starts & stalls

wilde1 · 02-04-2008, 05:20 PM

my 84 944 broke a timing belt and destroyed the valves after about 2 months i finally got it back together. now it starts and stalls. if i remove the plug from the coolant sensor before it stalls it will keep running. i have replace the sensor but still same problem. anybody have any ideas?

JivenJim · 02-04-2008, 07:20 PM

The Air Flow Meter? Wear a grove in the Copper. Theres a technique for bending the swing arm so it passes over a clean grove.
http://www.clarks-garage.com/ search for "elect-22"

That or Fuel pressure Regulator/vaccum leaks would be where I'd start.
Clark has tests for all that.. Praise Clark..

hpservertech · 02-04-2008, 07:35 PM

You sure you have the afm/tps hooked back up? I've forgotten to do that several times after working on things.

All hail clarks garage!

wilde1 · 02-05-2008, 06:47 PM

thanks for the help. u guys are right, clarks garage is awesome. didnt find the problem yet. tested airflow meter and tps( was out of spec. thought i had it). tomorrow im gonna build an adapter to check fuel psi.

Razorback1980 · Razorback1980's Garage

Also check the wiring for the injectors...might be loose and/or sometimes they have been known to break or loose connection in the wiring harness. I wouldn't think that pulling the plug on the temperature sensor would correct a fuel pressure problem and keep it running although it might make the injectors stay open longer...not sure about that. Use a noid light and put on each injector wire to make sure they are all working properly. I think the harness is wired in pairs so 2 injectors could work properly and 2 not causing it not to run perfectly.

wilde1 · 02-06-2008, 03:04 PM

just checked the fuel psi. a little on the high side. ( 37 @ idle) gonna try a regulator but just doesnt make sense to me. when i plug in the coolant sensor its just like you turn off the key.

JivenJim · 02-06-2008, 08:38 PM

I've heard of Temp Sensors shorting to ground or across to the Warning light. Maybe do Clarks test on that temp sensor and verify wires are not shorted. You may also try disconnecting the two or three wire barrel connector on back of engine, by firewall that goes to the O2 Sensor. Disconnect should go full rich mode.

Razorback1980 · Razorback1980's Garage

I am thinking like Jim....those wires are grounding out some other wires up there. Check the ohms between the wires and the engine or ground cable.

wilde1 · 02-07-2008, 02:23 PM

i checked the temp sensor wires and it checked out ok. i did notice with the noid light it didnt seem too bright. i checked power at the injectors and i am getting 12 volts. its hard to check ground because it varies. im starting to think i have a bad ground somewhere because the interior has a lot of moisture. not sure where to check.

wilde1 · 02-08-2008, 03:05 PM

when i removed the head i found 2 of the referance sensor wires nicked so i soldered them. could this have anything to do with it? if not should i but a dem? could the air actuator do any of this?

JonA · 02-08-2008, 04:40 PM

Are you saying that with a cold engine you have to have the temp sensor unplugged for it to continue running?
In the sensor resistance varies inversely with temp so unplugging the sensor will tell the engine that it is very cold??? You sure you got all your hoses and other connections back together? Maybe unplugging the sensor is correcting for something else that isn't right.

Jon

JivenJim · 02-08-2008, 04:44 PM

Don't know what Ref Sensor you referred to or what a nick means that would require resolder vs covering with tape insulation?

When it stalls does it sputter out or just cut out. Is it when accelerating or just idle? Will it keep running if you rev it above 3000 RMP's?

Did you watch that fuel pressure gauge just before car stalled?

Would not be a bad idea to clean Battery Terminals and especially the body gnd lug right next to battery (follow cable from neg batt). Remove the contacts, sand, file or wire brush till shinny.

wilde1 · 02-09-2008, 11:34 AM

i have triple checked for vac leaks and for something not plugged in. i resoldered the reference sensor wires because they where cut almost all the way through. when i unplug the coolant sensor i can slowly rev the engine up ( if i open the throttle fast it dies) when it dies i still had fuel psi. i still have injector signal and i still have spark. besides a noid light does anyone know how to check ground @ injectors? it cycles so fast my meter wont pick it up. the noid light doesn't seem too bright. i do have 12v