Jason89s4

Can I assume you meant 12.1 volts? Not 16.1?

RED928

Was reading off the wrong scale... actually 12.9 as best I can interpolate. But the reading is consistent across all the points you mentioned.

Steve

Jason89s4

12.9 is more like it.
With those readings think most of the grounds are good--at least sitting there. Maybe not so much if they are loose and you are moving.
Take your pick on the most convenient fuel injector plug and unplug it.
Turn the key to the "run" position (not "start") and test the voltages between (-) ground point close by, and each if the two female terminals on the injector plug you pulled. You should get 12v or thereabouts.
Someone asked about gauges when you cranked, but more specifically if you crank and crank is the tach moving at all? Even a "blip" when you stop cranking?
When (if ever) has your CPS (crankshaft position sensor) been replaced or the plug inspected? Take off the air cleaner housing and look at the CPS connection... post of pic if you can for Stan' analysis.
Jason

RED928

Thanks Jason

The CPS was replaced last winter as part of my trying to rule things out. Also replaced was the engine wiring harness (new one from SeanR), and all the injector wiring connectors. On crank in a no start situation the tach will move slightly.

Steve

Mrmerlin

Hi Steve after reading more of the thread it now appears that you have already swapped in a new engine harness,
this info would have been perfect to have been noted in the initial thread.
Also any other things that have been replaced, like the CPS replaced the LH rebuilt the MAF rebuilt the O2 sensor replaced with a factory part the temp 2 sensor and so on.
The more info you provide the more accurate the guess will be and the less time it will take to fix whats not working.
Otherwise your testing protocol could send you in an entirely different direction,
That said one thing that will kill an engine is the ground wires at the back of the V please inspect them carefully

Jason89s4

Ok. These intermittent issues are the worst, since when you need to test it when running it won't and vice-versa.
I'm going back to one of Stan's tenets: "what was the last thing you worked on." Just to clarify, you replaced the engine harness with one of Sean's, but was that after you were having these intermittent start issues, or before?
Again, for clarification, in your initial post you mentioned that you had a noid light set, but not clear on the results. When you crank, crank in the "won't start" mode, will the noid flash? Doesn't matter which one you test. And make sure you have the proper fitting noid.
Jason

RED928

Jason/Stan

I have rebuilt LH/EZK and spare. Although it's been some time since the processors were tested swapping them out when it's in a no start state makes no difference.

The engine harness has been replaced recently along with the CPS and injector electrical connectors. The fuse relay panel was removed and cleaned and all fuses/53 relays replaced. MAF is original as well as the other sensors. I've checked all the grounds several times but will hit them again, especially at the back of the V.

I have not yet tested using the noid light since I just picked it up. Was presuming the car needed to be in a no-start state for that to be relevant. Using the light correctly was what prompted this thread.

The intermittent start/stop has been plaguing me for about 2 years. I did a fair amount of work just prior to include new belt, water pump, fuel pump, valve cover gaskets, fuel lines, new interior (carpet / seats), new rotors/pads, and pod cleaned/odometer gear replaced.

Steve

soontobered84

Steve,
From experience, I can tell you that if the engine or computers do not find a ground, the engine absolutely will not run. It took me a year to find that my engine was NOT grounded at least intermittently through either the grounds at the back of the V or the main engine ground under the car on the passenger side. I cleaned those three grounds and reinstalled them and have had no problems since. YMMV

Listen to Stan/Mrmerlin.

Jason89s4

Steve,
When you can crank the car but it won't start, is precisely when you need the noid as a tool!
Whether they flash or not while cranking will tell you if the EFI (LH) signal is getting to the injectors. Goes a long way in deciding what direction you are headed.

It is certainly not fun to track down, but as mentioned repeatedly, a loose or bad ground will cause your intermittent problems and fixing them normally costs little except for your time and patience. Since, at rest, your voltages are good, I'm thinking you have a loose ground or connection that is only activated when you move. Has it ever just died on you while sitting in the driveway, or only when you are cruising along?
Jason

RED928

Three times this past week the car would crank fine but not start. When I checked the battery it was <100% and after charging to 100% the car started and ran fine. Battery was disconnected at the ground post when not in use and the charge initially showed 85-90% when connected and quickly rose to 100% when charging and the car started. Ideas? I remember seeing something similar in another post but cannot track it down.

Thanks,
Steve

Petza914

You say "most relays". Was the fuel pump relay one of those. If not, that would be a thing to try or create a fuel pump relay jumper, which is also good to have in the car tool kit. I made mine with a switch. You can turn it on before driving the car and off when you're done to see if the no start or the stalling happens when running off the jumper

Shark2626

..

SteveG

I'm not familiar with a meter that gives you a % of the charge. But .85 x 12.5 = 10.63. I'm assuming that is the base that your "% meter" is using?? If that is correct, that is part if not all of your problem, because it appears the rest of the pertinent electricals have been addressed, except the injector wire(s) question. And . . .

You said "most" relays replaced. The big 3 have been mentioned. Did you check those? The fuel pump relay jumper (shown by Petza) is most helpful here.