88' shelby Z quest for 11's (lots of pics)

[acannell]

What alternator problems specifically if I can ask?
Will do. I always check for corrosion everytime I put them on now since I had that problem once
that's definitely good
got zip ties on all vacuum line connections to keep them from popping off
the knock sensor seems to be working great, if anything it's slightly more sensitive than stock so that's a good thing
I always watch my gauges, everything seems good so far.
I am a firm believer is checking the plugs as well. I pop them babies out a lot

Cracked my third piston when I had alternator failure. Symptoms were headlights going dim and battery not charging, the usual stuff. Oh and fuel cut off under boost

Alternator was simply worn out...brushes were toast.

[Khajjathefang]

Mine had the internal regulator fail. converted to a LA external and never looked back

[OmniLuvr]

-make sure your injector wiring harness is absolutely 100% solid

this please, check the entire inj harness from connector to connector, mine failed just after the inj clip about 1/4-1/2" up, wires were twisted. eventually shorted out but only under load, and max duty cycle, i could free rev it no prob without misfire. cost me a headgasket by only the second boost run on 20 psi...

[moparzrule]

Calibration pretty much ironed out for the stock cam, got boost up to 18 PSI....runnin good.

Received PT lifters today, but no fidanza cam gear yet (it gets drop shipped direct from manufacturer, the lifters came from TU in stock).

On another note today, did a compression check just to get a baseline and just to know what it runs with the stock cam. 153,155, 154,155. Looks like my port job on the chambers was pretty consistent

[acannell]

Calibration pretty much ironed out for the stock cam, got boost up to 18 PSI....runnin good.

Received PT lifters today, but no fidanza cam gear yet (it gets drop shipped direct from manufacturer, the lifters came from TU in stock).

On another note today, did a compression check just to get a baseline and just to know what it runs with the stock cam. 153,155, 154,155. Looks like my port job on the chambers was pretty consistent

Do you have an Android? Download the GTR app and give us some 0-60 and 1/8th times man!!! the 15th is like years away!!! plus it would be really interesting to see before and after from 18psi to 30+ psi lol

BTW I like the GTR app because its simple, fast, and not just GPS. I tried a bunch and thats the only one I ended up using.

The best I got in july was 0-60 of 7.3s at stock boost!

[moparzrule]

Not really much point in that, I don't even bother with WOT in first and second gear on street tires lol.

[moparzrule]

Just made an appointment for Saturday at the dyno, was kinda surprised they had an opening but I'll take it. Need to make sure my A/F is reading correct, and also would just like to know

And to answer everyones question, yes I will take video LOL.

Now all I need is some race fuel so I can crank the boost

[turbovanman²]

Awesome man, can't wait to see what she does and the gain or ? with the R5 cam.

[moparzrule]

Well, here's to hoping the fidanza gear gets here by Friday lol. If not, this will probably just be with the stock cam for now. Just sticking the R5 in there straight up I probably wouldn't want to just give results of that.

[moparzrule]

Having issues with it breaking up in the upper RPM's pretty bad. Only running 18 PSI, I should turn it down and see if it still does it on low boost though.

Shouldn't be the calibration I don't think, A/F is good and timing should be fine. But, I had 2 thoughts. One, the stock lifters were crapping out with the heavy comp springs I have in there. So I just replaced them with PT lifters, still does it. Second thought, I never installed the ground strap from the firewall to the intake. It's just that I would have to drill and tap the intake to do it, but I'm guessing I need to do it to rule this out as a possibility. The injector harness itself looks to be in great shape.

Anyone have any other ideas?

Another thought I had was ignition. Running RN9YC's gapped to .032'', MSD wires, stock cap+rotor and stock coil. Not sure what could be wrong there.

[DaveSkrab]

Close the gap and recheck. Bet you are making some really good power. You also mention stock coil, is it original? Perhaps it is a bit tired.

[acannell]

Having issues with it breaking up in the upper RPM's pretty bad. Only running 18 PSI, I should turn it down and see if it still does it on low boost though.

Shouldn't be the calibration I don't think, A/F is good and timing should be fine. But, I had 2 thoughts. One, the stock lifters were crapping out with the heavy comp springs I have in there. So I just replaced them with PT lifters, still does it. Second thought, I never installed the ground strap from the firewall to the intake. It's just that I would have to drill and tap the intake to do it, but I'm guessing I need to do it to rule this out as a possibility. The injector harness itself looks to be in great shape.

Anyone have any other ideas?

Another thought I had was ignition. Running RN9YC's gapped to .032'', MSD wires, stock cap+rotor and stock coil. Not sure what could be wrong there.

Crapping out as far as missing? What exactly happens?

As far as ground strap you could just rig up something temporary just to make solid electrical contact between intake and chassis. Take a big wire and squish it under washer on the fuel rail mount bolt or something, then attach it somewhere on the firewall. Same thing.

Might want to take a multimeter and measure resistance from intake to battery ground just to make sure its not something crazy like 4 ohms or something. Could also measure current from intake to firewall and see if you get a significant amount of current through the meter (set to 10A setting).

Not sure what purpose the ground strap does actually....the injectors are turned on by grounding them through the harness and I would assume it has a bat+ lead in there too right? So its got its own circuit straight to the ECU?

Were things running okay at maximum boost and high rpm on the stock cal?

Is distributor tightened down?

How does the timing belt look? Running in the middle of the pulley? Not sure this matters as far as your issue but may as well check it.

You shouldnt have issue with the spark plugs or ignition unless there is something defective. I had no issues at high rpm at 28psi with crap-zone distrib/rotor/plugs/coil and RN9YC's at stock gap.

Can you record some audio/video of whats happening?

[moparzrule]

The coil is not original, looks like an autozone replacement. Previous owner did that.

Tighter than .032?? With only 18 PSI boost? That shouldn't be the problem. Maybe if I was running 30 PSI, but not 18.

As it's pulling through the upper RPM's about 5000 RPM or so it starts bucking, not violently but a definite miss.

dizzy is tight, belt is new and good and proper tension.

[acannell]

The coil is not original, looks like an autozone replacement. Previous owner did that.

Tighter than .032?? With only 18 PSI boost? That shouldn't be the problem. Maybe if I was running 30 PSI, but not 18.

As it's pulling through the upper RPM's about 5000 RPM or so it starts bucking, not violently but a definite miss.

dizzy is tight, belt is new and good and proper tension.

HMMMMMM!!!!

Very interesting batman...this is a good one.

Well at least its probably serious enough of a problem to where you can eventually find the solution, versus some intermittent subtle issue.

How did it run at high rpm/full boost on the stock cal?

AFRS are good..hrmm

As a side note I'd raise the warning flag for possible lean out conditions/detonation and see if you can troubleshoot this at as low boost levels as possible. 18psi is not somewhere you want to have missing occur. For instance, I had hep failure which caused random cutouts at stock boost levels (13psi max) and that caused cracked pistons. So you may want to turn your manual boost valve down as low as possible.

IN FACT

Set your boost to pretty much zero and see if the problem still occurs. That would tell you its almost certainly ignition or mechanical and totally unrelated to "beyond stock" things like fuel or high air flow or whatever.

Go over your ignition system again with a fine tooth comb. I know you've checked timing, but re-inspect every wire and spark plug for anything which might allow spark to escape.

Does the problem occur if you just rev the engine to redline at a standstill?

[OmniLuvr]

please remove ALL covering from the inj harness, from connector to connector, even that little rubber part right by the fuel inj connector, and recheck...

[acannell]

please remove ALL covering from the inj harness, from connector to connector, even that little rubber part right by the fuel inj connector, and recheck...

I would second this

Ive cut out my HEP connectors and injector harness connectors and soldered/heat shrinked the both. No problems in 6 years and 30k miles..dunno why there is even a connector on the injectors anyway.

[OmniLuvr]

im only concerned because this exact thing happened to me, didn't show up until higher boost levels with higher duty cycles caused the wires to short out, I checked the entire harness except that 1/2 of rubber right after the inj connector, its "burned" me twice. on my 91 Daytona I got an inj fault code, but the charger no such luck. I swapped plugs (which did help but didn't fix the problem) cap wires rotor, coil (which also seamed to help) but by the time I pulled the harness it was to late, to many lean conditions at 18 psi, headgasket eventually failed

[Reaper1]

I think you need to tighten up the plug gaps. At 22#'s on a stock engine I was running something like .027" (guessing, but I know it was tighter than stock). I know the stock gap would result in high boost break-up.

The ground straps help to make sure there is good continuity for the electrical system for a backup to the rest of the wiring harness, but the most important job is dissipating static electricity and EMF noise.

[acannell]

I think you need to tighten up the plug gaps. At 22#'s on a stock engine I was running something like .027" (guessing, but I know it was tighter than stock). I know the stock gap would result in high boost break-up.

The ground straps help to make sure there is good continuity for the electrical system for a backup to the rest of the wiring harness, but the most important job is dissipating static electricity and EMF noise.

I would disagree with this. I did dozens of passes at 28psi at stock gap on RN9YC's and had no issues at all at high rpm, car ran exactly as would be expected for the build, around 300hp.

[GLHNSLHT2]

It's not about boost #'s it's about cylinder pressure, New Intake, ported head, TU manifold, big turbo and nice intercooler are going to shove a lot more air into the cylinders than if you're messing around with a 1 piece and a stock head A 1 piece might have 30psi in the plenum but the pressure at the valve face is a lot less.