420A 2GNT No Start. At a loss, what am i missing?

[bc88]

This might be kind of long....
1995 eagle talon non turbo, completely stock. while driving at ~65mph on the freeway just completely cut off. got home found no spark, no fuel. replaced crank sensor, and cam postion sensor, still no spark and no fuel. pulled the ECM and looked as if it had a scorch mark internally, so replaced ECM with known and tested good one, still no spark and no fuel. Took to a mechanic and he said problem is in the harness and he didn't want to touch it. so i replaced the wiring harness from a parts car (no fun let me tell you) and i now have spark and fuel (~38psi according to fuel pressure checker). car just cranks won't start. I sprayed it with starting fluid car starts and runs until ether is gone. i replaced fuel pump, fuel filter, and installed new injectors, still no start. tested electrically that injectors are pulsing and they seem to be working perfectly. pulled off timing cover and marks align perfect, car is in time. at top dead center crank arrows line up and cam gear marks are facing each other. so then i thought maybe weak spark, replaced ignition coil, plugs, and plug wires. still no start. i then added a new good ground from engine block to firewall just incase bad ground causing weak spark. no change. what am i missing? compression reads 148 to 152 across all four cylinders. so i have spark, i have fuel, and i have compression. why won't this thing fire? what am i missing?

 

[dustyboner]

38 is low for fuel pressure. should be around 50psi.

Did you use a mopar replacement cam sensor? If not, it could still be the cam sensor. Autozone ones are the worst.

Mopar OEM Cam Position Sensor, 95-99 Neon DOHC / 03-05 Neon SRT-4 / 01-10 PT

If you own a 2003-2005 Dodge SRT-4, at some point more than likely you'll get a P0340 check engine light along with not being able to rev the engine higher than 2300 rpms. Its fairly common, but its an easy fix so don't worry. So, the cam sensor on the SRT4 is right on top of the engine on...

www.modernperformance.com

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you could pull the valve cover and turn the engine by hand to make sure both the cams are rotating to make sure you didn't sheer off the dowel pin on the cam. not sure if this applies to your situation cause i don't remember the exact symptoms beside not starting

 

[bc88]

i must have gotten bad info, site i saw said my FP should be 38-42psi?
the cam position sensor i ordered from rock auto, don't remember the brand, but if cam sensor was bad wouldn't that prevent spark at all?
what is throwing me the most is car runs on ether, but won't even crack or backfire without starting fluid.

 

[dustyboner]

if the cam sensor is bad it will just use the crank sensor as a failsafe but may not carry out normal multiport fuel injection.

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does it back fire from the intake side or just the exhaust when you use starting fluid?

 

[bc88]

if the cam sensor is bad it will just use the crank sensor as a failsafe but may not carry out normal multiport fuel injection.

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does it back fire from the intake side or just the exhaust when you use starting fluid?

backfire from intake side.

 

[dustyboner]

usually when it back fires on the intake side, its after a timing belt slips or breaks and the valves get bent.
Basically the mixture is igniting when an intake valve isn't closed all the way.

the replacement ecu and harness were both off a 95 (single ecu connector)?

is your coil pack connector the original or the newer style with the flat pins? If so maybe pin 1 and 3 got swapped when the connector was wired in. that would make the spark inverted so 2/3 would fire when 1/4 should be.

if your looking at the coil pack
( - - - )
1 2 3
1 is brown
3 is black/blue

 

[bc88]

i think the backfire is more a side effect of me holding the throttle body wide open as i spray either into it, if i spray a bit of ether into the throttle body and let it close, then start car like normal it starts and runs smooth, no misses, for 20 seconds or so until ether is burned out. it only backfire if i spray a heavy dose in and hold the tb wide open. although i haven't physically looked at the valve, i would think a bent valve would have shown in the compression check. all four cylinders read 148 to 152.

as for the ecu's i have three to choose from, all three single connector and all three part numbers match as compatible with the 420a. the one i currently have installed came direct out of another 95 eagle talon esi and has the same exact part number as the bad one i pulled out of mine.

the coil it the flat pin style. i traced the new pigtail bac to where it was spliced to the harness and it looks to be correct. plus as mentioned above it seems to run smooth on the ether.

i'm really starting to lean towards some kind of fueling problem. i needed to walk away from it for the day for mental health reasons , but i'm going to start by rechecking the fuel pressure when i get back to it. what about the TPS? do you think a bad TPS could cause the symptoms? maybe its starving the engine for fuel?

 

[dustyboner]

could be a leaking diaphram on you fuel pressure regulator. Get a homie to try starting the car while your pinching the return hose closed (with ur fingers)

 

[bc88]

i'm convinced it's a fueling problem. i'm not getting any fuel to the rail. the fuel pressure regulator, fuel pump relay, fuel filter, and fuel pump have all been replaced. even when i jump the relay and can hear the pump run there's no pressure at the rail check valve. is there any place where the fuel line can collapse and pinch off? or am i most likely dealing with a clog
somewhere in the hard lines?

 

[Clipsoe]

You should probably check the line in sections. Start at the fuel filter, disconnect it put the end in a bottle and cycle the fuel pump see if it comes out. If not the plug is before that, If it does, then reconnect and go to the fuel rail, Etc. Then you can isolate if there is a clogged/ pinched line.

 

[motomattx]

Maybe your fuel line is leaking in the tank where it connects to the pump, or your regulator is leaking internally, you say that you have 38psi of pressure though? then you said that there is no fuel to the rail? which is it? are your cylinders full of fuel? have you pulled the spark plugs out and turned it over to make sure that the cylinders are not flooded with fuel from a leaking injector or a leaking fuel pressure regulator? and YES that would still allow it to start on starting fluid and then stall, if you get pressure to your rail and it still wont start then I would check out the coolant temperature sensor.

 

[bc88]

at the time of my original post i had 38psi at rail. when i went back to check it today since i learned 38psi is actually low, i can get no pressure at rail. i jumped the relay and the pump runs. even if i let it run for a few minutes there is no pressure at rail. when i disconnect the pressure gauge and just depress the valve it doesn't even dribble a drop. pulled plugs and they're dry and still supplying spark. i replaced the coolant temp sensor and thermostat a few months ago, probably 2-3 weeks before the car died.

tomorrow i'm going to run a piece of line off the pump and see if i can determine how many ml/sec it flows (if its pumping at all) and then work my way forward from there.

 

[bc88]

IT"S ALIVE! ALIVE!!!
Motmattx wins the prize! the little piece of rubber hose that connects pump to sending unit was collapsing and restricting or sometimes pinching off all together flow of fuel from tank. thank you guys for talking me through and helping me pinpoint problem