Need a little help. Parked car witrh every thing fine. Went to drive car and found dead battery. Tried to jump with no luck. New battery and car won't start. No spark and no fuel to TBI. Changed distributor cap and coil. No help. Changed HEI. No help. Noticed car fired and fuel delivered when ignition turned off, Then we started checking further and found with fuel in TBI and four lead from HEI disconnected car runs fine till fuel is gone. Nothing else I try has gotten me any further.Has anyone ever experienced anything like this or have any sugestions where to go from here?? Any help appreciated. TIA Mike

 

Hi Mike, and welcome to the forums.

This may be a long shot, but have you checked the fuse for the ecm?

 

Yes checked fuses. Had a high performance chip in ECM and replaced with stock chip. No help. Car acts like ignition system polarity is 180 out. Was convinced it was the ignition until we unplugged the 4 lead from HEI module and car starts fine with fuel in TBI.

 

Ok, fuse isgood, I don't know exactly how your tbi setup is laid out, but next thing I would do is check the consolidated grounds, they could be bolted to thethermostat housing, sometimes they can be found bolted on the end of the heads, make sure none are loose or broken. If everything checks out,check the voltage on the throttle position sensor with it connected, and the ignition on,. You should have 3 wires, black should be ground, center wire is signal wire to the ECM, the other wire if the feed wire. Check the center wire with throttle at idle position, and at wide open throttleposition. Post your findings here.

While the engine is spinning, do you have any activity on the tachometer?

 

Also Mike, did the check engine light come on? if so, do you know what codes were stored?

 

Thanks for the ideas. When cranking the tach moves but when I turn the ignition off it jumps to 3000- 7000. I also should add that when I stop cranking and turn igniton off,I get a rapid clicking that I think is the fuel injector or fuel meter. It stops when disconnecting the four lead from HEI or disconnecting the lead from the coil to HEI.

The check engine light is a totally different issue. The only warning light I've ever had is Gen light. Before posting yesterdayI spent the afternoon trying to figure out why I don't get the other warning lights. Going through my shop manual I find zero reference to a check engine light. Only Gen / ECMwarning / Low fuel pressure all on teh instrument cluster printed circut board. All bulbs function when rotated to working light (gen), but no luck getting anything else. So, I'm not even sure where the check engine light is located. I'm guessing below the tachometer.

The search for check engine light began because I was going to activate the self diagnosis, realized I had never seen a check engine light and have had no luck finding it or getting any of the others to work.

Last, I'm not sure my meter will check voltage, but probably will if I can figure out how to set it. Will spend some time tommorrow looking it it again. Thanks again for your inputs. Will figure this thing out yet!!! Always the last resort of taking it to a dealership but desperately trying to avoid that.

 

You can use a paper clip or a small piece of wire to jump A & B inthis procedure

http://www.obd-codes.com/faq/read-gm...codes-free.php


A digital read out volt meter on the 20v scale is the best thing to use to check the tps, it's almost impossible to get an accurate voltagemeasurement with an analog meter.

 

Update. Must of moved / giggled something because symptoms changed. No longer get clicking from fuel meter when key turned off. Sounded like something under the hood powered up and that noise stopped. Tach is no longer moving when I crank engine. Needle moves alittle (8 oclock) when key turned on, goes to7 oclock when key turned off. Car will still start with 4 lead from HEI disconnected and fuel in throttle body.....and will now fire with 4 lead hooked up but won't run and sounds very rough.

Got a digital tester and test TPS. key on at idle .14, at full throttle 1.24 Also grounds looked good.

Messed with center console lights some more. Still can't get check engine light to work. Checked printed circut board with tester and there seems to be juice at check engine light socket with key on??? Since I can't get it to work I can'tput it into self diagnosic mode to see if there are any codes. But now gen light is staying on with key off.....I obviously have some electrical issues.

 

Is that the voltage on the center wire?

what color are the wires, black,blueand gray? if so , what was the voltage on the gray wire.

When you tried to jump start it, you didn't happen to cross the cables, even for just a second?

 

I put the tester on 20v. red lead to center wire and black lead to bottom wire.I didn't use jumpers, but stuck the leads in the backof the plug. Thought I was testing correctly.Don't remember colors for certain.

No, I never crossed the cables while jumping.