VinnieV02TA

iTrader: (7)

I have a 2002 trans am and i am having a intermittent ignition problem. Randomly the car will turn over strong but will not start. I will try to turn it over a few time and on the 5th try or so it will start right up like nothing ever happened. This seems to happen about once a day now and used to only happen about once every two weeks. I have had the car in the shop for this and they finally got it to fail while hooked up to the computer and it shows nothing wrong when it is doing it. Everything is getting the power where it needs to and air/fuel/spark is all good. They have no idea what it is. They thought it was my MAF sensor because there was another problem with that but it was not the problem and now idk what to do next. This does not happen every time i start the car so i have no idea what it is.


I am wondering could it be something with the stock security alarm messing up, the reason i bring this up is the first person who saw it thought i had a kill switch in the car, so that can help you think about what it is doing.

So if anyone has any advice i am all ears i am sick of sitting in my car turning it over. thanks

joecar

You say fuel/spark is good... how have these been checked (were they observed at time of failure)...?

(if you get spark at plugs and spray at injectors, then engine has to run)

Can be various things:
- VATS (like you mentioned),
- crank position sensor (and/or wiring),
- fuel pump,
- PCM (and/or connectors).

A good shop will diagnose this kind of problem fairly quickly.

VinnieV02TA

iTrader: (7)

yes they has on guy under the hood and one in the car with the computer and they say everything is good.

Is there something that could fail sometimes that they did not catch? i am down for any ideas right now. There is nothing wrong with double checking something they could have missed

VinnieV02TA

iTrader: (7)

well this is a pretty good shop the best in the area for performance cars. of the ones you listed wouldnt some of them throw codes.

joecar

Did they:
- pull several spark plugs and check that arc fires...?
- check that injectors fire...?
- check that fuel pump primes and runs...?
- check that fuel rail pressure was correct...?

If they checked those things and they said everything is good, then engine should start/run.

The computer is not going to tell them what the problem is, they have to eliminate each of the possible causes until they find the actual cause.

joecar

Those things won't necessarily cause trouble codes.

VinnieV02TA

iTrader: (7)

i am not sure exactly how they checked it they had the car for a couple days, they say that everything was right. It does start but sometimes takes a few tries. i have not yet had it not start at all.

joecar

Doesn't sound good to me... it should fire up immediately on barely turning the key.

You might need to try a different shop.

VinnieV02TA

iTrader: (7)

thanks for your advance to i am going to go back to them and ask about the stuff you mentioned, but assuming that is all good what other options do i have. id there anything i can check?

so how can i tell if it is the VATS?

joecar

Sometimes an intermittent no-start can be caused by a coolant leak... but this can be diagnosed with a cylinder leakdown test and a cooling system pressure test... any good shop would have done these things (especially on intermittent no-starts).

joecar

If it was VATS, the scantool would indicate that VATS was active, and the injectors would not fire, and other things IIRC fuel pump doesn't run.

VinnieV02TA

iTrader: (7)

okay well i have somethings to look into now thanks for your advice.

joecar

From reading another thread, something else to look at:
- fuel pump relay,
- ignition relay.

a338566

iTrader: (1)

i second the relays, i had this issue with my 01 ta and it was teh fuel pump relay.

sreve

iTrader: (3)

so how can i tell if it is the VATS?

P1626
P1629

are vats codes and will be in history for 40 warm-up cycles
Did they check for history codes?