No Spark - Unless It Isn't Needed

[TransAmRocker]

Hey Guys and Gals!

No I haven't fallen off the earth I h ave just been insanely busy running a company. Have an interesting issue with the 88 GTA though, some of you may find it interesting.

In April I drove the car to Alabama and back and it ran GREAT, rolled over 100,000 on the trip. The only problem we had was with the VATS, of course it sometimes doesn't like to allow the car to start even though the chip is in the key. Recently though we have had a new problem.

Every once in a while the car will just not start, I hear the fuel pump come on but nothing except for cranking over at the usual rate. I will then usually just drive the Ram to wherever I need to go them the next day or even once I get home to diagnose the problem but then the thing starts on the FIRST crank.

The GTA has always started on the first crank since I got it at 75,000. The big problem was back in October I was coming back home after gassing up and it just shut itself off. I attempted to start it after waiting 5 minutes, then sprayed starting fluid and still not even a pop. So I called for a tow. I went to finally get around to working on the car today since it was a nice 55 degrees, low and behold after a $80 tow it starts on the first crank and runs like a champ due to the premium fuel that was nearly $4 a gallon when it went in .

Any thoughts? My major thought is the VATS is disabling spark but I may be wrong on how VATS works.

[hoogiesngrinderz]

VATS is fuel related. What I would check first is your ignition module on the distributor.

[Dummybait]

VATS is fuel related. What I would check first is your ignition module on the distributor.

After this try looking at the crank sensor? different car and motor I know... i know.. but my Cousins 1989 olds 98 was doing the exact same thing... turned out to be the crank sensor..

[TransAmRocker]

Will check out both of those things today. I have a brand spankin' new ICM in the other Trans Am which is now dead, will grab that. Will also check that crank sensor. Whats driving me nuts is the only code its throwing is that it is running lean but that is like that on purpose and has been since the guy I bought it from had it.

[hoogiesngrinderz]

No crank sensor in these motors. There is a pickup coil in the distributor. Hell, just pull the whole dizzy from your other car and swap it it if you have the know how.

[hoogiesngrinderz]

And it shouldn't be throwing any codes, unless it has a big cam in it. If that's the case, it should have been tuned, and any good tuner can set it to run closed loop above a certain RPM/LV8 (or I can anyway )

[vipergtx500]

If you suspect the VATS is malfunctioning in the lock cylinder, you can by-pass it by soldering in a resistor along the ignition wire that's the same resitance as your key.

[hoogiesngrinderz]

If you suspect the VATS is malfunctioning in the lock cylinder, you can by-pass it by soldering in a resistor along the ignition wire that's the same resitance as your key.

Or it can be disabled in the PROM. Does your key have a letter stamped on it? Use that to look up the resistance value needed.

[killa89trans]

yeah agree with above statement, if the resistance is wrong the ignition wont start causing no spark or no fuel sometimes both depending on vehicle model and year.

[hoogiesngrinderz]

Through all my studies on the TPI, VATS only disables the injector pulse. All spark is controlled by the ignition module, the ECM only commanding the advance.

If the pickup coil isn't getting a pulse there will not be spark nor will the injectors fire. If the module is bad (more common) there will not be any spark, and it sounds like the no start is heat soak related...the modules in our cars absolutely HATE heat. They burn up quickly if the thermal paste on the back of them loses it efficiency due to drying out/age.

[hoogiesngrinderz]

But then again, it could be something as simple as the coil. Might be something as finicky as bad fusible link down by the starter.

[TransAmRocker]

Couldn't get into it today unfortunely, had a crappy call last night. Looking at going nuts and tearing apart the Trans Am and just swapping parts over. I did put a new cap and rotor in it though.

[hoogiesngrinderz]

I'd just swap the whole dizzy and coil over, have a 'pop' and call it a day. What's wrong with the TA?

[TransAmRocker]

After swapping in the new motor my mother decided to crash into an I-Beam which has been infront of our house for 25 years. That and the transmission is messed up thanks to the new motor. Would just switch it all out but not entirely sure I want to mess with popping a distributor out while our garage is full. Have both of them sitting in a parking lot at the moment.

[hoogiesngrinderz]

Well, if you feel like selling let me know. I have a low mile 700r4 that's mildly built sitting in my garage waiting to go into something.