New Engine Cranks but Won't Start

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New Engine Cranks but Won't Start

Unread postby Severus » Sun Dec 08, 2019 1:02 pm

I'm hoping someone can help me out here. I have a 92 GT with a CBAZA swap that Decipha helped me with earlier in the year. I recently finished building a new engine (306, B cam, gt40y heads, 1.7 rockers, cobra intake) reusing my known good injectors and wiring harness. When trying to start it for the first time I can get it to cough like it wants to start but that's all. I have validated that I have spark, and that my injectors are firing using a noid light. I can get a readout on the ECU with TunerPro and this ECU worked fine with my old engine. Only thing that has happened to it between then and now is sitting for a while with no battery. I reloaded the tune but no dice.

The engine has a new OEM style distributor (I have also tested with the older Ford OEM one, no change), new ACT and ECT sensors, new O2 sensors, new MSD coil, and the existing older BAP sensor. I have pulled the valve cover and validated that I installed the cam correctly and the distributor is installed correctly. I really don't think there is anything wrong with the ECU but I am out of other ideas. I want to get the basic engine start done before I setup a remote tune with Decipha so I don't waste his time. Any advice is greatly appreciated! Thanks in advance!
Severus
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Re: New Engine Cranks but Won't Start

Unread postby Severus » Sun Dec 08, 2019 2:19 pm

The more I diagnose this, the more I think the issue is weak spark. The inline spark tester will flash on the coil wire and a plug wire but not very brightly. Also, putting a volt meter on the coil connector I can see that the voltage is dropping to about 10v during cranking. The battery is a fully charged yellow top (albeit older). Any thoughts?
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Re: New Engine Cranks but Won't Start

Unread postby decipha » Sun Dec 08, 2019 6:19 pm

yea swap out the coil and if theres a box on it bypass it to test

the most usual cause for a no start after a rebuild is the distributor being 180 out... verify that first
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Re: New Engine Cranks but Won't Start

Unread postby Severus » Sun Dec 08, 2019 6:35 pm

Yeah, I have triple checked the distributor. Pulled the plug, rolled it over till I felt compression, set it to tdc and lined it up. I also tried my original factory coil to no avail. No MSD box or anything like that. Using the cranks but won't start checklist, I get to the part where I should see a test light flash on the coil connector. I get a solid light but no flashing.

I wonder if the TFI isn't signalling the coil. I looked at the wiring diagram but I'm not sure if the signal comes from the ECU on pin 56 or directly from the TFI module.
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Re: New Engine Cranks but Won't Start

Unread postby decipha » Sun Dec 08, 2019 7:48 pm

tfi

the ignition system is independent from the ecu even with the ecu removed the ignition system still works
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Re: New Engine Cranks but Won't Start

Unread postby Severus » Sun Dec 08, 2019 9:33 pm

Gotcha, out of curiosity, is the wire that is common between the coil, tfi, and ecu for the pip signalling? Also, I was expecting that if I used a 12v test light on the coil connector to see it flash but instead I get a constant light, any thoughts on where to start? I have been over this new engine dozens of times and short of pulling the efi wiring harness and checking every wire I'm at a bit of a loss..
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Re: New Engine Cranks but Won't Start

Unread postby Severus » Sat Dec 14, 2019 2:39 pm

I'm still at a loss on this... out of desperation I opened the timing cover just to double check that I hadn't put the cam in 4' above or below since you can do that with the comp cams timing set I have and it's exactly where it it should be. I also got a good A9L and removed the cbaza swap to no avail. I got a few ignition testing tools and validated I have good spark, and you can smell the gas after cranking it for a bit. I simply do not understand why this isn't working... It will cough and pop a little (sounds like detonation a bit in the exhaust) but that's all it will do.
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Re: New Engine Cranks but Won't Start

Unread postby decipha » Sat Dec 14, 2019 4:22 pm

it sounds like you have the diatributor 180 out. Pull it and check the gear too.
You said u lined it up when u felt compression. Did you verify you were on compression stroke and not exhaust stroke?

otherwise it would be a massive air leak
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Re: New Engine Cranks but Won't Start

Unread postby Severus » Sat Dec 14, 2019 5:26 pm

It should be on the compression stroke with the cam timing mark at the 6 o'clock position and the crank keyway at the 12 o'clock position. As far as I know that should be when I set the distributor in pointed to the number 1 cylinder.
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Re: New Engine Cranks but Won't Start

Unread postby decipha » Sat Dec 14, 2019 5:39 pm

where did you find that info ?
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94 5spd Rionda
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Re: New Engine Cranks but Won't Start

Unread postby Severus » Sat Dec 14, 2019 6:07 pm

That should be TDC no? I turned it around 180 and it's no different. In the original spot where I had it you can hear it firing into the intake but I assumed that was just needing to set the initial timing.
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Re: New Engine Cranks but Won't Start

Unread postby Severus » Sat Dec 14, 2019 6:15 pm

To add, I can smell a lot of gas when I crank it, and I just changed the oil after opening the timing cover and it smelled really gassy. I assume I flooded it and it seeped down into the oil after all that cranking over the last few weeks. Compression is good at around 120 psi and doesn't leak down.

I don't know how this would have happened but I wonder if these injectors somehow went bad sitting out of the car. They are about a year old, and I had them in a plastic bag while I build the motor. That makes no sense to me but I am running out of ideas.
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Re: New Engine Cranks but Won't Start

Unread postby decipha » Sat Dec 14, 2019 7:00 pm

if you cranked it long enough to flood it then youve most likely washed down the cylinders and took out the rings and bearings

anytime u have a crank no fire hold the throttle to the floor while cranking to shut off the injectors

if its firing through the intake then your distributor if wrong

you need to follow the ford procedure for installing the distributor correctly
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91 4r70w - Skarlett
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94 5spd Rionda
95 auto Aisha
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Re: New Engine Cranks but Won't Start

Unread postby Severus » Thu Dec 26, 2019 5:04 pm

I got this sorted out, needless to say I should probably hand in my Mustang card because I set the firing order clockwise on the distributor instead of counter-clockwise... I am officially an idiot.

I filled out the vehicle info form for a remote tune, but while you get ready to set that up, I am still seeing a super lean condition at idle and it's still backfiring a lot into the intake. I have looked it over and I don't think I have an air leak, so not really sure why it's so lean at idle. I considered messing around with the fuel but I wanted to see what you thought first.

Thoughts?
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Re: New Engine Cranks but Won't Start

Unread postby decipha » Thu Dec 26, 2019 11:25 pm

if its lean then it can only be a fuel issue or an air issue
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91 4r70w - Skarlett
92 (2x) 5spd & auto - Bianqa, Andrea
93 auto - Danika
94 5spd Rionda
95 auto Aisha
Vehicle 2 Information: Others:
00 Lincoln LS - Luanda
98 Camaro SS - Bounquisha
02 Harley F-150 - Sasasha
03 Marauder - DyShyKy
00 Explorer 5L - Bernyce
07 GMC 2500HD 6L - Veranafer

Re: New Engine Cranks but Won't Start

Unread postby Severus » Fri Dec 27, 2019 9:34 am

I was going to turn the fuel pressure up a lot just to see if it dials it out but any other recommendations would be welcome. I checked the vacuum lines off the engine and it holds a vacuum, I will check the underside of the intake again to make sure none of the caps are leaking.

When should I send you the paypal payment for the remote tune? Not trying to rush you, just not sure your preferred process. :)
Severus
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Re: New Engine Cranks but Won't Start

Unread postby decipha » Fri Dec 27, 2019 6:38 pm

now is good once u send it youll be upgraded

dont crank the pressure change it in the maf
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Vehicle Information: Supercoupin' x10
90 (4x 5spds) - Dante, Ruby, Daja, Ava
91 4r70w - Skarlett
92 (2x) 5spd & auto - Bianqa, Andrea
93 auto - Danika
94 5spd Rionda
95 auto Aisha
Vehicle 2 Information: Others:
00 Lincoln LS - Luanda
98 Camaro SS - Bounquisha
02 Harley F-150 - Sasasha
03 Marauder - DyShyKy
00 Explorer 5L - Bernyce
07 GMC 2500HD 6L - Veranafer

Re: New Engine Cranks but Won't Start

Unread postby Severus » Fri Dec 27, 2019 6:52 pm

Ok cool i'll send it over. Should I just try an across the board adjustment like adding 10% to the whole range or just turning up the first 1-2 maf counts values till I get the wideband to register something less that the max (1.20 in tunerpro, -- on the gauge).
Severus
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Posts: 55
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Screwdriver

Re: New Engine Cranks but Won't Start

Unread postby decipha » Sat Dec 28, 2019 1:55 pm

i misread i thought you had it running that it was just lean. If it won't fire off at all then the cranking pw needs adjusting. I posted your startup tune in the premium member section in your private thread. viewtopic.php?f=80&t=3496
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decipha
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Posts: 18494
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Vehicle Information: Supercoupin' x10
90 (4x 5spds) - Dante, Ruby, Daja, Ava
91 4r70w - Skarlett
92 (2x) 5spd & auto - Bianqa, Andrea
93 auto - Danika
94 5spd Rionda
95 auto Aisha
Vehicle 2 Information: Others:
00 Lincoln LS - Luanda
98 Camaro SS - Bounquisha
02 Harley F-150 - Sasasha
03 Marauder - DyShyKy
00 Explorer 5L - Bernyce
07 GMC 2500HD 6L - Veranafer


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