Lateralgeez

Good point about timing. I'll have to track down a timing light. Timing chains can jump? Uh-o need to look into that. Regarding the diagnostic port - the ground wire from the ecu>port has 20 ohms resistance!

Lateralgeez

Found out why the car wouldn't make it home from the shop... they left cyl 5 spark plug cover off! Der! Oh well.

I did another compression test. All the spark plugs were out which would reveal a head gasket leak between cylinders. Again cold and without adding oil. This time I kept the throttle open while I cranked 7 times each. The cylinders that are firing have the lowest compression! 1, 5, 8



If both headgaskets are bad wouldn't it be much lower? Also, it should smoke terribly out both pipes. Currently it only smokes a little out the passenger side pipe under hard acceleration.

Next I tested the ECU - diagnostic ground wire for resistance. Turns out it was around 20 ohms! Seems strange this suddenly happened after running well for a few weeks.

I still plan on taking the top end apart to see what it looks like. Unfortunately electrical is a new can of worms for me. I'll take a look at the ground wire near all 5 sensors and get photos.

Worse comes to worse we buy the McCully racing swap harness but it might require a MAF conversion.

See this work of art lol. The stang's ecu zip tied & taped to the dash

charchri4

It's not a compression problem for sure. That should run just fine with those numbers. I have seen them under 50 and still run OK so you have no problems there at all.

5.0MX5

OK, this is the "Country Boy" check for jumped timing procedure. With the plugs out and your finger over\in the #1 plug hole....turn the engine over. You can do this either by hand using a socket on the harmonic balancer crank bolt or sometimes possibly at the alternator pulley nut. Last resort is have someone engage the starter, problem with using the starter is the engine will spin past tdc very easly. If using the starter, I'd "only pull #1 plug".

When you turn the engine over you'll feel compression building, when it's just starting to build I usually stick a screw driver into the cylinder and slowly (by hand) rotate the engine...the piston will push the screwdriver out letting you know when it's at TDC.

With TDC located, see if the rotor is pointed at (or almost at) #1 terminal of the distributor cap. If you can see the timing marks on the harmonic balancer and water timing chain cover, just use that (and not the screwdriver) to locate approximate TDC.

If it has jumped time you need to replace the timing gear set along with the chain. If this ever happens when you're on the road, it's possible to rewire the dist. cap and get it running good enough to make it to safe haven. Done it more than once. However the good news in my experience, this only happens on high mileage engines....usually well over 100,000 miles.

Good Luck, RR

MRM331

I'm not sure what type of diagnostic scanner your mechanic hooked it up to. OBD1 Ford ecu's (speed density and mass air) are checked by jumping a few underhood connections and ether watching the check engine light (mass air) or hooking up a indicator light and watching it (speed density). The procedure is described here:

DIY KOEO/KOER/Cylinder Balance Self-Test Procedure

Speed density is actually more powerful than mass air but is much more susceptible to failure if anything is out of whack (it can't compensate like a mass air ecu can). Following the procedure linked above will have you perform an KOEO (key on engine off), KOER (key on engine running) and cylinder balance test, all of which will give the ecu the chance to tell you what it's trying to deal with.

Hope that helps,
-Jason

Lateralgeez

Thanks guys, looks like I've got the two next steps. Never thought to check timing and MRM331 that is a great link.

Just found these wires:
This is the wiring that connects injectors 1-4 and some sensors. Could this be part of the issue?



And again, the TPS connector. I'm a bit concerned it's not insulated.

Lateralgeez

Update - no slack in timing chain and TDC check looks good. I was able to watch the cylinder through the spark plug hole while I turned the engine over.

Lateralgeez

Tried to get codes with a test light but it doesn't work for some reason. The light never blinked.
Installed new distributor cap and rotor, nothing. Also got a new fuel injector relay because the old one was melted around one of the pins. No change either.



On a positive note, I scored an Explorer upper & lower intake manifold for $50

Lateralgeez

Made some door cards out of 1/8" lexan. Traced and cut out with a jigsaw. Ebay carbon fiber wrap (shiny but has orange peel reflection, would recommend 3M). 3/8" bolts thread into the pop out holes. Bolts from Home Depot and finishing washers from Ebay. About $100 in materials but I got the lexan free. Not shown here, I just lined it with small rubber trim to give it a more finished look - edges were a little ugly.

V8MiataMike

At this point you really need to see what codes you may have.

Did you have the test lead connected to +12V and the "pointy end" (?) on the MIL wire? The negative side of the MIL light is switched by the EEC (grounded) so the other side has to be on +12V.

Mike.

Sunshine Guy

I'm thinking the cylinders that are not firing have liquid fuel pooling around the tops of the pistons, taking up a few cc of space, thereby raising the static compression ratio and cranking pressure. That same, non-burning fuel will wash down the cylinder walls, break the oil ring seal and allow some oil to join the mix in the combustion space.

Lateralgeez

I put the test light pointy end in port 4... paperclip between port 2 and the gray connector thing. 12v power via jumper cables to test light. Pretty sure something is off with the whole self test arrangement

Lateralgeez

Is this what happens when a car sits for 3 years?

So I decided to take the engine apart & got a little further than last time! Thanks to fuel line disconnectors and a lots of pulling the lines came off. I might have never found the issue had 2 injectors not separated from the fuel rail...

Plugged up injectors explains why only certain cylinders were firing!!! Now I'm going to buy new injectors and some in-line filters. I will also be installing the GT40 intake manifold and using its fuel rail. I pray this is the only issue.

Lateralgeez

So I installed new injectors, fuel rail, and fuel line filters... won't start. Using a test light I determined that the injectors were getting power (red wire). However, a noid light (loaner from parts store) showed they weren't getting ground pulse.


Next I will test for resistance between injector harness and ECM. I suspect wiring problem rather than bad computer.

V8MiataMike

It may be very difficult to notice the incandescent light change (or is it an LED noid light) as I think it is a very very small/short pulse to the injector especially at low RPM starting.

tbone heller

Be sure that you are actually getting a 12v supply to the ECU by using a volt meter, not a test light. Low voltage will cause all of the problems that you have. Also check the ground as well.

Lateralgeez

Yeah I tried it with the lights off... nothing.

Lateralgeez

I hooked up the battery charger at 12v to make sure. Did some testing

11 volts dc at injectors
11 volts dc at IAB
11 volts dc at vpwr on black 10 pin (pepper)

Not exactly sure what this means though. Apparently anything less than 12v is not good.

Lateralgeez

Found this under the dash. Sometimes when I let the clutch out it will honk the horn. Didn't think much of it until I looked yesterday. The clutch pedal pushes the horn wire onto the bare blue wire (must be power).

Lateralgeez

"If an engine is experiencing repeated coil failures, the coils may be working too hard. The underlying cause may be high secondary resistance (worn spark plugs or excessive spark plug gap), or in rare cases a lean fuel condition (dirty injectors, vacuum leak or leaky EGR valve)."

http://www.aa1car.com/library/ignition_coils.htm

I did have very dirty injectors. Going to test the ignition coil.

Rabitz

seems like you are making steady progress. good luck!

Lateralgeez

Had forgot to re connect ecu after installing new coil pack. It started and ran! Idled at 2k rpms. Then the smoke alarm went off because some wire resting against headers.

Quick recap of the events to date:

Car sat for 3 years, empty fuel tank
Ran for a few weeks
Overheated when front freeze plugs rusted through
Ran on 3 cylinders, then quit
Turns out injectors were full of rust crud
Replaced injectors and fuel rail
Installed in line fuel filters
Replaced coil pack
Success

Also replaced plug wires, distributor hat and rotor, fixed bad tps wiring.

Thanks for all your help guys! This is only the beginning...

MX-Brad

Good work.

Lateralgeez

There is an autocross Saturday I'm hoping to make. So I changed my power steering pump. Turns out it is a 2002 Ford Explorer V6 pump. Haven't started it yet to see if it works. Here is the old fluid

Lateralgeez

Well it wasn't rust in the injectors.
I haven't been driving it because of the dirty fuel issue. I removed the fuel tank access panel and holy ****.



fuel pick up is ...








Inside the tank








And here is what I wiped off the bottom after pumping the tank dry.





I thought it was a rusty tank from sitting for 3 year. However, it doesn't seem that way. Somehow a lot of dirt has found its way into my tank. And that's not nice.