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Reattempted external fuel cell with no luck. Video of results: External fuel pump fed Into feed line from tank.
Fuel pressure gauge should arrive today so hopefully I can try that later.
Sure sounds like some fuel is getting to fuel rail while cranking and when engine starts to fire up, pressure and flow goes away until it re-pressurizes while cranking again.

Considering what was in tank to start with the hard line from tank to fuel filter could be mostly plugged up, only allowing enough fuel to pass to pressurize fuel rail but not allowing enough flow for engine to keep running. If so when you get your pressure gauge installed you’ll see pressure between 35-45 psi when first cranking, then drop to well below 35 psi when engine starts trying to run.
 

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Fuel pressure readings:

Checked belt timing again, all four cams are lined up with crank.

I'm not sure what I'll go at tomorrow but I'll post what I find.
The fuel pressure test indicates to me you’ve got more than one problem, at least two maybe more not sure yet.

1) The fact that engine fired up before fuel pressure came up, guessing from residual fuel in fuel rail, injectors or cylinders, but didn’t keep running after pressure was present indicates engine stalling is not from lack of fuel. Haven’t wrapped my mind around that yet, could indicate flooding (not sure) but will continue to think about it.

2) Obvious second problem is how fast fuel pressure dropped when engine quit cranking. Pressure at fuel rail should hold fairly consistent for some period of time after cranking or engine turned off, should slowly fall at very slow rate maybe something like couple pounds ever 5 min or so. This indicates a problem in fuel system and with speed that yours drops probably a bad or no check valve in pump, or severe leakage from pump to hat hard line allowing fuel to be dumped back into tank when pump stops.
 

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Looking back trying to determine what might have been missed, Bob’s @OhioSpryderman post #35 sparks a couple of unanswered questions. About compression, spark and injection timing.

Injector timing is hard to check, but ignition timing is easy with using timing light and monitor notch on harmonic balancer stays between 5 to 15° BTDC while cranking and during period engine fires then stalls. That would also confirm spark is not being dropped at any point during that period.

Not sure why compression would be low on a rebuilt engine, but only way to know is with compression check. Never know lifters could somehow be not allowing valves to completely close.
 

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Discussion Starter · #65 · (Edited)
The fuel pressure test indicates to me you’ve got more than one problem, at least two maybe more not sure yet.

1) The fact that engine fired up before fuel pressure came up, guessing from residual fuel in fuel rail, injectors or cylinders, but didn’t keep running after pressure was present indicates engine stalling is not from lack of fuel. Haven’t wrapped my mind around that yet, could indicate flooding (not sure) but will continue to think about it.

2) Obvious second problem is how fast fuel pressure dropped when engine quit cranking. Pressure at fuel rail should hold fairly consistent for some period of time after cranking or engine turned off, should slowly fall at very slow rate maybe something like couple pounds ever 5 min or so. This indicates a problem in fuel system and with speed that yours drops probably a bad or no check valve in pump, or severe leakage from pump to hat hard line allowing fuel to be dumped back into tank when pump stops.
Response to 1: Each time I've pulled plugs they were a little wet, not the most wet I've seen in other motors with crazy flooding but definitely wet.
2: I am wondering now if the fuel pump to hardline o-ring got disturbed or isn't making a proper seal. Will pull the pump and inspect/replace. Have people cut part of the hairline and just used a fuel system rated hose to connect the pump to the hardliner instead of that plastic clip and the lower "brace" holder part?
 

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Discussion Starter · #66 ·
Looking back trying to determine what might have been missed, Bob’s @OhioSpryderman post #35 sparks a couple of unanswered questions. About compression, spark and injection timing.

Injector timing is hard to check, but ignition timing is easy with using timing light and monitor notch on harmonic balancer stays between 5 to 15° BTDC while cranking and during period engine fires then stalls. That would also confirm spark is not being dropped at any point during that period.

Not sure why compression would be low on a rebuilt engine, but only way to know is with compression check. Never know lifters could somehow be not allowing valves to completely close.
If I have an extra set of hands today I'll run a timing light. I'll do a Compression test too
 

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........... Have people cut part of the hairline and just used a fuel system rated hose to connect the pump to the hardliner instead of that plastic clip and the lower "brace" holder part?
Yes that’s been done, just need to make sure hose fits top of pump and hard-line area snugly. Also might need to double clamp hose to both just to be sure of no leak under pressure. Actual I seem to recall some pump upgrade kit that comes with that arrangement, because the length of pump didn’t allow it to use factory mounting procedure.

Edit: Before going to all the problem of checking or modifying pump seal to hat hard-line bell in tank, might test FPR piston seal to make sure it's not causing the fast pressure loss. Since it's quick and easy by clamping fuel return line as @RealMcCoy explained in his post #50 shown below. Only difference would be to clamp it hard enough it couldn't pass any fuel and only supply 12v to test connector for just a moment for gauge to spike up to 40-50 psi or so, if pressure still drops quickly you can be sure FPR piston seal is not cause of the leaking and problem it's probably at the pump.
Fire up the pump from the test connector, and listen for fuel traveling through the system. If you have an operational pressure regulator, and you can hear the fuel traveling through the system, then you know it's over 40ish psi. Then take a pair of pliers and slowly pinch off the return line...
 

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Discussion Starter · #68 ·
Yes that’s been done, just need to make sure hose fits top of pump and hard-line area snugly. Also might need to double clamp hose to both just to be sure of no leak under pressure. Actual I seem to recall some pump upgrade kit that comes with that arrangement, because the length of pump didn’t allow it to use factory mounting procedure.

Edit: Before going to all the problem of checking or modifying pump seal to hat hard-line bell in tank, might test FPR piston seal to make sure it's not causing the fast pressure loss. Since it's quick and easy by clamping fuel return line as @RealMcCoy explained in his post #50 shown below. Only difference would be to clamp it hard enough it couldn't pass any fuel and only supply 12v to test connector for just a moment for gauge to spike up to 40-50 psi or so, if pressure still drops quickly you can be sure FPR piston seal is not cause of the leaking and problem it's probably at the pump.
I squished the return line from the fpr, cranked for a second or two and the pressure still dropped. I ended up pulling the tank today, cleaning it again, verifying the pump check valve works with pressure/vacuum hand pump, more cleaning, replaced all soft lines from the tank, and found a loose fitting for the fuel pressure gauge.

I'll have to take the gauge off and get the air bubble out but I think it dropped slower than before.

Will a bad ptu cause a weak spark across all cylinders? I might swap a known working one tomorrow if I go in.

Photos of crisp and clean tank


 

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I do not think that is the normal failure..

EDIT:: I was about to go into a long drawn out explanation of the PTU electronics, but then I realized that I was not qualified.
30+ yr. Software Engineer. I know enough about the electric/electronic part to get me in trouble...

Bob.
 

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I'll have to take the gauge off and get the air bubble out but I think it dropped slower than before.

Will a bad ptu cause a weak spark across all cylinders?
You can’t get the air bubble out of the gauge, that is a liquid (glycol maybe) put in the dial mechanism chamber to dampen needle vibrations and make gauge last longer in a vibration setting. The air bubble is intentional to allow expansion of that liquid without causing internal pressure.

I personal would say no to PTU causing weak spark, because it’s just transistors triggering the coils to fire. It doesn’t control how well coils function just when they do. I suspect Bob @OhioSpyderman might understand transistor functions better than I, which make me think he’s just being facetious with his comment.
 

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Discussion Starter · #71 ·
You can’t get the air bubble out of the gauge, that is a liquid (glycol maybe) put in the dial mechanism chamber to dampen needle vibrations and make gauge last longer in a vibration setting. The air bubble is intentional to allow expansion of that liquid without causing internal pressure.

I personal would say no to PTU causing weak spark, because it’s just transistors triggering the coils to fire. It doesn’t control how well coils function just when they do. I suspect Bob @OhioSpyderman might understand transistor functions better than I, which make me think he’s just being facetious with his comment.
Good to know, thanks!
 

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Discussion Starter · #72 · (Edited)
I was thinking the fuel filter crush washers weren't sealing 100%, so I replaced them and verified proper orientation of the filter. No change.
I had someone crank it over and the moment they stopped I clamped the return line from the regulator and the pressure held on the gauge. As soon as I let off the clamp it lost pressure. Bad regulator? The operating pressure-psi is rated at 49 psi on the fpr I bought, and a reference Delphi fpr is rated at 38psi.

Edit: I forgot the oem fpr isn't compatible with a pump hotwire. I'll delete that tomorrow and check again.
 

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I had someone crank it over and the moment they stopped I clamped the return line from the regulator and the pressure held on the gauge. As soon as I let off the clamp it lost pressure. Bad regulator?
Sure sounds like a bad FPR, as it should have held the pressure as long as that wasn't above its designed relief pressure. To give you an example, I tested my non turbo fuel system using test connector. It pressurized and maintained ~48 psi and when I disconnected the jumper from test connector, (IIRC) it dropped to ~ 46 psi and stayed there for ~ 2 or 3 mins before it even dropped one pound. I got tied of watching it and checked maybe 15 mins later and it was still close to ~ 40 psi (IIRC).

For some reason the NA engine system runs ~ 4 psi high than the turbo systems. But you get the idea and your pressure might not have reached more than ~ 40 cranking but should have stayed there for reasonable time without clamping return line.
 

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Discussion Starter · #74 ·
While I'm waiting on a warrenty for the fpr, I installed an oem one from the 91 vr4 and it holds pressure once the pump is off. Cranking psi was about 42-44psi. I'm starting to wonder if the used ecu I got is bunk too.
 

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While I'm waiting on a warrenty for the fpr, I installed an oem one from the 91 vr4 and it holds pressure once the pump is off. Cranking psi was about 42-44psi. I'm starting to wonder if the used ecu I got is bunk too.
That oem FPR seems to be doing the job correctly and cranking pressure sounds about right. Unless you have a particular reason for the aftermarket FPR, I’d stick with the oem FPR, they seem to be durable and less problematic than aftermarket ones.

I’ve wondered about the ECU since beginning, but considering 2 ECU’s original one and the used one and still same problem I kind of pushed it to back of my mind. Unfortunately without a proper bench test system, the only other way is trying your ECU in a running compatible car to see if then acts like yours.
 

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Discussion Starter · #76 ·
That oem FPR seems to be doing the job correctly and cranking pressure sounds about right. Unless you have a particular reason for the aftermarket FPR, I’d stick with the oem FPR, they seem to be durable and less problematic than aftermarket ones.

I’ve wondered about the ECU since beginning, but considering 2 ECU’s original one and the used one and still same problem I kind of pushed it to back of my mind. Unfortunately without a proper bench test system, the only other way is trying your ECU in a running compatible car to see if then acts like yours.
For clarity, the fpr I bought was an oem spec so it was the same style but a Standard Motor Products brand. I should've kept my original one but I tossed it because I thought with the fuel condition it'd be better safe than sorry.
I have access to an AEM series 2 ems for another 3000 at the shop that I can toss in and try a base calibration. That should be on lunch tomorrow so I'll post as soon as I get results from that.
 

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This thread after 76 posts seems to be all over the place between fuel pressure regulators ignition PTU, fuel filter crush washers and such.

When troubleshooting you need to stick and stay in one funnel. When your sure you have a problem identified moving back-and-forth does not help anything. Follow that to the end and ensure it is good. Then move on.

Going to throw an AEM ECM into this car may or may not give you an acceptable result.There been a number of ECM’s already installed. Now add one more variable into this mix ?

You mentioned you have access to a shop. If you or somebody at the shop understand how to use an oscilloscope, (heck just checking for good voltage at the ecm input ) start using it and check all of the pick up units, good and continuing 5volt supply, injector pulse outputs, ignition spark trigger and go through the ignition system completely, test each input and output, ensure a good ,clean signal or output at the proper time in relation to crankshaft position. but just guessing at this throwing parts is 100% the wrong way.

I don’t think the question was ever answered if the MFI relay is energized and has a good ignition power output after starting.

You might get lucky- (maybe) and eventually change the part out, but troubleshooting properly is the way to go here.

Please accecpt this post in the manner that it is intended meaning to try to get this car running.
 

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When troubleshooting you need to stick and stay in one funnel. When your sure you have a problem identified moving back-and-forth does not help anything. Follow that to the end and ensure it is good. Then move on.

Going to throw an AEM ECM into this car may or may not give you an acceptable result.There been a number of ECM’s already installed. Now add one more variable into this mix ?
Your advice is right on the point and I agree with it completely. But if you review his #1 post, that he's mostly keep updated, you'll see he has checked/tested most problem areas likely related to symptoms. Also last page and many more post has been following the questionable fuel related to a end and is now ensured it is good as you say, even you helped contributing to that aspect as well as the functions of crank/cam sensors etc.(y).

There is a voltage test input/output procedure of ECU pins for 91-93 ECU's but I'm not sure all pinouts are same on a '95 ECU. But I also worry about AEM ems being use to test for proper ECU operation, because some improper setup could farther confuse the issue but kind of understand because of him having it on hand, but not a running compatible car for him to test ECU's in.
 

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To the OP: I didn't intend to come off harsh. Sorry if it came out that way.

If you were nearby I would offer to stop over and help.

P
 

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Discussion Starter · #80 ·
To the OP: I didn't intend to come off harsh. Sorry if it came out that way.

If you were nearby I would offer to stop over and help.

P
No offense taken. I understand what you're saying, and I'm sure there are components I'm skipping that I should've checked. I haven't dug into the MFI relay since the pump test connector doesn't change the no start. It's my understanding that the test connector bypasses the relays and resister for the fuel system. I've been spending all my free time on this car since the beginning of April and the past month and a half or so just trying to find the no start. My coworkers have been helping hands and one of them runs our dyno/tuning which is great.

I wanted to try the AEM because he offered to do a base calibration and hopefully see some data streams. We ran into connectivity issues between the computer and AEM Friday so we'll try again Monday.

Unfortunately with this forum starting to get long its tougher to stay on top of everything so I'm definitely missing points. I'm pretty tired of it honestly and want to enjoy a weekend or two but I'm trying to stay on top of everything.
 
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