5.0 mystery trouble

Topic: 5.0 mystery trouble (Read 4156 times) previous topic - next topic

5.0 mystery trouble

Reply #15 – June 23, 2013, 01:35:21 PM

I think a this point everyone is just hurling spears at the elephant. Tom needs to chime in and give additional information or just pull the .44 mag out and save us all a lot of pain and tell us what the hell is wrong with it.

Darren

5.0 mystery trouble

Reply #16 – June 23, 2013, 06:33:26 PM

maf sensor or o2's is my guess.

5.0 mystery trouble

Reply #17 – June 23, 2013, 07:10:15 PM

You said it wouldn't spin the tires if you mat the pedal. Maybe the mat is too thick

5.0 mystery trouble

Reply #18 – June 23, 2013, 09:46:14 PM

90K and only mod is a fuel pressure regulator adjustable and under drive pulleys.

5.0 mystery trouble

Reply #19 – June 23, 2013, 10:20:40 PM

BINGO BLACK JACK AEROCOUPE AND JAY NAILED IT

The cylinder balance was ok because all the cylinders were low. This set all the codes. Naturally the only thing in common is what BLACK JACK and AEROCOUPE posted

THE TIMING CHAIN!!!!

5.0 mystery trouble

Reply #20 – June 24, 2013, 11:26:00 AM

Learn a little every day. I figured a worn timing chain might give poor idle...but now I can see why a cylinder balance would sometimes help in a diagnostics exercise.

You should have driven my '89 5.0 convertible before I started taking it apart. I can get that things are a dog with 3.08 gears in the back, but that thing was only slightly more hurried than molasses in January.

(pretty bad when car guys argue about who has the SLOWER car lol)

5.0 mystery trouble

Reply #21 – June 24, 2013, 11:48:49 AM

chain / cam,, whats the difference when your looking at low compression,, it sounds to me like that motor has been dogged out.
if the chain has been jacked up that bad, the things that follow it are due for an inspection.

maybe dumb luck will yeild just a chain is the root cause, im betting more than just a chain,, thats just my opinion.

and to be fair, its not a perfect cylinder balance but ,,, i tend to read between the lines and picked up on your not stating what defined the balance.
Normal people would have expectations that "perfect" would couple both the numeric value and the difference of the cylinders.. since ou didnt post the numbers... i made no assumptions.

5.0 mystery trouble

Reply #22 – June 24, 2013, 11:58:58 AM

It happens if they get ther asses handed to them on a regular basis. Feel bad for the older motors that came with a nylon cam gears. The engine that i originally built for my bird had one and when i tore it down to rebuild i actually was able to take the timing chain off by hand. Bonehead idea for saving money

5.0 mystery trouble

Reply #23 – June 24, 2013, 06:45:27 PM

I could easily touch my chain to itself between the gears on my old bird, and it had plenty of power for a 180k s.o. there is more wrong then the timing chain, unless it was skipping teeth.

my old 86 had over 290k with about 100k put on by me spinning the tires every time I got a chance. I'm sure it was original as well. had less then 90lb pressure on all 8 cylinders and would do a one tire fire through 40mph.

my current 87 has somewhere around.215k and the same thing. with the 5 speed I can spin completely through first and.chirp 2nd on a good solid straight run.

and all of these were with a single chain, not the double roller the h.o. motors came with from the factory.

5.0 mystery trouble

Reply #24 – June 24, 2013, 07:50:46 PM

Tom,

Did it skip a tooth or was it just so stretched that it basically gave it as poor timing as skipping a tooth? The only other thing I can think of is the motor had been into before and someone screwed up reinstalling the timing chain but it does not sound like that was the case.

Darren

5.0 mystery trouble

Reply #25 – June 24, 2013, 08:51:52 PM

To be honest the customer did not OK the repair or should i say the inspection. Timing chain is my feelings as all the cylinders are app the same compression pressure or reading. A stretched chain drops the compression evenly because the cam retards several degrees. This points to a stretched or jumped chain i am assuming. I once found a cam pin missing years ago on one. That was a KILLER. But what i was trying to point out was a simple compression test was all it took. The reason the balance test was ok and would come back all ok is the cylinders are all the same or close within 10%. And in my experience the ford roller motors never eat cams. What i should say is i never saw a flat roller cam in a FORD. So i was pointing out that some people just run codes and never go back to basics. A dozen shops overlooked this issue . So sometimes the old fashioned trouble shooting pays off. Thanks and your posts were excellent. Once the customer Signs a work order i will post further findings. Thanks So much for being good sports Tom!!

5.0 mystery trouble

Reply #26 – June 25, 2013, 02:51:24 PM

well dang it ,, now arent you just a pain in the butt! you made it sound like you knew where the prob is.,, good assumption though and to be honest,, i agree with your thoughts that the cam isnt jacked up yet, but the possibility is still there.

you prob didnt think to peek in the trunk to see if there is evidence of a bottle being used in the past.

5.0 mystery trouble

Reply #27 – July 01, 2013, 04:48:57 AM

excellent read! Keep us posted if you get to dig in!