Big John Posted March 1, 2012 Report Share Posted March 1, 2012 a local friend has a quest and it was running fine until a few days ago. now when you try to start it there is no injector pulse but if you shoot a little either in it and get it running so the rpm's get to 1000 or so bam! injectors start to pulse like normal and runs fine. i want to try to help him out but need some ideas on what could cause this. thanks john Link to comment Share on other sites More sharing options...
ucw458 Posted March 1, 2012 Report Share Posted March 1, 2012 Just a guess but maybe the ECU isn't getting a proper tach signal or mass air signal. Link to comment Share on other sites More sharing options...
button Posted March 1, 2012 Report Share Posted March 1, 2012 What year?Pre-86 will run/drive with no MAS. I'm unsure or 86+ I'd guess something in the distributor, or the knock box maybe? Link to comment Share on other sites More sharing options...
Big John Posted March 1, 2012 Author Report Share Posted March 1, 2012 its a 87 and the ecu was replaced with a new one and it did not change anything Link to comment Share on other sites More sharing options...
Turborusty Posted March 1, 2012 Report Share Posted March 1, 2012 It does sound as if whatever provides the signal to fire the injectors is not getting it's proper trigger, or a weak trigger....until the engine isspinning fast enough to generate a better trigger. I do not know what triggers the ECu to fire the injectors, though. Sorry Turborusty Link to comment Share on other sites More sharing options...
Indiana Posted March 1, 2012 Report Share Posted March 1, 2012 If there's no power to the ECU it won't fire the injectors but the ignition system is separate from the ECU. First there must be a tach pulse to get the coil to fire and that must be working or it wouldn't run but that signal can't do anything at the ECU if it doesn't get power. The ECI fuse link is in the holder behind the battery. Also check the wires in the distributor plug and the wires under the ignitor mounting scews. Those loop terminal wires under that ignitor need a clean ground. Link to comment Share on other sites More sharing options...
D-VO Posted March 1, 2012 Report Share Posted March 1, 2012 Distributor? Link to comment Share on other sites More sharing options...
Shelby Posted March 2, 2012 Report Share Posted March 2, 2012 come on guys ,, this is not how you fix a car ,,TROUBLE SHOOT , TROUBLE SHOOT ,,,,NOT GUESS sounds like many guys need to go read the fuel chaptor in the fsm,, first part " how every thing works and works togather "or some thing to that effect ,, if you have NO idea how some thing works you have less then '0' chance fixing it Link to comment Share on other sites More sharing options...
Komeuppance Posted March 2, 2012 Report Share Posted March 2, 2012 Have you tested the fuel pressure?? How's the ignition system, old fouled spark plugs?? -Robert Link to comment Share on other sites More sharing options...
StarquestRescue Posted March 2, 2012 Report Share Posted March 2, 2012 Dying ECI relay or dying fuel pump. Hot wire the pump and see if it kicks off promptly every time. Than move on to checking the relay. Link to comment Share on other sites More sharing options...
Big John Posted March 2, 2012 Author Report Share Posted March 2, 2012 thanks guys i will pass the information along to him john Link to comment Share on other sites More sharing options...
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