Okay to cut to the chase my 91 305 TPI T5 Z28 will not start. The motor will crank with the key (meaning that it is not VATs or the neutral safety) but the engine will not fire. I have checked all of the following things and need help!

Cap and rotor - replaced
Distributor - replaced (also tested ignition module and pickup coil)
Coil was tested
Tested for spark
Fuel Filter - replaced
Fuel Pump - replaced
Fuel Injectors were flow tested as well as tested for resistance
Fuel Rail is getting fuel
ECM was tested
Tested power going to fuel injectors
Tested ground continiuity from ECM to Injectors

Spraying carb cleaner straight down into the TB will get the car to fire up and start however it will not run long even with it WOT. I think that it is a fuel problem, hence the reason I replaced so much of the fuel system. I have a feeling that the injectors are not pulsing, however since they are getting power and their resistance is good and I had them flow tested, right in front of me on Saturday I cannot figure out why the car will not start!

Please help!

TIA

 

Randy,
It's TPI? If so, have you checked the fuel pressure to see what it's reading? How about the pressure regulator?

 

Yeah it is a TPI. I am planning on getting some noid lights to make sure the injectors are plusing as well as actually testing the pressure from the sharder valve. I did rebuild the regulator when I had the rail off to have the injectors tested. I have some feedback that apparently the VATs module might still allow the car to try to start but not allow the injectors to fire? Has anyone ever heard of that? I didn't think the injectors where wired through the VATs?

Thanks again

 

Something else to check is the ignition module. That little gadget can cause similar trouble.

I had one go out to where the car would not run for more than a few seconds.

 

Right, I tested it along with the pickup coil, and a completely different distributor - no luck

 

How about a diffrent computer, probably not the problem but always good to check into..

 

You guys aren't reading my first post are you?

I tried a different ECM no luck

 

Go back to my first reply – test the fuel pressure.

 

No problem, I definitiely appreciate any help that might help me figure out the problem - it was a very frustrating weekend

 

Check the ECM ground.

 

we did check the ECM ground.
And randy, dad got the noid lights, and fuel pressure gauge today. And no luck youre ECM fired my car right up as well

 

Yeah so far I am basically screwed no good reason why it won't fire

 

this may be a long shot... but did you happen to check for any wires that might be frayed, melted, or grounding on the block or body??

i had a similar problem with mine Randy.. and it happened to be some stupid relay in the kick panel on the driverside.. there are 2 big thick green wires there.. and i removed the relay and just attached the 2 wires together and it started.. not sure if this info helps...

if it doesnt then i'll shut up..

 

Thank you for the suggestion. We looked the harness over pretty much I couldn't find anything that looked melted or frayed. I was afraid of some aftermarket stereo with a kill switch or something, it looks like the alarm was pretty well removed from the car.

 

How about a map sensor? did you swap that also?

 

Different ECM.. different chip too?

Had a VATS problem years ago, everything worked except half the injectors werent firing.

 

The VATS does work the injectors & the starter so it could be the problem. If it is not the right signal ....no injector pulse.

Go into your prom and disable the VATS in the switch table and see what happens (that means burn a new chip)

 

Never did see posted what your fuel pressure is. Allen

 

The fuel pressure was a little high, actually at about 70 lbs. So we tried to blow out the returnline, and it was froze solid with what looked to be sugar. So after digging all of that out, and putting it back together (again) it fired up. Does anybody by chance have a IAC pigtail/connector?

 

Yeah,I do.

 

For those that are curious for the resolution. Well the noid light indicated that the injectors were indeed pulsing. A fuel pressure test indicated the pressure was around 80lbs. Obviously a bit high, so back down to the fuel rail I went. The return line was clogged, we I removed it from the fuel rail it appeared that a nice crystaline structure had blocked the return line coming from the regulator, kind of like as if someone had put sugar into my gas tank Anyways once that was cleaned and everything was bolted back on the car fired right up - thanks again everyone

 

Basically the high pressure created a hydralock on the injectors preventing them from firing - sweet huh

 

Good to Hear you have solved the issue.. Get a locking gas cap Randy.. Things are getting crazy in this world today..

 

Yeah that is what Donna suggested that we purchase locking gas caps for the cars

 

Randy,
That is EXACTLY what happened to my car. My car still ran though since it blew the diapraghm in the regulator and was dumping fuel into the plenum.

What brand of gasoline do you use? Do you use any type of fuel system cleaner?

I'm curious to see if there's some additive that's causing this.

 

I did purchase a bottle a sea foam after I bought the car based on the suggestion of Paul aka F1LS1. But I did have a blown out regulator when I purchased the car, I replaced the diaphram with a used one but it worked, this time when I ran into all these problems I made sure to purchase a new diaphram like I should have in the first place. I am probably going to be purchasing new injectors soon as well as a AFPR since I had some junk running through the lines, in fact I was thinking of replacing the fuel rail or at least soaking them in some cleaner for a day or two when I removed everything to make sure that I got out as much of the crap as possible


Maybe I can convince Donna to let me have a Stealth Ram

 

Sorry just to make things clear as a recap. I do not regularily use any fuel adative. The only adative I actually put into the car was the Sea Foam, I pretty much always buy Mobil Gas from the same two stations. When I removed the tank to swap the fuel pump the tank had been replaced (probably for the recall) but it had never been removed since then so replacing the pump probably wasn't a bad idea, I just wish I would have had a Walbro one handy to install. Because we all know I am going to have to change that Auto Zone one again soon

 

glad to here you fixed it dude

 

Thanks

 

YEAH

 

Yeah you never know what is going to happen.. A few months ago I was at a friends place and came back to my car and it had finger nail polish poured on the rear hatch..

 

Honestly, sugar in the tank isn't that devastating. It's a bit of an urban legend.

The sugar will simply sink to the bottom of the tank. The problem comes when the fuel gets low. The sock on the fuel pump or the fuel filter could potentially get clogged. It shouldn't get past the filter.

The stuff you and I found Randy must be the crystalized residue of some type of fuel additive. Possibly something the oil companies are using.

I use 76 and Shell gasoline. I was also using Lucas fuel system cleaner for a short time, just before my fuel return got plugged up.

The blockage was in the exact same place as yours — the first 1/4" of the return line, where it connects into the fuel pressure regulator. The rest of the line was clean, but the regulator block showed signs of pitting and corrosion.

I ended up buying a whole new regulator assembly.

 

When Don was putting Allen's car together we ran into the same problem with his fuel system. The residue looked a lot like aluminum oxide to me. I wonder if the fuel might have some moisture in it that is causing corrosion in the fuel rails and then having the bits of corrosion migrate to the fuel regulator. Isn't the regulator on the return side of the fuel system?

 

Sort of. The fuel rail is really nothing more than a loop. The regulator is in the middle of the loop.

Fuel enters the rail on the passenger side, passes thru the regulator, down the driver's side and then back over to the passenger side.

Once the fuel rail is pressurized, the diaphragm on the regulator opens up and lets some of the fuel return to the fuel tank thru an escape port. It's where the escape port connects to the return line that the blockage happens.

 

Hmmm. There's something to think about. My car had the same white stuff in the fuel line also I use Chevron and 76 and Gumout once in a while.

 

It would be nice to know if it is some sort of addative either from the pumps or one that is purchased. Again since I haven't really owned the car that long I can only speak of the addatives that I purchased, so I never know how many "Outlaws", "Gumout", or "NOS" fuel addative bottles went down the tank. I did replace the filter as well, it wasn't really too bad considering it appeared to possibly be the original filter.