what would cause it (99 sunfire auto) to start just fine when it sits for a bit, but not after just driving it?!! in the morning and after work it starts right up. but if i drive it home. shut it off and have to go somewhere shortly after the only way the engine starts is with it basically at WOT?!! injectors?
Intake air temp. sensor faulty.
Time to get it going again.....
Really?!? Can u explain why? % of certainty? Just Caught me by surprise...
These??
Looks a lot like the ECT sensor. Which one and is this on the TB or intake tube? Thanks for the help
If that were the issue would it not throw a code..Just asking...
the engine light is on... but the last scan pointed to the ECT sensor. which i replaced and it still said its faulty......so im guessing its obviously somewhere else. harness perhaps??
I guess i'll have to try the IAT sensor and see.... not sure if i understand how this would effect startup on warms starts...??
I might have guessed bad ignition components that get flaky at higher temp, but it does start at WOT? Have you tried cleaning or replacing the TPS?
Coolant temp sensor shouldn't make it that hard to start. If the code says that sensor is still bad after replacing, make sure you don't have an air pocket or bad wiring to the sensor.
If you need WOT, that means extra air, so I can see that maybe the IAT is telling the engine to dump so much fuel that it won't ignite without more air... but that seems like a long shot to me. Unplugging the IAT sensor tells most cars to default to lowest possible air temp = tons of extra fuel. Does it seem to run really rich?
Check the voltages and resistance of any sensors you think might be bad with a DMM. I'm sure you can find the data on here or Google.
I am having issues with my GFs 1997 2.2 also,Same issue.But we bought the car used so I did allot of work to it more to be safe than sorry..
I put in a new A/C Delco fuel pump,Filter,And fuel regulator,Also put in new coil packs,And a new ignition control module..
This issue was still there,I was thinking a bad injector so I have yet to replace all 4 of them..I swapped the IAT yesterday because I had another one,And still same issue...So if you do figure it out let me know..
hmmm
the biggest puzzle piece for me is why it will start perfectly fine on a cold start, but it wont after a short drive. Like tonight, after getting off work, it started right up. I then drove to get some food and it wouldnt start when I was leaving. In fact, I had to floor it to start and once i backed up and went to put it in drive it died!!!
WHAT THE HELL!!?! lol I have not idea if its running rich...what are some symptoms??
I was thinkin it could be injectors (havent changed those yet) the fuel pump (filter is brand new) and the IAT kinda of makes sense... but i would think that would be on warm and cold starts, no? I just dont want to dump money into it changing things that arent the cause of the problem!! lol oh the joys of owning a Jbody.
and the TPS has been changed
Take a can of a good throtle body cleaner and clean all the throtle body also map sensor and drop a can of fuel injector cleaner on the tank see if it helps, at least won´t be expensive. Check your air filter and also see if you hear the fuel pump when you turn the key with the car hot. You have to try to narrow the problem either to fuel or spark related.
I may do the cleaning tuesday if I have the day off... Pretty sure I hear the pump prime when I turn the ignition on... Or at least what I think is the pump! Any write ups for cleaning the TB? What should I use?
Workin 8 10+hr days in a row is showing additional drawbacks!! Impossible to work on or sell the car!!
When you floor it.. you're in "clear flood" mode... you know that, right?
I have the exact issue when I stall my Eco unexpectedly... (yeah, I stall once in a while..). It won't start unless I hold the gas pedal all the way down.
But do we know why?! Or how van I explain this to someone interested in buying the car?! Lol
changed the air filter today, cleaned the TB (was pretty dirty), and put in some Injector cleaner in the tank.... we'll see. so far, nothings changed, but didnt really expect the air filter or cleaning the tb to fix the probl.
Part of me just wants to drop it off at a body shop and have them look... i dont have many tools to test many components; and i dont like the idea of "testing" them by replacing them, cuz that @!#$ be expensive! lol
I really wish i knew what was causing this so i could just fix the damn thing and sell it.
My guess would be a bad fuel pressure regulator or a leaky injector. Pull the vacuum line off the regulator. If there is fuel there, replace the regulator.
