7M-GTE no start - has spark, inj op, fuel pressure, CPS & cam timing is good.. WTH?

[Wreckless]

I'm helping a friend with his 1988 built 7M-GTE Supra and it's got me downright boggled.

Significant Details -
1988 7M-GTE, 5MT, 550cc injectors, stock ECU, VPC/GCC, AFPR. Single Walbro
Toda 264 cams, AEM cam gears, ATI crank damper, J&E pistons Crower rods. CSI is eliminated. Ported stock intake manifold & TB.

Fuel pressure is 42psi off vacuum. Spark has been verified via timing light when cranking. CPS is set according to TSRM, cam timing @ TDC is dead on with ATI crank pulley and verified via chopstick in #1 with spark plug out. Injector operation verified by pulling fuel pump relay, unplugging an injector and using a multimeter to observe resistance in the injector plug while cranking. TPS has been calibrated per TSRM. Have attempted to start on two different ECU's both with and without the VPC wedge harness installed in the main harness, since the engine should start W/O the MAF.
Ignitor, coilpacks, and CPS are not suspect because spark has been verified.

It will crank, and on the first try it will hiccup *once* like it's trying to start, but after that it just cranks and nothing.

My thoughts so far:
-has anyone else known the Toda cams to be 'off' in any way?

-Is there a way to visually inspect for proper cam timing on the cams directly without having to tear down the whole top end of the motor?

-Can the AEM cam gears be installed 180* upside-down?

-Is there any ground or anything like that which could prevent the car from starting even though one has spark & injector operation and the CPS is timed correctly.

-Hang myself & install 2JZ/SBC/1JZ/RB26/1UZ/An Hero?


Any insight my fellow OG MK3 guys could shine on this one would be most seriously welcome & appreciated. It's been awhile since my last 7M build and I feel like I'm just missing some stupid detail I should have known.

 

[IBoughtASupra]

Try using some starting fluid but I would check for compression first. It is the only thing you did not mention. Spark, Fuel and ignition don't mean anything without compression. Try that and others will give opinions too.

 

[Wreckless]

Starting fluid is 100% unnecessary on a 7M-GTE, even without the CSI installed. The fuel pump relay is set up to go on at key-on, not after cranking begins so fuel pressure is good to go from the beginning.

The engine is 100% fresh and deviates about 1.5 psi between all 6 cylinders.

 

[jetjock]

Starting fluid is 100% unnecessary on a 7M-GTE, even without the CSI installed. The fuel pump relay is set up to go on at key-on, not after cranking begins so fuel pressure is good to go from the beginning.

Not only is that 100% wrong but based on what you wrote in the first post you really haven't verified much of anything...

 

[Wreckless]

Not only is that 100% wrong but based on what you wrote in the first post you really haven't verified much of anything...

You can take a second to say that, but you can't take a second to actually suggest what I might try or do?

I'm not here to drop my pants and tell everyone to whip out a ruler. I'm just looking for suggestions & ideas and I'm not claiming to be the world expert on anything here. :\


But when the heck would a 7M-GTE need starting fluid? I've never, ever, ever needed it in the past regardless of injector configuration, ECU, whatever.

 

[S.A. supra]

Pull the efi fuse give it a crank for a couple of seconds do that about three or four times. Then put the fuse back in and see if that helps.

 

[Wreckless]

Thank you for the reply. We tried that once but not for several cycles like you suggested. Gave it a shot, no dice.

Any other ideas?

 

[3p141592654]

Compression check seemed like a good suggestion? At TDC #1 both lobes should be pointing skywards and the CPS, well you already know about where that should be pointing, apparently.

 

[S.A. supra]

Compression check seemed like a good suggestion? At TDC #1 both lobes should be pointing skywards and the CPS, well you already know about where that should be pointing, apparently.

Not straight up I've seen in books where they are pointed straight up.

 

[IBoughtASupra]

Jetjock, are you saying I was wrong to use starting fluid on my 7MGTE when it was having a hard time starting since we just wanted to make sure no bottom end noises were present. We didn't even have the intercooler piping in, so that is why we used it. Anything bad in doing so?

 

[jetjock]

Depends on how big your ruler is

No, you weren't wrong. I was referring to the fuel pump comment. I should have done a better job with the quote...

 

[Wreckless]

Referring to what about the fuel pump comment? I've got 42psi of rail pressure @ key on and the injectors are working, I know that because I've taken the plug off the harness and monitored the resistance as the starter cranks and watched it go from ~2 ohms to OL and back. The fact that I'm getting some kind of cyclical response tells me that it's opening & closing(am I crazy or does that make sense??). Since I wasn't sure, I pulled off the upper intake and found fuel residue in all of the lower intake runners.

Jetjock, do you have any insight on the questions I asked in my first post? AEM cam gears/Toda cams? etc?

 

[jetjock]

If the fuel pump comes on with the key your car is either not stock or damaged. It's also dangerous. That aside if, as you claim, spark and fuel are there and timing is correct the engine has to run does it not? Means you need to go back and look again. And stop abusing your meter...

 

[nosman4]

I know you said you had spark verified by timing light, but that doesn't mean that your spark is strong enough to ignite the fuel. Try testing it with a spark tester. And recheck the timing, that's all I can think of.

 

[ForcedTorque]

A fuel leak can cause no start. There is also a relay in the engine bay fuse box that goes bad. I'm assuming you checked the EFI fuse as you pulled it.

 

[s383mmber1]

check fuel volitility...

 

[GrimJack]

I hate to ask the obvious, however, someone has to do it. Have you checked for codes?

 

[AcIdBuRn02ZTS]

How long has fuel been in the tank? sitting for any length of time? what about fuel pressure while cranking? you could be building pressure at first but when cranking and the injectors start firing, it could be quickly dropping off showing a dead pump...

Just to verify its not a fuel problem... hit it with a little starting fluid and see if it does anything... if it does... its a fuel related issue... if not... its electronic/spark related most likely...

cam timing could be 180 out which would do something simular to whats happening here... (however I dont have much expereince with the 7m's valvetrain... so I'm not sure if its possible to do.)

-AcId-

 

[Wreckless]

The fuel is fresh 91 octane, which is the best pump premium available in these parts. There are zero fuel leaks. Fuel pressure is 42psi at key-on and set up that way via a direct key-on relay and the pumps get their power directly from the battery. The fuelling is not the issue here.
The engine has yet to run at this point, and is logging no codes.

All I can suspect at this point is some kind of mechanical timing issue with the Toda cams & AEM cam gears. I did not assemble the long block, I was assured it was 'good' but we all know how that goes. With everything else testing good, all that's left is something wack in the valvetrain.
More than anything, I started this thread in the hopes that someone might have some insight on any crazy ECU grounding issues or any other very specific electrical issue that might create the same problem we're seeing, as this car has passed through a couple of different shops that only managed to make things worse. But since it seems like it must be specific to something in the cam timing, I'll check that out first just to be sure. Hopefully it's an easily fixable case of operator/builder error.

Thanks for taking the time to respond and offer what suggestions you have. I truly appreciate it, and my friend Paul who owns this car, and has not been able to drive or enjoy it since he was playing billy badass on unsuspecting 5.0L Mustangs at HKS Stage V back in 1996-97, also sincerely appreciates it.
While helping him work on this car, I found a circa 1997 HKS Catalog, I'll get it scanned and uploaded ASAP, it's quite nostalgic!

 

[syty1]

compression is the other required element for firing...check it.
If your valve-timing is sufficiently _ _ _ _ed to prevent it from running it will definitely show up on a comp test.
ALSO...did u follow fuel pressure WHILE CRANKING? As mentioned, a dying pump may give initial pressure w/ no flow but not maintain pressure when flow is required.
HTH