1991 #614 back from grave but no start, cranks just fine

[MRCFOUR]

Hello Z family! So, as you all know, #614 has been in reassembly mode since November of 2022. So, this week we decided to try and get it running. After, tear down of PS header to replace and reposition gasket so that the manifold studs could be installed, various mystery leaks involving the V drain tube, repair and verify all secondary vacuum hoses, removal and cleaning of contacts in starter, replacing ignition coils (verified spark at all 8 plugs), verifying of fire order, removal and testing of alternator, replacement of spark plugs and fuel filter and new single pump from DL Merrill (now have 50-55psi at crank with 45 and eventually lower after crank) setting of TPS voltage, and 2 different PROM chips we are at this stage?. Cranks, does not run unless throttle pedal is lightly feathered, back fire out of headers and TB, smoke puffs out of TB during cranking. Any insight would be greatly appreciated. This car has been off the road since 2019 and was bought in pieces so to be here at this stage is simply a marvel.

HELP! We are at our knowledge base limit and do not know what else to do. Replacement of injectors will be our next step unless this is something silly we are missing.

Thanks so very much!

[secondchance]

I would double check and make sure spark plug wires are connected to correct coil terminal.

[viper107]

Check fire order also

[viper107]

Also if you have a different ecm try that, they junk

[MRCFOUR]

Originally Posted by viper107

Check fire order also

Yes, firing order was gone over many times during plenum install. I have the OE wires that are numbered. Made it easier.

[MRCFOUR]

Originally Posted by viper107

Also if you have a different ecm try that, they junk

I?m trying to locate one to do just that. In the meantime, I?m sending mine to Marc to see what?s what with it.

Thanks for the ideas!

Chris

[MRCFOUR]

Originally Posted by secondchance

I would double check and make sure spark plug wires are connected to correct coil terminal.

Thanks. This was gone over many times prior to plenum install. Used the FSM diagrams and I have the factory numbered wires.

[tpepmeie]

Chris, I have an ECM I can loan you. I may be down your way in the next week.



Sent from my iPhone using ZR-1 Net Registry

[MRCFOUR]

Originally Posted by tpepmeie

Chris, I have an ECM I can loan you. I may be down your way in the next week.



Sent from my iPhone using ZR-1 Net Registry

This would be fantastic! I?d really like the opportunity to see if indeed that is the issue! If you know when you?d be down this way, we could just plug it in and see what happens!

Chris

[phrogs]

If the Different ECM doesn't work bring it to me ill take it off your hands. haha

Anyway how disassembled was this car when you got it? Is there any chance there's a issue with camshaft timing?

Injectors could really be an issue, I had a set of FICs on the shelf for a few years when I went to use them in my abandoned ZR-1 one of them decided to leak. like just a faucet of fuel dumping out of it, Of course I failed to double check them so I had to yank them out and test them and that's how I figured it out. with no input from the car other than fuel pressure. So perhaps you have a leaker or not even spraying. Of course the ECM could be the issue but I would have your injectors tested. If you want to send them to me I could do it see what they are doing before you buy new ones.