Getting my 85 to crank again
05-20-2013, 10:02 AM
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Getting my 85 to crank again
I bought an 85 recently that was running, running rich but running and starting up. Recently I did a swap on the MAF burnoff module after a discussion on this forum made it clear that this was an issue. It sat for a few weeks while I got the part and swapped it. When I tested it after it appeared to have an alternator problem, the lights dimmed as I slowed down and the car would shut off if I stopped giving it gas. I pulled the alternator, tested it at oreily's and sure enough they said it was bad. I got a new one and put it in. It was a 108 amp, and the previous was a 120 amp, but I have no options really on the car, and it was listed as a fit on rockauto. I managed getting it cranking again, but it would cut off quickly if I didn't apply gas. I have a connector close to the ECT which says "AMP" on it which is a little rough looking, it was not connected, so I connected it and played with it a little, and hit the starter, to get it cranked up. I would floor it and get n response, had to pulsate the gas pedal to keep it on. This let me to believe a new fuel pump might be needed. the part was cheap and it was easy to do so I said what the hell after checking the power going to the fuel pump. I did hook the old one up to the battery directly and it would turn on. The ECT sensor was replaced too but I do not think this is relevant at this point.
Now when I try to start it I can't even get any response, and if I do its not even strong enough to start the car if fuel is getting to the ignition point. the fuel pump is engaging when I turn on the ignition, but not every time, is there some built in time delay or should it turn on every time the ignition is turned on?
I have a new starter, but I have yet to put it in. Do you think this is my problem or am I wasting my time? How hard is it to swap a starter?
I'm trying not to throw parts at the car, and I do find it hard that all this stuff is going out at the same time, but the symptoms have been indicating as such.
It has a new:
Spark plugs/wires
Distributor Roter/Cap
Fuel Filter
Fuel Pump
Engine Coolant Temperature Sensor
MAF Burnoff Module
Alternator
Had no engine codes when I just checked, but it hasn't cranked since I disconnected the battery, resetting the codes. Previous codes were: 15,32,34,43.
THe ECT is replaced, and 34 was fixed with the MAF burnoff module swap I believe, all not important since I'm just trying to get it to crank.
Any ideas would be appreciated, and anyone close to middle GA who wants to spend a Saturday helping me gets $15/hour +beer
Now when I try to start it I can't even get any response, and if I do its not even strong enough to start the car if fuel is getting to the ignition point. the fuel pump is engaging when I turn on the ignition, but not every time, is there some built in time delay or should it turn on every time the ignition is turned on?
I have a new starter, but I have yet to put it in. Do you think this is my problem or am I wasting my time? How hard is it to swap a starter?
I'm trying not to throw parts at the car, and I do find it hard that all this stuff is going out at the same time, but the symptoms have been indicating as such.
It has a new:
Spark plugs/wires
Distributor Roter/Cap
Fuel Filter
Fuel Pump
Engine Coolant Temperature Sensor
MAF Burnoff Module
Alternator
Had no engine codes when I just checked, but it hasn't cranked since I disconnected the battery, resetting the codes. Previous codes were: 15,32,34,43.
THe ECT is replaced, and 34 was fixed with the MAF burnoff module swap I believe, all not important since I'm just trying to get it to crank.
Any ideas would be appreciated, and anyone close to middle GA who wants to spend a Saturday helping me gets $15/hour +beer
Last edited by elihall08; 05-20-2013 at 10:05 AM. Reason: Adding info
05-20-2013, 11:38 AM
#2
Just curious...
how much MONEY, TIME and GRIEF are you going to throw at this car by GUESSING at the problem(S) ????
like I said, I'm curious. I've always wanted to know what the limit was.
Would you be shocked to learn that a $17 part would have fixed it weeks ago?
I see in that list of parts, enough having been spent to have bought 3 FSM. ANY one of which would have the info needed to FIX this car right now. And all that other money spent would still be in your deep deep pockets..
I'm NOT trying to pick on a guy thats got a problem. I'm certainly NOT trying to start a fight.
I AM trying to make a POINT !
This website has a vast resource of members who have seen it, done it, been there and will be going because they do this for a living or used to. Or they may have 30 yrs of C4 experience.
They are all willing to share the experience like a bunch of vacation photos....with ANYONE thats sharp enough to come here for help.
BUT.....
the single most commom question from a member is.......
did you get your FSM yet? if not, WHEN?
'cause, you cannot fix a Vette without one. Without some deep pockets at least...
Spend the money on the FSM,. it will serve you well and pay for itself in weeks if not days. Its priceless when your car is down. DO NOT think that a $19 hyenas (haynes) manual or a childrens (chitlens) manual from AutoZone is the same thing....its NOT. Those are door stops. I'm talkin 'bout a REAL Factory Service Manual from GM.
There are soooooooooo many things on a Corvette that make it different than ANY other car that I could write another book on the subject. you have to understand the cars systems to be able to work on it. You can throw parts at the car till the next holiday season and still not get it running right...if you;re just guessing.
The FSM offers FACTs, diagnostic proceedures and detailed drawings of EVERY system on this car.; Detailed data for the tech to use to fix it the first time.
Go to E-Bay for used FSM sets for your yr. There is a link here for new sets,. You will spend about $75-$100. Less than some of your parts....
Now, to the problem...
1st, the fuel pump only runs 2 sec at key ON to prime the system. After that the ECM has to allow more pump time when it gets a signal from the dist that tells the ecm the engine is running on its own and not the starter. This is the design so it does not flood itself. No fireing, no more fuel. The 2 sec prime is plenty of a charge to start up and run. AT the 1st distributer reference pulse the ECM allows the fuel pump to run again.
Fuel pump also has multiple sources of power...relays, and a pretty slick back-up system from the oil pressure circuit.
next, Fuel is the ONLY system on the engine that does not set codes. Low pressure, poor inj health, weak flow & vol, corrupted inj signals. Shorted bank fired batch, blown fuel regulator. Non will set a code but any will prevent it from starting and running.
Get the pressure before doing ANYTHING else. low pressure makes it burp and backfire. Too low (below 30psi) and it will not start.
it needs about 40 psi at key ON (no cranking) to have a chance.
next, ohms test the injectors. They need to be close to 15.
go thru the harness grounds on the bellhousing or block by the oil filter. Go thru the jumper post hot wire collection and clean each.
Set TPS @ .54V idle
Now, are you saying that the engine does not crank, will not turn over when you turn the key?
or
does it turn over but will not fire and run? does it burp? backfire? even try to fire?
or
does nothing at all happen when you turn the key? No clicking,no starter, nothing? whats the volt gauge show when this happens?
cranking means the starter is turning the engine over well.
firing means that there IS some combustion while its cranking and tries to run.
Don;t be vague, remember we are not there. you have to be the eyes and ears of everyone.
So, assuming that it does turn over and its not firing at all, test for spark (spark tester or grounding a plug) and test for good fuel pressure...NOT just spraying the schrader valve... 4 psi sprays...you need 40. The amount of pressure is important.
IF you have good fuel and spark, it comes to how much of either and when.
Pull the vac line off the fuel reg and see if its wet inside. if so, blown regulator. Replace.
pull the dipstick and see if the oil level is high and see if it smells like gas.
Inj and regulators will short or blow and leak fuel into the cylinder which lets it drain into the oil. This will make the eng so rich it cannot start or run. bad for the internals as well...if it runs it runs like crap.
Fuel pressure, good spark and back to basics. Is the battery fully charged? it MUST be..this is a undersized battery and it has limited strength to crank this engine over. The HEI sucks the life out of a battery, so during cranking the starter and HEI are pulling every amp available from the battery. If its weak, it may not be enough to build a fire...
Clean ALL battery connections obviously.
Starters are easy...hard part is getting enough room underneath to work. 2 bolts in the starter, a support brace in the back. Just d/c the battery cause there WILL be sparks if you don;t ! Lots and Lots of sparks...IF you DO change the starter, DO NOT put in another like you have ! ! !
Go back and trade it for a 89 or later yr ND starter or buy a mini off the web. The stock delco is a boat anchor...or should be. Big and heavy. and they fail at the solenoid alot. The Nippon Denso or the minis are 40% smaller, easy to lift and fit in the tight space. and they work better IMO. They cost more, $120 to the $40 delco, but its well worth the cost. you drop 5 lbs and get a stronger starter.
You have done the fuel filter so you know where it lives...
Trying to get it to run, d/c the MAF plug and start it. It WILL run rough and barely stay running UNTIL the ECM sets the code for the MAF...at that point it SHOULD smooth out and run well...Takes about 8-10 seconds of forcing it to keep running so the ECM can see the fault and make a shift to LMH operation and run off the cal-pak.
Has the MAF been looked at yet? The OBD-I was not good for indicating a particular part was at fault, it only tells you what systems are effected. It may say the exhaust is lean but that does not mean there is an injector problem...
if it does run ok like this, we then know its sensor/control issues.
if it fails to run better after the SES lite comes on with the MAF unplugged, that narrows it to a fuel system issue sincen the ECM has no say over that area...
The other weak link is the EGR. test the EGR valve manually. The ECM only knows if the signal was corrupted, not if the mechanical actually did anything or not.
You need a $15 volt meter,
test light
noid lite (for inj)
spark tester
fuel pressure test gauge
and your FSM set.
Get all that in one pile and you WILL get it fixed.
Hope this was of some value.
how much MONEY, TIME and GRIEF are you going to throw at this car by GUESSING at the problem(S) ????
like I said, I'm curious. I've always wanted to know what the limit was.
Would you be shocked to learn that a $17 part would have fixed it weeks ago?
I see in that list of parts, enough having been spent to have bought 3 FSM. ANY one of which would have the info needed to FIX this car right now. And all that other money spent would still be in your deep deep pockets..
I'm NOT trying to pick on a guy thats got a problem. I'm certainly NOT trying to start a fight.
I AM trying to make a POINT !
This website has a vast resource of members who have seen it, done it, been there and will be going because they do this for a living or used to. Or they may have 30 yrs of C4 experience.
They are all willing to share the experience like a bunch of vacation photos....with ANYONE thats sharp enough to come here for help.
BUT.....
the single most commom question from a member is.......
did you get your FSM yet? if not, WHEN?
'cause, you cannot fix a Vette without one. Without some deep pockets at least...
Spend the money on the FSM,. it will serve you well and pay for itself in weeks if not days. Its priceless when your car is down. DO NOT think that a $19 hyenas (haynes) manual or a childrens (chitlens) manual from AutoZone is the same thing....its NOT. Those are door stops. I'm talkin 'bout a REAL Factory Service Manual from GM.
There are soooooooooo many things on a Corvette that make it different than ANY other car that I could write another book on the subject. you have to understand the cars systems to be able to work on it. You can throw parts at the car till the next holiday season and still not get it running right...if you;re just guessing.
The FSM offers FACTs, diagnostic proceedures and detailed drawings of EVERY system on this car.; Detailed data for the tech to use to fix it the first time.
Go to E-Bay for used FSM sets for your yr. There is a link here for new sets,. You will spend about $75-$100. Less than some of your parts....
Now, to the problem...
1st, the fuel pump only runs 2 sec at key ON to prime the system. After that the ECM has to allow more pump time when it gets a signal from the dist that tells the ecm the engine is running on its own and not the starter. This is the design so it does not flood itself. No fireing, no more fuel. The 2 sec prime is plenty of a charge to start up and run. AT the 1st distributer reference pulse the ECM allows the fuel pump to run again.
Fuel pump also has multiple sources of power...relays, and a pretty slick back-up system from the oil pressure circuit.
next, Fuel is the ONLY system on the engine that does not set codes. Low pressure, poor inj health, weak flow & vol, corrupted inj signals. Shorted bank fired batch, blown fuel regulator. Non will set a code but any will prevent it from starting and running.
Get the pressure before doing ANYTHING else. low pressure makes it burp and backfire. Too low (below 30psi) and it will not start.
it needs about 40 psi at key ON (no cranking) to have a chance.
next, ohms test the injectors. They need to be close to 15.
go thru the harness grounds on the bellhousing or block by the oil filter. Go thru the jumper post hot wire collection and clean each.
Set TPS @ .54V idle
Now, are you saying that the engine does not crank, will not turn over when you turn the key?
or
does it turn over but will not fire and run? does it burp? backfire? even try to fire?
or
does nothing at all happen when you turn the key? No clicking,no starter, nothing? whats the volt gauge show when this happens?
cranking means the starter is turning the engine over well.
firing means that there IS some combustion while its cranking and tries to run.
Don;t be vague, remember we are not there. you have to be the eyes and ears of everyone.
So, assuming that it does turn over and its not firing at all, test for spark (spark tester or grounding a plug) and test for good fuel pressure...NOT just spraying the schrader valve... 4 psi sprays...you need 40. The amount of pressure is important.
IF you have good fuel and spark, it comes to how much of either and when.
Pull the vac line off the fuel reg and see if its wet inside. if so, blown regulator. Replace.
pull the dipstick and see if the oil level is high and see if it smells like gas.
Inj and regulators will short or blow and leak fuel into the cylinder which lets it drain into the oil. This will make the eng so rich it cannot start or run. bad for the internals as well...if it runs it runs like crap.
Fuel pressure, good spark and back to basics. Is the battery fully charged? it MUST be..this is a undersized battery and it has limited strength to crank this engine over. The HEI sucks the life out of a battery, so during cranking the starter and HEI are pulling every amp available from the battery. If its weak, it may not be enough to build a fire...
Clean ALL battery connections obviously.
Starters are easy...hard part is getting enough room underneath to work. 2 bolts in the starter, a support brace in the back. Just d/c the battery cause there WILL be sparks if you don;t ! Lots and Lots of sparks...IF you DO change the starter, DO NOT put in another like you have ! ! !
Go back and trade it for a 89 or later yr ND starter or buy a mini off the web. The stock delco is a boat anchor...or should be. Big and heavy. and they fail at the solenoid alot. The Nippon Denso or the minis are 40% smaller, easy to lift and fit in the tight space. and they work better IMO. They cost more, $120 to the $40 delco, but its well worth the cost. you drop 5 lbs and get a stronger starter.
You have done the fuel filter so you know where it lives...
Trying to get it to run, d/c the MAF plug and start it. It WILL run rough and barely stay running UNTIL the ECM sets the code for the MAF...at that point it SHOULD smooth out and run well...Takes about 8-10 seconds of forcing it to keep running so the ECM can see the fault and make a shift to LMH operation and run off the cal-pak.
Has the MAF been looked at yet? The OBD-I was not good for indicating a particular part was at fault, it only tells you what systems are effected. It may say the exhaust is lean but that does not mean there is an injector problem...
if it does run ok like this, we then know its sensor/control issues.
if it fails to run better after the SES lite comes on with the MAF unplugged, that narrows it to a fuel system issue sincen the ECM has no say over that area...
The other weak link is the EGR. test the EGR valve manually. The ECM only knows if the signal was corrupted, not if the mechanical actually did anything or not.
You need a $15 volt meter,
test light
noid lite (for inj)
spark tester
fuel pressure test gauge
and your FSM set.
Get all that in one pile and you WILL get it fixed.
Hope this was of some value.
05-20-2013, 12:02 PM
#3
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Member Since: Mar 2013
Posts: 137
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Thanks for the input, I should have mentioned my previous forum post:
http://forums.corvetteforum.com/c4-t...y-problem.html
I do have a FSM, and a volt meter. I will look into getting the rest of the tools you suggested.
The MAF code did not come back in the rough 4 miles I drove it since the fix.
As far as codes go I think all but 32 are fixed I believe. 15 was the ECT which I just swapped, and the power was coming to the sensor properly. 43(knock sensor) was intermittent and possibly related to the MAF system failure.
Now step number one is to get the starter motor to turn on right? Because right now it is not turning over at all, all I hear is a click when I turn the key.
I have a trickle charger (2 amp, 40 amp, and 120 amp quick start capabilities) I have been using, I checked for a voltage drop acroos the battery on start up, the dash lights ups with the ignition on, I do not think the issue is with the battery.
http://forums.corvetteforum.com/c4-t...y-problem.html
I do have a FSM, and a volt meter. I will look into getting the rest of the tools you suggested.
The MAF code did not come back in the rough 4 miles I drove it since the fix.
As far as codes go I think all but 32 are fixed I believe. 15 was the ECT which I just swapped, and the power was coming to the sensor properly. 43(knock sensor) was intermittent and possibly related to the MAF system failure.
Now step number one is to get the starter motor to turn on right? Because right now it is not turning over at all, all I hear is a click when I turn the key.
I have a trickle charger (2 amp, 40 amp, and 120 amp quick start capabilities) I have been using, I checked for a voltage drop acroos the battery on start up, the dash lights ups with the ignition on, I do not think the issue is with the battery.
Last edited by elihall08; 05-20-2013 at 01:48 PM. Reason: long quote
05-20-2013, 10:58 PM
#4
Race Director
Another possibility is that the contacts are bad in the starter solenoid.
05-21-2013, 12:41 AM
#5
Yep...Cliffs right...
I have seen the cables rot to the point that there was no wire left inside the plastic sleeve...as old as they are, its getting common.
I also just replaced the starter. Mine had a cracked solenoid that would start fine one day...next it would do nothing. Wait 10 minutes and it would start. Thought it was a VATS problem the way it acted...
Pulled the starter off and found a cracked solenoid and burnt internal contacts.
Installed a mini that was lighter, smaller and more powerful.
Glad to know you have the FSM...at least the parts were bought with valid suspecion..
too many guys come here complaining about the car the cost and the effort...and THEN we discover they were guessing at everything they did without the slightest clue...and then all respond... "whats a FSM"? "whats it do"?
ooook.
dont worry...someone here already knows whats wrong. They just haven't seen your thread yet.
I have seen the cables rot to the point that there was no wire left inside the plastic sleeve...as old as they are, its getting common.
I also just replaced the starter. Mine had a cracked solenoid that would start fine one day...next it would do nothing. Wait 10 minutes and it would start. Thought it was a VATS problem the way it acted...
Pulled the starter off and found a cracked solenoid and burnt internal contacts.
Installed a mini that was lighter, smaller and more powerful.
Glad to know you have the FSM...at least the parts were bought with valid suspecion..
too many guys come here complaining about the car the cost and the effort...and THEN we discover they were guessing at everything they did without the slightest clue...and then all respond... "whats a FSM"? "whats it do"?
ooook.
dont worry...someone here already knows whats wrong. They just haven't seen your thread yet.
05-23-2013, 02:44 PM
#6
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Member Since: Mar 2013
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Looks like I am getting help Saturday from a licensed mechanic who has owned three corvettes. I will keep you guys posted, thanks for the input!
In other news I went out and got myself a nice 78 vette cause I saw I deal I couldn't refuse and I fell in love with it, but now I have the dilemma of needing to part ways with one of my cars. I have an old truck that definitely has to go, and I really can't justify 2 corvette's...
In other news I went out and got myself a nice 78 vette cause I saw I deal I couldn't refuse and I fell in love with it, but now I have the dilemma of needing to part ways with one of my cars. I have an old truck that definitely has to go, and I really can't justify 2 corvette's...