Here's the deal, I have fuel pressure, about 40 psi. My motor will crank, but will NOT fire(start). Any hints or suggestions. I did accidently run it out of gas, but its not the fuel pump, remember i do have pressure. Maybe the fuel filter?? No...... i have pressure...... I'm at a loss. ANYBODY PLEASE HELP MEEE UUUUGGGHHH!!!!

Oh by the way if this helps, I have an '89 IROC 305 TPI with a 700R4 trans.

 

Have you checked out the VATS system?

 

Got spark? Ignition module?

When my VATS died it wouldn't even crank and just display the security light.

 

i actually have the exact same problem currently i replaced ignition module which did test bad and still nothing. you gotta love this world xD

 

Checked your fuses?

 

Ok, no spark, the old ign module was bad so im changing the ign module. BUT any ideas which wire id the positive or negative? I got a yellow and I think a green dont remember its been a week since ive been under the hood. Its not the VATS System, the car will crank and crank until the battery dies. fuses.....? for constantly cranking and not firing? really? I work at an auto parts store and never heard that one before.

I think Im just gonna sell it. you guys wanna buy it? give me 5,500 for it and its all your to part out try to fix whatever you like. and you all know its worth WAY WAY WAAAYYYY more than that 1. because its an iroc and 2. its a vert roc

 

dont sell it

you have no idea the amount of times I wanted to blow mine up but when you get it all dialed in and feel confident in your work and the working condition of that 3rd gen you will not drive a better car

make sure you have injector pulse by buying a noid light and testing

what do you mean by the positive and negative wires

 

on the control moduel.... there are actually 4 plugs. 2 on the fire wall side coming out of the distributer cap. and 2 inside the distributer cap, on the back side of the ign mod. one is yellow and the other is green(i think), they plug into positive and negative prongs. I may just have them switched, but a guy said he did what im doing and still nothing. my distributer works, i have 40psi of fuel at the fuel rail, fuel injectors.....ugh sooooo hard to get to!

 

Update.....Checked EVERY fuse. All are good. changed fuel pressure relay. I'm about to give up!!

 

Still have you checked out the VATS system. VATS is a 2 part system where it disables the starter from cranking but it also sends a signal to the ECM to enable the injector pulse. It is very common that the VATS system appears to work (no security light) and the car cranks but the ECM is not receiving everything's OK signal to enable the injector pulse. This means the car will not start.

 

how do I do that I read up on the vats system and it told me how to bypass it. but it cranks so its no in the vats key thing. how do i check the ecm side?

 

noid light

 

so i check it with a noid light. assuming i get no light, does that mean I need to swap out the ecm?

 

Dosnt matter even if the VATS system was bypassed with the resistor trick and it cranks and all if say the wire going to the ECM was broken the VATS system would work fine so it wont set a light and allow it to crank but the ECM would never get the signal and the fuel injector spark would never be enabled. The VATS module itself could be bad as the VATS module is what activates the starter relay and also sends a signal to the ECM just because part of its working dosnt mean its working 100%. As stated what should be checked for is first with a node light see if the injectors are being fired and then if not well explore possibilities as to why.

 

No the ECM is the last thing to replace as they are a very reliable unit and there are lots of things that can cause the injectors not to fire. You could also try running the codes and see what comes up if anything.

 

I have no service engine light(hard codes). the injectors on the other hand, are less than a year old. if the injectors arent spraying, they get the signal from the engine control module. i think.... then that would mean the ecm is bad. if not then, what else would cause the injectors to not spray?

 

the car is 21 yrs old, and i have no idea if the ecm was replaced. so it might help to replace it anyways

 

Well your more than welcome to replace the ECM it wont do any harm. Probably wont fix the problem ECM dont usually fail in this manner. In theory if everything was good and the ECM was getting all the correct signals with good power and grounds and all the external circuity was good and it would still not fire the injector then yea logically the ECM would be to blame but thats assuming everything else is good when it hasnt even been checked. I still say the vats system is number one cause as its job is to enable the injector pulse and should be checked out thoroughly but befor we even jump to thoes kinds of conclusions a noid light should be used to see even if you have injector pulse or not.

 

ok rented some noid lights.....it flashed when i tried to start the car, dont know what that means. maybe the injectors are working right? idk.... if they are working the way they are susposed to whats next. vats keeps getting repeated, all i know to do is how to bypass the security lock out. dont know how to check anything else that involves vats. so we rules out the injectors, i think. i dont know where to go now.

 

ok stop i got your problem fixer lol it fixed mine. When you go to put the ignition module in did you notice the grease on the bottom of the old one well if you didnt look again the module actually grounds out and can ruin itself if it is not coated in a grease i used lithium spray grease out of a can its white grease and it sprays out just coat the bottom like i did but too much cause it could get hot and make a mess but with the right amount you could be good to go.

 

the VAT system will stop fuel flow to your injectors.

one way to determine if your injectors are firing is to listen to them. WHen you are cranking get a screw driver and press it against the number one injector and stick it to your ear. Do you hear a click-click sound? if not the injector is not being enabled which is in keeping with a VATS issue (starter/fuel cut-off).

BTW an outright ECM failure will throw a code 55.

 

Grease noticed, put enough. still nothing. one thing about that though. the 2 wires on the back side of the ign mod. inside the distributer....i have a green and a yellow wire, which is positive and which is negative?
Fuel injectors.....yeah i have Venom Injectors, dont need a screw driver to hear it click, plus checked it with noid lights, and light flashes when the car is cranking.
I'll try that white lithium a little later when i figure out which wire is pos and which is neg.

 

ok you have fuel and air going into the motor

time to check spark

your vats is working

these two wires at the ign mod concern me

you have mentioned it twice

I find that when there is a problem sometimes the solution presents itself in your mind but we dont listen.

check the spark and if you have none which distributor do you have

the one with the coil in the cap or external

we can get to the bottom of your problem but there is a order to which you want to look at the systems of your fuel injection

 

Checked spark.....no spark
external ign coil, upgraded to a MSD StreetFire coil the wire goes from the coil to the top center of the distributer cap

 

the two wires inside the cap go back to the pick-up coil, the green wire goes on the front spade the yellow on the back, not entirely sure it makes dffrence tho. Those wires are supposed to have a connector on them you may want to think about insulating them so they won't short out

 

does matter it happened to me before

dont worry about shorting out but if you do all you have to do is add a little electrical tape in fig 8 wrap

go try to put them the way john 89 said and see what happens