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PostPosted: Tue Jul 29, 2014 11:18 am 
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Location: Muncie, IN
Hey guys background is car has 63k miles...po couldn't get it started one day and it sat for past 8 years. Dropped fuel tank and cleaned it...new fuel pump and after a number of attempts at troubleshooting thanks to this forum I still cant figure out why the injectors aren't firing. Runs on choke cleaner. Previous ecu has suspect corrosion so I got another one ..looked clean on inside but same prob. Injectors have power to them and click when grounded. Mpi relay good. The resistor pack up by fuel rail has 3 wires. One is supposed to be for coil...when should this be hot?? At my wits end here lol

Thanks,

Eric


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PostPosted: Tue Jul 29, 2014 12:30 pm 
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Moved to the 4G15 tech forum. Are you sure the fuel pump is working? Are you building fuel pressure?

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91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

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PostPosted: Tue Jul 29, 2014 1:16 pm 
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I unbolted the connection at the fuel rail and put the line in an empty bottle while cranking the engine for a couple seconds and there is fuel that is coming out. If I'm not building enough pressure will that keep the injectors from opening??? I've had a noid light hooked up to test and haven't got the first pulse on any of the injectors.


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PostPosted: Tue Jul 29, 2014 1:47 pm 
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Quote:
I unbolted the connection at the fuel rail and put the line in an empty bottle while cranking the engine for a couple seconds and there is fuel that is coming out. If I'm not building enough pressure will that keep the injectors from opening??? I've had a noid light hooked up to test and haven't got the first pulse on any of the injectors.
I'd find a way to test the pressure coming out of the pump. Injectors have an operating range for pressure. If they're not getting enough, they may still open, but it may not be enough to make the engine run.

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91 GSX - 511fwhp and 352 lb/ft 25psi 110 octane, 7.68 @ 95.9mph 1/8th 21psi 91 octane, 11.93 @ 112.9mph, 117.7mph best trap speed, 20psi 91 octane
98 Volvo S70 T5 - DD

http://www.facebook.com/captaintonus


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PostPosted: Tue Jul 29, 2014 1:51 pm 
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Location: Tucson Az
after sitting 8 years i would replace the injectors..or have them cleaned/tested




Steve

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Steve 89 colt 2.3 stroker stock top end. evo3@20 psi 13.489@99.30mph 3/10 2012
On drag radials.auto trans.launching @ 5 psi and no traction thru 2nd.


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PostPosted: Thu Aug 07, 2014 9:04 pm 
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Location: Muncie, IN
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got some time to tinker with the Colt... pulled the distributor to do a visual check of components, wiring and verify timing. The cam timing mark/line? on the head was tough to see if it matched with cam sprocket mark. I really looked like the cam mark was above or shy of lining up with the mark on head. Perspective on pic makes it look closer than it is. ATTACHED pic to show marks in question. Put distributor back in and it tried to run For a few secs then died. Injectors were pulsing now ?? Odd I thought but progress maybe. I moved the distributor toward the drivers side fender and after about 3 secs of cranking ran and revved WAY up then died. Way up = approx 5-6000 rpm...no tach but it screamed. It started again and revved up that high but I shut it off after a couple secs bc I didnt want something to f up. Tried unplugging maf ...coolant sensor and no change. Only change was with moving distributor timing. Going to try to read computer for a code tomorrow. .. check TPS ... could cam timing be causing computer to over compensate? What else to check??? Thanks in advance.


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PostPosted: Thu Aug 07, 2014 9:33 pm 
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Loosen the throttle cable jacket that is bolted to the back/top of the intake manifold.

There needs to be slack on the wire coming out of the jacket. Any lack of slack, will equal constant opening of the throttle blade.

Confirm the throttle blade is closing all the way, before proceeding.


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PostPosted: Fri Aug 08, 2014 4:45 am 
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Location: Wisconsin
Double check all the vacuum lines and hoses as well, you might be missing one somewhere under the intake.

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Had a:
1991 Eagle Summit ES Hatchback - 4g15 12v 5spd
1991 Dodge Colt -4g15 12v 4spd
Have a:
1978 Oldsmobile Cutlass - 468BBO TH350
Round 3:
1990 Dodge Colt-4G63T 5spd


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PostPosted: Fri Aug 08, 2014 8:25 am 
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Well I managed to get the car to stay running this morning! *** The catch is I had have my test light probe in the lower left red/white pin on the MPI relay. I havent looked up the pinout of the socket yet but with ignition on and that wire grounded the fuel pump runs. To my understanding the fuel pump on runs on startup when cranking which explains why the car only acted like it would run with the starter turning over. After the car starts what takes over to power the fuel pump? Just wanted to update I'm headed to the manuals again!


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PostPosted: Fri Aug 08, 2014 1:13 pm 
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yeah just turning the key on will not activate the FP.. it only comes on for a sec when u crank it to prime the system (get fuel to the injectors).. once car is started then it stays on... I cant remember which wire it is but there should be 0 volts to it until the car is running. then the wire should have power.

so check the wires for power with key off.... then key on.. and figure out which wire/wires dont have power (other than grounds lol).. then test the one or few remaining wires once car is running (you might need a 3nd test light if it will only run when the 1 is connected.. it very well could be a bad MPI relay.



Steve

_________________
Steve 89 colt 2.3 stroker stock top end. evo3@20 psi 13.489@99.30mph 3/10 2012
On drag radials.auto trans.launching @ 5 psi and no traction thru 2nd.


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PostPosted: Fri Aug 15, 2014 7:54 am 
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Location: Muncie, IN
UPDATE: New MPI Relay and same results... Car will run when red/white wire on mpi is grounded... it idles rough ...kinda lopes but smooths out with some acceleration.... I stepped back to reasses... went to test/jump the fuel pump test wire in engine compartment and no response... but when red/white wire is grounded pump is on. I'm about to give up. ECU problems again??? Frustrating


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PostPosted: Fri Aug 15, 2014 5:20 pm 
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Have you found the schematics at lilevo.com/mirage/ ?

Click me

Some nice fanout sheets there.


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PostPosted: Sat Aug 16, 2014 3:31 pm 
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Thanks for the wiring schematic link...I was looking that over and the factory service manual pdf and found that I had been jumping the wrong terminal for the "fuel pump test". I was giving 12v to the Ignition timing adjustment terminal. I feel like an idiot lol After finding the actual fuel pump test terminal it turned the pump on with 12v + jumped to it. Have I done any damage or blown a fuse/fusible link by jumping 12 v to the ignition timing adjustment terminal???


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PostPosted: Sat Aug 16, 2014 7:05 pm 
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Try putting it in manual timing mode after warm-up, and also, if it runs well enough with no check engine lights, then likely you are in the clear.


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PostPosted: Mon Aug 18, 2014 7:04 pm 
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Well I've come to the conclusion that I need to try another ECM. I took the cover of the replacement ecm I've been using and under close inspection looks like it had evidence of leaking caps well.... Is it hopeless to try and find a used ECM ?? Lol


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