Brand New Motor - Won't Stay Running - Kinda Stuck

[Trent]

Hoping for some insight and some help with this issue. I'll give as good of a rundown on the parts as I can up front and see if there is anything that might help someone help me. After 8 hours today, I"m stuck.

This is a brand new from Toyota 7M block, refreshed/rebuilt head, etc. EVERYTHING on this motor is brand new or less than 100 miles on it. The car will start up just fine, runs for 3-5 seconds, and immediately dies. It barely recognizes me giving it gas and I can sometimes keep it running for a little longer.

- Fuel pressure is good
- No codes
- No vaccuum leaks to be found
- AFM tested good
- Brand new 93 octane in the tank
- I think I have all grounds in place, but would be glad to check for anyone who can tell me where they all should be. I have one behind the a/c compressor, wire bundle ground under the intake, ground strap from firewall on passenger side to head, one from body to the bellhousing of the transmission, and one at the transmission mount.

Again this is a new 7M with new Lipp turbo, 550's, Lex, AFPR, Walbro, new wiring harness, new plug wires, new plugs, no leaks or problems of any kind that i can find. Again no codes and it appears everything is working as it should, but obviously it isn't because it only runs for 3-5 seconds.

Any ideas? Thanks in advance for any help

 

[Nick M]

Video. Following assembly if it doesn't stay running but starts easy is an intake leak or plugged exhaust. Get a vacuum gauge on it.

 

[Trent]

Also forgot to mention that I do have the AFC Neo that has been updated to the most current firmware.

The intake has all been checked for leaks and all hose clamps verified tight. The exhaust is a BIC DP, RT Cat, and RSR Exhaust. No issues there.

 

[Zumtizzle]

Check timing?

 

[Trent]

How can I check timing when it only runs for 3-5 seconds and can't stay running? I've verified the CPS is installed correctly and have it right in the middle of the slide or adjustment slot that it has. Based on other MK3's I've built, this would at least allow the car to run long enough to adjust the timing.

 

[Nick M]

The intake has all been checked for leaks and all hose clamps verified tight. .

There is a lot more to an intake leak than having hose clamps tight. Like a crack. I don't know what it is, but if it starts easy, and you didn't say yet after asking, then I would think about something like that rather than engine control. And aside from that, I don't have a comment on your tuning if you interupted signals. Because starting and staying running is also two different things.

 

[Trent]

Yep it starts absolutely effortlessly. It's a brand new accordion hose as well but I have checked it for leaks and all the hoses coming off of it as well. Idle up vaccuum line is good, ISC hose is good, and the PCV hose is good too. BOV port capped. All IC plumbing is hardpipes and those well all taken off and checked as well.

Checked all grounds again today and all is good there too. Just pulled the #1 and #6 plug and they both look very good but smell like pretty raw fuel though.

Also if I start it with my foot slightly on the gas, it starts and will rev up to where I have my foot for a few seconds and then it is as if you just turned the key off. Nothing will keep it running. It almost seems like a fuel delivery issue to me but I've tested the pump and obviously if the spark plugs smell like fuel then the injectors are firing right?

Still no codes either

 

[jetjock]

I know something that could cause this but for now try it with the fuel pump jump on through the diag box.

 

[stew_7mgte]

Are you drowning the cylinders with fuel? Never played with a afpr myself but i know what it does. Sounds like to me that your drowning it.

 

[IBoughtASupra]

You should pull 20% across the board on the NEO. You went to a 550CC setup when stock is 440CC, so 80% of 550CC is 440CC. So pull 20% across the board. I am assuming you are running too rich and bogging down based on your assement of the spark plugs smelling like raw fuel.

Maybe its me but I don't like to run new motors with fuel upgrades from the first start unless I am using a standalone. I just don't believe in piggybacks at all, not one bit.

 

[Trent]

I know something that could cause this but for now try it with the fuel pump jump on through the diag box.

I didn't know if it would be safe to do that or not, but SURE ENOUGH I did that and it fires up and runs no problem. So now where does that leave me? Fuel pump relay?

 

[jetjock]

Why would it not be safe?

It makes sense that would have worked based on a logical analysis of your symptoms combined with a knowledge of how the car works and it leaves you to figure out what's wrong with the COR or fuel pump speed circuit.

 

[Trent]

Ok so I went and checked the Solenoid Resistor on the strut tower on the passenger side. Per TSRM all of them should check out at 3 ohms each. One of them does check out right at 3 ohms. The other is at 80-84 and the other registers nothing. I believe we found the problem

 

[jetjock]

You're confused. Try again...

 

[Trent]

You're confused. Try again...

I know it may not be your typical style, but can you please just tell me what it is? I am obviously missing it.

 

[jetjock]

I can't tell you exactly where your problem is but the fuel pump resistor, located on the pax side, has only one element. The injector (solenoid) resistor pack, on the driver's side, has three elements. Since you were on the pax side I'm guessing you were measuring the right thing but doing it the wrong way.

The pump runs when the key is held START. The ECU keeps it running through the COR after the engine fires. It then switches from high to low speed when reaching 500 rpm. Therefore it appears you have a problem with either the COR or fuel pump relay/wiring. Based on what you've written I'm guessing the latter.

Time for a meter and the schematic. If you can't do that it's going to be a little tougher...

 

[jetjock]

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=114

1) Unplug the fuel pump relay

2) Jumper +B to FP on the harness connector. Does the engine run?

3) Jumper +B to PR. Does the engine run?

Doing this will prove the COR, resistor, and wiring is OK.

Next test the relay itself. Do you even have one? Has that dumb 12 volt mod thing been done?