It should start.... but won't.

[WillWorkFoBoost]

So Im trying to get a 90 turbo running that has recently been rebuilt, Has fuel, spark and compression but wont start. It just burbles a bit like it wants to start. compressions fine, cam and ignition timing are on, fuelpump has been replaced and you can hear it flowing hard when its jumpered. plugs have fuel on them after cranking...... Ive checked each plug for spark, and theres 12 volts at each coil....
Only possible thing I can think of is that the spark may be weak?
Any input would be appreciated.
Thanks

 

[SupraSean]

Major air leak? Double Verify timing

 

[JStoked]

Is your cel light coming on?

 

[jetjock]

Sounds like timing...

 

[JStoked]

^ yes sir it does. But the op didn't give alot of detail. So I was just filling around and trying to get some more info boss.

 

[SRZMK3]

take a pair of vice grips and clamp your soft hose coming off of your furl pressure regulator and see if thats causing lack of fuel pressure, after that i would check if your ignitor is working properly.

 

[JSeaman]

How have you checked fuel? You can short FP and B+ in the diag block to try and rule out the pump

Is it a good clean bright spark?

Have you done a full compression test? What were the results?

I agree it sounds like timing, have you set the static timing then inserted the CPS?

Do all the dash lights come on? Checked out the wiring/fuse box?

James

 

[WillWorkFoBoost]

As stated in the original post, I checked fuelpump, which has been replaced, have tried jumpering it (fp and b+) its definitely working as theres fuel on the plugs. compression is fine, cam timing is dead on, ignition timing is as close to 10 degrees as one can set it with a timing light without the motor running, just turning over with starter.ignitor, coilpacks, both came from my other running supra, and the ones that came off this motor are on that one running it right now. and there are definitely no major air leaks. So as I said I have 12v at the coil pack connectors, so where else would I look to find a source of weak spark? the signal wire circuit?

 

[SupraSean]

It sputters? plug wires mixed up? other than fuel on the plugs, how did you verify fuel? Possible not getting full injector pulse when cranking. Check manifold ground.

 

[JSeaman]

OK if you've definitely got fuel covered let's look at spark and compression. For the spark I presume you have grounded the electrode of the plug and checked the quality? How does it look? The likelihood of it being too weak to ignite the mix is slim but possible.

Have you done a compression test?

Are you sure you haven't got the crank/cams out of phase by a turn?

Does the CPS look good? Wiring OK?

Do all the dash lights come on? Checked out the wiring/fuse box?

James

 

[WillWorkFoBoost]

yea compression was between 135-150 across all, which is a little varying, but i dont know if thats normal as these rings/pistons/walls have never been broken in yet?

Crank pulley tdc mark lines up with 0 deg mark of lower timing cover, and cams line up with the upper timing cover mark. so cam timing is on.

cps wiring and everything is fine and its a working cps that came off my running car.

Dash lights come on, looked at fuses and wiring in fusebox and all around ecu, nothing seems wrong there.

Spark isnt a super strong blue spark, but is a consistent yellowish blue spark, seems like youre saying it probably isnt due to a weak spark.

 

[JSeaman]

That's nothing to worry about on the compression front

As mentioned have you double checked the firing order? Don't rule out an obvious mistake at this stage

Also, have you measure fuel pressure as opposed to just presence?

 

[WillWorkFoBoost]

Yea firing order is fine 163425. and nope i haven't checked pressure, just jumpered fp, listened to it rushing, and when I crank it the plugs are wet and are blatantly covered in fuel. next step is to check pressure and all that but check this out....


So I was checking the grounds under intake manifold, they were not on the manifold but on the stud from the block that the j tube fuel return line is bolted to the block with. so I moved em back up to the correct spot under the manifold. then she wouldnt crank. checked battery with multimeter thinking it was dead, 12+ volts. jumped the fuel pump just for shits, pump starts pumping away. un jumper it and a minute or 2 later the fuel pump starts pumping without being jumped, turn off the key and its still pumping, no jumper, finally I pull the efi fuse to stop it. fuse back in, doesnt do it. still wont crank, just click from ecu region.

 

[MKIIISupraGuy]

OK you have a good cps but did you align it when you Installed it? I say this because I forgot this step and mi e wouldn't start until I pulled it out and lined it up. Started first try after that. Steps to this are on the tsrm

Sent from my DROID X2 using Tapatalk

 

[WillWorkFoBoost]

OK you have a good cps but did you align it when you Installed it? I say this because I forgot this step and mi e wouldn't start until I pulled it out and lined it up. Started first try after that. Steps to this are on the tsrm

Sent from my DROID X2 using Tapatalk

Yes I aligned it, and not only that but if you read above in earlier posts, it is set to around 10 degrees, verified by a timing light, which will need to be rechecked/reset when the motor is actually running and idling, but should start where it is timed. so yea there is spark at around 10 deg btdc.

 

[WillWorkFoBoost]

so I figured out the no crank, connector to the solenoid came off the starter. fixed that. still cranks no start, im gonna check fuel pressure next when I get a chance.

 

[SupraSean]

If you have access to a fuel injector pulser. try that pulse the shit out of and see if the cyl fills up

 

[SupraSean]

Also will it run on starting fluid??

 

[WillWorkFoBoost]

I can just ground the injector to cause it to spray i believe.... should have 12 volts to injector with key on? Il check fuel pressure and see if I can find something to spray in cyls to possibly start it on.

 

[WillWorkFoBoost]

Okay so I was just poking around with a multimeter and for some reason I have 12 volts from both wires of an injector.... theres a short somewhere.... the fuel on plugs may have been only from cold start injector and not enough to start it??? any obvious spots where injector wiring would be getting 12v put through the ground?
Possible bad ecu or wiring?
Im gonna check a couple other injectors and see if they have power going thru the grounds...