LocostUSA.com

I don't have a schematic for a 92 in front of me, but on gms around this time period, gm ground the fuel pump relay control winding directly with the positive side provided by the ecm. This provides a 2 second prime by the ecm based on power in RUN position.

After the engine is turning, the ecm provides positive voltage to control the fp relay based on the distributor output to the ecm as a cam sensor.

In parallel to the fp relay is a fat three prong oil pressure switch that provides power to the pump directly as a back up for a failed relay.

So, key in run position, fp on two seconds then off until dizzy spins to provide ecm input or op is high enough to short and drive fp. It only needs about 5 psi to close the switch.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

That in for is very helpful for my understanding of the fuel system. That stuff appears to be wired and I can hear the relay clicking. We will see after I diagnose the pump itself.

I tested all the wires for continuity up to the tank. When they came back fine, I directly connected the pump wires to the battery.

This didn't do anything, so I'm going to pull the assembly out of the tank and investigate.

The tank is easy to access, but it's snowing and the car is outside at the moment I'm waiting on that for a bit.

I did install a new steering wheel to replace the split air bags one. Since it (somewhat) dry inside...

I used a non-airbag kit using these instructions: https://www.thirdgen.org/forums/interio ... grant.html

Before:



After:

It was the fuel pump. I replaced it and it works just like you describe.

My fuel injectors aren't pulsing. I've installed a VATS bypass, and it turns over, so I think it may be related to my distributor. The cap is new, but the rest is old. I found a complete distributor for $50 so I'll give that a try.

The wiring SEEMS ok.

I also managed to trace the windshield and get a new one sent off and buy seals for all the doors and windows.


I installed a new shifter. The old one was questionable and was positions poorly.


Got an inner boot that fit.


Found some seats that should work.

The vw new beetle seats have rails in the side and a center slider that bolts in the middle front. So, rather that bolting to the floor, I will have welded rails on the sides. The also remove easily.



I also got a good deal on some focus st back seats. It will take some modification to fit, but will flip up for battery access.

Hopefully will start soon!

Whichever dizzy is now out, plug it into the wiring, attach a jumper cable between the dizzy body and ground, turn the key to run, spin the shaft and listen.

You should hear injectors clicking and observe ignition arcing.

Check the voltage at the ecm while cranking to ensure it does not drop below 9.5. If it does or it is borderline, make sure the two battery leads (one to each connector on the ecm) have only a 10 amp fuse between them and the battery distribution stud. I spliced mine together and ran 16ga wire to an inline fuse holder next to the battery.

Test your coolant temp sensor. Here is a values chart for the temp. Compare to ambient.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

Your wiring is different from mine. The closest schematic I have is for a 90 but it should be the same as yours.
B1 and C16 are direct to the battery through a fuse. Ignore IGN label on B1.

To test if your ecm is trying to run the engine, back probe purple/white wire labeled “ref pulse input” at dizzy connector with a paper clip then clip an incandescent test light to the paper clip, key on, momentarily touch the probe to the battery positive. You should hear the injectors click and the fuel pump will run for a second.
Make sure anything you trace out to a ground symbol is grounded but don’t just go by the labels. B5 and B6 are not chassis grounds.

Park/neutral input has to do with idle speed, not cranking/starting.

Common failure parts are the ignition module (thermal compound on bottom is very important), coolant temp sensor out of tolerance, and map sensor (a vac leak indicates higher load to the ecm so it will run rich). They are all about $10 each on ebay. Good to have new spares in the glove box for quick repair or troubleshooting.

I had a hurst shifter like that one in a SAAC Shelby Mustang replica. The positive stops are great! Don't have to be a ham-fisted gorilla to enjoy them.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

This is the only one I could find that would work. it was a bit pricey, but the cheap stuff is all for Mustangs.

We're going to have to rename this thread "MV8's V6 build" with all the help you are giving me.

So, I tested the coolant sensor. It is working.

I also checked the TPS while I was there. It works too.

Distributor test you described works.

The ref pulse input test also worked.

I checked the voltage on B1 and C16, and it was loooow.

Less than 1 volt. I hooked them up to the battery with a fuse inline.

Here is the weird part. My fuel pump stopped priming. However, if I hook the other end (away from the ECM) to the power as well, the pump primes like normal. However, I lose the 5 volt when I do this!

It still runs on starting fluid.

I ran out of daylight, so I didn't check grounds yet.

Thanks,
widdershins

Rereading the wiring diagram, I'm thinking I should be wiring only the out from the ecm wires to the 12v. And then leave the ones on the ecm disconnected.

Ebay is good for finding odd and ends like a shifter base that should be included when buying a T5 or go to car-parts.com to find yards in your area that have T5s to sell and may separate the shifter. Another option is a mustang trading forum. I bought a 70s 340/360 4bbl intake for my 80s d100 ram off a mopar site cheap.

I would not do any more testing until verifying all the wires are connected correctly and no splices that are not shown in the schematic. Wires for terminals that will not be connected should be coiled up and taped until you have it running properly. Every test risks damaging the ecm.

Grounds are just as important as pwr.

TPS is adjustable and should feedback less than 0.5v key on, throttle closed/idle.

A11 outputs 12v to the fuel pump relay control side. There are 5v outputs to the tps and map. I’m not sure what you are referring to regarding loss of 5v.

The ignition module provides the ignition and fuel pickups but I found it can provide either/or if there are intermittent connections or other issues in the wiring. If system voltage is low enough, ignition will continue to work but the injectors will not spray.

B1 and C16 direct to battery, A6 pwr when key is in run and/or start position. Check voltage at these points while cranking.

E15, D6, D7, D1, and A12 should all be grounded to the chassis and the chassis grounded to the battery and engine.

I can probably give better answers if you are more specific.

Thanks for the kind words. I’m never lacking for projects.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

I rewired the grounds. Then I wired the two 12v power directly to the battery with an inline 10 amp fuse.

I also replaced the fuel injectors, as they were slightly low for ohms and 2 did not match. I used some Ford ones that I found on Amazon because they were cheap and delivered fast.

I also replaced my VATS bypass because I shorted my other one during the above rewire

And it now starts, runs, and idles!

Here's a video of its fist and only run:

https://vimeo.com/391139553

Thanks again for all the help, MV8!

I ran out of gas pretty soon after, so I'll have to get some in there before I start poking around some more.

Ding ding ding! Congratulations! We have a runner!
Dynamic voltage drops can be highly frustrating. Some projects fail because the builder can never get them running properly. You’ve overcome what can be a major hurdle. You ate the veg. Now it’s all gravy.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12

It's alive! ALIVE!!

...this back and forth is this forum at it's best... we've all had gremlins stall a project, and it is so frustrating ...

I find myself jumping into stuff I'd never otherwise have the confidence to tackle if it weren't for the safety net of knowledge found here to help bail me out, particularly with the electrical stuff..

So cool she's running widdershins.. another project car is now back under it's own power.. a good day for sure

--ccrunner

_________________
Dean

1972 Honda N600 Restomod "ccrunner's N600 VFR800 repower"

1963 Volvo P1800 Restomod
http://locostusa.com/forums/viewtopic.php?f=36&t=16309

1959 Berkeley SE492 Restomod...
viewtopic.php?f=36&t=19397

"ccrunner's 1960 MGA coupe Restomod" found on MGExp.com

Well put. I've also learned TONS just from reading the build logs here.

Not getting the engine running would have been the death of the project. There are a lot of things I can figure out, but getting the engine running was first on the list, because it is the most likely for me to get stuck on! I need to start cleaning up the mess of wiring, then start fixing it up in earnest!

I have the same shifter and have been looking for a boot that fits. What one is that from, and do you have a part number?

This is it:
https://www.ebay.com/itm/Hurst-Billet-Plus-Shifter-Housing-Dust-Cover-Boot-Mustang-Jeep-Camaro/361427393761?pageci=84e6dc6c-1182-46f6-afb1-40f8d0d1d363&epid=1333401737

It fits over the adjustment nuts on the Pro 5.0 (that's the shifter I have).