Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
No injector pulse while cranking
(No ground side signal , has power side )
Check fuel pressure 45 psi
Check injector 11ohms all
Swap main relay
No check engine or codes
Car doesn't have injector pulse while cranking.
Car will start with brake cleaner and continue running with no problem. Meaning injectors firing onces car started. What fire up the injectors while cranking? I check almost everything except ignition switch,crank sensor or bad ecu. I really need help . Please show me light. Thanks . Stay safe and healthy. peteiiis@yahoo.com
Do you have spark?
Does the tax bounce slightly during crank?
During initial KOEO do you have check engine light that pops up momentarily? If not, use a volt meter check for 5v at any sensor.
How are you testing? Test light on Battery positive to the control wires during crank?
Do you have a scope or a multimeter?
Making Pressure Differential Sensors (PDA Sensors) for pressure pulse diagnostics.
Currently servicing Central Texas.
I test fuel trim by:
with test light n dvom,noid light
Positive side: test light ,lead clip to battery ground ,test light to injector power wire.
But I also try lead clip to positive battery terminal ,test light to injector positive wire, while crank there's an really small dim once. So is there voltage drop ?
Test injector pulse ground signal wire:
Dvom negative lead to battery postive, positive lead to injector signal ground. Nothing
Test light: lead to postive batt,test light to injector negative signal. Nothing
I only have an dvom ,noid light,test light and an basic scan tool that reads limited live data.
I will try testing the crank sensor soon and tell you the results.
Thanks a lot for the fast response . Appreciate it
When you say no check engine light, you absolutely should have a check engine light illuminate for at least about 2 seconds during initial Key on engine off. If not, go to any sensor and look for 5V. If you’re testing a thermostat you’ll have to unplug the sensor. If you Don’t find 5V then you need to check powers and grounds at the Ecm. Ground lead can be on battery negative and you can use the positive lead to find the 5v wire.
Making Pressure Differential Sensors (PDA Sensors) for pressure pulse diagnostics.
Currently servicing Central Texas.
The car might be in what's called "clear flood mode". In this mode the pcm will not pulse the injectors if the tps (throttle position sensor) indicates a wide open throttle - often >80% - while cranking.
Not all cars feature clear flood mode but the fact that the engine keeps running normally once you make it start with brake cleaner is a strong pointer.
A scan tool reading of the tps value will be very helpful. If you can't do that put your voltmeter on the signal line of the tps and move the throttle. The voltage should change when the throttle is moved. If it doesn't change disconnect the tps and manipulate the signal with a potentiometer and try to start.
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
its true, with key on, engine off the check engine light should be on. then goes off after the engine is started. assuming there are no faults. This is a bulb check, and also ensures the ECM is getting power and working to some degree. If this is not the case, I attached a diagnostic work sheet. please review it and report back.
ignore the model at the top, it is a printing error, this is for a 1998 integra.
Boss. I feel really bump....
It started right up after I replace the battery. ( Sorry I didn't mention, battery was dead ,so all this time I was using an battery jumper/charging unit, the big ones with wheels.)but why would annbad battery cause this ? Bad maybe ground ?
But for future reference can you please tell me. I'm trying to learn thanks.
If the rpms moves a little while crank, what does it indicate? Does it mean crank sensor is working ?
If the check engine light stays on for 2 seconds ,what does it indicate? Does it mean ECU is starting up
And if any of the sensors have 5v ,what does it mean ?
Thanks a lot sir appreciate
I am trying to learn , I went to trade school 17 years ago but never enter this field. Only work on cars as a hobby. Learning on YouTube. Thinking about going back.
Thanks boss. I feel so stupid. I didn't mention battery was dead. So I use an charger/jumper unit, the big one that rolls around with 2 wheels. I change the battery. It starts rite up. I am trying to learn. Why will an bad battery cause no injector pulse while cranking. Thanks. Stay safe stay dirty
Thanks bro. I was little confused. About the engine light...... Yes it stay on for like. 2 seconds
I forgot to mention battery was dead, so I was using an jumper/charger unit. The ones with 2 big wheels. Guess what I feel so stupid. I pickup an new battery. It started right up. I am trying to learn. Why would an bad battery cause it to have no injector pulse while cranking? Thanks appreciate it
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