Problem solved! Emergencyish Situation! Need a good MPS, MPS failure right before shipping car. Options

[hcdmueller]

I am in the middle of moving to the UK. The Air Force has already picked up all of our stuff. 2 days ago I tried to start my car and no luck. It's a 76 and after relacing or troubleshooting everything, it's still not starting. I bit the bullet and bought a vacuum pump from Harbor Freight to check out the MPS. It isn't a complete fail, but it leaks down from 20 to 14 lbs in < 4 min.

List if things I've done. New vacuum lines, rubber intake sleeves, injector seals, fuel filter, spark plugs, head temp sensor. Checked fuel pressure, injector function, TPS adjustment. I have the 123ignition distributor with new cap and rotor.

I have to ship this car in 10 days or less. Obviously it needs to be running.

Does anyone have a known good 2.0 compatible MPS I could borrow/rent/purchase right now?

I'm in Panama City, FL. Given the weather, something closer to me would probably be better.

Other options could be a good running set of carbs and intakes or if someone has a plug n play microsquirt setup sitting on the shelf.

Any help is appreciated.

[Bleyseng]

Thats not much of a leak down 20hg to 14 hg in 4 minutes. Especially for a no start situation. Does it fire up on starting fluid? Any firing at all?

[rjames]

I would think your MPS holds enough vacuum for the car to start.

Did it run before you replaced the things you listed?

[hcdmueller]

I agree that the MPS should be good enough, but I've gone through the whole engine and I'm running out of options. The car ran reasonably well on Wednesday. It was a little tough to start. I assumed it was the relatively cold weather.

Thursday morning, no luck. It sounds like it wants to fire, but just won't quite get there. I am getting spark and some fuel when cranking. I'm running non ethanol fuel. The first thing I checked was the TS2. It tested within range. Eventually even checked the TS2 connection at the ECU. I swapped in a new one that checked out, just in case.

I'm at a loss for the moment. Hopefully I missed something simple, but can't rule out the MPS after checking everything else.

[hcdmueller]

It probably sounds like I just ripped every part off the engine at once. Not the case.

This took place over Friday and Saturday. Started with verifying basic settings, then moved on to troubleshooting step by step. That's where I'm at.

Normally I'd ignore the car a few days and come back to it. I don't have that option this time. I'm open to suggestions. You can't offend me with questions. I'm really hoping I just missed something basic.

[iankarr]

I’d guess something distributor related if everything else checks out

[914LIVE]

=================================

How about HEAD SENSOR on # 3
cylinder head ?

I had that exact issue and happen to
be the wire on the sensor.

Check or replace the sensor. Check
connection to the sensor and to the
main wiring on the right loop.

Good luck !!!

=================================

[JeffBowlsby]

What does ‘some’ fuel mean? Verify the correct, even fuel flow from all injectors? Clogged fuel filter?

Verify the injector grounds
Verify the trigger point function

[Bleyseng]

A blown MPS usually means pig rich trying to start up like chug chug cough sputter....
Is it firing at all?

[sportlicherFahrer]

Have you tested all the contacts at the ECU connector? All are listed about a 1/3 down this page:

https://members.rennlist.com/pbanders/DJetParts.htm

[anderssj]

This may be a stretch, but is the fuel pump cycling on when you first turn the key?

Not sure about 1976 cars, but on earlier cars the fuel pump and the heater fan share a 25A fuse on the relay plate in the engine compartment. Fuse can go bad/lose connectivity due to corrosion. Check if the heater fan comes on; if no heater fan, likely no "+" to fuel pump. (Had this happen on second day of PCS trip from Langley to McChord back in the day.)

Please see Clay's post of relay plate diagram at bottom of this thread:

http://www.914world.com/bbs2/index.php?showtopic=351670

Hope this helps!

[burton73]

When I bought my 76 car from a guy in Texas 10 years, when the transport company went to pick it up it would not start even after it had been working well for the guy I bought it from.
I had it flat bedded to Zims at that time Clay worked there.
It was the fuel pump. New pump and away it went. Never had a problem with it not starting all the years I had it.

Bob B

[r_towle]

This may be a stretch, but is the fuel pump cycling on when you first turn the key?

Not sure about 1976 cars, but on earlier cars the fuel pump and the heater fan share a 25A fuse on the relay plate in the engine compartment. Fuse can go bad/lose connectivity due to corrosion. Check if the heater fan comes on; if no heater fan, likely no "+" to fuel pump. (Had this happen on second day of PCS trip from Langley to McChord back in the day.)

Please see Clay's post of relay plate diagram at bottom of this thread:

http://www.914world.com/bbs2/index.php?showtopic=351670

Hope this helps!

^^^^
Plus
Ground strap in distributor advance plates
Make sure the advance plates are clean and easily open and close...or expand and contract
Points, remove, clean with Emory paper or sand paper, re-install

Check spark, fuel, air
You need all three

[hcdmueller]

So, the problem has been solved.

After checking all the obvious stuff, out of desperation, I pulled the intake manifold and runners to check for any sort of leaks.

The paper gaskets on the phenolic spacers had been sucked in toward the head causing a huge vacuum leak. As far as I can tell, the cold weather was actually the problem. This car has only been run in temps over 65deg for the past 8ish years. First Arizona and now Florida. The day it decided not to start, the temp outside was below freezing. I guess everything loosened up just enough in the cold.

I just finished bolting everything back together and it fired up after a couple tries.

I appreciate all the questions, feedback, etc. It definitely reminded me to check everything more than once. I guess I'll have to build a new engine, this one's been in for over a decade and is starting to act up. Time to go big.

[rjames]

Awesome. Glad you got it figured out!