What component will make my car not start one minute and run fine another?

[SnowBird]

It stalled one day and took a minute to start then ran fine. Then it will stall and not start for 5 minutes and then run fine.

When it stalls and wont start Ive checked the spark it still gets spark, so I was wondering what would control the fuel, but ive rewired my fuel pump and if the pump died it would just die.

I was curious if this could be electrical since everything else on the car was changed at my engine rebuild except my CAS, power transister, coil pack and spark plug wires.

When the car starts, which it does most of the time, it runs like a beast. I tried wiggleing a bunch of different electrical connectors to try to make it stall with no luck. Im just afraid to drive it far now. My last car did this same exact thing but it was the distributor.

 

[VETTE_50_TH]

ECU is about to die. I bet thats what is going to happen. I traced that in my car. Or a very shotty ground on the battery or loose connection on the battery. I had that happen once or twice. Just enough touching to get power, but i go to start, and its not enough. Check that first.

James

 

[v2ner]

Or a very shotty ground on the battery or loose connection on the battery.

Start there.

 

[jj9320tsi]

try moving the harnesses a little also to see if you have any partial breaks in them. use a voltmeter to check the ect sensor and any other main ecu sensors as well.

 

[Ravenous]

Try checking for a bad coolant temp sensor connection or sensor itself. My plug had dried up and was brittle, it made the car hard to start and maintain idle intermitently, then it broke and made It nearly impossible to start and keep running.

 

[kenamond]

No CEL?

Might be the CAS. Mine died slowly. The car occasionally just wouldn't start. Eventually it threw a code for the CAS, but it took a couple of days. After I read the CEL and knew it was the CAS, if it stalled, I'd pop the hood, wiggle the CAS plug, and it would start up and run fine. I had to do that a few times before I finally got the new CAS installed.

 

[SnowBird]

ECU is about to die. I bet thats what is going to happen. I traced that in my car. Or a very shotty ground on the battery or loose connection on the battery. I had that happen once or twice. Just enough touching to get power, but i go to start, and its not enough. Check that first.

James

Damn that sucks. Reason to get an EPROM

try moving the harnesses a little also to see if you have any partial breaks in them. use a voltmeter to check the ect sensor and any other main ecu sensors as well.

Ive been wiggling the hell out of all harnesses. Ill check the main ECU sensors like you said; are they inside the ECU?

Try checking for a bad coolant temp sensor connection or sensor itself. My plug had dried up and was brittle, it made the car hard to start and maintain idle intermitently, then it broke and made It nearly impossible to start and keep running.

Huh, I had no Idea that would shut off the car if it was bad.

No CEL?

Might be the CAS. Mine died slowly. The car occasionally just wouldn't start. Eventually it threw a code for the CAS, but it took a couple of days. After I read the CEL and knew it was the CAS, if it stalled, I'd pop the hood, wiggle the CAS plug, and it would start up and run fine. I had to do that a few times before I finally got the new CAS installed.

Ha. No, no CEL. Ive removed all my emissions, and since I have a 90 I removed all the solenoids and crap up by the brake booster, so I dont even know if my car is capable of throwing a CEL. I checked my CAS, but I guess itll be one of those things that acts up here and there.

Thanks guys, I guess I just wont drive it to far until I find out what the hel it is for sure.

 

[blownturbotsi]

I've removed the same stuff and I don't have a check engine light either. It'll come on if something happens, don't worry! I would suggest getting another ECU from a friend in the area or something just to check it. At least you will know before you spent the money.

 

[TrboANTsi]

i had the same problem with my CAS i replaced it and the problem was fixed.

 

[hedrick]

Have you checked your ecu yet? The next time your car wont start look at the boost gauge when you insert the key and turn it to the second on position. If the boost gauge doesnt move to zero most likely you have an ecu problem. I had a 90 GSX that I bought with 120k miles and it ran great until one day it started acting the way you described. My problem was leaking capacitor in the ecu. I found a replacement ecu from a 90 and after that the car never had a problem again.

 

[SnowBird]

Have you checked your ecu yet? The next time your car wont start look at the boost gauge when you insert the key and turn it to the second on position. If the boost gauge doesnt move to zero most likely you have an ecu problem. I had a 90 GSX that I bought with 120k miles and it ran great until one day it started acting the way you described. My problem was leaking capacitor in the ecu. I found a replacement ecu from a 90 and after that the car never had a problem again.

You are probably right. It is a 90 and Im sure they arent even close to being in good shape, the thing is Ive done this test before but like an idiot Ive been looking at the gauge in my pod instead of the stock gauge. I will check this out first and then blame the CAS.

 

[SnowBird]

Just thread bumpin with an update, I couldnt find anything wrong and have put on 100 more miles on it without a problem. Only time will tell in how many miles it will be a problem again.