Hey guys... I have a 1989 IROC w/ 350 TPI motor (with a Lingenfelter SuperRam & '89 Corvette Heads). Other than that... everything is completely stock. ECU Prom may be an '88 or an '89... not positive...

Car was (is) running perfectly fine... but takes a VERY long time to start...

Cranks for at least 30+ seconds... (until oil pressure is all the way up to 20+ psi under cranking)... and then FINALLY will fire.

Once running, it seems to idle/rev/run fine.

So I'm confused as to what this might be caused from? I've replaced the Plugs&Wires... which didn't help a bit.

Any other ideas?

Thanks,
Dave

 

check the fuel pump relay.

 

Where is that? Against the firewall? And how do you 'check it'? Do I just need to end up replacing them? Aren't a couple of the ones on the firewall the same? Where I could 'swap' them?

Any other thoughts/suggestions would be great!

Thanks,
dave

 

I don't recall which one it is on the firewall since mine has been completely flipped around, i'm sure someone will though.

 

Any idea why the relay would 'delay' the start... and then decide to fire?

Thanks,
Dave

 

When the relay fails the fuel pump won't turn on till you build up enough oil pressure. GM did it that way because relays don't last forever.

The funny thing is that the OPSU's seem to go out more often than the relay does...

 

Mine does the long crank for the first start, then any other start is half a crank. My pickup coil is presumed bad and I'm replacing that, give that a try.

The pick up coil controls injector pulse and spark timing, a bad one will cause hard starts because the injectors aren't getting a signal as soon as they should. You can use a DVOM to test the resistance before you yank out the distributor.

 

Thanks guys... well so far... we've replaced the Fuel Pump Relay & Oil pressure sending unit... and still the same thing... won't fire until about 20 PSI reading on the Oil Pressure gauge.

Tested firing the car with oil pressure gauge disconnected... and still took a while to fire... but did.

I do have another Distributor... is the pick up coil different than the 'module' under the cap and rotor?

Are you saying I have to replace distributor or just module?

Thanks,
Dave

 

Unfortunately to take the pick up coil off you have to take out the distributor. if the ignition module was bad the car wouldn't run. You can test the pick up coil by using a DVOM and measuring the resistance between the two leads. Anywhere between 500 - 1500 ohms and it's good. It's the clip with the green and white wire that plugs into the ICM

 

hi did the pick up coil solve the problem? the exact same thing is going on with mine

 

isnt there a cold start valve that puts extra fuel in there for cold starts? sorry, im no expert with fuel injection. just thought id mention it.

 

Fwiw, I am also having cold start issues where I have to turn the engine over for 3-5 seconds, it fires up, idles for 1-2 seconds then shuts off. I went through the suggested checks ie... TPS adjustment, ohm check fuel injectors, check fuel pressure, and check timing.

I found my TPS was at .049 instead of .054, and my fuel injectors ohm'd out perfect. My fuel pressure was at 42 with key on, little to no pressure loss after about a minute, then dropped to 38 when running, and up to 45psi with the vaccum removed to simulate WOT, so all in all within specs.

After setting the TPS at .054 volts I rechecked the timing and found it was at 4* BTDC instead of 6*, so I readjusted the timing and buttoned everything back up.

I'm going to try a cold start today to see if adjusting these things have fixed the problem. I have an adjustable fuel pressure regulator from TPIS waiting to be installed but I'm waiting for my valve stem seals to arrive so I can get everything done all in one shot!

 

Try to spray a little carb cleaner or starting fluid in the intake before you crank. If it fires, you might want to check that it's getting fuel pressure (relay like mentioned before), that the fuel system holds adequate pressure past/during the 2 second prime, or that you have the correct 1989 prom installed.

 

Having a similar issue, takes 2-3 cranks before car starts, already replaced fuel pump relay, still getting same result.

Other than what's mentioned on this post to try, has anyone come up with the best solution? Or go to solution!

I might add, the relays on the left and right of the fuel pump relay, those are your cooling fan relays, my driver's side cooling fan wasn't working and replaced it with the old fuel pump relay, I replaced and fan is working fine.

 

Note: Certain 1989 programming has a delay of 8 reference pulses before it shoots fuel. Drives me nuts. I modified my PROM to shoot fuel immediately.

Tuned performance, linked in my signature, can do the same thing for you, too.

Reference:
https://www.thirdgen.org/forums/diy-...ong-crank.html
https://www.thirdgen.org/forums/diy-...alternate.html

 

If this is a issue in your profile 92 tpi. It does use the same table to enable injectors.
but should start quickly without modifying the tables. If you have stock multecs that might be your issue. You can ohm them to test the coil condition but they should be replaced before they cause a breakdown.

 

I gave advise to a 8 year old thread. #winning My comments were directed @ the 1989 long starts specifically, I haven't messed with the SD programming

 

Post 14 was from today. So we’re not doing that bad lol

 

Does the fuel pump run for 2 seconds at key-on, engine-off. If not need to fix that.

RBob.

 

I always get a little angry when people complain about someone bumping an old thread. I've looked all over the internets for the issue that is described here but this thread has some ideas I haven't come across yet.

#alwaysgratefulforbumpageofoldthreads!!!