1985 Corvette hard to start
03-27-2014, 12:53 AM
#21
Got a new battery (well, a year old for about $14) and the car started right up, but I was still not convinced this was the problem. Your suggestion of a fuel pump relay made sense, and being only $15 I thought it was worth a gamble. Put it on and the car would not start! Totally baffled I pulled the part back off and noticed that the connection was a bit melted and there was plastic and crud on the plug, so I dug the plastic out and used electrical cleaner and sand paper to clean the connection. The real shock was when I turned it over the three middle wires were bare about an inch. Two of the wire were lying on top of each other. I really needed a new plug in but I just separated the wires and taped them up. The car started instantly! This may have been the problem, I guess I will find out for sure tomorrow when I drive it around, but the car even seemed to have more pep and run a lot smoother. If this is the problem I will hunt down a new plug and replace this one and fix the wires better.
Thanks for suggesting this, I think it may have fixed the problem.
Thanks for suggesting this, I think it may have fixed the problem.
03-27-2014, 06:58 PM
#22
Melting Slicks
The 85 only runs Just over 30 psi standard, as they have the 24lb injectors. Always a good idea that when any changes are made or you start to run into problem's, check the Throttle position sensor is showing 0.54 volts dc. Or do a Base idle setup to get it starting quickly.
The long start did show you had a fuel pressure problem.
See the link below if you are having any starting issues in future.
http://forums.corvetteforum.com/1570563689-post1.html
The long start did show you had a fuel pressure problem.
See the link below if you are having any starting issues in future.
http://forums.corvetteforum.com/1570563689-post1.html
03-28-2014, 11:07 AM
#23
Safety Car
Okay, after posting my last item I went out and this time put jumper cables on it. It took several attempts but it finally started. Ran like crap until I took it for a drive for a few miles then it all smoothed out. When I got back I let it sit in the driveway and idle for about 10 minutes as I cleaned a spot out in the garage. Once I got it in I shut it off a couple times and it started right up, but it was warm then.
I'm thinking it may be something as simple as a bad battery. Maybe it isn't cranking hard enough to get it to start. I ran it down a few times. I think I am going to try that approach first and see what happens. I work at a place where I can get used batteries for $20, just got to find one that is good and will fit. Hopefully this is all it is. If not, I may be back to the cold start injector again since once it is running it is fine, so the pump I got is obviously working. There is still the possibility it is losing pressure when it sits... though not sure how.
I'm thinking it may be something as simple as a bad battery. Maybe it isn't cranking hard enough to get it to start. I ran it down a few times. I think I am going to try that approach first and see what happens. I work at a place where I can get used batteries for $20, just got to find one that is good and will fit. Hopefully this is all it is. If not, I may be back to the cold start injector again since once it is running it is fine, so the pump I got is obviously working. There is still the possibility it is losing pressure when it sits... though not sure how.
03-28-2014, 11:14 AM
#24
That would be the first step to see what's going on. Without it your just guessing and throwing parts at it.
03-28-2014, 04:27 PM
#25
the 85 uses a 9th cold start injector to fire up the engine when its cold,
sounds like there is a problem with yours, could be electrical or mechanical,
you will probably have to find out what the fault code is that is setting off the check engine light, do you know how to do this ?
sounds like there is a problem with yours, could be electrical or mechanical,
you will probably have to find out what the fault code is that is setting off the check engine light, do you know how to do this ?
03-28-2014, 05:37 PM
#26
Drifting
I put aluminum heads on my 85..no 9th injector...had everything tuned but still starts hard...once it fires....no problems the rest of the day....helps to start/restart...thought the tune could compensate but apparently not...paul
03-28-2014, 07:26 PM
#27
1985 Corvette no start problems
The worst time is after the car has been sitting a while. I didn't start it for a couple weeks and when I went to start it I actually ran the battery all the way down as it would not fire at all. Had to hook the charger up to it to get it to finally crank over. The funny thing is once it starts it will smooth out and run perfectly fine, until you shut it down and try and start it again.
It has always been hard to start since I got it but has gotten worse. I have never checked the fuel pressure on one of these, does anyone have information on how to go about this, and what is the pressure supposed to be at?
It has always been hard to start since I got it but has gotten worse. I have never checked the fuel pressure on one of these, does anyone have information on how to go about this, and what is the pressure supposed to be at?
03-30-2014, 07:13 PM
#28
I will have to look into this when I am on vacation next week. They car still runs really rough when you first start it, sometimes lightly backfiring, but then it smooths out after about 2 minutes and runs fine the rest of the day. But, if you let it sit for more than 8 hours it does it all over again. Even when it is in the garage all night it starts right up, but acts really cold blooded for several minutes. Need to clean it out, adjust it and check the timing.
03-31-2014, 05:56 PM
#30
Drifting
dude...these guys are telling you.....check the fuel pressure...a guage is only a few bucks....you are throwing money at a c4.......i've learned that can be a terminal condition....my 85 after some mods was a hard starter and ran like crap until closed loop...raised the fuel pressure and reset the timing...it was way off......now sweet as sugar....this forum will help you diagnose your problem...then fix that....just my .02
04-12-2014, 02:45 AM
#31
Well, thought I had things straightened out and was getting ready to drive my wifes truck off for the weekend leaving her the Vette. Went out to start it the night before I left to go fill it with gas and got the dreaded "clunk" sound. Starter went out! Had to leave in the morning so my wife was stuck without a car all weekend (she wasn't happy). Got back and changed out the starter, started up but still ran rough on initial start. Finally checked the engine codes and it was saying that the coolant temperature sensor was bad. Got a new one and went to change it to find the sensor wire came undone, wasn't even plugged it. Put the new one in anyway, put it back together but it still ran rough and the light was still on. Ran the test again and this time it said the air flow meter was bad! Took it off and got some cleaner and doused the thing. Put it back on and suddenly it started instantly and ran smooth from the get go. Drove out nice. My only problem now is it idles fine when you first start it but after you drive it a while it idles kind of high. Probably going to idle it down but I hope this doesn't create a problem with initial starts.
Went for a really long drive today with the top off, ran like a champ other than the slightly high idle. After a grocery list of parts being replaced it is almost perfect.
Went for a really long drive today with the top off, ran like a champ other than the slightly high idle. After a grocery list of parts being replaced it is almost perfect.
04-12-2014, 03:01 AM
#32
Race Director
04-20-2014, 12:03 PM
#33
Instructor
Member Since: Nov 2005
Location: Pittsburgh Penna.
Posts: 161
Likes: 0
Received 0 Likes
on
0 Posts
85 Corvette
I have an 85 corvette and have removed the EGR, Air pump and the 9th injector. My car always starts on the 3rd crank, waiting for the fuel pump to stop before attempting to start each time. Non of these changes have ever caused a code to be thrown. There is a sequence of things that have to occur for the car to start and I have seen low battery voltage cause the car to not start. You might want to find the start sequence and run through it to see if there is a problem there.
03-05-2017, 07:04 PM
#35
Drifting
03-05-2017, 07:58 PM
#36
New fuel pump and relay old pump was stuck cars been setting for a few years. temp sending unit has a broken plug will replace it and sender and press on to the next step.
Last edited by skoto1; 03-05-2017 at 07:59 PM.
03-05-2017, 10:19 PM
#37
Team Owner
03-05-2017, 10:21 PM
#38
Team Owner
03-05-2017, 10:23 PM
#39
Team Owner
I forgot if there is a difference in what year or not. Does that temp sender lead to the ECM or just the gauge? Hook up a scanner and see what the ECM sees. When you get it running and hot, hit the sensor (to the ECM) with an infrared thermometer and see if it agrees with the ECM reading.
03-05-2017, 11:13 PM
#40
I forgot if there is a difference in what year or not. Does that temp sender lead to the ECM or just the gauge? Hook up a scanner and see what the ECM sees. When you get it running and hot, hit the sensor (to the ECM) with an infrared thermometer and see if it agrees with the ECM reading.