momar

As of late my '86 N/A hasn't been starting. I've tried unflooding it but that doesn't work. A mechanic checked the injectors and reported that at idle the injectors pulse was like they were at WOT at 6000 RPMS. What could be the cause of this? Any help would be appreciated.

J-Rat

iTrader: (2)

As I understand it, the pulse is controlled by the ECU. But if the injectors arent closing, you could be flooding. Leaky injectors can allow the excess pressure in the fuel system to bleed down into the intake itself. Other causes could include bad fuel pressure regulator and loss of compression due to wear. My question is, how were the injectors tested? Do you have the right part number injectors? Most of the time, you will have people recommend the ATF treatment to restore lost compression, and to unflood. I have heard mixed results about it.... It worked great for me, but others have loosened up carbon deposits and really fouled things up. Might be something you may want to explore.

Rat

RETed

Water thermo sensor bad?



-Ted

J-Rat

iTrader: (2)

Another idea...

momar

My injectors are definitely leaking, as I have had flooding problems before, but it always started. The injectors are the stock ones, so that isn't a problem. Is there a sensor or anything besides the ECU that would cause the injectors pulse to be off?

J-Rat

iTrader: (2)

Can the thermo sensor cause hard starting?

RETed

The reason I mention water thermo sensor is that this sensor adds more fuel when the engine/coolant is cold.&nbsp When this sensor FAILS, the ECU defults to a a very cold setting, so it's enough to cause very rich conditions at idle.&nbsp An error code check would spit out this code though, so please try and check first...


-Ted

J-Rat

iTrader: (2)

As far as I know, there are no other sensors that DIRECTLY control the injector pulse, they all go through the ECU. And also, if memory serves, the pulse is pre-set for the startup cycle anyways. I am recalling from memory here, but sensors that control mixture include: Pressure sensor, thermo sensor, O2 sensor, AFM, MAP (?), and TPS. I am sure I missed a few, I dont have the FSM in front of me.. At idle, mixture is controlled by the Variable Resistor and the idle screw located under the blind cap on the throttle body. What I think personally is that your leaky injectors have gotten to the point to where they are jsut not closing all the way anymore. As far as measuring injector pulses and things like that, thats a little beyond my ability. My gut feeling would be that if the ECU was fouling up, it would be a little more severe then the problem you are having.

J-Rat

iTrader: (2)

Here is the trouble code diagnostics page. Very easy to do.

http://home.rmci.net/panther/86_88ecu.htm