93 2.3l number 1 and 4 exhaust header are getting red

[black_demon69]

Engine has been smoked and there are no vacuum leaks just fixed all the exhaust leaks. Number 1 cylinder spark plug looks like it is running rich I have not pulled the others yet. There is no CATALYST (was removed by previous owner). Spark plugs are iridium and have less then 10,000 miles on them wires were changed @ the same time. Idle is abit rough and when reved up you can hear pops in the exhaust.

I am thinking timing belt (I know that it was replaced @ some point) but I think it may be off a tooth or 2. Also fuel pump and fuel filter were replaced about 6 months ago and fuel pressure is around 35 to 40 psi. Want to maybe get some ideas as how to proceed.

 

[Bird76Mojo]

Yes, timing.

 

[PetroleumJunkie412]

You worry too much.

 

[black_demon69]

just to be clear when reved up it only pops in exhaust when gas is released and rpms start dropping.. kind of like a small back fire


PetroleumJunkie412
thanks for the video


Bird76Mojo
thanks for the reply . I might just do timing belt today.. I will let you know

i just want it to run better and increase gas mileage. my 94 4.0l gets better gas mileage.

 

[Uncle Gump]

To me it sounds like it's rich on those two cylinders... Leaky injectors perhaps?

Would explain the small backfire... rough idle... dirty plug(s) and the hot spots on the exhaust.

I would think if the belt jumped it would run like total garbage all the time.

 

[ericbphoto]

If it was timing belt, wouldn't it do the same thing to all the cylinders? I would be leaning more towards an injector problem with those two cylinders.

 

[black_demon69]

if 2 cyls running rich is it possible other 2 injectors running lean causing pcm to try and compensate by opening injectors longer causing 2 to run rich and other 2 to run fairly normal? or could o2 sensor be bad giving false reading?

i will start by running fuel pressure hold test...

 

[black_demon69]

Fuel pressure hold test is holding steady @ about 40psi for about 20 minutes now going to let it go for another 15 or 20 minutes

 

[Ramcharger90]

Do you're timing rebuild your injectors and figure out what your egts are. Thats definitely a timing and fueling combo problem. Ive seen it with those 2.3 dirt track cars with carbs and too much fuel going to two and not the other two. I would go as far as cleaning the intake also since tou dont have any diversionary flanges in there.

 

[Bird76Mojo]

Do you're timing rebuild your injectors and figure out what your egts are. Thats definitely a timing and fueling combo problem. Ive seen it with those 2.3 dirt track cars with carbs and too much fuel going to two and not the other two. I would go as far as cleaning the intake also since tou dont have any diversionary flanges in there.

An EFI 2.3 shouldn't have the same fuel distribution problems between cylinders..

 

[Ramcharger90]

An EFI 2.3 shouldn't have the same fuel distribution problems between cylinders..

It will if the injectors are going out or gunky, sure the most likely candidate will be timing but if the injectors are old and gunky they should be refreshed atleast. The principal should be the same the fuel still gets dumped into those runners just not from the top.

 

[PetroleumJunkie412]

IIRC, this is the second truck.youve had injector trouble with, correct?

 

[black_demon69]

IIRC, this is the second truck.youve had injector trouble with, correct?

not really sure what is causing the miss @ this point as i said i believe timing is the issue but could have been dirty / stuck injector also or combination of the two.

and yes kinda 3 of the injectors in my 94 were stuck so i cleaned and un stuck them and now they are working fine..

 

[black_demon69]

update decided to pull and clean intake and injectors (they were just fine but i cleaned them anyway) also ran son seafoam through it. tomorrow if time permits i might pull timing cover and check belt

 

[black_demon69]

just a thought could the ICM cause these symtoms?