like a smaller O2 sensor.