I have an 86 Fiero that I'm taking the carb off and swapping an 89 tpi onto. I have new injectors, new ignition module, new stand alone wiring harness, the ecu is a couple year old reman with no run time on it, the prom was tuned for the injectors and vats was taken off. I'm getting spark but no injector pulse. Tps is .022V, I believe that I have everything hooked up correctly but I'm pulling my hair out from the lack of injector pulse. The only code that I'm getting is a code 12 and the only thing that I know isn't hooked up is my fuel pump feed wire.
Can you guys help me out?
Thanks Pete

 

The tps setting is low for tpi maf but will not stop injector pulse. Since you have spark this can still be a bad icm. The purple and white wire from the icm is the reference the ecm must get a 5v signal to the ecm to pulse them after 400 rpm. Check your ecm grounds as well. Are you positive someone reprogramed out the vats from the memcal ?

 

If you need me to read the eprom send me a pm

 

The purple wire has .38v on it just sitting with the key on, once I start cranking it the voltage starts jumping all over. The shop the shop that tuned it said they removed vats, I also have a hypertech prom that does the same thing but I'm not sure if it has vats enabled still

 

If the hypertech was from a f body tpi it would need to be from a 86-88 to have vats deleted. The voltage from the icm is a square wave.

 

I believe the 5v square wave is the same as a tach signal so if you have a tach unplug the 2 ecm connectors and hok onto the purple and white wire to see if the ecm is getting a good tach signal when cranking. The ecm is obviously powered up since you are able to flash codes. I believe the 165 ecm has four grounds 1 dedicated for the o2 and one for the mat, tps cts and the other 2 for the ecm. If all that checks out fine you have a bad ecm or vats issue.

 

The hypertech prom is for an 89. I guess checking the voltage from the ICM wouldn't work real well with my meter on DC lol I'll check it again on ac

 

The 4 grounds are very low resistance to ground, b5 the purple dis reference wire has .2vAC when the ecu is unplugged cranking and 2.2VAC with the ecu pluged in. I'm not getting enough power for a reference am I?

 

I'm really not sure how the voltage would show up on a ac volt setting since it is a square wave.

 

Any idea where to go next?

 

I'm sorry on limited information I'm on dialup for the weekend. I think I recall reading once if you hook a test light up to the purple and white wire and it blinks it fine but I'm not positive. If that's fine it's a ecm or vats. I have built a test beech and can read the eprom for you anther cheap option is I believe on bay there is a seller selling a 30hz modulator to feed the frequency expected bye the ecm from the pass key module painless wiring also sells the modulator.

 

No problem, the only internet I have is on my phone lol. I'll try the test light later on tonight and see what I can come up with

 

No luck with the test light

 

https://www.thirdgen.org/forums/post...560-post2.html

http://easyautodiagnostics.com/gm_ic...n_module_1.php

 

if its a problem with VATS shutting fuel off, it should still start & then die within 2 seconds.
i believe 89 was the first year for VATS on the thirdgens.

from the second link vetteoz posted. i did a quick read thru and its a good article, but i disagree with a couple of things.
a spark tester is not a must have, they are handy, but not a must have.
you can do the same thing with either an old known good or a new spark plug simply by bending the ground tang away from the center electrode. that is what i have done for years.

on the test light, they say an LED light is a must have.
i have both & the one i reach for most is my standard test light.
sometimes on the newer vehicles an LED test light is needed, but not on the older systems such as thirdgens.

from the first link vetteoz posted, that is doing what is called a scratch test.
i have never been a big fan of putting a full volts to any of the ECM terminals. i have always used a standard 12 volt test light in place of the wire.
if i can remember to do it, there is something i need to verify tomorrow when doing this test.

 

I agree applying the 12v may fry the injector driver. I'm not sure but you may be able to use the coil tach signal as a test to feed the ecm a reference .

 

You said your fuelpump feed wire isnt hooked up? Is it getting 12 volts? (just wondering)
Which harness are you using? (name brand)
Does it have fuses? did you check them?
If I remember, the 89 vats wont even crank or start if the vats is active. (Its been awhile, i would have to look at service manual)
The LT/LS vats will start and die for sure.
If you have a decent harness, it should have a troubleshooting guide in it to help you.

 

I have 12v at the fuel pump wire for prime then nothing.
The harness is one off ebay that didn't really come with trouble shooting help but it does have the phone number for the place that made it
Both of the injector fuses are good, I'm getting 12v to the correct side of the injectors
My starter wire is from the stock Fiero wiring so it would still crank if vats was messing with my injection pulse
I'm running out off hair to pull out lol

 

ok, i wasn't sure about something when do doing the scratch test.
i verified when using a test light from the purple/white wire on the 4 wire connector at the distributor & while dragging the other end of the light across battery positive it should fire the injectors pretty much nonstop. the injectors should fire and the fuel pump should run.
if you do it this way, you can flood the motor if you do it too long or too many times without cranking the motor.

this is pretty much the standard way i always checked these older FI systems for a no start.
testing could change depending on info from the customer or known vehicle history.
does the MIL come on? yes/no
will it crank & does it sound right? yes/no
does it have good spark from the ignition coil & at the plugs? yes/no
does it have good fuel pressure & is the fuel ok? yes/no
if all yes to this point, check injector power & pulse, yes/no
if no pulse found, do the scratch test.
i feel you are at the point where you need to do this test.

 

If your getting 12vots to your injs on the correct side of the harness you should have pulse unless your not spray n fuel because the injs are stuck, bad, or?? Without seeing it, its hard to know whats going on..

 

That is correct , ECM doesn't run the pump relay again until it sees the ref pulses from the dist.
However most aftermarket harnesses duplicate the factory setup with the OP switch that runs the fuel pump directly as soon as the engine is cranked over.
So you should have fuel pressure available at the rails when cranking if the OP switch is working

 

this is pretty much the standard way i always checked these older FI systems for a no start.
testing could change depending on info from the customer or known vehicle history.
does the MIL come on? yes/no
will it crank & does it sound right? yes/no
does it have good spark from the ignition coil & at the plugs? yes/no
does it have good fuel pressure & is the fuel ok? yes/no
if all yes to this point, check injector power & pulse, yes/no
if no pulse found, do the scratch test.
i feel you are at the point where you need to do this test.[/QUOTE]

Mil light yes
I just pulled the carb off and it ran with that, cranks fine
Good spark
I will try the scratch test

 

Ttop 350

All of my injectors ohmed out good, I also can unhook all of them and still don't have any pulse on the ground side.

 

Did you test pulse with a noid light??

 

No in tested it with a test light to positive

 

Use a noid light.

 

OK, I will get one and try that

 

No luck with a noid light
I talked to tunedperformanc and am getting a chip that for sure doesn't have vats on it, I'll let ya guys know what I come up with on that

 

You lucked out your hypertech memcal had a dip socket in it. I'm hoping this does the trick. should be there bye the end of the week

 

When I do the scratch test I get pulse

 

that points to a bad/defective ignition module.
personally i recommend using A/C Delco for the replacement.
make sure you thoroughly clean the distributor where the module mounts & use the thermo grease when installing a new module.

 

I only use oem ignition parts for the same reason. Delphi is the same as the ac delco parts.
http://www.ebay.com/itm/NEW-DELPHI-I...a4bd19&vxp=mtr

 

I have a delco ignition module on its way, but I did just put a brand new bwd ignition module in about a week and a half ago

 

I just had my local parts store test my ign module, it passed

 

Did they test it about 10 times to heat it up?
How is the pickup coil? new?

 

the aftermarket modules don't always have everything in them like they should and they have also been known to use substandard parts, which is why both Tuned & i recommend Delco/Delphi. over the years i have corrected many no start & run problems by installing a factory part in place of a brand new aftermarket part.
the test done at the parts house isn't reliable, i've seen many bad ignition modules pass.

 

They tested it 8 or 10 times, it was getting pretty hot. The pick up is an older one, not sure on exact age. I have .4-.606V on the pick up while cranking.

I ordered the one that tuned put the link up for, it could be here Monday or Tuesday. I hope she does the trick

 

when they tested the icm I bet they were just testing the coil trigger. I made my own tester for $20

 

I got my new ICM in the mail today, put it in and had injector pulse right off the bat. I hooked up my dis cap and test fired it, she isn't running the best right now but its running. I have a ton of fine tuning to do on her but its running. I would like to thank all of you guys, I have been pulling my hair out on this off and on for a few years.

What should my tps be set to?

Thanks again Pete

 

Try to let it warm up first then set the timing with the est disconnected. Then set the minimum air speed than the tps tab.54v

 

OK, cool. I have to swap out a tranny before I get the engine fine tuned but I'll let ya know how it turns out. I can't wait to go back to the track with it

 

I set the timing at 6deg btdc, set the idle, and the tips. Now it runs a bit rough and I have a little it of spark knock. Is 6 deg the right timing for this setup?

 

Was the est disconnected ?

 

Yea, the est was unhooked. I remembered that I was running on gas that I put in when I went to the track late last summer, so I topped the tank off with fresh gas but its still about 70% old gas. With about 9-1 compression is that going to make a huge difference?

 

I don't keep gas around even for my lawn mower unless its a high octane and stabilized.
Are you actually hearing a ping or just seeing knock retard on a scanner ?
If your hearing it try retarding a few degrees.

 

I was kinda wondering how good that gas was lol. I haven't hooked up a scanner yet, but I can hear it for sure. I'll try backing it off a few degs tonight

 

I retarted the timing a little bit tonight and she runs a lot better. It smells pretty rich and stumbles a little bit here and there but it running decent. I'll have to get it out when the weather brakes and see how it does.

I was also wondering if anyone knows a ball park figure for tpi engines for HP and torque in there stock form? I had my car dynoed with a really rich 4 barrel on it and it was around 190 HP, 300 ft-lbs and the best I could get in a quarter mile was a 14.3 at 95 before I blew out second gear lol