gospeed81

iTrader: (51)

Damnit! After spending the WHOLE weekend swapping motors I think I just blew the new one.

There is hope though, as it seems I have an electrical gremlin. I am 75 miles from home, walked in the freezing *** rain the rest of the way to campus, and would really like to get home tonight and not have to get my car towed. It's on the side of University Dr. in College Station right now.


SITUATION:

Was accelerating in 4th...heard a pop, motor shut down, was at 0rpm when I pushed in clutch and looked down. Coasted over, turned it over wincing, and it spun freely.

Does not start. LC-1 reads leaner than atmo (21.7), a default value apparently (22.4), while cranking. Mine usually continues to display actual AFRs during cranking.

I do not smell fuel, but it's cold and windy, so no telling.

I have COPS, and didn't have tools to pull a plug.

Both lights on MS like usual.

Fuel pump humming away.

I checked all connections and all fuses.

I am unsure if it's mechanical or electrical. Acts like electrical issue now, but did go under load. Gave pop and rumble, but didn't seem violent enough to be a ventilated block.

Oil still clear from flush/change yesterday.

Oil pressure gauge was fluttering as it has been doing under load, but no audible detonation. I was considering changing sensor after hustler's recent account of his.



SETUP:

Brain's MS standalone
DIY COPS
"New" used motor that ran solid for 75miles (thanks Trey!)
460cc RX7 injectors



Thanks in advance.

Braineack

iTrader: (62)

you have GRID!

timing belt snapped?

Joe Perez

iTrader: (8)

Can has RPM reading in Megatune while cranking?
> AWSUM THX
> > K, iz lectrical.
> OH NOES
> > K, iz timing belt, mebbe CAS.

No has Megatune?
> K, is open oil filler, look at cam while turn crank.

gospeed81

iTrader: (51)

OH yeah, newish timing belt tight. Check deflection upon install, still good.

My dumbass left laptop at home. Tach works (spark output=MS CAS input check).

Joe Perez

iTrader: (8)

So, the dash tach read 0 when it shut down yesterday, but now it reads properly when cranking?

Or am I mis-interpreting you? The tach dropped to 0 after you pushed in the clutch, or before?

I can't find any fuses on the diagram that would shut down the injectors, the coils, or any of the critical sensors while still leaving power on to the MS itself, though of course, in your '96, the fact that the tach on the dash moves only means that the MS is seeing a CAS input, not that the coils are working, or even receiving a trigger.

Actually, where are you taking power from for your COPs?

curly

iTrader: (25)

You watch grey's, dontcha?

You said the new one was tight, do you have a cover off? Or are you just saying it's new. This is the used one from Trey, yes? Not your built one?

Edit: swap #1 cop for either 2 or 4, see if it changes.

Braineack

iTrader: (62)

never watched a funnier show!

hustler

iTrader: (6)

in for answer. I hope that motor lives on.

Cspence

iTrader: (11)

Lol, Had I read that a few days ago I would have never known wtf you were talking about. I saw that last night

chicksdigmiatas

iTrader: (11)

Where is willis? If your near SA i would gladly help.

rbluemx6

iTrader: (2)

That's still a long way from SA.

gospeed81

iTrader: (51)

Tach was at 0 as I coasted over to the side of the road this morning...just saying engine was dead.

Tach does move when cranking.

Mine's a '92...and tach is powered by my coil tach outputs. I assume this means the coils are working. Will have to remember where I'm pulling power from, but I hard-wired everything from the ingnitor per sticky thread.

I still feel like I'm not getting fuel. No smell of fuel, no change in AFRs, even after cranking.

gospeed81

iTrader: (51)

Me too...I was incredibly excited to see all of this weekend's work come to life, and also because I'm nearly "done" with my car for a while.

Ran strong for 75 miles, will diagnose over the next few days, but may have to sit til weekend due to exams/projects this week.

Joe Perez

iTrader: (8)

Ok, so nothing to prove that the ignition or triggers crapping out were responsible.

Yeah, sorry. I mis-read your sig. You're correct- a working tach means that power and triggers are reaching the coils.

I don't think you'd see any AFR indication on the wideband in the absence of combustion, but you're right- if you've got spark, and you've got compression, then fuel is the only remaining suspect.

A quick test would be to disconnect the tube from the throttle body inlet and have someone shoot a bit of starting fluid in there while you crank the starter. If that produces a result, and you both survive, then you know you've got a fuel problem.

Disconnect the electrical connector from an injector. Use a voltmeter to look for +12 between the white/red wire and ground.


Oh- this may seem like a random question, but do you have a CLT indication in Megatune? Yeah, I know you haven't got your laptop at the car right now, but it's something to check if you can.

gospeed81

iTrader: (51)

^^^I don't know for sure yet if I've got compression...so am going to be checking all three: spark, fuel and compression.

Since this thread is worthless without pics:

On the side of the road for 2 hrs



Then for another 2 hrs after coffee and some studying




On the truck for another 2 hrs (trip usually takes me 1:20)





I had coolant indication this morning when setting base timing.

Will have to do the old starter fluid trick.



If this motor **** the bed expect to see a very large part-out here shortly. I'm almost afraid to do a compression test, and have been writing the FS ads in my head.

Joe Perez

iTrader: (8)

Yeah, I bring it up because the ECU's CLT wire passes through the same common connector (X-12) as the injector lines. So if you had CLT before, and now suddenly you don't, it means that you're a retard who forgot to snugly latch down that connector.

gospeed81

iTrader: (51)

Thank you...you rock.

Will go check retard status.

EDIT: I know what you're talking about and did check that connector. Actually selling that whole harness with a set of injectors to make the RX7s PnP for the buyer, and will be hardwiring my own 550s since they have two different plug styles.

MegaTune still sees coolant temp...

Sparetire

Following along and learning much....


Joe, stupid question time, but if a T-belt had snapped then the CAS will not send signal and so then COPs will not fire and thus no tach reading right? So its 100% certain that the T-Belt is doing its job?

Braineack

iTrader: (62)

you gotta do something fierce to acutally "pop" a motor to the point it seizes up and cannot continue to run. like throw a rod.

make sure all your MS values look good. did you get in boost? most of the time the dread pop is an IC coupler falling off in boost cuase your dumb *** forgot to tighten it again, but on MS it should continue to run

gospeed81

iTrader: (51)

I was in boost under hard load.

The transmission we put in was my back up 5pd which I wanted to test the shifting on.

Turns out it shifts smoother than my other tranny, but only has the bottom row of gears (missing 1st, 3rd and 5th).

Due to this I was carrying 2nd high, and hitting 4th low all morning. I was about two seconds into 4th, just shy of 4000rpm when it "let go."

Had I not been jamming Chevelle I might be able to better describe the sound.

Funny thing is it spins freely now, actually never was seized up, but did shut down,