Well it happened again, my TPI engine won't start. It seems the injectors are not firing, they don't light a noid light while cranking. I have good fuel pressure-48 psi indicated on the fuel rail.
I sprayed starting fluid down the throttle body and it fired right up and then runs fine. I'll drive it a few days and the no start condition returns.

Why would it start and run fine with start fluid and not start by itself??

John


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86 Camaro Sport
383 Speed-O-Motive Crate Engine, Trick Flow Heads, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Dynomax Cat-back, Serpentine belt setup.

http://64.176.105.239/octride.htm

 

sorry I'm retarded

[This message has been edited by vortecfcar (edited October 24, 2000).]

 

Yeah I'm stupid too, can't imagine whats wrong.

 

Im in L.D. classes. Sorry.

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1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust

 

See, I knew no one would know the answer because I've posted this same post in differant sections for the last two weeks.

 

Have you checked to see if your injectors are actually getting pulses from the ECM?

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1984 Silver Z28, 383 cid 4 bolt, ARP Fasteners, 2 1/2" Cowl Induction Hood, 600 cfm Performer Carburetor, Torker II Intake, Performer RPM Heads, XE268H Cam, Magnum Roller Tip Rockers, MSD6AL Ignition, Blaster2 Coil, Recurved HEI Distributor, 700R4, TransGo SK, 2.73:1 Limited Slip Dana 44, Terminator Headers, Custom 3" TIG Welded Stainless Exhaust, Flowmaster Muffler, 4 Wheel Disc Brakes, Oil Cooler

 

I'm not Vader, but I would like to know what year that TPI system is? If it is older than but not including '89 then that system uses a cold start injector. Check to see if it sprays fuel into the engine while cranking. I know a cold engine won't start without it, but am not sure if it fires in conjunction with the other injectors or if the engine gets its fuel for start up soley from it.

 

John,

Just a couple of things to consider:

First, when posting here and asking for a specific member to reply, you not only exclude many others who could likely get a correct response to you a lot faster, you risk alienating some people who might otherwise be willing and able to lend good advice. (i.e., Vortec, Jester, and the Primate) I certainly don't mind replying to a post when I think I may have some useful input, but it doesn't always happen immediately, and I don't always have the right information. The forum is designed not only to solve your problem but to enable others who may have similar problems to view the replies and results. It also is an opportunity for others who might have had similar problems to share their experiences and knowledge. Without those qualities, this board would just be like "public" email. Incidentally, I'd bet there are many others who read over the topic and didn't even look, but could lend valuable input, like Engine, GMT, RD, Glenn, some who did reply, and many I haven't mentioned.

No flames, just a friendly reminder.

As for the problem at hand, if you have the original PROM, ECM, and wiring harness there should be 12VDC on the tan/black wires to the injector connectors whenever the ignition is turned on. The blue and green wires (right and left banks) are actually the injector ground connections to the ECM. The ECM will ground the wires to complete the circuits and "fire" the injectors.

You've already determined that spark is not a problem, and that there are no injector pulses when this occurs. I'm guessing that the reason you don't start until the fluid is sprayed is due to the lack of fuel. Once the engine initially fires on the spray fluid, SOMETHING is moving enough to complete a connection and let it operate normally. I would have guessed that the HEI is not sending distributor reference pulses to the ECM, but since you are getting spark to fire it with the spray fluid, that just about eliminates that possibility.

The next time this happens, instead of your starting fluid, grab a meter to check voltage at the injector harness. It will be very helpful to know if the 12VDC supply is present and the ECM isn't functioning, or vice-versa. Frankly, it would be easier to find a break in the 12VDC line and repair it than to continue diagnosing the ECM, but we'll take whatever data we can get. If the 12V is present, we move on the the ECM harness. If it's not there, the job just got easier.

On the bright side, at least you now have good fuel pressure and the check valve issue is eliminated.

And understanding how the system works and the importance of good connections, even though you've probably done it a hundred times already, make sure the engine and chassis ground straps are clean and tight. One of those could be that "something" that's moving just enough to get the engine started.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

first thing you need to solve a problem is an open mind........and the ability to listen

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87GTA,350,Auto,MAF screens removed,195 thermostat,cold start injector UNPLUGED,K&N,modified air intake,ADSchip,3:70s,3inch cat back Flowmaster single outlet,TPS.54,Bosch Plat plugs,base timing 6BTDC,22 MPG and runs like a bear,Bilstiens in the rear....,don't let yer meat loaf

 

LOL the only reason I said what I did was cause you said NO ONE but vader could answer it, so I wasn't about to let my fellow 3rd gener down. Plus I really didn't know the answer.


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1992 Camaro RS 3.1L
T5 Manual 5 speed
Open Air Intake
Z-28 Exhaust

 

I figured it out! I was lucky enough to have the no start condition in my driveway. I once again started all troubleshooting all over again.
-Fuel pressure good
-Spark good
-Test light on injector, bad

OK, no pulse to injector. Next I disconnect the 4 pin connector at the distb. and inject 12 volts with a test light to the purple wire on the car side of the connector while the noid light is still connected to injector. When I touch and release the 12 volts to the purple wire, the noid light should puls and the fuel pump should run for 2 seconds. That check worked good indicating the ignition module or wiring is bad because the module should send a pulse to the ECM to tell it I'm turning, go ahead and pulse the ECM. So I'm changing the module tommarrow.

What I don't understand is if I shoot starting fluid down the throttle body the car will start and run fine all day long.

P.S. I aplogogize to all on this board if I typed the header of this message in a way that offended anyone, I was despriate for an answer because this car of mine has left me stranded. I have posted this problem on this board before several times with very little response. I have learned a lesson, thanks thirdgen!




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86 Camaro Sport
383 Speed-O-Motive Crate Engine, Trick Flow Heads, 58mm Accel TB, 3.73 Auburn Pro, SLP Cold Air Induction and Headers, Dynomax Cat-back, Serpentine belt setup.

http://64.176.105.239/octride.htm