Today I fired my Monte LS up then it quit after about a second, luckilly in my garage. I have verified that when cranking there is spark, fuel pressure is between 35-40 psi but there is no light when the noid light is connected to an injector. I also swapped in a spare ECM without any change, for kicks. The injector fuses are also ok, along with the ECM fuse.

Not sure where this leaves me, I believe it might be the ignition module or pickup coil, according to my shop manual.

The TPI setup is from an 87' Trans Am and still the MAF setup without VATS.

 

Try using starting fluid in the throttle body to see if it will fire up. Repost the results. Also have you ohmed the injectors?

 

trace the power on the injector wires. ign on you should get a constant 12 volts at the injectors.

 

Wouldn't the noid light tell me basically the same thing as tracing power to the injector wires? If it's not getting power when cranking, would it still show 12v with the ignition on?

The plug I pulled was dry too, not that it would of been wet when there is no power to the injector when cranking.

 

With the ignition key in on/run position the injector fuses should provide power to both banks of injectors. Test light to any injector on either side should light up, no light no power. ECM pulses ground side of injector harness so even if you have power that doesn't mean injectors will work. With power to injectors OK, and no noid light activity means requirements for ECM to pulse injectors are not being met. assuming no wiring/fuse problem - if no VATS then Distributor reference pulse is absent, or possible injector resistance overload.

 

Mine was doing the same thing...I took apart ECM cleaned it really good. REplaced it and made sure all pins where in good shape.

It fired right up after that...

 

I swapped out the ignition module for kicks, no luck. Need to get a battery for my meter, then will test the wiring harness and resistance of injectors. Double checked fuses, all are good.

 

Still working on this, the injectors all ohmed out at 15.6-15.7, there is no voltage to any of the injectors with the key on. I didn't see anything visibly wrong with the wiring and swapped my spare ECM in without any luck or change. Any tips on tracing the wiring issue? Could the pickup coil or another sensor affect the injectors getting voltage? TPS readings are normal, IAC reading was 165 with the key on. Any help appreciated.

 

I have a '90 Iroc-Z with a 5.0L TPI and I'm having similar issues to what you're having. I changed the Cap & Rotor, Ignition Module, Coil, and Spark Plugs thinking that would solve the problem. That didnt help so then I changed the Knock Sensor and MAP sensor. After that I found out that the Timing was off. Every time I set the initial timing to 6 degrees like the specs ask for the car runs beautiful with full power for about a mile or so then it gives and runs like crap all over again. The computer advances the timing for some odd reason. The computer isn't throwing out any codes NO matter how much of a rough idle it has. Does anyone has any idea where the ESC Module or ESC Sensor is located? Now the car wont turn over at all and after cranking it over so many times trying to figure out what's wrong, I fried my starter solenoid and I waiting for my replacement. I'm looking for any other sugestions as well.

 

bad injectors?

 

you should have constant 12v, with the key on, sounds like your injector fuses are blown.
Not sure about the Monte, but on an F-body they are marked inj1 and inj2.

 

Fuses are ok...when I did the TPI swap I added spots on the fusebox for the injectors, so there is some of my own wiring work involved here, but I did the swap back in 02/03' and haven't had this kind of issue since. Just wondering what to check along the wiring trail since it is an apparent wiring issue. Also a very odd coincidence that the problem first occured after messing with the battery area.

 

check any fusable links that would supply power to fuse panel also

 

bang on the comp while your crankink. it may work

 

check out what I jut posted in the other thread maybe it will help.

FIXED IT, now starts all the time on a dime. it was the pick up coil inside the dizzy, good thing I got a couple extra distributors laying around I changed everything almost I have a gang of extra parts laying around, even if the ignition module test good it has to get a signal from the pick up coil to fire the injectors, the computer will do the rest after it gets the signal, The reason I missed this is because I put a so called new msd distributor in when I put the motor in so I never intended to look at the dizzy as the problem, now I know why they said to alwways use GM products this set me back almost 2 weeks for a 5 minute fix as soon as I dropped it in it fire right up I really hopes this helps out someone else.....

 

Thanks for the response.

I figure I should post what the cause was, or so I'm 99% sure it was anyway. Haven't logged many miles on the car since the discovery, but so far so good. Basically it stems from my wiring changes when I converted the car to TPI back in 02'. At the fusebox I wiggled some wires and the car would cut out or not start, then after wiggling the injector wiring would start again. Going to go over all of the wiring changes/splices soon, before I start driving the car normally again. I also see some things I don't really like as far as how things are wired into the ignition/key on voltage.

 

Right on Monte, Youre on the right track. Ignition mod or pick up coil are not going to affect ign power to the injector circuits. These get switched power from the fuse panel. Check all splices and connectors. Just FYI. I always solder and heat shrink splices. It prevents this kind of headache.

 

I'm kind of ashamed to admit I've been running this car with just spliced connections for 8 years . Bought a soldering iron and will be doing just that (with the heat shrink) to be sure on things. Peice of mind not to mention what I should of done since time of the conversion.

 

Ok, so as an update I changed fuel injectors, EGR valve, and fuel pressure regulator, and Ignition control module, as to everything else I previously changed..... Still the same problem (Poor Performance, Hesitation, and Rough Idle). I'm completely Lost

 

So this same thing just happened to me several days ago. I had to have my car towed from work to my house (less than 1 mile). Since ive had it towed i went ahead and i checked the ohms on all my injectors and all of them are over 13.0 ohms. As for the fuel pressure, i checked that too and im running at 47.5 lbs of fuel pressure. Next I pulled my spark plugs and saw that all of them were still good. I dont know what else to check to make my car run again. The only thing i could think of would be if my injectors themselves are bad. I don't think the injectors have been changed on the car at all, since its been running for 180k miles now. I know that sometimes when i give a little throttle, it does hesitate a little bit trying to go. Any more input on what else could be causing my car to just crank over and over and over and not start, please feel free to give me your input.

 

Were your plugs wet or dry when pulled? Did you check injector voltage with the key on? You might be getting fuel to the rail but not to the injectors.

 

No all my plugs were dry. I checked the voltage to the injectors with the key n the "on" position. As for the fuel, i checked it off the schrader valve on the fuel rail. Im assuming since i read 47 psi that it was getting pressure to the injectors. How could i tell if im not getting psi to the injectors?

 

If you have pressure at the scrader then you have pressure at the injectors. You need to go back to basics and check for spark and injector pulse. These intermittent performance issues are often caused by the pick up coil in the distributor. When you replace the ignition module, you should always at least test this coil. It is the green and white wires that connect to the back of the module. Its commont for the P/U coil to fail when hot.

 

So whats the voltage i should be looking at on the P/U coil? and same thing again as far as testing goes, test with the key in the on position correct?

 

You test the coil for resistance. Factory says it should test between 500 and 1500 ohms. I say it should be closer to 800-1000. If its closer to 500 or 1500, replace it. Be sure though that youve checked everything else mentioned on this post. The injectors should have 12v on either side of connector with key on engine off.

Once youve verified that, check pulse either with a test light or noid light. Do you have spark? If you have spark then the P/U coil is doing its job. If you have spark and no injector pulse, even with 12v to the injectors, then you have an injector drive issue. Check power and grounds to the ECM. Test to be sure youre getting at least 10v to all power and ignition sources at the ECM while cranking.