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420A Gas,air,fires,no start

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Mrdjflores

Proven Member
35
1
Jul 10, 2016
Louisville, Kentucky
Engine starting puzzle
First let me say that i'm new to Eclipses and the 420A engine. I'm not new to cars and fuel injection. My project car is a 95 Eclipse RS, A/T (going to be my daughter's first car) Car started and ran okay when i got it, had bad rings and low compression. so continued on to do a complete engine rebuild. Now the engine is back in it's happy home, but have come across a starting problem. At first, the engine ran good, then mysteriously quit running (long story short, out of fuel...DOH...) Put gas in it and it fired it up hence the following: 1)Started, ran rough, found #4 injector leaking - replaced all injector O-rings 2)Started, ran rough, found Fuel line inlet leaking - replaced O-Ring 3)started, ran rough, started checking plugs and connectors - engine died 4)Now won't start.... Here is what I know: *getting a little over 40psi at the fuel rail when cranking. *fuel getting into cylinders (fouling out the plugs) *getting spark at coil packs and spark plugs (seems a little weak for a spark) *Tested CAS (only get 9v at harness, others tests okay) *Tested TPS - good *Tested IAC - good, but going to retest off engine *Tested MAP - good *Tested Engine Coolant Sensor - good (have to wait for better weather to test CPS and Knock Sensor) *Double checked timing belt and alignment - good *Replaced spark plugs again, and gap accordingly I have a replacement ECU on the way. I'm also beginning to suspect fuel pump again, maybe it can build up the pressure but not deliver the volume?? I vaguely remember hearing the fuel pump prime when you just turn the key on, but now i don't, but does build pressure when cranking. Any thoughts?? Anything I obviously missed?? thanks, Dan
 
latest update....
did a continuity test on all the pins from the ECU to their respective plug at the sensors....all good
my CAS and Coil pack have different harness plugs...also, the CAS plug wouldn't reach to the Coil Pack anyways.

had all injectors cleaned, spray good now...
so..
1)fuel pump is pumping (getting about 45psi at rail)
2)fuel in cylinders
3)strong spark at plugs
4)great compression on all 4 cylinders
5)timing belt and tension checked again
6)camshaft timing marks rechecked
7)wiring harness checked
8)battery fully charged
9)fingers crossed
10) changed fuel filter
.
.
.
.
cranks, no start....

I have a handful of used sensors i've been gathering from some of the yards around here: CPS, CAS, MAP, IAT, TPS, IAC & ECT.
Will start testing these to get a good set.....

Any other ideas?????
 
If you don't have spark you should be getting a code . try cranking engine for at least 10 seconds and then scan it again but make sure you didn't create any codes by having the key on and sensors unplugged . if you still don't come up with any codes then check all your powers and grounds at your ecu . also check your sensors for voltage and grounds you should have something there 5v 8v ect. the ecu supply's that voltage to the sensors .
 
I ran into an issue similar to yours when I dropped a motor back in. Verified spark fuel and air. Timing was dead on. There was fuel pressure but the injectors were not firing. Turns out I mistakenly connected the iac connector to the injector resistor and vice versa. Don't know too much about 420a's but is there a way you can actually verify the injectors are injecting fuel? If u have spark and fuel then it should at least stumble.
 
not sure if the 420a has an injector resistor....but keep in mind, the new motor was running...
..got spark, got fuel, got compression, got fuel pressure, timing spot on, swapped out known good CPS and CAS.
don't know what else to try.....
not figured out soon, going to the scrap yard
 
checked all sensors for voltage, ohm, ground and signals....all good....checked harness, all good

it's possessed
 
You say great compression on all 4 cylinders but what is great compression psi wise? The other only thing I could think of is bad ECU. Pretty rare though but I know 420a ECU's are in the engine bay, maybe some water or condensation fried something? Maybe post up a picture of your timing marks so we can verify?
 
180-185 compression on each cylinder, changed out ECU already...timing marks are aligned to each other inline with head mating surface..
these are the junkiest motors ever made, no wonder why you see so many in the junkyards
 
No, but if this dont work, ive already called the fire department up the road. They'll burn it for a fire training exercise and i can write it offf on my taxes as a donation, since it is a volunteer fire department
 
Have you tried starting it with the throttle slightly open? If you have good compression, spark, and fuel, all thats left is air. Maybe your idle air control motor is stuck closed.

You could also try replacing the magnet on the end of the exhaust cam.

Have you verified the injecrtor circuit with a noid light?
 
Hang in there man, the car will be great once it runs again. Possibly bad fuel? Did you try starting fluid? Dangerous, but it can't possible just "not run" if everything is new/correct
 
injectors check with noid light...good
tried starting fluid into TB...still nothing

this is baffling
 
Last edited:
Is it possible the exhaust is plugged? we always assume you are getting air, but maybe you actually aren't.

If you know air is going through the engine, then it has to be a spark timing or lack of spark issue. The starting fluid should light no matter what.
 
I also believe that your timing is off . it's very tricky to set the timing on those engines . i have seen cam sprockets get switched by mistake causing engine not to start . can you take pictures of the cams and timing alignment on crank sprocket and cams .when all your marks are lined up are the cam lobs to # 1 cylinder facing around 2 o' clock. another thing is if you had a scanner that would show cam and crank signal you could see if they are in sync . the problem with that is a scanner like that is very expensive .
 
I'm not sure how it could be timing if it ran after all the work was done then now wont start.
 
timing marks lined up perfectly....took a few tries because the tensioner taking up the slack....
spark plugs are sparking
fuel injectors firing (good fuel too)

noticed FSM gives a specific spark gap, but when buying plugs, different types of plugs list a different gap

thoughts??
 
It did run but very rough like something was off . If the timing is off it will run rough and then plugs could get fouled up to the point where they can't fire . try taking a plug out and see if it's wet . also have you tried dropping the exhaust to see if that's your problem .
 
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