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No start what i assume is a wiring issue... details inside OGs and wiring gurus help

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So here is the setup so there is no confusion:

90 x8

2jzgte

jzz30/jzx90 harness and ecu

SAFC

fpr

fic fuel rail

630cc injectors

hx40

 

So I took the car out the other day for a ride and it was a little wet did a 2nd gear pull car spun bang limiter and then completely dies out. I coast off to the side of the road and try to start it back up. It cranks sputters and then dies out every time. I tow it back to the garage and begin looking over things. All vacuum lines are good. Thought maybe I jumped a few teeth on the timing belt but timing was spot on. Though maybe the trigger wheel on the crank came loose from banging limiter(had it happen before) Trigger wheel was perfect. Checked cam position sensors both gave me good resistance #s did the same for the crank position and it checked out as well. Though maybe the ecu took a shit I have a few known good ones layin around tried them and got the same result cranks, sputters and dies. I have good fuel pressure. took the coils out and did a compression test as well as checked for spark. Compression #s were normal but I noticed that coil #5 was not firing. I have a few sets laying around and same thing when plugged into #5 no spark when plugged into any other sparks like normal when cranking. Though maybe the igniter took a shit have a few known good units laying around all the same thing cranks, sputters and then dies. So im beginning to think its something in the harness. Ive looked though a few things and haven't found anything out of the ordinary. Any input or suggestions would be greatly appreciated i need this thing up and running asap i have an event on the 26th and need time to get the car dialed in. Thanks in advance

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#5 No fire is NOT going to prohibit the engine from running. It WILL run but lope and idle rough. There's something else amiss here. I had an intermittent/no fire/weak spark on #5 cause we put the pins in it backwards. It only fires one direction.

 

Make sure you didn't snap a cam. Also, you said you have good fuel pressure. Are your injectors firing? Did you blow something into the MAP sensor? Like an intake backfire...

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I had the same though about the fact that it should still run even if #5 didn't fire but didn't think of the wires being reversed i will see if that solves the spark issue. I left out that i tried several map sensors also with the same result. Crank, sputter and dies. haven't actually pulled the covers to see if i snapped a cam but id assume there would be some noise or something coming from the head if that were the case but i will check it none the less. I checked for power at the injectors and they all have power but honestly couldn't tell you if they are actually firing as i have no way to check don't have a noid light to see(if that is even the correct tool to check with im not very experienced with wiring or diagnosing electrical issues)

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Any way to confirm the safc is working? If you have fuel and spark or no fuel that's what id look at. To check for injectors firing have someone crank it over and listen with your ear over a screwdriver placed on one of them and you should hear the clicking and might be able to feel by hand.

 

If you suspect the harness it might be faster pulling it apart to inspect the spliced areas for the safc? Rather than checking resistance in between shit and for short to ground or voltage. I've never done a safc so not 100% on what gets wired in and what not or even its functions.

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I will deff do the injector check tomorrow. As far as the safc goes the unit functions as normal and the connectios at the ecu are solid and I can see all the correct sensor functions througb the unit

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You've been pulling your plugs. If the injectors are firing and it's still not starting the plugs should be wet immediately after. Also the screwdriver stethoscope is a new one. I've seen actual stethoscope ear pieces with a small tube instead of a doctor's bell, but the screwdriver sounds like an amazing life hack.

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Come to think about it I don't remember the plugs being wet but the question is why wouldn't the injectors be firing?

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Don't worry dude; I do the same thing. I get all worked up and need someone to talk me through breakdowns too.

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i got soo caught up on 5 not firing that i over looked such a simple thing. i bet it if i sprayed alittle starter fluid in it would fire right up. Injectors are high impedance so they don't need a resistor pack

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Three things cause injectors to not fire. Cam/crank/IGF signals. Sensors may check out okay, check wiring for continuity. This isn't the first drive right? Something just out of the blue? Check connection at ecu? Also you check for codes?

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No it wasn't the first drive... only code I get n is an o2 code because ita noy plugged in I've checked continuity for both cam sensors to the ecu plug and also the crank sensor everything seems to check out fine

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Just checked cams did not snap... kyle when you say igf I'm assuming you mean igniter feedback which would be pin 78 on my ecu and pin 3 on the small plug on my igniter just checked that and its got continuity from plug to plug... gonna throw the intake manifold back on and see if I can't get it to run on starting fluid to completly verify that its deff the injectors not firing

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Ok so I think I found the issue... a shitty solder joint from when I switched from a 91 chassis to a 90... so now I have a new issue and want to clear something up... when you wire up the harness at the round plug (square plug on 91 and up) that goes into the fuse box what goes where? all the wires are black and red but they are not all the same. if you guys need pics or something to determine what plug im talking about exactly I will gladly post them up

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Was just looking through the ewd for the chassis and I believe the plug im talking about is the b1 plug

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yeah, b1 plug. gimme a little bit and I'll confirm off my car, but two of the wires should have continuity on the chassis side and I believe those go to ignition and injectors. On the later model plug the wires are noticeably fatter than the third, early round plug was more difficult to tell so I used continuity to confirm, plus my ewd. But yeah. the one that doesnt have continuity should be your +b circuit. Didn't you already fix an issue with this plug? Starting to think since you found one solder issue it could possibly be another or something shorting somewhere.

 

And yes, I was talking about igf signal. since cam/crank/igf is fine you should have injectors. Make sure everything has power everywhere. do some jiggling, etc. sounds like the spin jarred something.

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Pretty sure I figured the b1 plug out as per a pm from kyle back in the day.. now here's my issue injectors 3, 4 and 5 are jus fillubg the cylinders with fuel... 1,2 and 6 appear to be running normal... 1 should the injectors have continuity to ground say a strut tower bolt if b1 is unplugged? 2 is it possible I somehow fried 3 injectors? If so why?

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Sounds like 3 4 5 are short to ground on the ECM side of the circuit but if its 3 and not 4 injectors on full time then the short is before the splice since yours should be paired injection right?

ECM controls the grounds so that's my view of it. The injector ground should go through a transistor in the ecu so it should be full on 0 resistance continuity and honestly should be no continuity.

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Figured it out... one of the solder joints for the b1 plug broke and after I fixed it the reason the injectors were running wide open was I had the harness unwrapped to look things over and I guess over time on of the injector wires rubbed though its coating and it was grounding out against the inside of the intake manifold... Problem solved... thanks for all the input and quick responses

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Nice work and I meant shouldn't have cont to ground. Typed on my phone.

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