HughG

I have a 1985 Corvette that, after I got it, I changed all the plugs, wires, etc, basic tune up. I have two problems.

1) It is very hard to start. It will crank over for an extended amount of time before it will fire up. Once it starts it runs great. And, I know it doesn't make any sense since this is fuel injected, you have to pump the gas pedal for it to fire up. If you don't it will crank forever, but it you pump the pedal a few times then it will finally fire up. Does this point to a bad pump or a cold start injector. And if it is the injector, where the heck is it? Not sure of the location.

2) Most of the emissions items is missing on the car, so when I had to put a new water pump on it I went ahead and removed the pipes from the air pump and knocked the fins out of it, plugged up the lines on the manifolds, and eliminated it. Now I have a SERVICE ENGINE SOON light that will not go off. Anyway of eliminating this?

Actually, there is one more problem (there are actually several little problems but I am only listing the most annoying ones), the fan on the heater no longer works. Worked fine one day and the next it just didn't work at any speed. Fuse is fine, got a heater relay, it did nothing. Any ideas?

Thanks for your help.

blackozvet

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 ?

tunedport85inject

driver side

HughG

What is the cold start delete? How does that work?

Thanks for showing me where it is at.

I used to know how to figure out the codes when I had my 84 Vette but I have forgotten. I have had a 1999 and a 1975 since then, I just got back got this 85 a few months ago, have to remember everything I used to know as the C4s are a completely different creature.

blackozvet

find your ALDL plug (under the dash) ,
jump the A and B terminals , (last 2 plugs on top on the right side)
ignition on (engine not running)
the service engine soon light will flash, once-pause-twice quickly, repeated 3 times, this means the number 12, number 12 is a system check number,
it will now flash any error codes, repeated 3 times, first number slow (one), then second number (being the number of flashes) quickly , have a piece of paper and pen handy,
doing a search of this process here or on google will produce pictures etc to help.

having said all that there is no specific fault code for a faulty cold start injector (if that is the problem)
the service manual says to check the thermal switch first, that is the brown plastic unit in the front of the inlet manifold (right next to the coolant temp sensor) make sure its plugged in correctly and not broken or cracked etc.
if thats ok, the next check is fuel pressure check, fit the fuel pressure gauge while engine is cold (run engine for a short time to check pressure),disconnect 4 wire plug at distributor, then turn ignition on and crank engine for at least 2 seconds, the fuel pressure should drop more than 20 psi if the cold start injector is working correctly.

DanielRicany

It sounds like you are flooding your engine. First place I'd start is checking fuel pressure.

If it fires up when you hold the gas or pump the gas while cranking then it is flooding some how.

If you pump the gas before trying to start, then that doesn't make sense to me.

Cliff Harris

The ECM has to be reprogrammed to put in more fuel when the engine is cold to compensate for the cold start injector not being there.

That's fairly easy on a 1227165 ECM because it was used in 1989, which didn't have a cold start injector. You can run the '89 calibration in earlier years (the 1227165 ECM was used in '86 - '89).

tunedport85inject

Since your 85 has a "one year only" ECM,the #870,you can't delete your cold start injector.CSI lasted on the TPI L98 untill 1988 under the #165 ECM.From 1989 it was phisically deleted and on the prom there is a specific Cranck enrichment mode that pump more fuel into the engine to compensate the lost of the CSI.

Jig A Low

I'M sorry, did you say something, I was distracted by your avatar----DAMN!!!!!!!!!!!!!!!!

tunedport85inject

ops she's my little sister helping me at the shop...

Ray Quayle

Jesus, can I help at your shop?

HughG

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?

ex-x-fire

You can rent a tester at autozone, spec should be 36-42 while running. Pressure with the key on/engine off 45-50 psi. It should hold pressure when the engine is off, if it isn't, then it could be cause the problem your describing. If it goes down, then pull the vacuum hose on the pressure regulator & look for gas.

tunedport85inject

these are are 29 years old,plus we leave these garaged for weeks sometimes,engines has to run to be fine and smooth,electricals and injections systems too.I think the best cure is a regular fired engine,everyday,two times a day for some minutes,if you can drive it,is the best. i would ceck the thermo switch for the CSi on the front of intake manifold,fuel pressure,even the cold start injector itself may be clogged or dirty.

Jig A Low

how far out west are you? I may be able to come "lend a hand" occasionally (when THE NEED arises )-----as long as she'll be there to help me turn my wrench

HughG

I ended up buying a fuel pump from Autozone, car started great... for a while. I took the car to get painted at Maacco just to get me buy until I can afford to paint it right. Went to pick it up and it fired right up, drove it home. I let it sit for day because I needed to put some stuff back on it and when I went out to start it tonight it would not start for nothing. When you initially turn it over it fires, but not enough to start it... it then just cranks over and over doing nothing. I tried cycling the key over several times to build up fuel pressure but it does the same thing every time, initial fire and then nothing but cranking.

Do you think this a bad fuel pump? Is there something I am missing. I would suspect the cold start injector but even before I changed this fuel pump it would eventually start, now it is doing nothing. This is all very frustrating... especially since I sold my other car expecting to start driving this everyday.

Any thoughts on this would be appreciated.

HughG

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.

DanielRicany

Test for continuity on the Thermo Time Switch when the engine is cold.

Cliff Harris

You really need to get a fuel pressure gauge on it to see what is happening.

It sorta sounds like your fuel pump relay is not working. When that happens the oil pressure switch has to turn on the fuel pump. It takes some cranking to build up enough oil pressure to turn it on.

Mark8801

That would be the first step to see what's going on. Without it your just guessing and throwing parts at it.