ShadowLP

Recently my 1986 L98 Coupe has become hard to start after sitting over night. The engine was tuned up over the winter and has never failed to fire on one or two cranks until recently. Once it fires, subsequent starts are normal and the engine runs strong. I would appreciate any suggestions. thanks

RRT vette

I would put my money on the CSV (cold start valve). That is exactly what the situation would be like if the CSV (9th injector on 85-88 vette) was not working. Learn more about it here

RRT vette

I had a starting problem a while back. Problem was, on the first start of the day it would take about 4 different turns of the key for it to start. After I had it warmed up it would start on the first turn everytime. Knowing that my 86E has a CSV, I decided to test it. After I found out the fuse was blown, I replaced it and it starts on the first turn everytime cold or hot (like new). If this is what yours is doing, I would check it out.

The CSV is located on the drivers side intake. The fuel line curves toward the back and connects to the fuel rail. It is triggered by a thermal switch that as the engine warms up the switch slowly cuts power to the CSV. The ECM does not operate the CSV, in any way, as it does the other 8 injectors. It is powered by the starter solenoid. There is a fuse located behind the DIC in the dash. I would start by checking the fuse and then testing the CSV connector with a test light while cranking. The CSV is not active at engine temps above 95*, but is at any temp lower. You can ohm the CSV also and it should read 4-6 ohm....the other 8 injectors will read about 16 ohms.

AGENT 86

Good place to start looking

RRT vette

Another thought, do you hear the fuel pump prime when you turn the key to the on postion cold or hot? This might also be a faulty fuel pump relay. Since fuel pressure usually leaks down over night and you start with ~0 pressure in the morning. When you turn the key on the ECM sends signal to the relay to prime the pump for about 2 sec. This pressurizes the fuel rail so enough fuel is available. While cranking, once the oil pressure reaches 4 psi the oil pressure switch will close and send the 12v to the fuel pump thus adding more fuel to the lines. Now after the engine is running for awhile and you shut it down, you now have pressure in the lines for the next time you try to start. Just a thought. If you don't hear the fuel pump prime...the relay would be something else to check.

ShadowLP

I have been reading all of the suggestions plus found some earlier threads on similar situations from other 1986 owners. I went to the car this morning as turned on the ignition, without engaging the starter. I heard two faint noises. I cycled the ignition switch off, waited, then on again. I heard the two faint noises again, then engaged the starter. The engine tried to start then just cranked. Before the engine would just crank. I went through the cycling two more times and the engine started. Once fired, it starts on 1/2 a turn and runs strong. I would like to check the fuse as this seems like an easy first step. Could you please let me know where it is located and an idea of how to get to it. thanks. I really appreciate the info.

RRT vette

Remove the center trim piece that goes around the radio by removing the screws. Once it is our you will need to remove the DIC (where the service engine soon and other lights show up) and you should see about 3 or 4 fuses. It should say CSV or cold start. It's been awhile so I'm not exact but this should get you close enough. Takes about 10 min to tear down and replace. When you turn the key to "on" you should hear a humm from the rear.

Da Mail Man

......is it the same on an 88?

RRT vette

Yes! It should be.

Da Mail Man

............humn...that could explain my starting problem, that, or a misadjusted iac. i get pressurization at the rail when i turn the key but, it only appears that it starts when oil pressure reaches 2-4lbs....the only thing is that the car doesn't start well even when warmed up and after sitting for 15min....it is not a leak down problem as i had checked that.........tried to remove the iac some time ago to clean and set but, couldn't access it..........thanks for info. by the way, any idea as to fuse rating?

AGENT 86

You can't adjust the IAC, you can only adjust it for safe installation. After installed the IAC will reset it self. Removing the TB will make IAC removal a lot easier.

RRT vette

The fuel pump relay is located next to the Windshield washer motor on the drivers side on the car. If you have a 4+3 tranny there will be two and they are the same. If not there will be one and it's mounted close the the firewall in the description above. Rather than purchasing an new one (for now) you can use a piece of short wire (12ga) and disconnect the relay and use one end of the wire in the first terminal and the other end in the last terminal of the wiring connector. If the relay is bad this will bypass what the relay does and when you turn the key on you will hear the pump prime.

RRT vette

For the IAC when installing, you need to make sure the tip of the pintle is no further than 1 1/8" from the flange. If it's further you may have damage to the windings. The CSV fuse is a 5a fuse and there will be a few more fuses next to it located in the dash behind the DIC. Even if there is no fuel pressure leak down that will not tell you that the CSV is operating. Remember it is only active when engine temps are below 95*...any temp past that and it doesn't do a thing because of the thermal switch. First thing I would do before removing part of the dash is use a test light on the CSV connector while you crank. If it lights up (under 95* engine temp) then the CSV is getting signal to operate. When you ohm it, it will only read about 4-6 ohms.

RRT vette

Da Mail Man

..i think there is an adjustment proceedure for the iac as well as it can be cleaned too...i did find out about removing the tb but, haven't gotten to it yet....

Da Mail Man

..i think there is an adjustment proceedure for the iac as well as it can be cleaned too...i did find out about removing the tb but, haven't gotten to it yet....

Da Mail Man

...i think this is for "shadow"....