Hello everyone. Totally new here and hope someone can help me out on this. I have a 1990 firebird formula 305 tpi. Its been stored in my garage for a while. After taking care of all the basic maintenance i.e. draining the fuel tank new fuel filter spark plugs yada yada yada I got her started fairly easily. I had a check engine light that was a coolant sensor which I changed and it seem to really be running pretty good. Then it all went downhill.

First the catalytic converter got so hot that it actually melted the carpet on the passenger floorboard. Bought a new cat for it and was gonna go get it installed and all of a sudden she started but stalled out after a few minutes. Another check engine this time the O2 sensor was shot. I assumed the catalytic converter was so clogged from the faulty sensor it might've been causing the stall. I changed the o2. Attempted to start it and stalled again. Attempted to crank it a couple more times and I got no crank it all.

The dreaded security light came on which is obviously a vats issue. The good thing is I have remote start installed. I waited four minutes and engaged the remote start and I got no crank but no security light this time. I did the remote start again and tapped the starter with a hammer and I got a little bit of a crank but it cut out. So with the remote starter I get no crank but no security light. With the key I get no crank and a solid security light .

I already know that the previous owner had bypassed the ignition using resistors so I know the key or ignition switch is no good. But here's the weird thing. When I tested both the key value and removed the resistors to test those it came up to a value of 5.35. I had my multimeter set it to 2k but nothing came up at all so I switched it to 20 and that's where I got the 5.35. From what I can see GM didn't use anything close to that value with the 15 options they had . What the hell was that all about? So I assume that may be the resistors had went from being old so I assembled new ones at 5.35 and that didn't work. Then I proceeded to make one for every one of the 15 values and tested each one with four minutes in between and that didn't work. I tried jumping the starter enable relay and that didn't work.

From what I can tell I got a mess of problems here probably starting with a bad starter but now I'm not sure which part of the vats system is failing. I ordered a bypass from baker electronics today, but if the problem is somewhere else in the vats system will this even work? If anyone has had issues with this please let me know.

Just a quick disclaimer I am not a mechanic nor do I play one on TV (lol) I'm really just starting to get into all the stuff but honestly don't have much of an idea except for some very basics. I have purchased the Haynes manual as well as the 1990 dealer service manual which has helped immensely except the fact that I failed to get this damn thing started . She's goddamn killing me

 

Hello, welcome to TGO!


It's a little difficult to read through your issues, you may want to break it into smaller paragraph forms next time, most people just skip really long posts.


If I were you I think I would put the original vats bypass in and with an assistant ensure that I am getting power at the starter terminal. If not work back and jump the start enable relay, and if still not than park/neutral safety switch, and if still nothing then I would start looking at the wire. With the start enable relay jumped the starter should crank, vats or no vats.


Also check all your connections, main battery terminals, main chassis grounds, connections at starter.


Based on your description my money is on a bad starter

 

Hi mcgarnicle,

Thanks for the reply and I appreciate your feedback. I got the starter out and its definitely shot. While I was under there I found a busted connector for the temp send unit so I'm now waiting for that to come before I finish up. I'll post the final outcomeonce its all together.

I just have to say this site is amazing! I have learned so much just from reading previous posts and it has helped me so much this point.
I look forward to learning more and participating on this forum as I get further into this restoration project.

 

Okay, so I am almost sure that VATS module itself is shot. I get a crank with the starter jumped but no start. The security light comes on but it will crank with the key. So neutral safety, ignition switch, fussible links, batt and grounds all good.

I'm going to try to figure out how to install the bypass module I bought from baker Electronics. That should get the injectors going...I hope

Is it comon for the VATS module to completely fail? I mean the resistor bypass was working fine since I've had the car and now out of nowhere it just doesn't. Then last week it started right up once and then not again since.

 

It's not the most common thing for the VATs module to fail, but is certainly possible.
Does the engine crank without the starter relay jumped?


So the engine is cranking now, but the fuel injectors are not pulsing?


Things that prevent the injectors from pulsing:
1. Bad PCM
2. No Tach signal
3. VATs


VATs issues are probably the most common, but I've also seen a lot of bad pickup coils in the distributor causing a no pulse symptom.


While cranking watch your tach and see if it is bouncing.


There is also an inline fuse by the battery that is the main ECM fuse check to make sure it isn't popped.

 

I installed a vats bypass module from Baker yesterday and it started right up. The Vats module must have died. It was hard to diagnose because there were other issues with the cranking system. Once I got everything else fixed it was easier to narrow down.

So after it started I took it around the block a few times. It was the first time I drove it in 11 years! The engine is running pretty good considering. I have to replace the cat because its clogged and I'm sure a lot more will come up. Let the restoration begin ��

Thanks for your help