420A wont Start

[dsm93turbo]

Ive searched and couldnt find anything to help me. Heres what happened. My freind bought a 97 Talon Esi 5spd with 135k that was leaking oil bad. We took it apart replaced cam seals, Changed timing belt just to be on the safe side. Well we fixed the oil leak and went for a drive for about 10 miles and then it just died on us and wouldnt start back up. We then tore it back apart to make sure the timing was on, well it was dead on nuts.Then we pulled the spark plugs and their coated with gas and tested to make sure there was spark. My question is what would cause it to get too much fuel? Thats what we came to its just getting wayyy too much fuel.

 

[Colt4G63 also]

Check your fuel system to see if it holds pressure after you shut the pump off. If the pressure bleeds down real quickly, check for leaky injectors or a leaky fuel pressure regulator. (it would leak through the vaccum hose)

If its not there, check your temp sensor. If your computer thinks it's -54F it will flood like crazy.

There's other things you could check as well: Boost leak, clogged fuel return, fake fuel, weak coils, bad O2 sensor, overzealous MAF, evil gremlins...

 

[dsm93turbo]

I tested the ect and it tests out fine. Itll act like it wants to fire when i hold the throttle to the floor but back fires through the tb.

 

[djjohns55]

Pull the valve cover and check your exhaust cam. I had a problem like this and I had found out that the exhaust cam had got got binded in the head. Mines backfired through the tb also.

 

[dsm93turbo]

Exhaust cam looks perfectly fine, Im leaning on crank angle senser. tomarow im gonna replace it and see what happens.

 

[dsm93turbo]

Were still stumped we just changed the crankshaft posistion senser and still the same thing. Any dsm wisemen have any idea?

 

[240sxpooter]

Were still stumped we just changed the crankshaft posistion senser and still the same thing. Any dsm wisemen have any idea?

Ive been a technician for all most 10 years now here is what i would do.

1st. Check spark with a spark energy tester. Or something with a decent gap. Ive had cars with strong enough spark to cross the gap of a plug out of an engine but not in one. So make sure the spark if STRONG.

2nd. Check for fuel. I like using a noid light to test for injector pulse. And a Fuel pressure gauge for pump operation.

3RD! Timing, timing and timing. There are three timings you need to think about. First and most important is engine timing. Ive had 420a engines brake cams and the cam gears stay in time.
So when in doubt take the Valve cover off and make sure every cam lobe moves and looks "in time". Second timing is Ignition timing , if you hear a backfire then most likely your cam or ignition timing is off. You check this with a timing like and some TDC mark on the crank. Third is injector timing but really has never been a issue with any cars i ever messed with.

 

[dsm93turbo]

Thanks 240sxpooter, We found the problem. Someone had the car apart before use and we didnt pay that close attention to how tight the intake cam gear was because we figured it has never been taken apart. Well the intake came gear was just turning and broke the little pin that sticks out and cause it to get out of time, and there went all 8 of the exhaust valves. Thanks to everyone for the input and help.